Why did this rebuilt engine fail? Was it the engine rebuilder’s fault?

[makesumwake]

Why did this rebuilt engine fail?* Was it the engine rebuilder’s fault?

I recently purchased a rebuilt 350 GM marine engine from a cheap engine rebuilder.
Block #10243880, aluminum pistons, bored .030 over.

CONFIGURATION:
Mercruiser inboard-outboard setup, 2 barrel carb, salt water cooled.

This engine failed after 10 hours of normal use.* Oil was shooting out the dipstick full force (massive blow-by) and lots of white smoke from burning oil.

After failure compression check results (triple checked):
1 - 90 psi
2 - 180 psi
3 - 150 psi
4 - 0 psi
5 - 180 psi
6 - 0 psi
7 - 30psi
8 - 180 psi

(Unfortunately, no compression check was done for comparison before using engine)

Tear-down by engine rebuilder revealed chip out of top of #7 piston, chip was melted to top of piston.* The piston also has a crack running down the side, right under the point where it chipped.
See all pictures here, the rest of the pistons looked ok.* All rings looked ok.* Cylinder walls were ok.* There was a raised ridge on #7 cylinder bore where the piston had failed.

pics
http://s144.photobucket.com/home/makesumwake/index

No issues found with #4 and #6 pistons / rings / bores.* Zero compression on 4 and 6 must have been due to sticking valves.* Discoloration/rust on #4 and #6 valve tops confirm this?

Engine never overheated - Overheat alarm never sounded, checked temperature of engine with temp gun while running, verified correct operation of water pump, water flow was verified, thermostat was checked and found to operational.

Engine had sufficient oil before failure - oil levels were correct, new oil pump had been installed, oil pressure gauge never showed lack of oil

Engine wasn’t running lean.* Spark plugs, piston tops, valve tops all blackened with carbon.* Carburator was taken to carb shop and verified to be a good working order.

Engine cam/crank shaft alignment was verified to be correct before engine assembly.

Spark timing was done by setting distributor to fire #1 plug when #1 cylinder was at TDC, on compression stroke.

Engine had brand new exhaust manifolds (salt water cooled) and brand new risers.* All new gaskets were installed.

Upon installation, engine started right up and ran great / sounded great.* No hesitation or lack of power.* Smoke start coming out of breather a few hours later.* Finally a lot of smoke and oil was noticed spurting out of dipstick when engine was run WOT.* Engine was idled home immediately after this.

Engine builder claims it isn't his fault.* He claims that the valves were sticking due to being melted.* The #7 piston damage occurred due to ring becoming red hot, expanding, and forcing piston to chip.
This explanation is BS right?
He claims that melted valves and piston was due to incorrect timing.

I think that he performed a poor head job, resulting in sticking valves.* And he installed a bad piston, resulting in the damage.

What do you think?

 

[chiefalen]

Bad block to begin with.

Was the block sand blasted.

Was it magnafluxed ?

Was it pressure test, spin tested, and compression test done after rebuild ?

Hey that block couldn't take a 30 thousand overbore cause it was a rusted pos piece of iron before it was rebuilt.

Show this reply to your rebuilder and tell him to give you one thats good.

 

[hystat]

have you removed any of the valves?
I'd start taking them out -keep them all in order....and look for collapsed springs, bad guides or excess valve stem clearance.

Exhaust blowing past a bad guide can heat the valve spring to the point it collapses.

I'm surprised the valves look as good as they do - especially on the one head. They all look closed now.... if the springs are ok, then how tight are the rocker nuts.... but you said it ran well at first...odd

I always get slagged at these boards for setting valves on marine engines with a compression gauge/remote starter switch. I think it could have avoided this mess. I always crank on the starter, tighten the nut till comp drops, then loosen it till it clicks, then split the difference.

 

[RicardoMarine]

Was it the engine rebuilder’s fault?

It's very easy to want to blame this re-builder....., but Fair is Fair, and we must look at the Forensics and piece together any Facts from there! There is no other way!

Spark timing was done by setting distributor to fire #1 plug when #1 cylinder was at TDC, on compression stroke.

The procedure that you mention for ignition timing is incomplete! You have not quoted any actual timing specs (BASE or TAT), so my guess would be it was done incorrectly!
Quite honestly, you have NOT posted any numbers, with exception to those derived from after the fact!
So you can see that ignition timing is going to be a difficult arguement, for you, should it come to that!
(had you posted actual ignition timing numbers (before the fact), we'd be discussing them!)
No offense, just offering a fair observation!

Your piston damage very much ressembles damage possibly cause by ignition induced "Detonation"..... that, or a very poor fuel grade. I'd say, more than likely one or the other, or both!
(this is "Detonation", not to be confused with Pre-Ignition....... the two are not the same!)

This is a very typical example of gasoline Marine Engine Detonation damage.
There is NO Question about it......, especially when all of the valves are still in tact!

....

If the re-builder did anything incorrectly, it was the use of the Flat Top pistons with the Vortec cylinder head.
The Vortec combustion chambers are 64cc.
The smaller 64cc chamber, used with the Flat Top pistons, will render a C/R that is not desireable for Marine Cruiser use.

He should be using a "D" dish or a Low Compression Q/E piston with this chamber! He should know better!
However, this alone is not likely the primary cause of your Detonation damage.

Preferably, the piston used with the Vortec cylinder head (in a 5.7L), would be something like this, but of course with the correct dish volume to accommodate the desired Marine SBC C/R. This gives the Marine SBC the much needed Quench Effect, when the correct head gasket is used!

******************************************

In all honestly, and unfortunately for you......., I think this one is on your dime due to the detonation damage. The Re-Builder had no control as to how you would tune YOUR engine.
Sorry to hear of this..... it's a tough lesson to learn!

Next go-a-round, make sure that you not only set BASE advance, but also verify your ignition curve and ignition TAT (total advance timing) as per OEM specs.
This is extremely important for a Marine gasoline engine.
Preferably, your balancer will be marked off for this.

********************
BTW, Chief brings up a good point!
IMO, we should NEVER attempt to over-haul a previously Salt Water cooled engine.
A good automotive core is just too dang inexpensive to NOT use!

.

 

[kghost]

I think a valuable lesson has been learned no matter what the cuase is.

Of course we have no idea what your engine tuning was after instalation so we can not make any assumptions YET!

But you said CHEAP REBIULD. WHat did it cost in your time to remove the old + reassemble the new +install the new + remove the failed new + tear it down to find disaster = a lot of time which = a lot more money than antisapated and at this point it is all for NOT.

Obviusly you will get another engine and put it all back together, SO start to plan a better PLAN so this does not happen again.

My suggestions:

1. Choose engine size and horsepower you want.
2. Choose either a used marine or remanufactered motor or a new long block ( automotive or marine based on whats available).
3. Make sure you have a manual to set up timing and other tune up specs for proper engine operation.
4. Make sure carb is good and set up propperly.

Engine choices:

1. Craigslist for used and some remanufatured engines.
2. reputable remanufacturer who distributes nation wide. (google search)
3. local engine biulder WHO KNOWS WHAT AND HOW A MARINE ENGINE SHOULD BE BIULT.
4. Brand new long block from a online source, IE: summit racing 350 290 hp . see example link. Of course it would need to be marinized with proper gaskets, freeze plugs etc etc.

http://www.summitracing.com/parts/NAL-12499529/

anyway I think you get our points. Keep us informed on your progress and decisions.

Good luck!

 

[Docksidemarineservices]

Please check to see if the heads were correct. If you install 5.0 ltr (305) heads on a 5.7 ltr (350) with flat top pistons, this will be your result. I purchase my long blocks from a good re-builder. His product is good, but, I always check casting numbers and reset all the rockers before I install.

 

[RicardoMarine]

Am I the only one seeing this as detonation damage?

I've been involved with the SBC since the mid 60's, and I've seen my share of damaged engines, ranging from detonation damage, to bad piston fit (or selection), to bad wrist pins, poor component selections, poor machining techniques (of which may include cylinder head work), etc. Some damage can be a result of incorrect engine tuning after the correct assembly has been performed.
This damage appears to be limitted to the upper end ONLY...... is this correct????
Again.... I'd not point fingers just yet. It's going to require some honesty on behalf of both of you, and some honest forensics.

Your forensics should include putting your ignition distributor on an old school distributor machine, and actually operating it........., testing/checking the advance curve and limit.
This will either rule out, or determine, the distributor as being a contributing factor.
If this is one of the Mercruiser EST TB systems, then the control module will need to be used during this test.

Once this is determined (or any other source), you and the engine builder can get together and make a plan for the repair. You may do better with him, given that this has just occurred.

NOTE: if you were to stay with this guy......, and have him re-do this, now is your chance to fit the correct pistons for Marine use. Steer clear of the full dished and the F/T's with these 64 cc cylinder heads.
A properly built Q/E SBC for Marine use, can effectively use a few points higher on C/R. Detonation potential is also greatly reduced.
The cost to do so is minimal, comparatively!

Food for thought!

.

 

[RicardoMarine]

Here is your engine block #;
10243880... 350... 95-00... 2 or 4... Vortec truck, Gen.I crate motors and "ZZ4", roller cam, one piece rear seal

From the looks of your image, these are indeed the Vortec cylinder heads.
You may be able to identify the cylinder head by casting number on this site.


You may find this interesting also.

 

[bondo]

Ayuh,... No block pictures,..??

What I see is Alota Rust...
Bad intake or exhaust,..??
That'll explain the hung/ rusted valves...

The pistons were smoked from Detonation...
Could be bad timing, or a Lean condition...
Just because the Carb checks out, don't mean the rest of the fuel system is up to snuff...
Bad fuelpump,..??
Clogged filters,..??
Water in the fuel,..??

Both the pistons, 'n the heads show massive signs of Water....

Engine builder claims it isn't his fault.*

At this point, with what's shown,... I tend to Agree with the builder...

 

[Docksidemarineservices]

Am I the only one seeing this as detonation damage?

I've been involved with the SBC since the mid 60's, and I've seen my share of damaged engines, ranging from detonation damage, to bad piston fit (or selection), to bad wrist pins, poor component selections, poor machining techniques (of which may include cylinder head work), etc. Some damage can be a result of incorrect engine tuning after the correct assembly has been performed.
This damage appears to be limitted to the upper end ONLY...... is this correct????
Again.... I'd not point fingers just yet. It's going to require some honesty on behalf of both of you, and some honest forensics.

Your forensics should include putting your ignition distributor on an old school distributor machine, and actually operating it........., testing/checking the advance curve and limit.
This will either rule out, or determine, the distributor as being a contributing factor.
If this is one of the Mercruiser EST TB systems, then the control module will need to be used during this test.

Once this is determined (or any other source), you and the engine builder can get together and make a plan for the repair. You may do better with him, given that this has just occurred.

NOTE: if you were to stay with this guy......, and have him re-do this, now is your chance to fit the correct pistons for Marine use. Steer clear of the full dished and the F/T's with these 64 cc cylinder heads.
A properly built Q/E SBC for Marine use, can effectively use a few points higher on C/R. Detonation potential is also greatly reduced.
The cost to do so is minimal, comparatively!

Food for thought!

.

I see it as Detonation damage/lean condition also.

 

[duo_prop_dad]

Raised ridge in the failed cylinder probably interfered with stroke of piston/ rings and therefore it cracked.

(pressure leaked past piston into crankcase and blew oil out of dipstick tube)

Ridge in cylinder is from previous long term wear that should have been machined out in the rebuilding process.

(rebuilders fault!)

Not properly setting timing wasn't a good idea, but is most likely not the issue.

(timing was set at 0 deg. TDC, and typically is set at 8-10 degrees advance idle, the distributor should advance to 32 degrees(typical)

when rpms increase to 3000 approx.; if anything the timing was retarded i.e. only 26 degrees at 3000 rpm)(32-8=26)

The block will accept a ZZ4 roller cam, but the heads will not accept that much valve lift per cam specs (.474 and .510 respectively)

without machine work to the valve guide tops and different valve stem seals/springs.

I didn't see any info on what cam was in this particular engine.

Makesumwake did state that it was a 2 barrel carb, so it was likely not a 3-400 hp engine !

Rick -in regards to pistons and compression ratio; according to Dennis Moore, author of "Small Block Chevy Marine Performance", he made a statement in his book that INCREASING C/R would prevent detonation in a marine motor.

(It was chapter 5, Pistons)

The correct/typical piston for a Marine 350 engine is the flat top with 4 relief cutouts for valve clearance.

The reduced compression piston (dished) was for smog reduction in automotive use, not necessary in a boat.

I do agree that timing advance, C/R and "quench" is critical for longevity/performance in a marine engine!

( I am in the beginning stages of adding Vortec heads and a roller cam to a donor Merc.5.7 block for install in my boat- Volvo)

john

 

[RicardoMarine]

John, the OP says;

bored .030" over..................
See all pictures here, the rest of the pistons looked ok. All rings looked ok. Cylinder walls were ok. There was a raised ridge on #7 cylinder bore where the piston had failed.

Raised ridge in the failed cylinder probably interfered with stroke of piston/ rings and therefore it cracked ............. Ridge in cylinder is from previous long term wear that should have been machined out in the rebuilding process. (rebuilders fault!)

Well...... Chicken or the Egg????
Possibly, but see OP's comment re; boring .030".

Not properly setting timing wasn't a good idea, but is most likely not the issue.

Respectfully disagree!
I'm basing my opinion on what certainly appears to be "Detonation Damage" in my book. I could be wrong!

(timing was set at 0 deg. TDC, and typically is set at 8-10 degrees advance idle, the distributor should advance to 32 degrees(typical)
when rpms increase to 3000 approx.; if anything the timing was retarded i.e. only 26 degrees at 3000 rpm)(32-8=26)

Well, until we know which ignition system the OP was using, it remains an unanswered question.
BTW, the BASE Advnace may be 6-8*, but the distributor module will typically only add approximately 22-24* advance.... equaling a total of approximately 26-28* at/near 3k rpm.
32* would be on the high side for an OEM Merc ignition system, I believe.
Again, the OP is very vague on ignition timing. I'm basing my opinion on the piston damage that I see.

The block will accept a ZZ4 roller cam, but the heads will not accept that much valve lift per cam specs (.474 and .510 respectively)
without machine work to the valve guide tops and different valve stem seals/springs.
I didn't see any info on what cam was in this particular engine.

Yes, I too cannot comment on that one! The OP offered no info on cam profile.
If this were the case, I think we'd be seeing a different type of damage.

Rick -in regards to pistons and compression ratio; according to Dennis Moore, author of "Small Block Chevy Marine Performance", he made a statement in his book that INCREASING C/R would prevent detonation in a marine motor.
(It was chapter 5, Pistons)

I think you may have misunderstood Dennis! (see following)

A properly built Q/E SBC for Marine use, can effectively use a few points higher on C/R. Detonation potential is also greatly reduced.

IOW, it is the Q/E that helps reduce the risk of Detonation.

The correct/typical piston for a Marine 350 engine is the flat top with 4 relief cutouts for valve clearance.

Well, it used to be the preferred piston for a 5.7L, using 76cc chambers only...... and would ideally be single valve relief F/T's! This combo offers a good C/R and Q/E when the correct head gasket is used. This would have been prior to the smaller chamber cylinder heads being more commonly used today. That's why I made the comment about the F/T's NOT being a good choice with the Vortec chambers.
Dennis explains chamber/piston combinations in his book.

The reduced compression piston (dished) was for smog reduction in automotive use, not necessary in a boat.

Amen...... and they have absolutely NO PLACE in a SBC Marine Engine.
Shame on GM for continuing to use this piston!

I do agree that timing advance, C/R and "quench" is critical for longevity/performance in a marine engine!

Yep...... has everything to do with PCP right where it needs to be. We certainly agree here!

( I am in the beginning stages of adding Vortec heads and a roller cam to a donor Merc.5.7 block for install in my boat- Volvo)

Be careful with which pistons are used.

.

 

[duo_prop_dad]

Another scenario.....

Head gasket failed ; (notice rusty spot on head next to cylinder wall- #7?

Water intrusion into cylinder and turned to steam or hydrolocked?

Causing piston to crack and destruct?????

and profuse white smoke!!!!

Would be interesting to hear more details of engine failing.....

John

 

[widi59]

John, the OP says;
*
Well...... Chicken or the Egg????
Possibly, but see OP's comment re; boring .030".
*
*
Respectfully disagree!
I'm basing my opinion on what certainly appears to be "Detonation Damage" in my book. I could be wrong!
*
*
Well, until we know which ignition system the OP was using, it remains an unanswered question.
BTW, the BASE Advnace may be 6-8*, but the distributor module will typically only add approximately 22-24* advance.... equaling a total of approximately 26-28* at/near 3k rpm.
32* would be on the high side for an OEM Merc ignition system, I believe.
Again, the OP is very vague on ignition timing. I'm basing my opinion on the piston damage that I see.
*
*
Yes, I too cannot comment on that one! The OP offered no info on cam profile.
If this were the case, I think we'd be seeing a different type of damage.
*
I think you may have misunderstood Dennis! (see following) IOW, it is the Q/E that helps reduce the risk of Detonation.
*
*
Well, it used to be the preferred piston for a 5.7L, using 76cc chambers only...... and would ideally be single valve relief F/T's! This combo offers a good C/R and Q/E when the correct head gasket is used. This would have been prior to the smaller chamber cylinder heads being more commonly used today. That's why I made the comment about the F/T's NOT being a good choice with the Vortec chambers.
Dennis explains chamber/piston combinations in his book.
*
*
Amen...... and they have absolutely NO PLACE in a SBC Marine Engine.
Shame on GM for continuing to use this piston!
*
*
Yep...... has everything to do with PCP right where it needs to be. We certainly agree here!
*
*
Be careful with which pistons are used.
*
.

*
I feel bad for both OP and the rebuilder, however, we live in a sue happy society and someone must be blamed.
*
If I'm the judge (who probably knows absolutely nothing about pistons, detonation, timing, etc. etc.) and if I'm convinced that the wrong pistons were used by the rebuilder, and if I'm convinced that other mitigating factors (timing, lean mixture, water in fuel, etc. caused engine destruction, they both will split the cost of this mishap equally.
*
How much money will it cost to hire a forensic expert to testify?
*
The OP and rebuilder should man up and meet each other half way.***

 

[makesumwake]

Thanks for the great feedback guys. very detailed.

1) it was a 260hp engine.

2) TIMING
I didnt use a timing light, i just set the distributor up to 0 advance, and then adjusted the distributor position (rotating left or right) during engine operation.
we took the boat out, ran it on the water at 4000 rpms, i turned the distributor left till the engine started sounding weird, marked spot. then i turned it right till the engine started sounding weird, and marked the spot.
then i put the distributor cap back in the center position between those 2 marked points.
this is how i was advised to set timing at an marine repair shop i have used in the past.

Ive also set my the timing on my old firebird this way and never had any issues at all with the car.
so im very surprised to hear that the problem could be from having the timing set wrong.

3) im not trying to sue or blame anyone. i just want to know what happened so that i can make sure it doesn't happen again with the next engine!

4) im really doubting the detonation theory for a couple reasons:
first, i know what detonation sounds like, and i never heard any detonation at all.
second, the piston should show some signs of detonation on their tops. there should be pitting marks, etc. the piston tops are perfectly smooth except for carbon deposits.
detonation would have cleaned the carbon off the tops of the pistons at the very least i would have expected ?

5) i have no idea how water would have gotten into the cylinders. the exhaust manifolds were brand new with new gaskets, as were the risers, with new gaskets, tightened down good.

 

[RicardoMarine]

Thanks for the great feedback guys. very detailed.

1) it was a 260hp engine.

2) TIMING
I didnt use a timing light, i just set the distributor up to 0 advance, and then adjusted the distributor position (rotating left or right) during engine operation.
we took the boat out, ran it on the water at 4000 rpms, i turned the distributor left till the engine started sounding weird, marked spot. then i turned it right till the engine started sounding weird, and marked the spot. then i put the distributor cap back in the center position between those 2 marked points. this is how i was advised to set timing at an marine repair shop i have used in the past.

NOTE: DO NOT take any further advice from this shop!

Marine loads Demand that Ignition Timing be dead on with regard to Marine Specifications!
At the lower RPM range, the Marine Gasser may be only 3 or 4 degrees away from Ignition Advance that may promote Detonation. This is Extremely Critical that it be set correctly, and as per OEM Specs! No Deviation, unless we know precisely what we are doing.

There is a good post on ME.com that I wrote some time back, regarding setting Ignition Timing that includes the correct procedure for checking/adjusting TAT.... (total advance timing). I'll see if I can locate it for you.

Ive also set my the timing on my old firebird this way and never had any issues at all with the car. so im very surprised to hear that the problem could be from having the timing set wrong.
You should not be surprised at all!
These are two entirely different power demands and load durations.
Even the most remote comparison cannot be made between these two. Sorry!

(I've been working in/around the SBC since the mid/late 60's...... I know what I'm speaking of regarding this.)


3) im not trying to sue or blame anyone. i just want to know what happened so that i can make sure it doesn't happen again with the next engine!
Since you used nor kept any datat on how you came up with this distributor position, I highly doubt that you can recreate anything that would offer any forensic value. Looks like you passed that point when the distributor was removed.
Please do youself the favor of NEVER again setting ignition timing like you have described. That is a recipe for exactly what you have described, IMO.

4) im really doubting the detonation theory for a couple reasons:
first, i know what detonation sounds like, and i never heard any detonation at all.
Again, you may be confusing Pre-Ignition with Detonation. (I mentioned this earlier)
Detonation can be very difficult to hear in a Marine installation as it will not necessarily rattle valves as will "Pre-Ignition". The two are NOT the same!

See below for a few links that I have included.

second, the piston should show some signs of detonation on their tops. there should be pitting marks, etc. the piston tops are perfectly smooth except for carbon deposits. detonation would have cleaned the carbon off the tops of the pistons at the very least i would have expected ?
You may want to read up on this topic.

5) i have no idea how water would have gotten into the cylinders. the exhaust manifolds were brand new with new gaskets, as were the risers, with new gaskets, tightened down good.
Agree, I don't see this as water damage.

Here is an article by Allen W. Cline.
Allen primarily discusses automotive engines, but minus the more critical limits for Marine, the principles are very much the same.
Pay particular attention to paragraph 3 on page 1, and again to paragraph 6 on page 1.
Be sure to read all 8 pages.
Detonation that may occur in an automotive engine, is paled by comparison to that of Detonation that may occur in a Marine Cruiser engine. Make no mistake, No question about it!


Here is another by Bob Hewitt.
Again, mostly automotive related, but some valuable info here. Pay particular attention to point #4.
You may give some importance to point #3, as your builder did not use the correct piston/cylinder head configuration, IMO.
However, keep in mind that your ignition advance can no longer be verified.
Cylinder pressures being excessivley high is one thing..... but I'll tell you for certain, incorrect ignition advance is more often the culpret when it comes to this type of detonation damage in a marine SBC.



Portions of this are from EngineBuilder.com .... (author not mentioned)
Detonation Damage:
When combustion temperatures and pressures exceed the octane rating of the gasoline that’s being used in an engine, it causes the fuel to ignite spontaneously. The result is multiple flame fronts that collide in the combustion chamber and produce high pressure shock waves that hammer the pistons.

Over time, detonation can be very damaging to the pistons as well as the rings, head gasket and rod bearings. Detonation damage typically includes cracked or broken ring lands and cracks in the piston itself.

Replacing the damaged pistons will temporarily solve the engine’s mechanical problems. But the new pistons will likely be hammered to death, too, unless the conditions that are allowing detonation to occur are diagnosed and corrected.
Possible causes include over-advanced spark timing, an inoperative EGR valve or plugged EGR port, engine cooling problems, too much compression (carbon build-up, milled heads, wrong heads, high compression pistons) and low octane fuel.

************************************************


I certainly appreciate your honesty with regard to posting your ignition advance procedure, or should I say, the lack of!
Again, and IMOO, I'm looking at this as though it is ignition induced detonation damage, based photos and particularly this recent ignition timing information.
I think you would have a difficult case if you were to argue otherwise.

Like suggested, see if you can stay with this re-builder, and see if he is willing to re-work everything!
However, I think this is on your dime, unless he can be convinced that the F/T's should not have been used in a Marine SBC build....., and that the F/T's may...... I say "MAY", have contributed to a portion of this detonation damage.

I wish you the best on this!

 

[haffiman37]

I feel like going a bit in 'defense' of the re-builder.
A 260 Hp Mercruiser with a 2-barrel carb??
What is the re-builder NOT responsible for:
Intake manifold and carb??
Cooling components like manifolds, thermostat housing, impeller pump??
(Was one manifold running hotter than the other?)
Engine installation??
Tune-up of ignition and carb??
Initial start-up and break-in of engine?
There are too may ??? to straight put the blame on the re-builder.
Why was the 'original' engine replaced??
The type of pistons may not have been the optimum choice, but why no 'traces' or damage on the others??
I do not think I would go to court with this case.
The carb was 'tested' by a shop, but was it tested in bench (flow-tested), on an engine or just visually 'inspected'??

 

[RicardoMarine]

However, I think this is on your dime, unless he can be convinced that the F/T's should not have been used in a Marine SBC build....., and that the F/T's may...... I say "MAY", have contributed to a portion of this detonation damage.

I need to qualify the above statement, if I may.
It's not that the F/T's were a bad choice for Marine use..... fact is, they are a good choice in a 5.7L with the 76 cc chambers! (i.e., they will offer the valuable Q/E, plus a usable C/R w/ this bore/stroke)
It's rather that they were a poor choice for use in this particular 5.7L with the 64 cc chambers. (see the article by Bob Hewitt again)

I just wanted to clarify that!

.....................
The type of pistons may not have been the optimum choice, but why no 'traces' or damage on the others??
I do not think I would go to court with this case.

haffiman, I tend to agree with much of what you posted.
I will say, that detonation damage may not affect all pistons. I've seen where only a few had reached the actual point of failure, while the others did not quite get there.
IMO, this is not all that uncommon, any more than finding one or two burned valves, while the others remained OK! It's a tough one to explain!

*********************************

What interests me in a thread like this, is that this info will be viewed by on-lookers who may not actually be posting to the thread, but may benefit from reading it, and will hopefully not make the same mistake themselves.

Even something as simple as changing to the Vortec cylinder heads (to an existing engine block that may be fitted with the F/T's), could cause the same damage.
Likewise with going from a 76cc chamber to any of the smaller chamber heads with this same F/T piston. IOW, when a cylinder head is selected, we'd better also select the correct piston to accommodate it...... and visa-versa!
Plus, make certain that the correct q/e head gasket is used. The wrong gasket, and we deminish the q/e!

The other thing that I hope can be learned from this thread, is the importance of proper ignition timing, and/or fuel metering.


BTW, this may be the ignition advance/timing thread that I mentioned earlier. For some reason I had ear marked this one.
.

 

[bondo]

I didnt use a timing light,
3) im not trying to sue or blame anyone. i just want to know what happened so that i can make sure it doesn't happen again with the next engine!
4) im really doubting the detonation theory for a couple reasons:
5) i have no idea how water would have gotten into the cylinders.

Ayuh,... #1, 'n #3 are related,....
An incompetent mechanic did the install....
What vintage is this Mercruiser,..?? What Igntion,..??
Electronic igntion can't be set by ear, like an old points system...

#4, You can doubt it all day long, but That's what smoked that motor....
Probably due to yer timing exercise..

#5, I'd be lookin' to the Intake manifold...
That motor ingested a ton of water from Somewhere...
Atleast all that Rust says so...

 

[widi59]

I feel like going a bit in 'defense' of the re-builder.
A 260 Hp Mercruiser with a 2-barrel carb??
What is the re-builder NOT responsible for:
Intake manifold and carb??
Cooling components like manifolds, thermostat housing, impeller pump??
(Was one manifold running hotter than the other?)
Engine installation??
Tune-up of ignition and carb??
Initial start-up and break-in of engine?
There are too may ??? to straight put the blame on the re-builder.
Why was the 'original' engine replaced??
The type of pistons may not have been the optimum choice, but why no 'traces' or damage on the others??
I do not think I would go to court with this case.
The carb was 'tested' by a shop, but was it tested in bench (flow-tested), on an engine or just visually 'inspected'??

A judge can only rely on what evidence is presented to the court. You never know how the judge will rule. Lemon laws have been legislated. Who knows, the judge may view the rebuilder like a back yard used car salesperson and that could have an influence on the outcome.

The best solution would be for the two parties to reach a compromise and get the engine done over and tuned right.

 

[chiefalen]

Wrong cam-wrong crank maybe both ?

Ingesting water in the 2 middle cylinders. Usually it's the 2 closest to the risers. Thats why i guess it's cam-crank related.

" Water shooting out the dipstick " < from the first post.

I still think the block got a crack from day one, before it was rebuilt.

 

[RicardoMarine]

OK..... let's reverse engineer this, somewhat.
If..... I say IF this is damage was caused by incorrect ignition timing (of which it likely was, IMO), then the damage is from detonation. No question in my mind, given what I have seen/heard thus far.

Some of you guys may not be considering the heat generated from detonation damage.
What may appear to be rust, may be a result of these very high cylinder temperatures, and the following head gasket failure, that no doubt shortly occurred.
Plus..... he is running in salt water if I understood him earlier!

Much of this subsiquential damage may be a result of the primary damage.
Such as..... cracked block, heads, etc..... although this has yet to be confirmed.

I'm just suggesting this.... sort a throwing it on the table here for discussion.

The best solution would be for the two parties to reach a compromise and get the engine done over and tuned right.

Ditto!

 

[widi59]

OK..... let's reverse engineer this, somewhat.
If..... I say IF this is damage was caused by incorrect ignition timing (of which it likely was, IMO), then the damage is from detonation. No question in my mind, given what I have seen/heard thus far.

Some of you guys may not be considering the heat generated from detonation damage.
What may appear to be rust, may be a result of these very high cylinder temperatures, and the following head gasket failure, that no doubt shortly occurred.
Plus..... he is running in salt water if I understood him earlier!

Much of this subsiquential damage may be a result of the primary damage.
Such as..... cracked block, heads, etc..... although this has yet to be confirmed.

I'm just suggesting this.... sort a throwing it on the table here for discussion.

Ditto!

Agree 100%.

"Tear-down by engine rebuilder revealed chip out of top of #7 piston, chip was melted to top of piston".

Way too hot in that cylinder.

The piston also has a crack running down the side, right under the point where it chipped".

Thermal stress?

"All rings looked ok.* Cylinder walls were ok.* There was a raised ridge on #7 cylinder bore where the piston had failed".

Part of the piston material "welded" there?

Appears things were hot. When OP backed off from WOT, he may have thermal shocked the block and heads. If they're cracked, could be from that.

 

[chiefalen]

Any rebuilder runs a motor after building it. Even if it doesn't ship with the carb and all the externals they RUN THE MOTOR.

 

[RicardoMarine]

We do not yet know which form the OP actually purchased this engine in..... Long Block, or Complete!

Chief, are you suggesting that if a re-builder provides a "Long Block", he's going to run it before it goes out the door?


.

 

[makesumwake]

thanks guys. i realize that this was probably my fault, at the very least because im not familiar with marine engines. all my engine experience has been with autos, and that is limited also.

I totally forgot how much the extended WOT running (that occurs with boats and not street cars) changes the situation.
now it makes perfect sense why anything short of perfect ignition timing could cause this problem.

********************

Next question:
the rebuilder is offering to fix the engine and put it back together for only $500, since all we need are "new pistons, a block hone, new rings, new gaskets, new valves and some valve work".

is this a good idea, or should a complete rebuild be done?
should i go with a more reputable builder, aka, not a cheap rebuilder?
or maybe a quality remanufactured marine engine, like a jasper?

 

[RicardoMarine]

thanks guys. i realize that this was probably my fault, at the very least because im not familiar with marine engines. all my engine experience has been with autos, and that is limited also.
Again, sorry to hear of this. It's certainly biting the bullet, isn't it?

I totally forgot how much the extended WOT running (that occurs with boats and not street cars) changes the situation.
now it makes perfect since why anything short of perfect ignition timing could cause this problem.
We should NOT be doing WOT RPM running, period.
WOT RPM is for testing to see if we are geared and propped correctly.
Having our WOT RPM correct is especially important during break-in period.

Do the WOT running at your own risk, IMO.

********************

Next question:
the rebuilder is offering to fix the engine and put it back together for only $500, since all we need are "new pistons, a block hone, new rings, new gaskets, new valves and some valve work".

is this a good idea, or should a complete rebuild be done?
If he is confident that no further damage has occured, then why not?
He will be able to look at heads for straightness, rod bearings, cylinder walls, he'll probably pull the valves, etc.


Question: Does this rebuilder fully understand the issue with the F/T's being used with 64cc chambers?
And make DAM sure that none of the fully dished pistons are used to lower C/R with these 64cc chamber heads!
(see one of my previous posts on the Q/E piston, Low Comp Q/E, and D-dished piston! Another is called a Reverse Dome!)

should i go with a more reputable builder, aka, not a cheap rebuilder?
or maybe a quality marine engine, like a jasper?
I would not put J___r in that category! Not from what I've read!

Again, good luck. Keep us posted, and particularly what further findings reveal!
It's always good to have a true barometer to check yourself against.

 

[haffiman37]

If the 're-builder' is close enough to do installation and final tune-up, might be reasonable.
If not, find someone closer that may do the complete job and deliver the package 'on water', ready to run.

 

[widi59]

My machinist/mechanic, works on and flies his own airplanes!!

His runway is a long field behind his house.

He flies over my house every summer and tips a wing!

That's about as social as he gets, but his work 100% precision!!

 

[o2batsea]

That engine looks awful gunky for having less than ten hours on it. I fear that someone's not giving the whole story.

Oh, and you can't operate a brand new engine under "normal use" conditions...it requires a break in period. If you said it failed while breaking it in, might be different...just sayin.