Logo
FULL SITE MENU

Quality rebuilds??

C

captal

Contributing Member
Well haven't had to be on here for a while.... Good thing, huh? But the season is coming on and it's time for a freshen up. I have a pair of 350 Crusaders (270hp) in my Luhrs. It's the engines that were in it when I bought it 7 years ago and I have no idea the total hours. They do sound a little rough at idle and make noise at speed. The port engine is starting to knock pretty good so I'm going to get a set of long blocks and replace both. Most of my bolt-ons are new as are the manifolds. Question is who is a good reputable company to buy from? I'm on the coast of the Carolinas and there a few local companies in the area but after looking on-line I see that I can get a better deal even after shipping. There is a company in the north west,USMarine Engines, that claim to use better parts to give you more hp and better fuel economy. Did a little research but they seem to get some terrible reviews from customers. Searched here and see that Michigan Motorz seems to get pretty good reviews. So anyone have experience with any companies they would recommend? Do want a good warranty but take out and send back is a pain in the a**. Would rather get a good quality engine with no problems. So any ideas????
Thanks!! Capt AL
 
Last edited:
Capt. Al,

I repowered with a long block from Rapido marine down in Florida. They not only had good prices their shipping was very reasonable as well. look them up and talk to Raul. (correct spelling)
 
I second Rapido Marinme, Hollywood FL, I have it in the Boat 6 months now and I am very happy with the motor. There shipping prices are great they shipped the motor to me by boat as I live in Panama it took 1 week to get here and the shipping cost was fantastic.
Speak to Raul he's a super guy.

Joel
 
Use who you feel comfortable with, and who can offer you great references and a great warrantee.

MichiganMotors also has a great reputation.
They are also on board with offering an alternate SBC build using a slightly different combustion chamber design (different style piston profile) for the asking.
Not too many other shops offer this, nor even understand the difference.
Most fall into the "norm" and give us the old standard GM build using the GM style full dished pistons! :mad:
And when you ask for the alternate Qunch build, you'll sometimes get that "Deer in the Headlights" look!

Look at this thread for a basic idea of what this involves. The thread title is somewhat misleading.

Here's another similar thread, but mainly pertains to the 377/383 build, although the principle is very much the same.


Unless you are comfortable with the standard build, if you get that "Deer in the Headlights" look, I'd suggest that you find another shop!

BTW, this is nothing new.... engine builders have been doing this for years.
In fact, GM's very first SBC (265 cu in V-8 1955) used the Quench Effect principle.
We have simply fallen into the run-of-the-mill GM builds (resulting from the 70's emmisson control erra), and we don't ask for anything other.

No other major changes need to be made to the build. You end up with a suitable compression ratio for a Marine Cruiser engine, and with a build that offers better torque from the SBC.
The cost difference to do this is peanuts.... and the end results are well worth it.

You can ask your local library to bring in Dennis Moore's SBC Marine Performance book for you.
Dennis goes into great detail as to why this is important.
This is NOT a high performance upgrade, per 'se..... it's an improvement for our Cruiser Engine use.


.
 
Last edited:
I am in Maine and when they shipped it if I remember correctly shipping was around $150- and part of the shipping was flying the thing from Atalanta to Manchester NH.
 
Capital,

Where are you located? My boat is at Ocean Isle.


attachment.php
 
Last edited:
You're going to be purchasing two of these. That's quite a chunk of change in terms of initial cost.
You no doubt want these to perform well, and to offer good power and torque.

FYI and FWIW: no mater who you go with.... brand new or re-man'd....... you are most likely going to get so called "Marine" version SBC with the GM style full dished pistons. That's what is OEM in these engines, and that is what most re-builders use.


Here's what these look like.


This style piston is not capable of creating a quench or squish, and should NEVER be used in a SBC Marine Cruiser engine application. :mad:

If better detonation control and a more torque are not all that important, then there ya go. These will work OK for you.
But if these aspects are important to you, you may want to look into this alternate build.
Most any good re-builder will do this build for the asking.

Perhaps give Dennis Moore's SBC Marine Performance book a read.
Don't let the word "Performance" cause you to think that this is a Hot-Rod or Go-Fast boat build.... it's not about that.


.
 
Super information guys! Ricardo I took your advice and read up on the quench and squish. You can bet I won't go with dished pistons. Learned a lot about the quality of rebuilds. At least I can be a little more informed when I start checking out companies.
But getting back to my original quandary, who to buy from. Seems we all, myself included, love to rant and rave about bad service but not many of us go on about good service. Seems like every company I check out has all the horror stories posted about them online and very little if any good stuff. Just like here, got good input about Rapido Marine in FL but then get a post about south FL motors being cheap.............. Chris would you recommend anyone in your area? Not many marine engine rebuilders around here. How about you Ricardo? Anyone good in the NW? One company, USMarine Engines in WA have a lot of webpages but all I can find online is a few bad reviews. Would love to hear from anyone that has a rebuild that’s been running a few years and who you got them from.

Allen, I'm at Holden Beach, NC
 
I'd personally build my own.
But if having one built, MichiganMotors gets good reviews.
Phil (at MM) and I have spoken several times regarding the quench build. They perform this build for the asking and upgrade cost, which by all rights should be minimal.

Several ways to achieve the quench in a SBC 5.7L, depending on cylinder head selection.
(this applies the 5.7L 3.480" stroke stroke only)

1.... w/ 76cc chamber cylinder heads, the single valve relief flat top pistons offer a near correct C/R, yet are capable of the quench when the correct piston deck clearance and compressed head gasket thickness is used.

2... w/ the 64cc chamber standard chamber heads, we now use a D-Dish or Reverse Dome piston with the correct piston dish volume to achieve the correct C/R.

3... With the 64cc Vortec combustion chamber, we use a Low Compression Quench style piston, also of the correct dish volume to achieve the correct C/R.

Piston selection is easy once the perameters are known. Any good piston supplier can accommodate you.
Once selected, this requires nothing else out of the ordinary to the build.
The piston deck clearance will be checked anyway, and they're going to make a head gasket selection anyway.
The rods and cylinders won't care which pistons are fitted, nor will the piston rings care.

NOTE: With a good Marine quench dimension (the target is .038") we can increase the C/R some, and with little risk for increased detonation potential.
Our total ignition advance is now also increased a bit, and again, with little risk for increased detonation potential.

IMO, it's a win-win no matter how you slice it. :D


.
 
OK after hours of research and hair pulling (and I ain't got much left) I think I'm going to go with new engines. But that brings me to a new question. I can get the exact replacement Crusader or there are a lot of Mercrusier engines with a little more horsepower for about the same cost. They are all SBC so my mounts and manifolds should all work. Anybody have any good advice- Crusader vs Mercruiser???
 
Last edited:
captal said:
OK after hours of research and hair pulling (and I ain't got much left) I think I'm going to go with new engines. But that brings me to a new question. I can get the exact replacement Crusader or there are a lot of Mercrusier engines with a little more horsepower for about the same cost. They are all SBC so my mounts and manifolds should all work. Anybody have any good advice- Crusader vs Mercruiser???
Click to expand...

Yes, all of your mounting will the same. SBC is SBC all day long when discussing the external dimensions, head bolt pattern, engine mount bosses, rear engine flange, etc.
Depending on year model, you will see a change to the intake manifold bolt angle. You'll also notice a change to the intake manifold with regards to the Vortec engine.
There is also change to the rear crankshaft flange as well. Difference being the 2 pc rear main seal (pre-1987) and the single rear main seal (post 1987). This means a different flywheel for each.

As for Mercruiser -vs- Crusader -vs- Volvo Penta, most any of these that come from GM that are Marine equipped, are going to be fitted with the full dished pistons. In order to get away from this, you'll need to have these custom built.
As suggested earlier, MichiganMotors offers this engine in this configuration. The only real change is piston selection, deck clearance and proper head gasket selection.

If a bit more torque and less concerns for Marine Load Detonation interests you, then this is the correct way to go.
If you are not concerned...... then go with the GM version.
Just don't become too aggressive with your ignition TA, and you will be just fine.


Watch for horse power and torque ratings. These are not all Apples to Apples.
Look at the RPM at which the rating was taken.
You may remember when GM introduced the Vortec in the Marine version. They rated this Vortec Engine at 315/320 hp, but at 5,300 RPM.
Unless you're operating your engines at/near this RPM range, you won't realize these numbers. And if you were to operate at this RPM, you'll shorten the engine life substantially.


IOW, don't be fooled by the numbers game!



Back to the build for a minute.
My applogies....... as I may sound rather anal re; the quench build, but I'll tell you that it's for good reason.
Understand that the SBC Full Dished piston was designed during the 70's emmissions control erra, and it just stayed around.
It's a very cost effective piston to produce...... cheap even....... and one piston p/n fits all 8 bores, so it's an easy one to use as well. But it's just plain wrong for use with the SBC cylinder head combustion chamber.
GM and the rebuilders will continue this because we buy into it! As long as we continue buying into it, they'll continue providing it.

In some 45+ years of building the SBC's, I've never built one using this silly full dished piston!
The Q/E is nothing new. The HP auto guys have been using this principle for years, and it's nothing new to the Chrysler Wedge Head boys either.
Plus, it's not necessarily a HP upgrade when it comes to the SBC Marine engine......, it's moreso to combat detonation potential, and to offer us more low end torque.

OK... rant over! :D


.
 
Last edited:
I went new when I repowered in 2007. I went with Crusader. Mercury did not have right hand (opposite) rotation new engines. I wanted to reuse my old Velvet Drive transmissions and props. Right hand rotation is an additional $1100. New motor mounts, wire harnesses, exhaust, cooling water hoses &fuel filters are additional costs that add up. Your old gauges should work with the new engines even with EFI. For an additional $900 each the dealer, 1800runsnew shipped my engines with rebuilt Velvet Drives bolted and plumbed to the cooler with new dampers. They were test run before they left their shop. I had the room and could drop them right in. Exhaust at the risers went from 3” to 4” required modification of the collector. I had an inch of pitch taken out of my old props to get the RPM’s up. I did the work myself and it went very well. I took a lot of weight out (had to move the waterline). I went from 1984 454ci Merc. 340HP to Crusader 5.7(350ci) EFI 330HP with the “returnless” fuel system. Fuel consumption is better at the same cruise speed but, now it stares us in the face with the Powerview gauges reading everything off the computer. The only thing I can add is that you need to really like the boat you have and plan to keep it for awhile as your putting lots of $ in to it. The repower will add some value to the boat but the year it was built is the overriding factor.

Best of luck
Lou
 
I did check with Crusader for a bobtail but the salesman couldn't tell me the type piston they use. Got the "they are run at the factory before sale and have a good warranty" speech. I'm going to check with Michigan motors for the SBC with custom pistons. I guess they will know the right combination of heads and gaskets.
But here's another question. The Crusaders have been around for ages. I've seen them with over 2000 hours on them. From what I've read they all have the dished pistons in them. If I go with a stock Crusader how do I avoid the piston problems? Do I follow the factory recommend timing? I'm just a pleasure boater and take it pretty easy. Whatcha' think Rick?
 
Captal, what are you going to do with your old motors. Would you possible part them out. I have 270 crusaders also, and always looking for parts. Thanks Mike
 
captal said:
I did check with Crusader for a bobtail but the salesman couldn't tell me the type piston they use. Got the "they are run at the factory before sale and have a good warranty" speech.
Not uncommon!
We can look at most any advertised Marine SBC engine, and we'll see that they'll list Hypereutectic pistons (example only), but will say ZERO about the piston profile.
This is a result of either NOT knowing the differences, or a result of NOT wanting to advertise the Full Dished pistons. :mad:

I'm going to check with Michigan motors for the SBC with custom pistons.
When a quench build is done, these aren't necessarily "custom" pistons.
(see ** below)
They're simply a different style piston that is extremely common among a majority of SBC enthusiast.

I guess they will know the right combination of heads and gaskets.
Yes, and you may want to speak with Phil Abejean about this since there are several approaches regarding the different cylinder head selections.

The single valve relief F/T pistons w/ 76cc chambers is only one approach.
When we use the 64cc chambers (such as the Vortec cylinder heads), a different piston profile is used (LCQ piston for example).


But here's another question. The Crusaders have been around for ages. I've seen them with over 2000 hours on them. From what I've read they all have the dished pistons in them.
True! Same with Merc, Volvo Penta and the others when the GM base engine is used.

If I go with a stock Crusader how do I avoid the piston problems?
The piston itself wont be problematic. These are good and strong pistons.
It's the full dished profile, and what this does to the combustion chamber dynamics, that is the problem. :mad:


Do I follow the factory recommend timing?
For a non-quench build..... Yes! These are typically very conservative numbers.
For a quench build..... NO! We can become a bit more aggressive.

I'm just a pleasure boater and take it pretty easy.
Same with me, but I custom built my SBC engines incorporating a Q/E into the build.
As I've said, this is not a Hot Rod nor Racing build..... it's a build that better suits our Marine Loads.

Whatcha' think Rick?
Click to expand...
Not much that I can say here without being terribly redundant, and I've already over-stepped my boundaries. The guys are probably getting tired of hearing this! :mad:

These SBC engines that are built using the GM style piston do fair well. No real concerns here. The C/R is rather conservative, and the ignition timing (the TA portion) is held back in order to combat detonation potential.
(Pre-Ignition and Detonation are two entirely different phenomena)
These non-quench built SBC's will last for years and years when taken care of.

The quench style piston simply removes a portion of the dish from underneath the flat surface that is off to the side of the cylinder "wedge" style combustion chamber. With a good tight quench, there's no place for the a portion of the flame front to hide.
Instead, the gasses becomes squished and forced into the flame front.
This results in a much more full "burn", and detonation potential is greatly reduced.

Ignition TA can now become a bit more aggressive.
With a more aggressive TA, we now place the LPCP closer to the desired 12* to 14* ATDC, where better torque is made.
C/R can remain the same, or it can be raised a point, helping performance even more so.


I believe that I mentioned earlier that GM designed the full dished piston in the 70's for emissions control purposes. It worked well for the SBC automotive engine during this era. It's cheap to produce, one piston p/n fits all 8 bores, etc, etc.

** The irony of this is..... that we've become so acustomed to seeing the full dished piston used in the SBC, that we think of this build as being the "norm" or "standard". When a different piston profile is used, we tend to think of this as a "custom" build.
Prior to the 70's (I don't recall the exact year) the full dished piston was not used in the SBC.

The quench build can be a "hard sell" simply because GM has shoved the full dished piston down our throats for so many years. Many Re-Builders tend to follow suit!
You can bet that the GM Bean Counters had a "say-so" in the continued use of this piston, and that the GM Engineers had very little to say about it.
I'll go so far as to say that no engineer (who is worth his salt) would recommend this piston for Marine use.


As for longevity, there should be no difference between a Quench Build and a Non-Quench Build.
However, if we were to undergo detonation with the Full Dished piston SBC, we can expect a shorter life.
And just to clear and fair..... we can still detonate a quench built SBC if not careful with F/A ratio, ignition timing and/or with sustained excessive lower RPM loads.

As said, no other major changes to the build are necessary, and the assembly requires very little additional time, if any at all.
A few calculations, a phone call to their piston supplier, piston-to-rod fit requires more attention, a few additional checks, and they can move forward just as they would otherwise.



Ya see...... I warned you that this would be redundant! :D


If it were me, I'd have no decision to make, as it would be a Hands-Down decision towards a quench build!

Either engine will work just fine.





.
 
Last edited:
BTW, captal, your thread title reads "Quality Rebuilds", so I've made the assumption that you were asking about Rebuilt Engines, not necessarily new engines.

Whether you go with a standard build or a quench build, either style build can be of high quality or not so high quality, depending on who is doing the rebuilding.
If all of the specs are used correctly, the machining and assembly is of high quality, and when the engines are properly set up and ignition timed correctly, etc, either style build will give you good service.


.
 
Well after getting prices from companies all over the country, I found that the Crusader plant is right here in SC. I can pick them up and bring them home. Unless I find some killer deal real soon, new Crusaders are probably the route I'll take. I can sell off my cores or extra parts and make a little of my money back anyway. I'll keep ya'll posted!
 
captal said:
Well after getting prices from companies all over the country, I found that the Crusader plant is right here in SC. I can pick them up and bring them home. Unless I find some killer deal real soon, new Crusaders are probably the route I'll take. I can sell off my cores or extra parts and make a little of my money back anyway. I'll keep ya'll posted!
Click to expand...


10.jpgNothing like that new motor smell. This is the way mine were delivered. I was in such a hurry to drop them in I forgot to turn the transmission mounts around. Heart skipped a beat when the couplings were way out of line.
 
AL:

If you are talking to the factory, they used to have a few other options. The whole engine & gear, then a new engine (complete - aka bobtail), and then they had partial engines which I think were new...they may have a rebuilt option now...Mercruiser had also offered "factory reconditioned" engines, in a variety of configurations, but I haven't checked on them in a while.
 
When I replaced my 5.7 mercruiser with a rebuilt from Mercruiser. I payed top dollor for the factory rebuilt just to feel comfortable with the the big guy Mercruiser doing the work and there quality control that they boast about. What a mistake that was. They didn't replace the freeze plugs with new brass plugs and the old steel ones rusted out and blew out my starter and alternator. They did all that work getting a engine block machined and shipped but didn't replace simple plugs in the block. When I called and told them what happened they said to bad. What great Customer Relations Dept. they have. They won't see anymore money from me.
 
Last edited:
captal said:
Well after getting prices from companies all over the country, I found that the Crusader plant is right here in SC. I can pick them up and bring them home. Unless I find some killer deal real soon, new Crusaders are probably the route I'll take.

I'll keep ya'll posted!
Click to expand...
Did you by chance give Roger at MichiganMotors a call?


Just for fun, (and I'll not pitch the quench build any further here), but during many of these threads where have pitched it, I came upon this image one day.
This SBC has the correct pistons (for 64cc heads), and would be a quench build, if not for one major Boo Boo.
And if you can believe it..... the guy ran it this way!

Can you see what it is?




Here's a hint! ;)

 
Last edited:
John and Jeff........... Yes, the pistons were installed upside down.
I stumbled across the image while I was searching for an image of SBC pistons. The dished areas and the quench flats were just oposite of where they should have been.
I dont' recall the web site where he had posted this, but he did say that he ran the engine, and apparently it did not cause any damage.

.
 
When contrasted to how this should look (see second image)..... these pistons are rather odd looking! :eek: :eek:






Here the piston's quench area is at the top of the cylinder, where it's able to mirror the wedge chamber's "quench" surface.
(the dished are is confined to being underneath the main chamber)

 
Last edited:
You can tell from the carbon pattern on the pistons that the upside down trick was not allowed to run for long. Must of made some kind of funny sound.

As for your picture, it's been too long since I have seen the inside of one so shiny and new. Brings back memories.

CaboJohn
 
Back
Top