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Need A 454 pistonhole in old one What went wrong

swampdonkey

New member
I'm the process of fixing

I'm the process of fixing my 89 crusader 454. Any help on situation would be appreciated. Here's the scenario.

I was underway in my 34' luhrs when I noticed the stbd exhaust smoking and rpm drop. immediately shut it down. Started diagnostics on engine and found no compression on adjacent cylinders. Figured it was just the head gasket. Pulled the head and head gasket was blown but to my dismay there was a 3/8 hole melted/blown in the center of the piston.

I'm not sure what caused what. The piston melting or the headgasket blowing between cylinders. I want to believe the head gasket blew leaned out the cylinder causing it to run hot an melt the piston. Or was that cylinder running lean from a vacuum leak or something else and it caused the head gasket to blow. To me it looks like the head gasket was blown for a while b/c there was a groove worn between the combustion chamber on the head.

Luckily the cylinder wasn't scored so I'm going to attempt to hone it in the boat and just put a new std. piston in.

I'm having trouble finding the piston though. Does anyone know the part # for a 1989 454 crusader piston. The casting on the piston is 353062 and I have the gm part #. Problem is I cant just go to a Gm dealer and get a piston b/c they told me they have been discontinued.

Any help finding a piston or comments on what went wrong with the engine would be appreciated. The motor only had 600 hours and the rest of the internals looked great.
 
"Matt,

This is by NO means


"Matt,

This is by NO means gospel...BUT a place to start according to my parts books MIGHT be Crusader Part # 30246 for Standard size and 30249 for .030 over. Ring set is #30184 and 30185 for .030 over...Good Luck, maybe you will be able to cross reference these numbers as well"
 
Thanks for the numbers Al. I s

Thanks for the numbers Al. I saw those part #'s on marine engines website. They have a pdf of of sierra replacement parts. But it doesn't look like they can get the std. bore piston. Guess I will have to give them a call on monday to see.

Does anybody know who manufactures sierra's pistons? If its speed pro I've tried that route at the local napa.Problem is the speed pro piston doesn't match up exactly to the old piston. The skirts are different. I'm not sure if it matters or not.

If any body has more knowledge of that subject feel free to chime in.
 
"matt:

if you have a good m


"matt:

if you have a good machinist or machine shop, take the old part and the block casting number and i bet he can hook you up. Write down the head casting number, too.

Most of that vintage was a 'standard' marine long block put together by GM. They got sold by the tractor trailer load to the marine OEMs who then bolted on their stuff and made a product.

I'd check the cylinder bore to make sure the standard piston won't be too loose.

Based on your description, it sounds like the piston died from detonation. When it occurs, it is deadly and very quick. If the top of the piston, especially around the hole, has a sandblasted look, that's a pretty positive sign.

oh - ebasicpower has a merc 7.4 piston in std and +0.030". http://bpi.ebasicpower.com/mm5/apps/ieprts.php?id=33. looks like a federal part which used to be a speedpro"
 
yup its got the sandblasted lo

yup its got the sandblasted look. The edges of the hole look sandblasted/melted. Like a hole was burned threw it with a torch. I haven't ruled out detonation as there was some old fuel in the boat. But I topped the tanks off when I purchased it and put a bunch of additives in it. So its probably a 50 /50 mix of good and bad. It smell and looks fine though.

I checked the link you provided and the picture of the piston is the exact one I got from napa which came in a speed pro box. If it comes down to it I just use this piston and hope for the best?
 
strange that it only burnt one

strange that it only burnt one piston. you may have had detonation or a lean mixture from an intake manifold gasket.
 
"Good point. You need to dete

"Good point. You need to determine WHY it did that to you or it could happen again.

Is that a Q-Jet carbed motor and, if so, were you relying on that tiny little gas filter in the carb body? Those *@%!# are responsible for lots of burnt pistons.

Jeff"
 
"Matt, I burnt 1 piston in my

"Matt, I burnt 1 piston in my 454 Crusader with less than 350 hrs on a rebuild. I know it was caused by a crossed wire and ethanol/dirty carb running too lean. I was lucky and no scoring of the bore. Honed, replaced piston, rings and have put 30 hrs on and knock on wood, running fine. Be extra careful to get the correct piston and ring set. Deep oil groove versus shallow."
 
"Jeff,
I definitely don't


"Jeff,
I definitely don't want it to happen again. I do have one of those ceramic filters in my holley. Do you think they cause it to run to lean by restricting flow or by letting dirty fuel in. I have another bigger inline filter before the carb. I think that is doing the job.

Dwight,
Do you recall the where you got your piston/rings from. A machinist told me it woudld be ok to use a shallow grove ring in a deep grove piston? Do you remember the specs on the deep grove as far as oil ring depth?"
 
"matt:

you never did say wh


"matt:

you never did say which cylinder it was; the front ones are famous for leaning out first, especially when in an inboard installation.

Little late now, but did you ever check the timing to see what it was at full advance?"
 
I can't remember the gm fi

I can't remember the gm firing order off the top of my head but its one cyl. from the back on the port side.

Never checked the timing but if it was all the way advanced I don't think the motor would have run well enough to turn up into the upper rpm's under load.
 
"Your fuel filter setup sounds

"Your fuel filter setup sounds good--IF it didn't need changing. With "evil-nol" gas crap working on the crud in our tanks, one needs to change filters more often, so...

Jeff"
 
Fuel filters and racors were b

Fuel filters and racors were basically new. I did a bunch of routine/yearly maint. A month before the engine went down.
The boat has been sitting for quite a while so if I do get everything back together and it works I'm gonna pump the tank and start with fresh fuel.

I just wish there was some clear sign as to what caused this cyl. to lean out. The rest of them looked fine.
 
"Matt; have you inspected all

"Matt; have you inspected all the spark plugs for abnormalities? At least one should show evidence of hot combustion or maybe metal from the piston. If it shows overheated ceramic, then check the other plugs fed from the same carb bore."
 
"good call dave!

matt - I c


"good call dave!

matt - I checked with some of my 'race car nuts' and got a nice paper on the evils of detonation. according to them, it is quite possible to lose only one cylinder to that event. you described cyl #5; nothing i have indicates that area to be subject to any recurring issue. If you get a deposit and it get hot, the piston can go rapidly. If you'd like the paper for reading, just ask & I'll email it.

You can have too much timing advance and still have the engine run and sound 'fine'. The acoustics on boats are notorious for changing things when compared to cars making audio clues hard to use.

If the heads haven't been cleaned up yet, you can also inspect them for clues as to how widespread the damage may be. valve color is a good indicator, too."
 
"The plug on the #5 cyl show s

"The plug on the #5 cyl show some signs of being burning lean but nothing extreme. The combustion chamber on the #5 showed obvious signs of the piston going south. Aluminum flakes from the piston scattered on the chambe and valves and shows signs of burning hot. The valve were not carboned up like the other cylinders. If I get a chance I'll take a picture of the head and try and figure out how to post it.

I hope to have all the parts I need ordered by the end of the week. Anybody know where to get a decent cyl hone from for a reasonable price. I've seen a few online but am skeptical of there quality/performance

I wouldn't mind reading over the paper.
Send it my [email protected]"
 
the picture posting instructio

the picture posting instructions are under one of the HELP entries (at the top of this www page). may want to read it first then take pics.

will send paper tomorrow if I can get into work.

I suggest using a ball hone - they will tolerate a good bit of flex and still do the job. Last one I bought was $30 but that was almost 10 years ago.
 
(Luckily the cylinder wasn

(Luckily the cylinder wasn't scored so I'm going to attempt to hone it in the boat and just put a new std. piston in.)

I'm no mechanic but can this be accomplished from the top side without pulling the motor to drop the pan? Just curious!
 
I'm no mechanic either...j

I'm no mechanic either...just cursed with stuff taht always breaks. luckily I'm still semi young and can contort my body into tight spaces. I was able to get the pan off with some sweat and cussing with out pulling the motor or jacking it up. I got the rod unbolted to and popped the piston out in about an hours time. Way better than pulling the motor.
 
Matt:

Gonna keep you in min


Matt:

Gonna keep you in mind 'cause I may need your services some day! That's an amazing piece of work.

Jeff
 
"I had about 10 people look at

"I had about 10 people look at the motor an everyone told me there was no way the pan was coming off with out jacking the motor up or pulling it out of the boat. If it was going to come to pulling the motor I would have dumped the boat for cheap b/c I don't have the time to undertake that project. So I gave it a shot and it worked out just fine. I should have taken some people up on there bets that I wouldn't get it out. Obviously putting it back together will be a little bigger of a headache but it will be worth it if it solves the problem.

I'm not a mechanic by trade just out of necessity. I don't trust anyone around here to fix my problem s the right way and I'm cursed by wanting to make old sh!t new again.


Anybody want to buy a 89 luhrs 34' tournament edition and a boat slip on the outer banks of NC? Priced to sell
"
 
"Matt, I was also able to drop

"Matt, I was also able to drop the pan without pulling the engine but could not get it back on. I lifted the engine in the boat with an A Frame and come-a-long in the cabin while the boat was in the water last summer."
 
Thats not good news...but hope

Thats not good news...but hopefully it will go back on. I don't see why it wouldn't. If i got it off I'll get it back on. Just have to remember how I wormed it out.
 
"Matt; I admire your stick-wi

"Matt; I admire your stick-with-it-ness. I did a recent rebuild and did make one mistake, i'll pass on. I used a new pan gasket set, 4 piece, and did NOT RTV the forward front gasket. It's the one with a crosshatch pattern, and runs along the timing cover. THat was a mistake, maybe not with a car, but a boat oil pan tends to be a sand casting, not a smooth steel stamping. Anyway, I lost a quart of oil per hour!! out of the front gasket, until I removed the timing cover and applied a coat of ultra =-copper to the gasket. Now, its perfect. Be sure and replace the big end bearing shells exactly how they were installed, alternate the rod nuts torque 10 ft/lbs at a time, and put a dab of RTV on the pan gasket connections, at the corners. You should be ok..."
 
Found a set of good used pisto

Found a set of good used pistons for $25. I'm in the process of putting it all back together. Hopefully it will run!!!!!! I'll let you know how it goes. Thanks to all the chimed in with such good info.
 
did you get the rods with the

did you get the rods with the pistons or do you get to press the old ones back on?
 
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