Thread: mangled piston on a 454

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If you had your own measuring tools, you could tell. Even a dial caliper would be of use in determining that bore size.

even if it is toast you could always just sleeve it

tomorrow when it's light, I'll take pics of the other cylinders. And, I have a dial caliper somewhere, I'll see if I can dig it up. thanks guys for all your help so far.

Originally Posted by gassersrule_196

even if it is toast you could always just sleeve it

I'm debating what would be the quickest, best and cheapest way to get fixed. I've seen a couple of rebuilt 496 (454 bored .060 over) on ebay with forged internals for approx. $3000. On the other hand, I'm probably looking at almost that much for forged stroker kit and machine work. Or, just changed pistons (but that's probably out given the cylinder wall damage) and ride her like I stole her the rest of the summer LOL.

Originally Posted by AdamB

Hi, was boating the other day and the engine starting huffing smoke out of the one valve cover breather (engined stalled and I had to get towed). Figured it was a good time to take apart the motor and install my new 781 heads and weiand 177 blower. Anyhow, took the old heads off expecting to find a bad exhaust valve or something, and this is what I found (see pic).

Anyhow, question is, (see that I want to get back on the water ASAP), can I just put a new piston on the rod and reassemble (quick fix) for now, or won't that work? Should I take the crank out and have it checked/ fitted to new rods and pistons etc?

Just looking for quick fix now, and will probably stroke it to a 496 with forged parts this winter....

Thanks.

Looks to me like to much boost on cast pistons.

that stuff on the top side of the bore is what was your piston ..i would say from detonation no more or less you could pull that one piston out and ball hone it. look at the rod bearings if beat out if not a new piston and go for it . if you just want to run it this summer.i seen this alot when i work on boats.it is hard load on the engine and junk gas and cast pistons. you need to fix why it is eating pistons i have two engine in my shop that look just like yours. i have seen them run till all the pistons are in the pan so your lucky i have sleeve the 454 blocks that small piston melt down no way it needs a sleeve i have bore the stock 454 of a thick wall sleeve i bored the to 4.500 for the sleeve the wall may not be great at 040 ? hard to say with out it in front of me with out a bore gauge but .i have scrap the old piston off the wall and hone it out with just abit more piston to wall to save a bore

Originally Posted by erik erikson

Looks to me like to much boost on cast pistons.

This engine never had boost yet (well not from me, maybe previous owner) I run 11 psi of boost thru a Ford 302 (in a mustang not a boat) with cast pistons and never had a problem, the weiand 177 only runs around 5 psi of boost.

I know that the boat motor will work harder and at higher rpms, that is why I was going to go with forged internals, but am just thinking about boating more yet this year is all.

I never made it to the marina today to get the engine pulled out, maybe tomorrow I'll drop it off.

Thanks for all your input... keep it coming. I would think a .060 bore would definitely take care of the problem. Anybody know what is the cheapest I can get a quality 496 forged stroker kit for a 454? I've seen them on ebay for around $16-1700.

that cylinder looks a little scuffed to me, but to get u by the rest of the year a good light hone and a fairly close weighted piston i think would be fine. Obviously some sort of foreign material entered the cylinder then blew out...(check your risers, could still be something hanging around in there) but that block is certainly not a (junk block) due to this, im certain.

Justin

Originally Posted by jsthunter

that cylinder looks a little scuffed to me, but to get u by the rest of the year a good light hone and a fairly close weighted piston i think would be fine. Obviously some sort of foreign material entered the cylinder then blew out...(check your risers, could still be something hanging around in there) but that block is certainly not a (junk block) due to this, im certain.

Justin

What's a riser??

Just do yourself a favor and pull it out,and rebuild it. your only going to create more work for yourself in the long run trying to "quick fix" it. Never put a blower in combo with cast pistons.It wont last period!! Well not in a boat anyways. What kind of boat is this in and at what RPM are you cruising and what is your full rpm?

You are very lucky that piston is not in a million peices in the bottom of the pan.Also that little peice of piston that is missing will be throughout the engine IE oil pump lifters ect. It needs to be torn down and inspected.

Just my pennys worth on the subject. Ive seen this alot.Looks to be a bone stock deal so that blower really isnt going to do much with the current set up but blow it up again.

On the Ebay builds, just remember you get what you pay for. Boat engine need to be marinized,which means opening up the tollerances. If you have a closed cooling system they will work ok and could last 10 minutes or 10 years.Just be cautious and do your home work on the builder.If your running a jet boat,it wont last.

futs.

Originally Posted by erik erikson

What's a riser??

Sits above the exhaust manifold and keeps lake/ocean water from entering the engine. The water would have to enter boat via tail pipes (so to speak), then rise way up against gravity to get into the engine via the exhaust manifold.

My boat is a 26 ft Celebrity Andretti, kinda like a cigarette with a long skinny front.

you do not need to put a blower on a boat to get pistons like that. work at a boat yard . that is one of the nicer pistons i have seen

Well, still waiting to get my engine pulled at the marina, but I've talked with the machine shop and they've dashed my hopes of a .060 bore with my crank now, then swap in stroker crank later and have a 496. They said it takes different pistons for the stroker kit (duh!). I should have thought of that, but now I might just have to bite the bullet and do it right.... otherwise I'm gonna buy parts now just to swap soon anyhow.

why not bore it to .060 over? for a 496 you just need the bock

4.310 bore x 4.25 crank is a 496. we just built a 10:2-1 pump gas N/A tunnel ram (with 2 holley 600 cfm) 496 that made 710hp @ 6100 rpm.It hauls ass.