mangled piston on a 454

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.

Turn the engine over (so the piston os deep) and take another pic for us. I see something in the cylinder wall that's not good and want to be sure my old age is not getting the better of me.

also if that is the head gasket still on there, remove it before anothe picture is taken. take one with the piston down in the cylinder as well up for us, it sure is a small mess you got going there.

most of the head gasket came off, but I'll try to scrap some more. Was going to wait until the motor is out of the boat to use my little high speed sander air tool with the scotch bright discs.... I'll crank the engine over and lower the piston down to bottom then take another pic. It almost looks as if I lost a valve seat or something, but the head on there is okay??? I'm wondering if the previous owner screwed me here a little since this motor never had the power it should have, and only recently starting huffing smoke... I wonder if the piston was coming apart but decided to go all the way....

Hard to tell in that pic, but something looks real bad in the cylinder wall right where the piston is missing the biggest piece. Like the others, can't tell if it is the gasket or the bore though.

Okay, series of pics that zoom in on the spot. There is a little roughness, tried to capure it. Will probably need rebore I guess...

To give you an avenue, your season is done until this thing comes out and is repaired with major surgery. The pistons don't have enough depth on the ring lands to survive blower pressure and decceleration reversion extremes. This will happen again with your current setup. I recommend a blower piston with deeper lands to prevent this from happening again on the repaired motor. I also noticed a tell-tale sign on top of the piston of a heli-coil. Is there a repaired thread up on the intake area or elsewhere a heli-coil can let go and enter the cylinder?

I didn't even run a blower on this motor yet, was going to but will change the pistons. Do I have to have the crank redone to install new pistons and rods? or can I just reuse the rods with new pistons.... trying to get back in the water fast.... but don't really want to break down again on the water. Sucks....

I realize the fact you haven't installed the blower yet. I was a bit premature in that area. I wanted to to know where you were at the present time and I apologize if I concluded a bad assumption there. Your cylinder wall is toast for all practical porpuses. I'm sorry, but nobody should run that block like that again. If you wish to re-use your rods and internals, just have them checked out. I would like to see you use as much as you can for rebuild. What about the heli-coil issue? I do not always see everything in the pics as I sometimes pressume.

I didn't see anything wrong with the heads, helicoil wise. Course the old owner said he had just given it a valve job... so maybe he knew about the issue.

Anyhow, you say the block is ruined, or can be reused after a bore out?

Oh, those marks I took pictures of are just barely there. I had to zoom in pretty close to photograph them. Can just barely feel if you know what I mean. I think a .060 over (496) might cover????? I'll have to wait until my machinist see's them I guess....

The boring will be dictated by how much has already been removed. Is it safe to say this block is already at .030?

the pistons say 00, so I don't think there is any bore done.

Give it to the shop and let them measure and check. Then your game plan can start forward.

unless I'm reading that wrong. I put .040 pistons in my SBC and they said 040 on them

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.

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Originally Posted by gassersrule_196

even if it is toast you could always just sleeve it

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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.

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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.

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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

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Originally Posted by erik erikson

Looks to me like to much boost on cast pistons.

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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

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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

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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.

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Originally Posted by erik erikson

What's a riser??

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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.

okay, here are some shots of the pistons. Some of the pistons say 8, and some say 6, so I guess my theory on the 00 for the bore is wrong. Anyhow here they are. I see some scuffing on piston 4 also...

Oops, forgot close up of piston 4

Pat, I want to eventually build this into a 496 stroker, but I thought I needed a different crank for that. I'm trying to get this fixed for cheap and fast, I am still finishing a 1600 sq ft addition on my house need to pay for that yet. I had hoped to bore it .060 over and buy forged pistons now, then reuse them with the stroker kit but the machine shop said that won't work. Will take different pistons for stroker kit. I guess I could just buy cheapo .060 over pistons now, then buy the good ones to install in my forged stroker kit.

Hey important is it to use a forged crank? Or could I get away with one of the cheaper cast stroker cranks? Or shouldn't I cheap out there?

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Originally Posted by pat mccarthy

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

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The standard 454 crank is 4" crank right? I am planning on running this stoker combo with a weiand 177 (actually a B&M 177) blower but still want the stroker crank for the added torque.

I probably shouldn't rush this, or try to fix it cheap because I know I'll just run into problems, I'm just not ready to accept that my boating season is over so soon, and I still need to finish my addition on my house

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Originally Posted by Futs

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.

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Unfortunately the fiance won't allow me to spend big $$ on the boat and leave the house like this

i did not say you could use your crank .489/ 496.. they both would need the 4.250 crank i build more 496 then 454 s the number are not over size but could be piston position i do this the i bore and hone the block and find smaller size pistons in the set or useing used pistons that need to go in that bore for size this i do by the fireing order .but they are not in any order but have seen this on many 454 from GM if they are over size they will be 060 or040 or030 them number do not mean much i would say it done for the year and i woul build it to a 489 .030 bore and 4.250 crank with a 6.375 long rod on the boat i would use at lest a 4130 crank and a srp pistons you could use a cast steel crank and I beam rods with hyper pistons but ? with the blower and in a boat you would not save much money so i would lean to better parts i have put alot of power thru the scat cranks they for the money work good in the 4.250 size i have used many

Pat, so you're saying I should just do a .030 bore, not the .060? I guess the power differance wouldn't be that much from the 489 to the 496 and I would save some cylinder material for later use...

I'll see how much the machine shop says I need to bore the cylinders...

Thanks for the comments. Oh, Pat, I should have bought the merlin heads you were selling, I ended up buying some $400 781 heads, but then needed to do $440 worth of machining to them. At least they have the 2.19/ 1.88 SS valves and hardened seats and brass guides now. Plus they have been ported and polished by previous owner so with the blower should make good power I hope.

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Originally Posted by pat mccarthy

i did not say you could use your crank .489/ 496.. they both would need the 4.250 crank i build more 496 then 454 s the number are not over size but could be piston position i do this the i bore and hone the block and find smaller size pistons in the set or useing used pistons that need to go in that bore for size this i do by the fireing order .but they are not in any order but have seen this on many 454 from GM if they are over size they will be 060 or040 or030 them number do not mean much i would say it done for the year and i woul build it to a 489 .030 bore and 4.250 crank with a 6.375 long rod on the boat i would use at lest a 4130 crank and a srp pistons you could use a cast steel crank and I beam rods with hyper pistons but ? with the blower and in a boat you would not save much money so i would lean to better parts i have put alot of power thru the scat cranks they for the money work good in the 4.250 size i have used many

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well you will not see any thing with a030 bigger bore less you build a 4.500 to4600 bore 4.250 crank**)

Okay, you lost me. I'm not a mechanic, just an amateur, but:

CID = 8(cylinders) X. 7854X 20.25(bore of 4.5 squared)X 4.25 (stroke) = 540.7. Wow, love to build that!

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Originally Posted by pat mccarthy

well you will not see any thing with a030 bigger bore less you build a 4.500 to4600 bore 4.250 crank**)

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Originally Posted by AdamB

Okay, you lost me. I'm not a mechanic, just an amateur, but:

CID = 8(cylinders) X. 7854X 20.25(bore of 4.5 squared)X 4.25 (stroke) = 540.7. Wow, love to build that!

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well try this 4600.with a 4.750 crank all alum donovan block it will run on pump gas i will be selling it soon:3dSMILE: