70 454 Broken Piston
Thread Starter
Advanced
Joined: Mar 2003
Posts: 98
Likes: 3
From: Oglesby Illinois
70 454 Broken Piston
OK, I need some help. I never thought it would be so difficult. Maybe I am just looking in the wrong places. I have a broken piston and want to change all 8 out. I have a 1970 454 LS5 motor with stock pistons. Where can i go to get the stock pistons?
Thanks.
Thanks.
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
What do you mean by stock?
Cast vs Forged?
Standard bore vs Oversize?
You should be able to find them at any auto parts or performance parts store.
Is there something specific you're looking for?
Cast vs Forged?
Standard bore vs Oversize?
You should be able to find them at any auto parts or performance parts store.
Is there something specific you're looking for?
Pro
Joined: Nov 2008
Posts: 542
Likes: 3
From: Bloomfield Hills MI
I looked for stock pistons for my '70 454 a while ago. Can't get them 'off the shelf' due to the (unique for that year)10.25:1 compression, or so several speed shops told me. They could take an existing piston and custom modify it (expensive!) or go with a different piston and lower the compression. And that's what I did, went with about a 9.5:1 ratio (Keith Black pistons) for pump gas and got the valve seats fitted with hardened inserts. Now, this is what I was told and given the smattering of research and cross-shopping of stores (and advice from some old-timers) I tend to believe it.
Good luck!
BTW: Here's what I found in my oil pan that suggested I had a 'broke' piston:
Good luck!
BTW: Here's what I found in my oil pan that suggested I had a 'broke' piston:
Last edited by spinadog; May 5, 2011 at 01:21 PM. Reason: ppl love photos.
Pro
Joined: Jan 2009
Posts: 576
Likes: 3
I've never tried but I thought piston manufacturers like Ross could duplicate pretty much anything at a decent price.
Curious as to why a piston skirt would break.
Othet than this here:
http://cgi.ebay.com/ebaymotors/Genui...op=12cessories
Curious as to why a piston skirt would break.
Othet than this here:
http://cgi.ebay.com/ebaymotors/Genui...op=12cessories
Last edited by Imo Apita; May 5, 2011 at 03:48 PM.
Race Director
Joined: May 2006
Posts: 18,756
Likes: 2,589
summit racing has lots of different pistons for the application
http://www.summitracing.com/search/y...?Ns=Rank%7cAsc
http://www.summitracing.com/search/y...?Ns=Rank%7cAsc
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Drifting
Joined: Jun 2010
Posts: 1,781
Likes: 15
From: Oxford Ohio
You are going to put an unworn piston and new round rings back into a hole that is nolonger round. You will have sealing issues from the start. How many miles on the engine?
I agree with the "{time for rebuild" suggestion if it is in your budgit. If not look for a used piston on Ebay.and don't be surprised if there is a compression or blow by issue.
I agree with the "{time for rebuild" suggestion if it is in your budgit. If not look for a used piston on Ebay.and don't be surprised if there is a compression or blow by issue.
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
Suck it up and do the right thing, ... rebuild the motor !
it is the only way to ensure those little broken metal peices,
do not cause a problem in your future.
it is the only way to ensure those little broken metal peices,
do not cause a problem in your future.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
Advanced
Joined: Jun 2005
Posts: 52
Likes: 0
From: mckinney tx
For the big block guys. I have found out on big blocks especially 454's that the back of the timing gear (the one that bolts to the cam) will wear into the block due to lack of oiling. the trick is too drill a .050 hole at 12 o clock in the front of block above the #1 cam journal. The hole you drill will tap into a oil gallery. This will fix the oiling problem and SAVE your block! I have pics some where I will have to dig them out and post them up.
SO pay attention the this area when you tear your motor down.
Jeremy
SO pay attention the this area when you tear your motor down.
Jeremy
Last edited by BONESTK87; May 7, 2011 at 11:18 AM.
Drifting
Joined: Jun 2010
Posts: 1,781
Likes: 15
From: Oxford Ohio
Yes, I Know, That's why I said you USED to have to mill the face. As a matter of fact if the block face is damaged you may still may have to mill it smooth. That torrington bearing deal began a long time ago, using one that was from another application thus reguired relief in the block face.
I still find core blocks that have so much wear damage they require some attention.
I still find core blocks that have so much wear damage they require some attention.
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
I looked for stock pistons for my '70 454 a while ago. Can't get them 'off the shelf' due to the (unique for that year)10.25:1 compression, or so several speed shops told me. They could take an existing piston and custom modify it (expensive!) or go with a different piston and lower the compression. And that's what I did, went with about a 9.5:1 ratio (Keith Black pistons) for pump gas and got the valve seats fitted with hardened inserts. Now, this is what I was told and given the smattering of research and cross-shopping of stores (and advice from some old-timers) I tend to believe it.
Good luck!
BTW: Here's what I found in my oil pan that suggested I had a 'broke' piston:
Good luck!
BTW: Here's what I found in my oil pan that suggested I had a 'broke' piston:
The machine shop recommended the 9.5:1 compression ratio to ease finding gas with sufficient octane. I had hardened valve seats put in for the exhaust valves. Wonder at time how much HP the .75 drop in compression ratio cost...
If I were to do it over I'd probably look at restoring to 10.25:1 and installing a modern cam design to compensate.
Very interesting to hear. The face on my block was worn. I'm not sure what the last shop did to address this. I usually tear the engine down but with the cost of big block parts had paid the shops to reassemble.
