Turbo Holden 5lt V8 engine pulldown - Broken piston & ring!!
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- Опубліковано 4 жов 2024
- April 23 Project Update - #2 Piston and ring broken. Starting on a new naturally aspirated project shortly. Happy to answer any questions - You can contact me here or via the COM-MOD Facebook page link FACEBOOK / com-mod-1099. .
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Good to see people still playing with Holden V8's. Sorry to see the blow up.
I think you were running too much timing. My stock bottom end 304 with just a cam made 380 rwhp though a 4000rpm converter on 10psi boost and I was running 20 degrees timing.
The motor did powercruise and other events and when I pulled it down it was perfect apart from worn cam bearings.
It's a shame to here you're moving on from it
dyno video of it making around 350whp showed a AFR of 17.0! thats so lean it cant not cause damage especially with boost.. ring gap is a big thing for boost, heat and the extra pressure too!
Bugger! Definitely a lucky break though haha. Curious what rings you used? Acl supplied in the kit ?? Im guessing they wouldn't provide recommendations for gap considering they arent intended for that application.. but the ls guys teach us a bit here running near ot at 1000hp on factory pistons.. most pro advice ive seen on turbos is 7 thou per bore inch and i know Richard holdener uses 28'ish.. whether that would have made the difference who knows.
Cool project mate i hope someone keen can take it from you and give it a new life
Hi Mate, I used Hastings chrome moly rings. I'm tipping the manufacturing process of the newer LS factory pistons are slightly better than the 2nd hand 30 year old ACL pistons i had lying around were haha. That motor you mentioned makes twice the horsepower and boost of my motor so I'm not convinced my .024" / .025" gap was that small for what i was running. Also there was no scaping or pick-up marks on any of the bores from tight rings either. I should've just put a set of forgies in it simple as that haha. I've had a few people contact me about the setup hopefully it goes to a good home :)
That's typical of insufficient ring end gap for that application 😢
Maybe. I Think it was a combination of a few things. Water/methanal, timing and detonation aren't forgiving to cast pistons.
Don't forget you had nos on too didn't allow for it boost ,nos cast piston ring cap . You got lucky just put another piston in it wind the boost down take the nos off it. Build a real motor in the meantime.
@@Jimmyk63 It's a water methanol plate not NOS. Thanks for the advice lol
What was your ring gap when the engine was built?
@@busarob1969 .024" on the tops. All other pistons looked fine.