Valve blowby at less then 10k miles

RUTNUT150 · Post by **RUTNUT150** » Wed Jun 22, 2016 7:15 pm

My 351w has around 8k miles on it, runs pretty decent but seemed to have lost some power so I decided to do a leak-down test. It has pretty severe blowby on the intake valves (i have all the rockers/pushrods removed) and I cant really understand why. When I first built the engine, it had none. The heads are N351's that i had assembled by a local, pretty reputable, machine shop. The valves I'm running are the Ford stainless valves that are recommended to be used with these heads. Why would the valves wear so bad so quick? Would it maybe be better once the engine was warmed up? At this point I'm ready to pull the heads and have them reworked.

decipha · Post by **decipha** » Wed Jun 22, 2016 7:42 pm

most prob you have the wrong rockers, the n351s require an offset rocker

I havent seen or heard of them heads in over 10 years amazing

RUTNUT150 · Post by **RUTNUT150** » Wed Jun 22, 2016 8:04 pm

I have the offset rockers. But both the rockers and pushrods are removed. So both valves should remain fully shut during the leakdown test. I know the heads are oddball, but I wanted to stick with steel heads and I really like the n351s.

jsa · Post by **jsa** » Thu Jun 23, 2016 7:19 am

Valve clearance / bent valves ?

Valve blowby at less then 10k miles

Re: Valve blowby at less then 10k miles

Re: Valve blowby at less then 10k miles

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