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Sickened

Posted: November 17th, 2021, 4:53 am
by Bubby
Fresh built 4.6. 20 minute breakin with in 40 minutes the oil pressure dropped to 11 psi. At idle.The stroker kit was bought from a well respected jeepstroker man. Engine built by a well established race engine builder. The crank that was sent was so undersized that different size rod bearings needed to be used and still ended up with a .0022/.0023 clearance. The mains that were sent was used but was left with a .0027/.0028 clearance. Melling 81 oil pump.
I broke it in with 10w30 as reccomended. The builder gave me some brad pen 10w40 but losses pressure at hot idle still. I really believe im losing pressure from the bearings. Were else?
I didnt have an oil pressure drop b4 the build. 6k is alot of money for large clearances and oil pressure drops.
Thanks

Re: Sickened

Posted: November 25th, 2021, 12:41 am
by TR1Hemi
What do cam bearings #2 and #3 look like?

Re: Sickened

Posted: November 26th, 2021, 3:34 am
by Cheromaniac
Your bearing clearances are excessive and you already know that so there are two possible solutions. One is to have the existing crank reground to the maximum rod & main bearing undersize available (0.030") and use matching bearings that provide the correct clearances. The other is to get a new crank.

Re: Sickened

Posted: December 1st, 2021, 8:08 am
by Bubby
Thanks for the reply fellas
I pulled the motor and gave it to the shop. Iv notbeen there to loook but was told thatevrything lookwd fine with the exception of the crank thrust washer. It appears that the converter is pushuing against the crank and wearing on the washer. Not sure what would cause that.
As far as the clearance i believe it is excessive as well. The builder offered the same solution and that i would be waiting, possibly months to get it back.
I dont know how to reply to you individually

Re: Sickened

Posted: February 20th, 2022, 10:22 pm
by bagusjeep
It does not take months to grind and polish a crank!!!

Your guys should have known that there were specs to follow and should have advised you to do it properly.

As said, was it the crank bearings or the cam bearings? The cam bearings are a notorious place on this engine for losing pressure.