I didn't know I'd learn as much about the role of the intake manifold gaskets in keeping oil out of the motor as I have

Bottom line, my motor has been sucking oil in various amounts since it was rebuilt over a year ago. The problem throughout has been improperly sealing intake manifold gaskets.

The problems have been on several fronts, in no particular order -
1) my torque wrench was giving incorrect readings at light loads (Craftsman "click" type - 30ft-lbs is at low end of range, torque wrench is >15 years old and in need of recalibrate)
2) I was not retorquing after initial install - I found that after initial run-in, 2nd re-torque I was moving the bolts at 20ft-lbs, on the 3rd they were moving at 25ft-lbs. I think 1 more retorque and I'll be set for life
3) To me, there is a distinct difference in the quality of the GM Performance parts and the Fel-Pro alternative, IMO. I won't say that the Fel-Pro wouldn't seal properly given the correct install procedures, but, the GM part appears to me to be a better quality part.
4) Truly a biggie, was the fact that my intake manifold ports were SUBSTANTIALLY smaller than my head ports and the gaskets I was using were matched to my heads meant that I had very little sealing surface contact between the heads and the intake. I did swap intakes from a holley to the Air-Gap to get a port matched situation.

 

72 Greg ... I wanted to check the torque on my intake yesterday morning and found that I could only get my torque wrench on just a few of them. I guess the only way to do it right is to pull everything off the manifold. Your torque wrench is really only accurate in its mid range. Way low or way high on its range reduces its accuracy, but at least all bolts will have pretty close to the same torque.

 

Do you remember the GM part# for the gasket you used?

 

I'm glad you found the intake as the problem.
Were you the one thinking about valve seals etc??

I was also amazed that the intake manifold could cause such a un-manifold type of problem :mad

Rock on!

 

Wanderer - there is no way that I could figure out to get at the bolts short of pulling the carb off. I am using a universal joint and a claw foot on some, which ain't optimal, but, I can't figure a better way (having done it 3x here recently).


Paul - the P/N is 10147994 and it fit the ports on my Edelbrock intake/heads very nicely - check out the goodwrench site.

427V8 - I have posted several times on this problem, hopefully NEVER AGAIN! :D

 

Excellent! That is the set recommended by Joe Lucia for my L-82 aluminum intake. Obviously it works for Edelbrock also . I have been so busy enjoying driving (and pouring in oil ;)) that I have not gotten around to the job. Your results are certainly encouraging. Did you use the Permatex Copper on the front and back instead of the rubber gaskets? Did you use the Permatex (or some form of sealer) on the gasket itself? If yes; top, bottom or both? Also, did you use a sealer on the manifold bolts? Glad you licked that problem. My turn next :yesnod:.

 

I used the rubber saddles that came with the gasket kit. I did use RTV around all the water ports and at the corners where the gaskets came together. I used permatex non-hardening on the bolt threads. The holes adjacent to the water ports are blind so it's not necessary.

 

Thanks, Greg. Much appreciated!