Help! Intake manifold not fitting well

Dave Bilyk

Dave Bilyk
I fitted the intake manifold, but was suspicious of the fit as the lower part of the gasket looked a bit loose, sure enough I can get a feeler gauge in there. Not just in one place, but each cylinder. The top part of the gasket is sealed but not the bottom as though the angle is different.
As I see it, the possibilities are;
The cork gaskets at the ends are preventing closure. I doubt this as I would expect it to pull down in the middle, but it hasn't.
or The angles are slightly different, or slight discrepancy in dimensions in which case I may need to remove heads, replace gaskets and try to tighten heads and manifold together. Maybe a thicker intake gasket would help as well.
I'll have a closer look tomorrow.
Any experience of this / comments from you guys?
Dave
 

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To decide on end cork thickness do trial fit with manifold gaskets only with bolts just snugged up and measure gap across pan rails- this is the thickness of end corks you will require.
To check machine work of manifold remove all gaskets and set manifold in place against bare cyl head faces, check with feeler blades or light bulb in valley for gaps.
Another check is to get some 5/16 UNC threaded rod and cut into a dozen 2.5" long lengths, fit these into manifold bolt holes on cyl head- now check manifold fit- it should slide up/down freely on studs, push down and repeat light test. Machine manifold faces or open up bolt holes as reqd to get best fit, then fit manifold. There are later model intake gasket sets that have silicone/rubber with steel core end seals which are much more tolerant.
 
Dave, is the clearance the same top to bottom or is there a taper? What is the clearance on the oil galley side, same?

JacMac responded while I was typing but we're on the same page. My first guess was that you will require machining.
 

Dave Bilyk

Dave Bilyk
Thanks Tom, it fits at the top, clear at the bottom every cylinder. Same both sides, I easily got a 3 thou feeler in there, I will see how much more I can get in tomorrow then I will undo and check without Cork etc as Jac said.
Dave
 
Dave,

I had to put on two intake gaskets to get a port match, but I don't think I had a problem with angle mismatch. I have a Dart SBF block, Pro-Topline (Racing Head Service Pro Action), and the Borla eight stack fuel injection.

-Bob Woods
Tornado GT40 in Texas
 

Dave Bilyk

Dave Bilyk
Thanks Rod and Bob, The block I don' t think has been planed but dont know for sure. The pistons are flat top and flush with the block if that is a clue. The heads I bought new so definitely not planed. They are Edelbrock Performer RPM heads.
Dave
 
Hi Dave,
I had a similar issue when I’ve installed these manifolds. The cork gasket is too thick preventing the manifold pulling down. The manifold I used had a groove to take some o-ring cord, so this was used with silicone sealant. If your manifold doesn’t have this groove, I would seal this area with a thick bead of silicone
Regards,
Andy
 

Dave Bilyk

Dave Bilyk
Thanks Andy, once I do Jacs checks I will be able to see if that works for me. If I can do it without resorting to machining I will
 
I used to own a machine shop and have had to fix many nae brand heads that were machined wrong. We also used to angle mill heads to get more quench or compression then have to mill the intake to fit.
 

Dave Bilyk

Dave Bilyk
:thumbsup: Panic over, when I remove the cork gaskets, I only need to nip the 4 corner bolts to seal everywhere, the gap at the ends is only 0.6 to 0.7mm, this will come down a little more when all bolts are tight, so I will just use some sealant to complete the job.
Thanks for your help guys, good teamwork as always.:thumbsup:
Dave
 
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