FStanley

I have a 1979 Olds 88 with Olds 350 with EGR.

New engine with only 14K mi. on it.

I have to smog this car every 2 years.

It leaks between intake and head at #5 cylinder, runs lean and will not pass smog.


Had intake magnafluxed and milled straight.


See dry fit check photos using Red plastigage .002-.006" on each port. Note upside down



I have tried MANY different gasket and sealer combos over the years. Single gasket turkey tray, SCE, MR. Gasket, etc etc etc 40lbs torgue spec, checked many times...


The one that lasted the longest was a turkey tray with an SCE fiber with raised beads on top of it with Right Stuff on ports , 6 years.


Never a problem with coolant or valley leaking..


Runs great for awhile, then... high HC, leak near #5.



EGR burning the stuff out???


Looking for long term solution.



Ideas??

Fred

FStanley

Photos

joe_padavano

The EGR simply routes exhaust gas from the existing exhaust crossover under the carb. There is no additional heat from the EGR. That is not the problem.

How do you know you have a leak there? Are you performing a leak test with propane or carb cleaner with the engine running?

The use of plastigage is clever, but I'm not sure if you will get an accurate measurement, given the weight of the intake manifold. Have you checked both intake and head for flatness with a known good straightedge? Has anything else been cut (like the heads)? How much was milled off the intake? Obviously you've now made the intake narrower, which doesn't help sealing.

I can't say that I've ever seen this problem before, especially with an iron intake. I always use the FelPro metal intake gasket only, with RTV around the ports as detailed in the CSM. Never an issue. Have you magnafluxed the head to look for a crack there? Have you verified the angle of the sealing surfaces, not just the flatness?

FStanley

Checked heads for straightness but cannot find anyone with an tool that can measure the angle.

and I have tired 5 machine shops...


I suspect the angle is off.


When I put carb cleaner at #5 between intake and head it smooths right out, rpms go up


But it will seal for "awhile" smogs great and runs great, then over sometime... smog test fail high HC.


put a new gasket in and good again... I've done this no less then 8 times...

Ready to glue(JB Weld) this sucker together..

Fred

wr1970

The money you spent is gone!That amount would be about the cost of a known good intake! It is the heads or the intake causing the problem! My guess is the intake unless the guy who rebuilt the engine milled the heads!