Gun Jam

I am using an edelbrock 7220 intake gasket with an air gap intake.

This intake does not have an exhaust x over.

The gasket failed at the location of the exhaust x over. Hot exhaust gasses literally cut the gasket in half and then blew it out the top of the intake along the head.

These gaskets come with a stupid piece to block the x over but I did not use it because it fit poorly and felt thicker than the intake gasket and is very hard. I was concerned that it would not seat proper like and would not compress allowing the intake gasket to leak.

Well apparently I have to use this piece what trick are you guy doing to get that block to fit right? What about thickness and compressibility and possible leakage.... did anyone sand one down so it was a bit thinner?

Any help on this would be appreciated.

Thanks

-Gun

racer_dave

I've had them on other applications not SBF, it's a small metal pad that has a bit of a flange on it. You just make sure that the metal is facing the exhaust gasses. I just use a bit of spray glue to hold it in place until the gasket and intake is on and tightened down. I've never had one leak or blow out. On the Chevy ones its towards the center of the bolt pattern for the intake (I'm assuming the Ford is the same) so make sure that you tighten down the intake using the correct pattern (Middle -out).

Gun Jam

Okay Ill make sure I get it facing the right way.

I remember the last one did not fit well and interfered with the intake gasket its self.

-Gun

barnett468

ive never had a prob with the metal plate.

if i remember correctly, your engine has around 100,000 miles on it. if this is the case, it is about time it blew out anyway. yours lasted longer than most.

i wonder if this was part of the reason one of your plugs was almost black.

Gun Jam

The intake only had about 6k on it...the top end is all new.It blew as a direct result of hot exhaust gas cutting the gasket apart.

The trace on the head showed exhaust gas leaking into intake 4 intake runners the two on either side of the x over on both sides of the engine.

I'll track down each and see which cylinder it feeds into!

Im guessing this is why I noticed a decrease in vac also it seemed like it was down 2 to 3" I bet this is why....

thanks

-Gun

Gun Jam

I was thinking about it from the wrong end of the equation...obviously the exhaust gasses leaked into the neighboring intake runners on the head....so cylinders 2,3 and 6,7. Cylinder 5 was the one with the darker plug color its gasket appeared intact.

Gun Jam

After replacing the intake gasket:

Engine idle was very low as a result air leak elimination.

Carb tune is rich for the same reason.

Vac is up 3.5" to 4" all situations

The stumble went away that I was noticing at about 3k rpm.

The clutch now engages smooth and the apparent engine knock during easy acceleration I had mentioned in a previous post is eliminated.

All the horrible sounds that it was making that I blamed on valve train but could not locate are gone.

This issue crept up so slow and over such a long period of time probably 8 months that I would adapt or compensate to fix the problems that it was causing and it would be okay for a month or so and finally second guess what I knew was right or update what I knew was right (hum I thought I always got 14.5" of vac at idle I guess maybe it was 13" then 12" when it finally got to 9.5" I just assumed the top end was coming apart and when it failed I would find the problem....Glad it was just an intake gasket.)

Thanks for your help

-Gun

ps. I installed the x over block offs this time metal side towards the exhaust. They did not fit right this time either it took 30 min extra to clean them up and trim the intake gasket until it fit right and tight enough that I used a hammer to install them and they did fit flush with the rest of the intake gasket.