EGR leak from turbo center iron on 6 port motor
 

Hello,

I’m helping a friend bring a parts car back from the dead. The car is an 87 N/A, when the engine was rebuilt it needed a center iron due to rust. The builder used a turbo iron because it was an extra just lying around. After we assembled everything and started it up, the EGR passage under the ports of the turbo iron leak like it’s unrestricted. I noticed the gasket didn’t cover the passage, but didn’t think anything of it.

The confusing part about this is another friend of ours has the same setup except he is using an S5 lower and RB header. According to Mazdatrix the gasket is the same S4 or S5. Could the RB exhaust flange be the reason it’s not leaking on his, and leaking on this one?

Any experience you can share would be appreciated.

Thats a weird one, :icon_tup: for putting another back on the road

The egr ports are on rotor housing though.(If I remember correctly.) A small hole right under the exhaust port on the rear housing.

On a series four Turbo imtermediate housing, the rectangular hole just below the two oval intake holes, is the passage for the ACV air going to the exaust ports.

On a non turbo series four, the ACV air splits off and goes to a somewhat square hole on EACH rotor housing. The EGR passage is a half inch hole under the exaust port on the rear housing that feeds air up thru the intermediate housing to the top of the intermediate housing to the EGR valve. Ever notice that hole in the exaust gasket??? Half inch hole? EGR feed passage.

So you have a non turbo series four engine with a turbo intermediate housing. Are both the ROTOR housings for a non turbo and DID THEY PUT THE FRONT ROTOR HOUSING IN THE FRONT AND THE REAR ROTOR HOUSING IN THE REAR???? Or did they use two front rotor housings or two rear rotor housings with the thought it did not matter?

It's kinda goobered up. I'm still trying to figure where the air is coming and going.

On a NON TURBO intermediate housing, there is no open rectangular hole below the two oval intake holes. There is a ROUND hole blocked off with a round freeze plug. Seems to me you need to fill that hole with??????? Something solid. Mabe a piece of aluminum cut to fit and ...epoxy'd in??? Yes.

Your getting exaust gas out that rectangular hole??????? Not much pressure involved there so a aluminum filler might work.

OR as Houston suggested, remove the exaust manifold. Turn the exaust gasket so the hole, the half inch hole, does not let exaust gas into the rotor housing. I'm not sure tha'll work though. Gotta block that hole someway. AH. I got it. Weld the hole in the exaust manifold. CAnt' pass exaust gas back into the housing if it's welded up. Like stick the shank of a large bolt in there and weld around it to block the passage.

I think I need to learn how to spell exhaust. Kinda dropped a letter or so in the above.

IF it's the port in the intermediate iron that is the problem, then just remove the intake manifold, pack the hole with a lot of jb-stick-weld, and reinstall the manifold. Problem solved. I've done this before with good results. You need to use about half a stick to do it right, though.

Flip the exhaust gashet and the EGR feed hole will be block off. No more air will go into the intermediate housing.

Thet's why your firieds's car works. He has the RB manifold with NO hole in it to feed the * EGR*passage from the exhaust manifold. You'll do the same by just flipping the exhaust gasket. The hole in the exhaust manifold will now be blocked off. The small approx one inch feed hole is the one I talk about.

That’s great news! I was starting to worry.

I’ll flip the gasket first and give an update. Then we will probably fill in the hole under the intake ports for safe measure next time the manifold is off.

Thanks for all the replies.

Jim

Just in case her'es a picture of a gasket. IT is not turned just right for a non turbo install because this picture was taken from another thread I made.

But if you look to the left of the six inch scale, you'll see the half inch hole that feeds the EGR. So you flip the gasket so that half inch hole is below the FRONT rotor housing and not the left rotor housing wrhere it 's supposed to be on a normal install.

Do this. Get a shop air hose and blow in that rectangular hole and see where the air is coming out below the exhaust ports. It should be the half inch hole below the rear rotors exhaust port.

https://www.rx7club.com/attachment.p...3&d=1175185426

Update
 

I flipped the gasket today, and now the leak is gone. We got a few more things to work out still, then it will be back on the road after a 9 year nap.

Thanks for the replies and your experiences.

Jim

This thread just made my day. We just tried to torque the hell outta the manifold and it was still leaking, we finally stuck a camera down there with flash so we could see what was going on. Been searching for about 30mins now for someone else that had this problem. Oh, and if you ever come back this way Hailers, this isn't the first thread you've been in that has helped me out with a puzzling issue with my car. :) All Hail Hailers! :D