[DylanZ]

I have an '83 with the head off for a gasket, and I seen these little restrictive looking steel sleeves stuck in my nice big exhaust port. What was the function of these? Insulation? Emmissions? Also, I'm not using a manual, so I don't know if this is just a z thing, but is my car supposed to have double valve springs? Also, would wear on the camshaft be visible, or would it wear evenly and square across the lobes? Also, all those little bolts for the heat shroud on the exhaust manifold broke off during removal. Instead of spending hours and valuable skin on my knuckles trying to remove these things, I was thinking about not using the shrouds and going with some sort of heat wrap aka. asbestos or simmilar. Any thoughts??

Thanx,
Dylan

 

[yo2001]

Sleeves were to quite down the exhaust and emission I think. I took them out on my p78 heads

 

[DylanZ]

So these sleeves can be removed?? How do you do that?? Do you have to do a bit of porting after to get rid of the humps they ride on?

 

[madcowz]

it's probably not worth it to remove the liners. try looking for a p90 or a p90a head off a turbo zx. they are identical to the p79s but lack the exhaust liners. the liners would get real hot and burn off some of the unburnt gas while it went through the exhaust port to lower emmisions. the liners aren't that restrictive and don't make that much of a difference in power unless you are looking to have a race car. if your car needs to pass smog and is pretty close to failing you might want to keep them in.
madcowz

 

[yo2001]

screwdriver, hammer, and lot of slamming. it's two piece so it comes out. I took it out then port it to smooth the humps. But exhuast ports get larger than intake, so it head loses lot of low end. but after 2500rpm with 274 degree cam. it pulled real hard to 6500rpm redline @7000rpm

 

[DylanZ]

Ha, I feel sorry for all ya who have to worry about emissions. I can burn a gallon of oil a day while getting 10 mpg without a problem (I live in Canada) Emissions is'nt a problem. However, I do like the fact that my car has a bit of grunt under 2500. Mabee it is'nt worth it, as much as l'd like to get rid of everything on this car resembling emissions. Has anyone else out there stripped the liners?? What kind of results did you get? I have a completely stock car, mabee that would help with the decision (restrictive exhause anyway)

 

[lucky2505]

If you're keeping the car stock, you won't notice a bit of difference in performance by pulling the liners.

 

[yo2001]

I forgot. I had my intake runner reworked at the sametime