I just got a monza header and took the old manifold off and noticed the inserts in the exhaust ports. should I leave these in or take them out???

 

You know, I was wondering the same thing... Was going to search on it, but hadn't had much luck with "Exhast Port Insert"...

Interested in seeing any replies.

 

Leave them in. You would gain nothing at all by taking them out, and you'd increase exhaust temps.

Some race engines take them out, but that's cause it actually helps them since their exhaust ports are bigger than the sleves.

 

Removing the sleeves = decreased flow.

(unless your porting is bigger than the sleeves, of course)

 

I thought about pulling them to allow me more room for inspection of the apex seals (and to allow me to put a mirror into the hole so I could inspect the housing's). How hard is it to pull them out and put them back in while the engine is together?

 

Ok, if you're boosting, should you remove them?

 

They are there to resist the eroding effects of hot, fast moving gasses traveling out of the exhaust port.

The exhaust port is typically the hottest part of the housing because the gasses traveling through are transferring a good deal of their heat to the surrounding metal. I can explain why if anyone cares.

They're made from a much harder steel than the housing to resist damage from these hot gasses and not allow the high temps to be transferred to the housing itself.

I don't know that removing them would damage anything in the short term, but long term, the concentrated heating of that area in the housing would eventually cause stress cracking or eroding. The condition would be even more extreme on a turbocharged car.

 

Thanks

 

hmmmm, very interesting