1989 exhaust manifold question.
#1
Thread Starter
Newbie
Joined: Jan 2010
Posts: 4
Likes: 0
From: Toronto, Ontario
Year: 1989
Model: Cherokee
Engine: 4.0L
1989 exhaust manifold question.
Hi everyone, new to the site. I have a question for the experienced xj owners. I have a cracked exhaust manifold and i was looking at buying a new one rather than welding the old one to patch it up. the only thing is the aftermarket brands dont offer much for pre 91 engines. Being an 89 with EGR only a few places have them and look OEM, i was looking a more at a perf header. has anyone ever removed the egr and do they recommend doing it or what? any advice would be great.
Thanks
Thanks
#2
IMHO (and CA emissions testing has borne me out...) the EGR system isn't practically necessary on our engines. Why? Low compression.
[THEORETICAL]
So, it's entirely possible to remove the EGR without any ill effects on the engine. In fact, I only run mine (plug it into vacuum) when I have to go get smogged - the thing runs better without it, puts out fewer harmful emissions (particularly HC and CO,) and even gets notably better calculated fuel economy. Therefore, I don't see a problem.
[/THEORETICAL]
That thread is likely a standard size (I don't know which at the moment,) and any competent exhaust shop can weld a bung in for you, if you specify the location. You can mock the thing up and figure out where the bung needs to go - and they should sell you the bung, drill the tube, and weld the little beggar down for $20 or thereabouts (it is not the same M8-1.5 thread used on the HEGO bung, it's some odd flare thread. I just don't know which one.)
NB: If you swap to a later manifold, you are likely to need a new downpipe - header to cat pipe - made. I think they changed where the collector flange ends up for 1991, but don't hold me to it at the moment. This should likewise be no trouble for a competent shop - but do insist that the bolted flange at the front of the catalytic converter be maintained. It makes quite a few jobs rather simpler...
[THEORETICAL]
So, it's entirely possible to remove the EGR without any ill effects on the engine. In fact, I only run mine (plug it into vacuum) when I have to go get smogged - the thing runs better without it, puts out fewer harmful emissions (particularly HC and CO,) and even gets notably better calculated fuel economy. Therefore, I don't see a problem.
[/THEORETICAL]
That thread is likely a standard size (I don't know which at the moment,) and any competent exhaust shop can weld a bung in for you, if you specify the location. You can mock the thing up and figure out where the bung needs to go - and they should sell you the bung, drill the tube, and weld the little beggar down for $20 or thereabouts (it is not the same M8-1.5 thread used on the HEGO bung, it's some odd flare thread. I just don't know which one.)
NB: If you swap to a later manifold, you are likely to need a new downpipe - header to cat pipe - made. I think they changed where the collector flange ends up for 1991, but don't hold me to it at the moment. This should likewise be no trouble for a competent shop - but do insist that the bolted flange at the front of the catalytic converter be maintained. It makes quite a few jobs rather simpler...
#3
Member
Joined: Dec 2009
Posts: 122
Likes: 0
From: Fairfield, CA
Year: 1989
Model: Cherokee
Engine: 4.0
there's this newer header that has flex joints near 1 and 6 exhaust port where they usually break. I'd get that if you got the money.
third one down http://www.teamcherokee.com/Exhaust/index.html
third one down http://www.teamcherokee.com/Exhaust/index.html
#5
there's this newer header that has flex joints near 1 and 6 exhaust port where they usually break. I'd get that if you got the money.
third one down http://www.teamcherokee.com/Exhaust/index.html
third one down http://www.teamcherokee.com/Exhaust/index.html
NB: Exhaust collector cracks are typically caused by failed/failing engine mounts. Check your engine mounts, replace all three if required.
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