HO Exhaust Manifold on Non HO head

I have a 89 XJ with a seriously cracked exhaust manifold (and broken bolt in the head). I had picked up a used HO manifold and had intended on switching it out. Well I have removed the old unit and I have put the HO manifold up and it looks like it will fit without any issues. I have not measured the flange thinkness yet, and I have not put both the intake and exhaust up together to make sure there are no issues but from a preliminary look I think it should work fine. Only issues I see is that I need a new down tube (I need one anyway) and the EGR tubes will not work (I can weld a flange and make one work, if I need to).

I did search and found very little info but (several "maybies" or "could be done") but has anyone actually done this.

I am considering not using the stock manifold and getting a Borla or Banks or cheapy of e-bay, has anyone done it with any of these instead?

Any input appreciated,
Thanks,
Michael

Id like to know the same thing. Most companys sell HO headers, but very few for the non HO. Ive seen several maybes as well.

I had a Pace Setter set of headers. They were ceramic coated. They worked OK. I had them on my Comanche over three years. I sold them. I put on a set of Cliffords. I'm going without and EGR and rewiring to '95 electronics. But the Cliffords do have a bung for the EGR tube. I've heard the HO OEM headers need the dowel holes drilled a bit up or down to fit.
Tom

the exhaust ports and mounting bolts on Renix and HO heads are identical - so no problem. You have already identified the EGR tube problem - If emissions testing is not a problem just delete it - the early and HO's run fine without it.

rsalemi said:

the exhaust ports and mounting bolts on Renix and HO heads are identical - so no problem. You have already identified the EGR tube problem - If emissions testing is not a problem just delete it - the early and HO's run fine without it.

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THANK YOU!!!

It looked to me like it should work fine. So, why do the after market companies not put a provision in for a EGR tube and sell to both HO and Non HO applications? This doesn't make sense to me?

Any ideas,
Michael

I put a complete HO engine/intake into my 89 and it passed emissions with the EGR deleted. I am not sure what all it could have done to help emissions if it passes fine without it...

2xtreme said:

THANK YOU!!!

It looked to me like it should work fine. So, why do the after market companies not put a provision in for a EGR tube and sell to both HO and Non HO applications? This doesn't make sense to me?

Any ideas,
Michael

Click to expand...

Because AFAIK the XJ was the only Jeep to get a non-HO 4.0L. A HO header will fit on a TJ, YJ, ZJ, and WJ besides the 91+ XJ. The market for an HO header outweighs the market for non.

Well, I am going to put the HO exhaust that I have on. I am hoping to make it last a few years before putting an aftermarket one on.

But I am having a heck of a time with the sheared stud that I have. The stud in the very back sheared off inside the head. Trying to get a drill back there is very difficult. Getting a drill to cut the stud is even more difficult. So far I have broken 4 drills and my hole is still way too small for the ez out. Back to the store to find some more small decent drill bits.

Michael

Theres no hole for the o2 sensor also. Dont see how you missed that...

There was a hole for the o2 sensor in the downpipe on the 93 exhaust I put on my XJ. Are you talking about a different sensor, or am I?

summitlt said:

Theres no hole for the o2 sensor also. Dont see how you missed that...

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Drat, I missed it tew.

When I put mine on, if I recall correctly, you will have to grind away some of the flange on the header to clear the intake. It really is not a big deal.

When you get your exhaust down tube made the shop should have an adapter that is made for your o2 sensor.

Can you weld something to that bolt you broke off to get some leverage on it? Just a thought.

afd516 said:

When I put mine on, if I recall correctly, you will have to grind away some of the flange on the header to clear the intake. It really is not a big deal.

When you get your exhaust down tube made the shop should have an adapter that is made for your o2 sensor.

Can you weld something to that bolt you broke off to get some leverage on it? Just a thought.

Click to expand...

I was going to mention that the down tube maybe bent differently but wasn't entirely sure until you mentioned getting the new down tube made.....

I looked into using the ho manifold on my 89 but it looked like the bottom collector was bent/swept differently.

Yes, the down pipe is different and the HO has the O2 sensor in the down pipe instead of in the manifold. So with the new down pipe that fixes the O2 issue.

I have not fitted it up yet, broken 4 drills so far trying to remove the stud (what a horrible place to try to work on it). I bought a bunch of new Cobalt drills and am hoping to have better luck over the next few days. I like the welding thought but the stud is actually below the level of the block and it would not be easy (but I might try it if I can not get a decent hole in it for the EZ out, only other option is pulling the head and I would prefer not to have to do that if I do not have to).

In my mind (before doing all of the work) switching to the HO manifold was a easy swap. I am not conerned with the EGR but even that is reasonably easy to fix, down tube needs to be replaced anyway (get rid of all the kinks from stock and my pinion), and it looks like it will bolt right up.

Once I have done it I will let you know if there are any other issues I run into.

Thanks again for all of the posts,
Michael