00-01 XJ Cast Iron exhaust manifold swap

[89 MJ]

In an effort to help keep under hood temperatures down, has anyone considered swapping to a cast iron exhaust manifold like the 2000 and 2001 XJs have?

 

Walker makes a pipe that way the two cats right on the manifold don’t have to be used. I would think that the cast manifold should absorb the heat of the exhaust instead of radiating it like the tubing exhaust manifold that our trucks came with. This should help with heat soak and keep engine bay temps down, I’d think.
Has anyone tried something similar?

[75sv1]

Part of the problem is that the flange might not cover the exhaust ports on earlier heads. I use ceramic coated headers. On my Xjs, I use Doug Thorley's. I have use a Pace Setter on the Comanche. The old style ones. I didn't like the coupling sleeve on the old style. The new ones for the Wranglers, I like the coupling system. I did buy one used. Then had it modified to fit an XJ. I did install it, but gave away that XJ. The new XJ ones have two tubes that are slip ons. I think better than the old style. Still, I wish they used the spherical flange. Ceramics cut about 40%-50% heat or so. Wraps do a bit better, though rust is an issue. I did install a ceramic coated compact header to replace the CI exhaust manifold on my 2000 XJ. PITA. 

[89 MJ]

57 minutes ago, 75sv1 said:

Part of the problem is that the flange might not cover the exhaust ports on earlier heads. I use ceramic coated headers. On my Xjs, I use Doug Thorley's. I have use a Pace Setter on the Comanche. The old style ones. I didn't like the coupling sleeve on the old style. The new ones for the Wranglers, I like the coupling system. I did buy one used. Then had it modified to fit an XJ. I did install it, but gave away that XJ. The new XJ ones have two tubes that are slip ons. I think better than the old style. Still, I wish they used the spherical flange. Ceramics cut about 40%-50% heat or so. Wraps do a bit better, though rust is an issue. I did install a ceramic coated compact header to replace the CI exhaust manifold on my 2000 XJ. PITA. 

Good point about the ceramic coating, I had forgotten about that. I don’t think that the wrap is worth it for the rust, like you said. On a race car, maybe, but not on a Jeep. 

[ghetdjc320]

I’ve had the best success with the Gibson silver ceramic header. Never warped, cracked or deformed in any way. 

[89 MJ]

1 hour ago, ghetdjc320 said:

I’ve had the best success with the Gibson silver ceramic header. Never warped, cracked or deformed in any way. 

Good to know. Part of the reason I’m hesitant to use aftermarket stuff is because headers are known to leak and crack and cause problems. 

[ghetdjc320]

31 minutes ago, 89 MJ said:

Good to know. Part of the reason I’m hesitant to use aftermarket stuff is because headers are known to leak and crack and cause problems. 

The banks and all the knock off copies really gave 4.0 headers a bad rep. That and missing the exhaust hanger near the crossmember. Too much weight and running lean can lead to stress cracks quick. If all the hangers are in place and the engine is not running lean, the stock manifold with the bellow tubes work just fine. Obviously they aren’t the best for performance though. 

[89 MJ]

10 minutes ago, ghetdjc320 said:

The banks and all the knock off copies really gave 4.0 headers a bad rep. That and missing the exhaust hanger near the crossmember. Too much weight and running lean can lead to stress cracks quick. If all the hangers are in place and the engine is not running lean, the stock manifold with the bellow tubes work just fine. Obviously they aren’t the best for performance though. 

True. I should’ve said it, but I was talking about all headers in general there, not just for Jeeps. They always seem to leak, but I’m sure that’s a quality of the product issue too. 

[75sv1]

I might try to ceramic coat and then wrap a header at some point. Probably way over kill on the XJ/MJ. Also, I think Banks headers had early issues, and then cropped up again recently. Also, I think Borla had issues. I've seen two of them cracked. 

[89 MJ]

1 hour ago, 75sv1 said:

I might try to ceramic coat and then wrap a header at some point. Probably way over kill on the XJ/MJ. Also, I think Banks headers had early issues, and then cropped up again recently. Also, I think Borla had issues. I've seen two of them cracked. 

Probably. Knowing all of this, if I were to change anything, it would be a ceramic coating on the HO manifold on my truck. 

[75sv1]

1 hour ago, 89 MJ said:

Probably. Knowing all of this, if I were to change anything, it would be a ceramic coating on the HO manifold on my truck. 

I have the horseshoe type 99+ Intake on my 2000 XJ that is ceramic coated. I did have it on my MJ on a WJ block. I didn't run the WJ motor. I've only run the ceramic coated on about 200-500 miles. So, I can't give results from that. I am also running one of my ceramic coated Doug Thorley's. Now for even more fun, I did have the valves for my '10 Chevy Avalanche ceramic or thermal barrier coated. Yeah, haven't run that yet either. Close though. Looking at ceramic coating valves and intake ports in the future. 

[89 MJ]

24 minutes ago, 75sv1 said:

I have the horseshoe type 99+ Intake on my 2000 XJ that is ceramic coated. I did have it on my MJ on a WJ block. I didn't run the WJ motor. I've only run the ceramic coated on about 200-500 miles. So, I can't give results from that. I am also running one of my ceramic coated Doug Thorley's. Now for even more fun, I did have the valves for my '10 Chevy Avalanche ceramic or thermal barrier coated. Yeah, haven't run that yet either. Close though. Looking at ceramic coating valves and intake ports in the future. 

Now that sounds interesting. I’m familiar with ceramic coating the exhaust and intake, but this is the first I’ve heard of that for the internals. I get why you’d want to do it though. 

[75sv1]

First, I think doing the header or getting one that is already ceramic coated is the first step. Kill two issues. First less overall under hood temps. That relates to less heat to the intake manifold. 

        Most of my info on ceramic coating is from David Vizard's books.  I am building an LS for a 2001 XJ. I planned on doing ceramics on that one. I did get a set of Thermal Barrier coated pistons from Speed Pro or such. I remember $350. So, not much more than Stock type hyper eutectic. I still have those pistons slated for the LS for the XJ. I did buy a Chevy Avalanche and a lifter dropped. So, I rebuild the motor. The heads for the XJ LS went to that.  I did have Swain coat the pistons though. Vizzard says valves first, Swain says Piston tops. On the intake and exhaust Vizard was doing a 4 cyl Chrysler ports. So somewhat the same as the Jeep 4.0L. A lot of ??? until I get some things running.

      Another thing I want to try on the LS for the XJ is a dry sump. Its suppose to keep temps down among other advantages. Looking at Adavid.  Then maybe use Evan's polypropylene glycol.  I have that in my Bricklin. Not entirely confident in it. Temps run higher. Suppose to scavenge the heat better though.