4.0 Head is cracked. Any other upgrades I should do when I am in there?

[rang-a-stang]

So my 2000 XJ just cracked its head after 170k miles. I ordered a replacement/rebuild TUPY head and FelPro head gasket set. I have 4 hole injectors, a header, and cat-back. This Jeep is pretty much just a driver and rarely goes offroad. I will check compression today but expect it to be fine. It runs like new.

Anyway, are there any other easy upgrades I should consider while the head is off? 1.7 roller rockers? Any easy porting/gasket matching? I drive this in the cold (to 0 degrees F) and hot (110F with A/C going) so I don't want to mess up drivability. Don;t want to spend $1000 to get 30hp but $250 for 10hp seems legit...

Thoughts?

 

[75SV1]

Bored TB to 60MM. I'd also 'port' the Thermostat housing. The inside radius is more of a point. I rounded this up. HESCO 'CNC's' them. I took a HESCO I bought, and rounded up the edges. Then I did another I had laying around with a grinder.
I'd replace the harmonic balancer. Basic port match. Maybe the Injector bosses inside the ports. Grind them to the same diameters. I do have 1.6 non adjustable roller rockers. Sort of mixed on that vs the cost. Also would need shorter push rods.
The consensus is there is 15 to 20 HP with a ported head. Also, you might see about a thinner head gasket to bump up the Compression ratio. Have to watch the quench though.

 

[Ol Blue]

Welcome to the cracked 0331 club. Its a fun place to be.

If you have piston slap when the engine is cold (like I do) I'd consider throwing new pistons in there. Wish I would have done that when I did the head. Pan has to come off too but you're most of the way there already.

 

[rang-a-stang]

Compression was
1= 124
2=125
3= 124
4= 127
5= 126
6= 124
That looks pretty darn healthy to me! I ordered a rebuilt TUPY head and Mahle head gasket kit HS5713A. Both are supposed to get here Saturday. I have coolant ready to go so Friday I will pull the head and do some other prep. Hope to have it running Saturday afternoon.

Bored TB to 60MM. I'd also 'port' the Thermostat housing. The inside radius is more of a point. I rounded this up. HESCO 'CNC's' them. I took a HESCO I bought, and rounded up the edges. Then I did another I had laying around with a grinder.
I'd replace the harmonic balancer. Basic port match. Maybe the Injector bosses inside the ports. Grind them to the same diameters. I do have 1.6 non adjustable roller rockers. Sort of mixed on that vs the cost. Also would need shorter push rods.
The consensus is there is 15 to 20 HP with a ported head. Also, you might see about a thinner head gasket to bump up the Compression ratio. Have to watch the quench though.

Those all make sense. I'll do the research for the specifics and add them (Port match, TB bore, clearance the injector bosses, and thermostat housing) to the list. I am also working on getting my truck (71 Glad) running so my days are pretty slammed but I need my XJ back on the road too. I am comfortable doing a port match and nibbling on the injector bosses but I can't do much more than that as far as "porting" so I won't see/feel much difference but it's worth the time since the head is off and I am in there right? The thinner gasket makes sense but I went and ordered my kit already so I am getting when I am getting.

Welcome to the cracked 0331 club. Its a fun place to be.

If you have piston slap when the engine is cold (like I do) I'd consider throwing new pistons in there. Wish I would have done that when I did the head. Pan has to come off too but you're most of the way there already.

Thanks! Glad to be here (not)! hahaha! I don't *think* I have piston slap? Runs/sounds fine when cold. Is there another way to check?

When I bought it (4 years/20K miles ago) I did the pan gasket and checked a few of the bearings while I was in there. They all looked fantastic so I am hoping I can get away with just the top end. Also, the previous owner did a head gasket at about 120k miles but that was like 10 or 15 years ago and I think they did a head-gasket-in-a-can; that stuff is EVIL. I am still trying to clean that crap out and suspect it clogged a coolant passage that lead to my cracked head because I have NEVER gotten it hot.

 

[Ol Blue]

You'll hear it if you have it. If the piston slap is bad you might be able to rock the piston back and forth in the bore. But I'd imagine it would make noise if it could rock in the bore