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Should I Bother Rebuilding These Heads?


FirstGenRanger

Active Member
Joined
Feb 3, 2017
Messages
34
City
Alberta
Vehicle Year
1986
Transmission
Manual
I picked up a set of 89TM cylinder heads at the junkyard last year.
I just got around to tearing them down and inspecting them today.
They were sludged up pretty bad, and when I pulled out the springs and valves I noticed this.
Is this something I can get a machine shop to replace?
I couldn't find anything on Rock Auto or Summit for valve spring seats. Unless they go by a different name.
36917
 
Those are the valve guide bosses... which I believe are part of the head casting.
 
Valve guides, no?

Im way too visual with this stuff.

My head rebuild was:

"looks important. Flip through book. Find pictures. Run go/no go numbers. flip to next part that looks important. Check trs posts. verify between trs, haynes, pruett. rinse. repeat because its cold AF in here"

Haynes manual is 15 bucks. Pays for itself when it hits your passenger seat.

This forum, a Haynes book, and the pruett Bible are how I learned all this crap.
 
Them heads would make excellent boat anchors.
 
I will stick with my original post...

Valve guide bosses... part of head casting... and they're broke. I would venture to say those heads have been serviced once and got a couple new valve guides. I've seen others crack like that when installing valve guides. You typically heat the head and freeze the guide and installation goes fairly easy. If the head wasn't warm enough... the interference fit of the guide cracks the boss while driving it home. The boss does two things... help retain the guide... and set the depth for how far to install the guide.

You would be wise to stop by a machine shop and ask someone that deals with these things... and see what they say.
 
Itll pry cost you more to fix then another set of 89tm heads.
 
Yea they apear to have a zillion miles on them and have obvious damage that cannot be repaired. They could probably run ok with those chunks of the casting broken off but A. There's probably more damage you haven't found yet and B. Why bother putting money into them, cut your losses and buy another set.
 
I will stick with my original post...

Valve guide bosses... part of head casting... and they're broke. I would venture to say those heads have been serviced once and got a couple new valve guides. I've seen others crack like that when installing valve guides. You typically heat the head and freeze the guide and installation goes fairly easy. If the head wasn't warm enough... the interference fit of the guide cracks the boss while driving it home. The boss does two things... help retain the guide... and set the depth for how far to install the guide.

You would be wise to stop by a machine shop and ask someone that deals with these things... and see what they say.

Sounds good. I'll give my machine shop a call Monday and see what they say.

Yea they apear to have a zillion miles on them and have obvious damage that cannot be repaired. They could probably run ok with those chunks of the casting broken off but A. There's probably more damage you haven't found yet and B. Why bother putting money into them, cut your losses and buy another set.

Considering how cheap they are, it would make more sense to get a new set, but the late model 2.9s are getting pretty rare in my area. Most of the ones I tore into at pick n pull had early heads. It took me a decent while just to find these ones.
 
That's why I suggested taking them into a machine shop... see what they have to say.

On VW heads... I've run heads that had broken bosses. There was sufficient material below the boss to retain the guide. In most cases... I would machine the bosses thin to install dual valve springs... if you serviced the guide after that... the thin boss would crack 99% of the time. It would be left there as depth control.
 

I dont know what a valve grind goes for these days, but id buy these and put the springs rockers and valves in and be done.
 

I dont know what a valve grind goes for these days, but id buy these and put the springs rockers and valves in and be done.

Rusty, I think those are 4.0 heads. And I think that price is for 1 head (weight 30.6 lbs)

I installed a new set of heads from the eBay seller in the link below back in 2004, and they're still in my daily driver. I bought a new set a year or so ago for a new build, and the only problem I have with them is it appears that they use old springs and valves in the new castings (the heads I bought from them in '04 were probably the same, but I'm going to install new springs and valves). Also, whatever 2.9 heads you get, make sure the thread size for your alternator/PS/AC brackets are correct for your truck. My '87 has 10mm bolts for the brackets and the new heads have 8mm threads. I discovered this too late to return them, and my understanding is that '89(?) and later have the 8mm threads. I was told by the seller that you have to use a "bushing" in the brackets.

 
Last edited:
Rusty, I think those are 4.0 heads. And I think that price is for 1 head (weight 30.6 lbs)

I installed a new set of heads from the eBay seller in the link below back in 2004, and they're still in my daily driver. I bought a new set a year or so ago for a new build, and the only problem I have with them is it appears that they use old springs and valves in the new castings (the heads I bought from them in '04 were probably the same, but I'm going to install new springs and valves). Also, whatever 2.9 heads you get, make sure the thread size for your alternator/PS/AC brackets are correct for your truck. My '87 has 10mm bolts for the brackets and the new heads have 8mm threads. I discovered this too late to return them, and my understanding is that '89(?) and later have the 8mm threads. I was told by the seller that you have to use a "bushing" in the brackets.

Shit those are 4.0 heads. My bad. I shoulda looked closer.
 

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