Head differences

[Sunk]

I'm getting a new engine for my truck and it looks like I have a choice between an '88 and a '90. Both have around 100k. I've been looking around and saw that somewhere the head design changed. I even looked in the Tech Library and saw how the design was changed, but not when. I'm leaning towards the '90 since it is already pulled, but if it has the stronger heads I will almost for sure get it.

 

[Hahnsb2]

Some people say 89 and some say 88 had the "good" heads. Im not sure, I do know Ive had my 88 2.9 at 230*F while wheeling several times and have never had a problem, my rig has 235,000 miles on it. I also heard there was some bolt that threaded into the head (alternator bracket perhaps?) that was like 8mm on the "bad" heads and 10mm on the "good" heads. I couldnt tell you which bolt though, since B2.org's database was also recently lost I cant find it.

 

[Sunk]

Ok, thanks for the input. I was surprised the head gasket blew, it hadn't been hot in a while, and ran fine up until then. I was thinking maybe the head designed changes later and that my 88 had the bad ones... we'll see.

 

[AllanD]

I have NEVER seen the better heads on an '89 (much less an '88) unless they were swapped on.

Infact I've had THREE '90 engines and they didn't have them either.
The heads are most ewasily identified by the threads of the bolt hole in the END of the head where the alternator bracket mounts, the early heads use 8mm threads, the later, better heads use 10mm threads.

For all practical purposes you need to find a '91 engine to find the
better factory heads.

BTW, 2.9's don't blow head gaskets.
They crack heads up in the rocker area.

so a typical machinist looking for cracks in the combustion chamber will usually find nothing.

AD

 

[Sunk]

Thanks Allan. I'll check the heads on the engine just to see what I have. I'll take either engine because they are my only options pretty much and its already been more than a week without my DD.

And its good to know that the gaskets don't blow. There is water in the oil though, so the heads are toast. Good to know. Im glad I didn't try to put new gaskets on it.

 

[AllanD]

If there is coolant in the crank case you almost certainly need a new engine.

The thing is that the Cam and ain bearings go out on 2.9's but I have yet to personally see a bad rod bearing on one... and I've pulled the oil pan and caps off of around two dozen.

Yeah, I've had a BUNCH of 2.9's apart. I have yet to put one back together.
Nor will I ever....

remember that the best engine donor is a Ranger or Bronco2 with EITHER a
disassembled transmission in the back, a deep impression of a utility pole
(or tree) in the body OR "road rash" on the side and roof.

If you don't see one of these things on the engine donor buy your engine
out of another vehicle.

 

[Sunk]

Ok thanks. The engine i will most likely be buying was pulled for a 5.0 swap.