2.9L heads or scrap it all?

ecgreen · Feb 5, 2019

Just looking for some opinions from those with a lot of 2.9l experience.

So the 2.9l in my 89 BII was overheated by the previous owner. I took the heads off and the magnaflux says...both are cracked.

What's your opinion guys? Assume the block and all else is good, buy new heads and roll or find a new engine? (and yes I am aware of the 4.0 option)

adsm08 · Feb 5, 2019

I suppose that would depend on how badly it overheated. It doesn't take much to crack a 2.9 head, but a severe overheating will damage the rings too. Did it still run?

ecgreen · Feb 5, 2019

adsm08 said:
I suppose that would depend on how badly it overheated. It doesn't take much to crack a 2.9 head, but a severe overheating will damage the rings too. Did it still run?

It did run, but not much power on acceleration (it had a plugged cat too so I dunno). Seems like paying for new heads is a gamble

07nhbpsi · Feb 5, 2019

ecgreen said:
It did run, but not much power on acceleration (it had a plugged cat too so I dunno). Seems like paying for new heads is a gamble

Well, I’d have to agree with u there....seeing how stupid people can be....overheated and ran with plugged cats? Who knows how long this motor was neglected? I’d personally start looking for a good used motor... :icon_thumby:

ecgreen · Feb 8, 2019

I am having trouble even finding a donor. Didn't realize how scarce this motor was. At the moment the BII is in pieces and I am dealing with rust, so I guess I have plenty of time lol

IIBRONCOS · Feb 8, 2019

I've got a nice pair of orig heads off of a 1988 BII 2.9 with only 46,000 orig miles. They need to be cleaned up and exhaust studs removed. I have them under parts for sale so you can see a picture.

4x4prepper · Feb 8, 2019

ecgreen said:
Just looking for some opinions from those with a lot of 2.9l experience.

So the 2.9l in my 89 BII was overheated by the previous owner. I took the heads off and the magnaflux says...both are cracked.

What's your opinion guys? Assume the block and all else is good, buy new heads and roll or find a new engine? (and yes I am aware of the 4.0 option)

How much money do you want to spend?

If you do not need to pass emissions I would install a rebuilt long block 2.8L, stick a carb and duraspark system on it, and be done with it. If you have a manual transmission you can upgrade to the 4.0L flywheel. FWIW: I converted my 2.8L to points!

Bird76Mojo · Feb 9, 2019

After my experiences with 2 different 2.9 blocks and around 5 different heads, I'd scrap the entire thing unless I was swapping engines for something entirely different.

The 2.9 is a joke. A complete money pit.

GB

ecgreen · Feb 9, 2019

Bird76Mojo said:
After my experiences with 2 different 2.9 blocks and around 5 different heads, I'd scrap the entire thing unless I was swapping engines for something entirely different.

The 2.9 is a joke. A complete money pit.

GB

Your making good sense...maybe I need to bit e 4.0 bullet

britanyweel · May 10, 2021

If it's that bad, you should buy another one. I had a similar situation a while ago, and in the end, I chose to buy a new one. It would have cost me a fortune to fix it, so it wasn't worth it. Scrap car collection helped me realize that it's better to scrap it and maybe keep the pieces if there are any good ones. In my case, it wasn't, but with the money I got, I was able to buy something that worked perfectly

I don't think we should always reinvest in used things. Sometimes it's time to change them.

ecgreen · May 10, 2021

britanyweel said:
If it's that bad, you should buy another one.

In the end thats what I did. Junkyard special.

Cees Klumper · May 17, 2021

Well on mine that had developed a coolant leak inside one of the cylinder heads (or both) I toook the gamble and got two complete new Maxperformance heads, for around $500 delivered to my home. Some new gaskets and head bolts and a couple hours work later, and it's running stronger than ever, could not be move pleased.
Your mileage may vary ...

McWillies · Jun 5, 2021

Cees Klumper said:
Well on mine that had developed a coolant leak inside one of the cylinder heads (or both) I toook the gamble and got two complete new Maxperformance heads, for around $500 delivered to my home. Some new gaskets and head bolts and a couple hours work later, and it's running stronger than ever, could not be move pleased.
Your mileage may vary ...

I can't find anything about "maxperformance" cylinder heads... Did you mean "promaxx performance" by chance? I got a pair of those for about $500 with valvetrain installed when I cracked a head last year from running it hot (thermostat stuck closed). They fit great and it's been a year with no issues, but I also haven't overheated it again.

Cees Klumper · Jun 5, 2021

Sorry, yes, Promaxx. Mine also still running strong (touch wood).

richard booth · Jun 14, 2021

Odessa cylinder heads are the better casting and I have a set that are working great.

2.9L heads or scrap it all?

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