Need to do a rebuild...advice?

[JoeCanada]

So some of you may have assisted me before with my overheating issue this past summer. Long and short of it...took the heads to the machine shop, and they were cracked. It's a 4.0 OHV with over 235,000kms, and evidence of past overheating issues, so I suppose that's really no surprise.

At any rate, the rest of the engine is coming out, I figure if I'm gonna do it, do it right. Now's the time to replace all the seals and whatnot while it's out.

Question is, with these engines in general, after having heads die on them, what does that mean for the block? Should I scrap that too? The cylinder walls don't look cross-hatched anymore, if that makes a difference. And I suppose it's possible the deck is warped, but I haven't had a chance to scrape all the old gasket off to check it with a straightedge.

Also, who's gone with the OE head bolts, and whose used aftermarket bolts (ie. ARP)? Which is better, or does it really matter?

I hate to slap new heads on an old block and have the bottom end fail, thus forcing a do-over, if you know what I mean.

Thanks!

 

[Wicked_Sludge]

if it were me...and the engine was running good before it cracked the heads, i would take it apart and only replace parts that need replacing. check the deck for straightness, hone the cylinders, replace rings, check bearings, crank, cam, replace gaskets and seals, ect.

the head bolts are torque to yield...any OE replacement (doesnt have to be motorcraft) will be fine.

 

[94 splash]

i rebuilt my motor and jsut took it to the machine shop they decked the heads 2 thousands and the block 2 thousands re cut the valve seats and replaced the exhust valves , bored the motor 10thousands and turned the crank and it only cost me 265$.... seemed well worth it to me i mean the whole engine over hule cost me about 800.... but its got 24000 on it and it runs better then new... never had one prob after it ..... oh also forgot they also swaped my rods for me

 

[AllanD]

If it were my truck I'd throw a running junkyard engine into it.

but then again I can get an engine that I get to SEE running
(often drive it around a junkyard) BEFORE they pull it
for LESS than the cost of a head gasket set.

So I tend to regard engines as a disposable commodity.

there are plenty of perfectly good 4.0's sitting in junkyards
bolted to dead A4LD's.

I'm especially fortunate inthat here in Pennsylvania where I live
We have a longstanding "Rust law" so vehicles that run get junked
because they won't pass inspection and are not cost effective to repair.


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[SoLongStang9499]

Allan, are you a fan of the junkyard EZ Pull? Its up above middletown

 

[JoeCanada]

Thanks for the replies, I appreciate it.

If it were my truck I'd throw a running junkyard engine into it.

but then again I can get an engine that I get to SEE running
(often drive it around a junkyard) BEFORE they pull it
for LESS than the cost of a head gasket set.

I think that would definately be the most cost-effective way to do it. It had crossed my mind, the only problem I have is I can't really test the engine at the Pick n Pull here. I think at most I could do a compression test, but I don't think that would be enough to indicate if the heads are good or not. I hate to risk another lemon, especially with the head issue being common on these engines.

Having said that, you raise a good point about the A4LD...I suppose if I looked for a lower-mileage 95-96 4.0 hooked to the auto...there's a good chance it's there because of trans failure and not engine failure.

 

[MAKG]

Pick'n'Pull is a bad idea for this.

You need a full-service yard. Insist on hearing the engine run before you buy it.

Unless you're willing to go through more than one (and it sure sounds like you aren't).

You might be able to get a $150 engine from Pick'n'Pull, but it's very much a crapshoot as to whether it works.

 

[shadetree]

A hint if you are going to a pick a part. Look for a vehicle that has been wrecked, and one with low mileage if possible. Non-wrecked vehicles are usually there because they are worn out, or high mileage with minor damage.shady

 

[Giant squid]

i just went to the picknpull and grabbed a pair of heads cause i have a cracked one. I got 98tm but there were hard to find so i grabbed a pair of tm97 and im going to slap those on. the explorer was wrecked because of a valve stem seal blow and the plugs were fouled. But the heads look fair so im going to clean them and slap them on. My cylinder walls are still cross hatched (175xxxkm) so i just cleaned the lifters and slap on new bolts/gaskets. Even though the top end is very weak, ive found most of the engines at the yards are top end toast so if you remove some you coulda wasted a day of your life just to find some cracks, On the other hand i got all head componets including rods/lifters, and exaust manifolds for 100$$

 

[JoeCanada]

I suppose junkyard parts are all find and dandy for the price, but I've decided to go the safer route (Read: I don't want to destroy $200+ in gaskets) and just replace the whole top end with new/rebuilt rockers, pushrods, & heads. I'll have the existing block/crank assy machined and cleaned up. I'm sure if anything is way out of whack with the block, the machine shop will tell me, and I think I'll save money in the long run by not replacing old with just-as-old.

 

[Giant squid]

Makes sence to me, Let us know how it goes!