Bad heads, should block be replaced? | Ford Explorer Forums - Serious Explorations

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Bad heads, should block be replaced?

xploder98

Well-Known Member
Joined
March 4, 2011
Messages
174
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12
City, State
Hemet, Ca
Year, Model & Trim Level
1998 Saleen xp8 #27
How’s it goin everyone. Haven’t posted since doing the roll cage in the xploder but now I’m back with some questions about the same truck. 1998 4.0 ohv with manual trans. Been a good desert truck but during last 4/20 weekend I think I blew a gasket or cracked heads or both. Finally started tearing it apart a few days ago and got the heads off this morning and sure enough there’s a crack from intake to exhaust valve on cyl 3 and cyl 4 (both heads). I’ve always felt I had a small coolant leak and upon inspection of the heads, cyl #6 is horribly corroded/ rusted in the bowl of the head. Possibly an internal crack from a cooling jacket? It’s hard to tell without it being cleaned up yet. I’ll post photos of everything. My question is, do you guys think the block is ok? Or should I opt for a reman engine or something along those lines? I’d love to just swap in a reman but am leery after reading a lot about reman engines having problems. Let me know what you guys think and as always, suggestions are much appreciated.

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How’s it goin everyone. Haven’t posted since doing the roll cage in the xploder but now I’m back with some questions about the same truck. 1998 4.0 ohv with manual trans. Been a good desert truck but during last 4/20 weekend I think I blew a gasket or cracked heads or both. Finally started tearing it apart a few days ago and got the heads off this morning and sure enough there’s a crack from intake to exhaust valve on cyl 3 and cyl 4 (both heads). I’ve always felt I had a small coolant leak and upon inspection of the heads, cyl #6 is horribly corroded/ rusted in the bowl of the head. Possibly an internal crack from a cooling jacket? It’s hard to tell without it being cleaned up yet. I’ll post photos of everything. My question is, do you guys think the block is ok? Or should I opt for a reman engine or something along those lines? I’d love to just swap in a reman but am leery after reading a lot about reman engines having problems. Let me know what you guys think and as always, suggestions are much appreciated.

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I had same problem my 97 OHV STARTED steaming out the tail pipe.
It was going through a gallon of coolant every 15 mi. Had local shop replace bad hd. W/ j yd.and valves done on both.Prob. was didn't use new head bolts.year later same problem not as bad on both Sides .I found these heads have design that is prone to cracks in valve st. I think the new design is called P400 I got mine from Odessa cyl. hds. in Ocala fla. I think they were $400 Plus 200 for gskt.HD bolts etc. As long as you didn't over heat it the block should be fine but I would put a straight edge on it to be sure. I wish I had known about hd.prob. before would have saved me $600.hope this helps .
 






I had same problem my 97 OHV STARTED steaming out the tail pipe.
It was going through a gallon of coolant every 15 mi. Had local shop replace bad hd. W/ j yd.and valves done on both.Prob. was didn't use new head bolts.year later same problem not as bad on both Sides .I found these heads have design that is prone to cracks in valve st. I think the new design is called P400 I got mine from Odessa cyl. hds. in Ocala fla. I think they were $400 Plus 200 for gskt.HD bolts etc. As long as you didn't over heat it the block should be fine but I would put a straight edge on it to be sure. I wish I had known about hd.prob. before would have saved me $600.hope this helps .
1 other thing I see u have removed ex.manf.from Y pipe now would be good time to repl.O rings on oil fltr.adapter.Its a common prob. on these 4.0 s.The prob is Y pipe has to be removed to access the bolt .they're are3 O rings rock auto has 2 I think the other is a dealer item or E bay
 






Check the deck for warpage. If it’s flat, I would [gently] clean the bores. Check for scoring/excessive wear/roundness. Then I would check for cracks with dye penetrant. That’s just me.

And if you get used heads, I would clean and dye pen them as well.
 






Thinkin I’m just gonna go with a complete reman engine. It has milky oil, wasn’t run too long on it but I’d hate to go through the work of installing new heads to find out the bottom end wasn’t up to par. Considering atk but like I stated earlier, I’m very leery. Anyone have a remanufactured they recommend?
 






@xploder98

Just asking 'cause I'm curious, how many miles on the OHV Engine?

With regards to Commercially Available on the shelf rebuilt OHV's , I haven't read about any particular brand that offers the mileage that you get from the factory original, German built engine.

10 to 12 years ago, you could stull get a factory FORD long block (from FORD) that utilized all the original German parts, but those days are long over...

Bottom line w/ regards to the commercially rebuilt ones; most will have a majority of Chi-Com parts, that don't hold the close tolerances of the original German parts.

From the experiences that I've read here with guys trying to keep their "daily driver" running, you'll spend about $2,500 (+) Labor to get about another couple of years out of your Ex.

What stands out to me from others experiences is that quite a bit of the re-man engines have noisy valvetrains right from the first turn of the ignition key - due to the loose tolerance hyd. roller lifters, soft push rods, and soft rocker arm "cups" (where the rocker arm connects with the push rod).

Also, I recall reading a LOT of cases of "piston slap" - again due to loose tolerances - this time with cast pistons and cheap rings.

I can't remember how many times I've read about a guy putting all the $ and time into installing the rebuilt engine, only to quickly post right after installation something like "why is my re-manufactured engine so noisy" or "why is my remanufactured engine running so rough"?

They are forced to "settle" because the rebuilt engine company says "they're all like that" ....

Then, after a couple of years, the "pita" problems start to emerge; cheap gasket problems such as timing cover gasket (BIG pita - factory original is Teflon coated green paper and rebuilders just use regular paper), bad water pump, oil pan gasket leak, oil filter adapter leaks, etc...

When I came to the point where you're at - factory heads going bad - utilizing mine as a "daily driver", I realized that I was at the point of diminishing returns.

In your case, if your Ex is just an off-road play toy (as opposed to a daily driver) then perhaps you're willing to forgive any inadequacies in return for the off-road utility you'll get for a few more years.

Not saying that you can't get a off-the-shelf rebuilt engine that will meet your standards, just saying I've read a lot of guys that daily drive not being happy with their replacement powerplant (compared to the factory engine).

Hope that helps w/ your decision :)
 






Yeah…concur. I’d either roll the dice and slap good heads on, or yank the block and rebuild the whole kit n kaboodle yourself. That way you can maintain tight quality control.

Remans cost a premium. The only advantage is the warranty, IMO.
 






As for labor, I’m doing the work myself. While the engine is out I’ll be installing the true travel 4.5” long travel kit (will see how it holds up) and upon receipt of the engine I will be reinstalling the engine myself. I more or less lack the time of rebuilding myself, with work I don’t get much side time. I’ve thought about pricing out a reman short block and then ordering updated complete heads and new rockers, new pushrods, new lifters etc and assembling the top half myself. It seems that would be the best way to go for my time and quality control constraints. At least then I can maintain quality control from the head gaskets up.
 






I can see factory cross hatching easily on the 5 good cylinders. I can barely see it on the cylinder that had the corrosion on the head. At this point trying to determine if I’m ok with this block. Obviously I’d still pull the pan and get the inside clean and install a new water pump, high volume oil pump etc. I’ve never had blow by issues with this block or a noisy lower end. I’d hate to spend the extra money on a complete bottom end for it to be noisy, faulty and or full of cheap replacement parts when the one I have seems ok
 






I had the same cylinders crack on my 00 Ranger
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4.0 both heads. I just replaced the heads. Think about also replacing the lifters if the engine has alot of miles on it because once the heads are on you cannot remove the lifters.
 






I’ve decided to clean out the block, install a high volume oil pump and aftermarket screen, new water pump, ordered new heads from Clearwater, ordering all new sealed power lifters and getting the hardened rocker pushrod combo from deltacam. Also throwing on a new clutch, still trying to decide which one to get. The truck gets used hard in the desert sometimes but I don’t recall ever really having problems with what I assume was a factory clutch. Hoping to have the engine done before the long travel kit arrives.

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Oh you have the short block out?

I’d consider a light refresh at that point. If you’re concerned about cracks, you could have the block magnafluxed, deck cleaned up.

I know you’re tight on time, but sometimes taking a little extra time ends up saving you a lot of time, if ya know what I mean.
 






I’m just not trying to get into rings and bearings etc. this engine will only be used until august of next year. Would just like for her to hold up until then.
 






^^^^

@C420sailor has some good & valid points, especially:
"I know you’re tight on time, but sometimes taking a little extra time ends up saving you a lot of time, if ya know what I mean."

I'll add to it, you wrote in Post #9 that the cross hatch pattern is worn off inside the cylinder that suffered from water ingress.
I imagine that you wrote that because your little voice inside you was talking, and you were listening, hence posting that :)

OK - so In my mind, that tells me that the motor oil in that cylinder became diluted with both coolant & steam.

So, at minimum, I'd wager that your compression rings & oil control ring in THAT PARTICULAR cylinder are probably toast due to the metal to metal contact that effectively "erased" the cross hatch pattern (FWIW - the piston in that cylinder is PROBABLY OK for what you're after- a "quick" fix).

Now the condition of that particular cylinder may not matter IF you do not have an upcoming smog check before next August AND you only want to get through next summer OFF-ROAD.

BUT realize that unless you re-ring that cylinder you will probably have an imbalance of power leading to a really rough idle, not to mention the gasoline blow past the worn-out rings into the crankcase

Gasoline blow by will wear out your 22 year old short block in no time flat, probably drive your 02 sensors nuts (rough idle "hunting" all over the RPM range), and probably kill your main cat.

I know what you're trying to achieve - but just wanted to throw that out there for you to consider since you're spending some good $$$$ (not to mention your time - I'd like to give you an "atta boy" - you work pretty damn fast ;)).

Hope that helps :)
 






Welp, it’s been a while since my last post lol. I figured I’d let everyone know the engine is back in the truck and doing great! No blow by so the rings must not be too bad. No loss of oil or coolant and power is good so I’m happy. The long travel is holding up well, I will be starting a thread on that install here shortly. Thanks for everyone’s suggestions and responses!
 






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