Engine Overhaul question

[TrexMex]

My truck's 20th birthay is approaching, and I am planning to perform a major overhaul on the engine, tranny, transfer case, rear differential (did the front not so long ago) and any other thing that will come apart in the process, including once and for all getting back the AC to working condition.

My question is, would it be cheaper to just get a reman engine rather than to disassemble and overhaul mine? A reman engine is around 2K, and for what I've been seeing servicing all the parts in my current block/heads would get me closer to that...

Thoughts??? I'd like to make the best decision so I enjoy my ride for another 20 years

 

[RonD]

If time is not an issue then rebuilding your current engine would be my choice.

Machine shop time is what delays things, hot tanking the heads and block, and then resurfacing seems to be a two/three week job, lol.
Check which head are on there now, some were prone to cracking.

This would have to be cheaper using the same quality parts, if not then lower quality parts were used on the reman engine.

Since this is a MAF system you can change the engine a bit for better performance, i.e. cam and pistons

 

[TrexMex]

If time is not an issue then rebuilding your current engine would be my choice.

Machine shop time is what delays things, hot tanking the heads and block, and then resurfacing seems to be a two/three week job, lol.
Check which head are on there now, some were prone to cracking.

This would have to be cheaper using the same quality parts, if not then lower quality parts were used on the reman engine.

Since this is a MAF system you can change the engine a bit for better performance, i.e. cam and pistons

Thanks, I have been reading the tech section on rebuilding the 4.0. So many configurations it got my head spinning for a while...

So it seems the heads prone to cracking are the 90TM castings which run all the way to '94 since 93TM is identical according to the article... That might explain why coolant has been disappearing mysteriously.. also I revved up the engine and the radiator cap leaked like crazy, I did not pay a lot of attention and just replaced it with a new one but now I'm connecting the dots...

I will run a compression test and a leakage test over this weekend. One other thing I noticed when doing an oil change was that there were some sort of bronze-like particles in the used oil... I saw the same particles in the coolant so I'm guessing the wise guy I sold the truck to (and then bought it back from..) put stop-leak in it "just because"... I see engine compression ratio is 9:1 so should I be expecting ~132psi or below? I'm at sea level and temp around here is in the mid 70s this time of the year so that should be accurate... What's the minimum acceptable?

Another thought: Maybe buying a 2000 junkyard engine and rebuilding that would be a good option? I am interested in the part where you say you can increase performance. I thought there was not a lot of juice left for these engines... how much more can you get? HP or Torque or both? would these improvements be in the high rev region or the low rev?

Man I know those where a lot of questions but I have been thinking on doing this as soon as I'm done rebuilding the Willys and I must confess I'm an information addict. Don't just want to jump into it and find myself in the middle of the whole thing scratching my head lol...

 

[RonD]

You can do the Glove test to check for possible cracked head/head gasket issue.
Engine cold
Coil unplugged
Latex glove or "similar" over rad cap opening
Crank engine

Video here of finding blown head gasket or cracked head with "glove" test:
http://www.youtube.com/watch?v=vFGquUimXro&feature=youtu.be

If test shows a cylinder leak you can remove 1 spark plug at a time, repeating test each time, when "glove" stops inflating the last spark plug removed was the leaking cylinder, reinstall it to confirm.

With all spark plugs removed, throttle plate open and a good battery, compression should average 170 psi
My 4.0l with 300k has 165-175 psi

Good read here on a 4.0l OHV rebuild
http://www.therangerstation.com/forums/showthread.php?t=25632

 

[TrexMex]

You can do the Glove test to check for possible cracked head/head gasket issue.
Engine cold
Coil unplugged
Latex glove or "similar" over rad cap opening
Crank engine

Video here of finding blown head gasket or cracked head with "glove" test:
http://www.youtube.com/watch?v=vFGquUimXro&feature=youtu.be

If test shows a cylinder leak you can remove 1 spark plug at a time, repeating test each time, when "glove" stops inflating the last spark plug removed was the leaking cylinder, reinstall it to confirm.

With all spark plugs removed, throttle plate open and a good battery, compression should average 170 psi
My 4.0l with 300k has 165-175 psi

Good read here on a 4.0l OHV rebuild
http://www.therangerstation.com/forums/showthread.php?t=25632

Thanks, I'll see how it goes this weekend...

Have you heard/know anything about this site? http://engineguy.com/ Their engines come cheap, $1700 w/$200 core replacement...

By the way, that "glove" seems to only have one finger

 

[4.0B2]

4.0's are usually considered a "custom" machine shop job since they are not a chevy 350 or Ford 302, aka common stuff to rebuild... therefore, it gets expensive QUICK.

I'm not saying don't have the block machined, I'm just saying look into the price at a local shop before deciding.
I had a 302 machined for about $400 locally, same shop wanted $1250 for the 4.0....

 

[TrexMex]

4.0's are usually considered a "custom" machine shop job since they are not a chevy 350 or Ford 302, aka common stuff to rebuild... therefore, it gets expensive QUICK.

I'm not saying don't have the block machined, I'm just saying look into the price at a local shop before deciding.
I had a 302 machined for about $400 locally, same shop wanted $1250 for the 4.0....

That does it then, I'm putting a 302 in

kidding... thanks for the advice, I'm finding out quick there's not a lot of options laying around for 4.0s

Any input about that engineguy site?

 

[adsm08]

Compressions numbers aren't consistent enough to give a number on what your engine "should" have. 90 PSI is generally the minimum needed to run, and at 90 PSI it will have no balls and barely run.

I looked through that EngineGuy site. I haven't dealt with them personally, but I would probably do business with them if I was looking. I rebuilt my own engine, but not everyone has the skill set or tools for that. I think I would call them and ask if the warranty is still good if you install the engine yourself though. Some places won't honor the warranty in powertrain assemblies if they aren't installed by a professional mechanic. I have even had some co-workers fight with a few companies over warranty stuff because they installed engines or transmissions at home and certain companies want a work order and shop history before they consider it "installed by a professional".

 

[TrexMex]

Compressions numbers aren't consistent enough to give a number on what your engine "should" have. 90 PSI is generally the minimum needed to run, and at 90 PSI it will have no balls and barely run.

I looked through that EngineGuy site. I haven't dealt with them personally, but I would probably do business with them if I was looking. I rebuilt my own engine, but not everyone has the skill set or tools for that. I think I would call them and ask if the warranty is still good if you install the engine yourself though. Some places won't honor the warranty in powertrain assemblies if they aren't installed by a professional mechanic. I have even had some co-workers fight with a few companies over warranty stuff because they installed engines or transmissions at home and certain companies want a work order and shop history before they consider it "installed by a professional".

Thanks for the advice, today I went ahead and changed the t-stat as I had fluctuating temps and didn't really know if my buddy removed it or whatever.. It got dark by the time I was burping the cooling system and instead of the rad burping I got it puking.... It easily threw up around half a gallon. I re-filled it again and while I was pointing my flashlight at the rad filler neck I saw some golden crap in it (stopleak.. MoFo...)... Re-filled it and I could see how level would slowly rise and then throw up again. I have burped this very same truck several times before and never had I saw so much antifreeze being thrown out by this procedure...

Anyways, I talked to my buddy over the phone... He mentions he paid around a thousand bucks for the head gaskets to be replaced a year ago... it's clear he got ripped off...

I'll still do the compression test this weekend just for kicks and jiggles, but at this point I've made up my mind on taking the engine out and do a complete rebuild myself over the holidays break. I want an engine that will last at least another 20 years and I want to make sure what's in it. I'm still missing a couple of tools, but I guess this is the perfect excuse to stop slacking on rebuilding the '62 Willys engine and the '73 VW bus engine I have on my projects queue

 

[LIMA BEAN]

I build alot of engines so there is never a question of wether I would re build or not. You need to source all your parts first like bearings, rings, pistons, seals/gaskets, oil pump, cam, head bolts ect. first and look at oversizes. Call machine shops and get prices on Hone/bore per hole, crank grind/ inspection, rod recon, hot tank and head recon/ valve job. If I am doing an engine for myself I come in less money than a reman and a by far superior engine, if for a friend beat a reman price and again a superior engine. I have used alot of Enginetech kits and I like that I can pick and choose parts and sizes and it all shows up in one box on your door step. These guys...

http://enginetechcatalog.com/Default.aspx

 

[TrexMex]

I found a dirt cheap 99 4.0 OHV from a 2WD Expo with only 76K miles in it in a local Junkyard, tempting...

I've been doing a lot of reading on the swap and it seems that I should only need to swap my upper intake (pretty obvious since one is plastic vs aluminum), oil pan (oil level sensor not present in 99) and also the exhausts as I have Cali emissions (EGR)... Seems that Engine mounts would not be a problem going from a 99 to a 94 but it's a problem the other way around.

Anything I might be missing? Read something about cam sensors but not a lot of info on that...

thanks!

 

[TrexMex]

Anyone? BTW I checked the engine, it's a 98, 107K miles out of a 2WD auto explorer...