Engine help

[bcrosson92]

i had a compression and leak down test done on my 90 renix 4.0

results are:
1 75 psi 80%
2 90 psi 25%
3 100 psi 15%
4 93 psi 32%
5 88 psi 35%
6 85 psi 30%

All leaking into crank case and some valves also

now ive found a shop that will do a used engine with 100k on it with a 12m/1200 mile warranty on it for 2575 out the door. thats fluids install and tax.

does it sound like maybe just rings or something that would be cheeper then a new engine being put in? cause if i could just have new parts put in that would be best right now.

[Pookapotamus]

Most likely just rings


Having 4WD means getting stuck in more inaccessible places!

[bcrosson92]

i would love for it to be that simple and just do that for now and do a whole new engine in like 3 or more years

[denverd1]

you can pull the head and inspect it to nail down if its valves or rings. 5 of 6 cylinders are beyond acceptable loss #s, so it may be cheaper in the long run to replace it.

You could always rebuild the current motor and sell it to recoup some of your cost, but you're likely throwing good money after bad on this one without a full rebuild. Ring jobs aren't easy to do even if you have the time/skill/interest.

[denverd1]

Does the engine currently run? wouldnt' think so, just curious

Any chance your head gasket blew? Cylinder 3 being the only one holding pressure and #s getting worse as you move out kinda points in that direction. again, pull the head and inspect if before you unload $2500 on it

[bcrosson92]

the head sould have blown. yes it runs i drive it almost 200 mile a day it just idles really low.

[bcrosson92]

head could have blown but my inspection hasn't said anything about it

[denverd1]

overheat?

[bcrosson92]

only when going over a mountain. but never in the red

[Mudderoy]

i had a compression and leak down test done on my 90 renix 4.0

results are:
1 75 psi 80%
2 90 psi 25%
3 100 psi 15%
4 93 psi 32%
5 88 psi 35%
6 85 psi 30%

All leaking into crank case and some valves also

now ive found a shop that will do a used engine with 100k on it with a 12m/1200 mile warranty on it for 2575 out the door. thats fluids install and tax.

does it sound like maybe just rings or something that would be cheeper then a new engine being put in? cause if i could just have new parts put in that would be best right now.

msmoorenburg rebuilt his 4.0l for about $700 I believe that included taking the head down to the shop and having a valve job done, and head checked.

[bcrosson92]

did he do that him self?

[denverd1]

did he do that him self?

He did. Not terribly difficult to do if you've got a few tools and some time to sort it out. a friend to help doesn't hurt either. These engines aren't complicated, just a couple specs and tolerances to be aware of.

[bcrosson92]

i dont have the time to be without the jeep that long. if i was doing it that is. i havnt found a shop that will rebuild mine. they will only put in reman units or a used one

[denverd1]

Your price isn't bad IMO for a running 4.0 installed. Prolly includes a core charge of your engine, so getting cash out of it later may be off the table.

It's odd that cylinder 3 has good compression with the others leaking as bad as they are. Have you always had the jeep? Or bought recently?

sent from my Samsoon S5 from the bottom of a mud hole

[bcrosson92]

ive had it for 3 years or so. it could be a blown head gasket and bad rings. if im lucky thats all it is but until i have a shop tear into it i wont know. but if they get in to it and its too far gone and i need a new one that 3k that i dont have

[denverd1]

Since you can buy another XJ for that money I wouldn't dump 3k into yours.

sent from my Samsoon S5 from the bottom of a mud hole

[denverd1]

After thinking about your situation, I don't think a gasket is your only issue. Cyl 3 would be one of the hottest and it's got the best numbers.

Wouldn't hurt to pull the valve cover and see if you can hear/feel any valve seat leaks while it's running. Try to rule some things out

sent from my Samsoon S5 from the bottom of a mud hole

[bcrosson92]

Yeah I can buy another for 3k but I'd have to swap suspension over and cut all the metal and stuff. I'd probably just swap engines and keep one for parts. I may pull the valve cover tomorrow and see.

[Mudderoy]

did he do that him self?

With the exception of the head cleaned, checked and 3 angle valve job, yes.

I can't remember but I think he took the block to the machine shop to have it boiled and checked as well, no I take that back I know he did because they bored it. So that $700 included new pistons as well. I think it is .030 over.

Pistons and ring kit was from Titan Engines out of Florida.

He checked and reused the factory CAM.

I believe the crank was turned by the machine shop, so all bearings were new.

[bcrosson92]

Update

I ended up driving around with the low compression for a while. I parked it last winter and started saving for a new engine. I got a used one from a friend of mine out of a 93 for 400$. 137000 original miles and my friend heard it run before it got pulled.

I have been cleaning up the 93 engine to put in and i am moving over the renix parts and accessory. The 93 intake does not have an egr port below the TB. Im using the renix intake because i didnt get a TB on the 93 engine. My question is can i delete the egr system altogether?

[4.3LXJ]

It can be done, but if you have smog inspections, better leave it there

[bcrosson92]

no smog. just visual plus mine is so old the dont really care. i have read that no egr mean the engine could run 20 degrees hotter? because its not cycling in un burnt fuel to reduce combustion temps. but that don't make sense to me because at least on mine the egr valve is just a hole in the side of the intake. i dont think it has ever worked.

[4.3LXJ]

EGR was basically an emissions thing

[bcrosson92]

yeah it sucks some exhaust back into the chamber and reburns it to reduce hydrocarbons and lower the temp so you dont get pinging. the thought is with out the egr the o2 sensors will see more o2 and will run rich but to me i dont see that being bad. considering how lean the 4o runs from the start

[Infidel Edition]

I pulled the head on mine (old XJ) and bought new parts on RockAuto for a rebuild...
...took it to a local shop and they rebuilt it for cheap.

While the head was off, I checked the block for level surface and cleaned it up.
New gasket and all was well.

If the block isn't straight, you'd need to get it decked. But that may fix the issue for under a couple $$$

[bcrosson92]

*****Update******

Ended up buying a used 93 engine off a friend for $400 got it in the body last fall. new valve cover gasket, rear main, intake, exhaust. Head hadn't been leaking in the jeep it came out of so i left it alone. stored it over winter mounted up and sealed with oil in it over winter. Now i cant turn the crank with a ratchet like i could before winter. the engine inst wired up or anything so i cant try doing it with the starter. what would be "locking" it up. tried all the positions of the transmission and the spark plugs are now out.

[jonb8]

Did you leave the plugs out? Probably just stuck put a little transmission fluid down each cylinder, put the plugs back in and leave it alone for a week. Then start working it back and forth till it free's up.

[Infidel Edition]

Without the head (and the tranny not in gear), I want to say it like 18 Lbs to rotate
With the head on it's WAY more... Not sure, but I thought something was locked up.
And if you put the plugs in, add to that.

Think plastic pop bottle.
No cap is easy to squeeze
Cap on = not so much