My 1991 LS 3.0 has some engine issues. 1st oil PSI at hot idle about 10. Second, I just replaced lash adjusters that were beat. I mean most of them where locked up and a few were real hammered on the valve stem ends. One actually beat the valve stem up pretty good. I have 1 cylinder seems to not be firing. it has great spark so Ill run a compression check today.
The engine uses NO oil, no smoke and had the heads rebuilt some time ago by previous owner. The truck has NO rust.

SHould I pull the motor and just to a rebuild? Pull it and do the oil pump and heads again? Buy a used ***** imported 3.0 and drop it in or what?? Drive it like it is until it quits??

sjgrupe@rstarmail.com

scott

The rebuilt heads by the PO may be somehwat moot if you had to do the VLAs like you said. Not firing on a cylinder while also losing no oil doesn't add up to compression to me, though I admittedly know far less that others here.

A solid Montero is always worth new motor, ir you are inclined to keep it as whole, as opposed to chunking down coin for new, or newer.

That all said, if you run it until it stops, I'd be interested on the complete roller...

10psi on what weight oil? If it's 10w30 or 5wstuff, I'd go with 20w50 castrol dino oil.

I'd suspect a clogged/bad injector, except that chewed valve stem tip bothers me. I'd do a compression test and if:

The compression is good, remove/check/clean the injectors (first, crank it, then pull the dead cyl. plug and smell it for presence of gas odor, or wet gas. Do test on a cold engine and run no longer than 15-20 seconds - if you've got gas smell, SOME gas is getting squirted).

If the oil pressure comes up at idle with heavier oil, and you have at least 10psi of oil pressure per 1000rpms (20psi at 2000, 30psi at 3000), and at least 55ish psi at 5000rpms, the oil clearances in the block are pretty good for quite a while yet, and I'd just put a set of fresh heads on it, with waterpump, hoses, belts, tensioners. NOTE fully theaded depth on head bolts to get proper head clamping force. Search "head bolt" under username "FrankR".

Head rebuild is probably cheaper in Vir. than here so you might want to have those heads rebuilt( sounds like they,ve been thru hell).
If your oil pressure is really running low , like 10 at 2500k you might as well get a Hyundia 92-97 3.0 (same valve timing on those heads , and cheaper than saying Montero). The bottom end of these engines is pretty tough, unless your oil is really low.

My gauge has been running inconsistantly lately with low pressure at idle. I have oil blowing on the sender and am thinking bad contact. I'm gonna solder the terminal to the sender to see if that helps. Gonna ground that wire to the frame to see if my gauge will go to max reading for a test.

Frank R has stuff on here somewhere torque and shortening headbolt lenghts so the bolts don't bottom out on a multi shaved head.

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<img src="/forums/images/graemlins/confused.gif" alt="" /> you just gotta explain that... are they interchangeable? just gotta know.
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im with the others on a monty in good shape is always worth getting the tinmans new heart.

I've recently done alot of research on this ( with alot of help from Frank R). I'm paranoid on how long my "?good?" engine will last , with the chewed up ,off balance crank snout(H.B./ bolt damage).
The Japanese front wheel drives with the 3.0 switch in easy . The CHRYSLER stuff has weaker blocks , timing sprockets, etc. etc.
THe Diamante engines fit good but have 10:1 compression and higher H.P. and Torque band.
The 92-97 (maybe 98 too) Hyundai Sonata has the closest plain jane intertnal setup as the 89-94 Montero, 8.9:1 and valve timing . Will match up with the ECUs without causing any CA emmisions problem and maybe wear problems that might happen down the road with the 10:1 Diamante/Stealth engine. I guessing a Hyun. engine wouldn't have pulled a heavy load (unless abused) as a family car and there are alot ones newer out there than looking to gewt a good one out of a rarer montero.

There's one in a yard halfway from my town to the Yosomit trip coming up that I'm gonna check on , on the way to the MTNs that is supposed to have 5K on it..

Weaker blocks? not so sure about that one. But yea your right, There's a ton of interchange out there for the 3.0.

The oil PSI runs up to about 30 max at high revs. Im running valvoline 20w50 synthetic. I have no leaks or drips. I have a dead cylinder and its the middle one on the left bank. Sparky is fine. Ill have to do the injector check. Boy, I sure hope its just an injector because this Monty is just too nice and Ill have to fix it.
The beat up valve stem was on the other bank of cylinders and the motor is quiet lifter wise.
Yea, the guy( mitsu shop)who did the head job short cut on replacing the lifters.

Since I got this truck of a friend Ive replaced the following over the past 10000 miles and its a daily driver.

Brakes, cap, rotor, wires , plugs, water pump, timing belt,idler pulleys , front crank seal, alternator( just last month it crapped out). Now Ive just replaced...lifters, intake gasket, valve cover gaskets, thermostat, etc etc.

Scott

Well it looks like I have bad rings in the center cylinder on the left bank. so....pull the motor to fix or pull the head, drop the pan and slam in a new piston and ring and do it on the cheap? Im looking at a used ***** import for 1100.00 shipped to my house. Any you guys used these outfits?? Ive spent alot of time in SE Asia and know the JAPS ship their used low mileage mills all over the place out there, especially the PI. and they are very happy with them. My local machine shop even recommends gettng one.

However, since Im pulling the motor....what Better, more power full motor could I put in it with ease? How about dropping in a imported Diesel?? Could it be done without a lot of modifications??

s

yeah... currently my heads are out of a chrysler minivan. makes it that much better when im on the trail, get those grocery getter looks & then tell them in on my way to my kids soccer practice.