4x4Wire TrailTalk

4g54 Rebuild

Posted By: BSRJIRONMAN

4g54 Rebuild - 04/29/15 09:18 PM

Hey all,

new to the forums. I've got an '87 Montero. Had it for about a month. Long story short, I didn't do a compression test on it before buying it, I just assumed the 2.6 sounded "lopey". After trying to track down and fix some oil leaks, I discovered high crank case pressures (high velocity air coming out of the oil cap, and dipstick tube). Finally did a compression test, results as follows:
1=70psi
2=160psi
3=160psi
4=175psi

Oil in cylinder resulted in pressure increase to 150psi (cylinder 1) soo...rebuild is in order.

Anyway, looking for any tips and known issues to look for in these 2.6 engines, as I will be breaking it apart myself. I'm kicking around the idea of just doing a re-ring and honing it myself, but I guess I'll just wait to see what condition the cylinder wall is in. Anyone with experience doing just new rings?
Posted By: JAVYPRO

Re: 4g54 Rebuild - 04/30/15 02:04 AM

Get the MFS or is it MSF or FMS or SMF???? Bah!!! the manual you can download from http://www.mitsubishilinks.com/

This engine is so simple so normal simple tools and torque wrench will do.

Others will chip in on anything that you might have a question on.

Javy
Posted By: zarktheshark

Re: 4g54 Rebuild - 05/01/15 10:46 PM

I'm in a similar situation where it was rebuild the 2.6L or do a motor swap. I had it rebuilt once, but it blew after 30k and it was not because of abuse. This time I'm doing the swap. I have a new GM TB efi tuned for the 2.6 if interested...I'm not going to need it anymore <img src="/forums/images/graemlins/lol.gif" alt="" />
As for things to look for and possibly upgrade, look at the head. Most go with a Clearwater head that eliminates the jet valves as that is a weak point if ever the engine gets a little hot. Outside of that, don't use cheap parts and do not reuse the head bolts\studs. Probably best to spend a little more and use OEM stuff.
Posted By: Malykaii

Re: 4g54 Rebuild - 05/02/15 10:12 PM

Here's my story, maybe some of it may be useful. I was swapping from g54b na to turbo only to realize the donor turbo engine was shot. So I built the na block to turbo spec. All I had do was pull the pistons and swap/hone. Upon removal I see one of my rod bearings was destroyed and could have spun. Since I needed to now have the rods inspected and ground back to round, I decided to order new pistons and have the machine shop press them on instead of diy press on the used ones. In your case since your not swapings, check your rods for roundness and bearings for signs of damage. Get new rings and get new main/rod bearings. Rockauto closeout is your friend here. ($3 sealed power rod bearings for me) Sealed power and clevite are good suppliers. You can, like me, do this rebuild without even dropping the trans or removing the engine, just roll the bearings in. Harbor freight hone and ring compressor do a great job here.

Next up, do all the timing components. Cloyes does well. Check oil pump for clearances as they usually are fine. A new,one is pricey, so if yours is shot, nothing wrong with a good used one. Pull and check your balance shaft bearings. Mine were chewed up so I eliminated the balance shafts. Your discussion here. I got the cheapest,master gasket set, dnj?, as paper and rubber are all pretty similar. Threw out the head gasket and got a fel pro, as here it counts. Bam, with machine shop,timing parts, pistons and all I was out $300 with my time. You could do the bottom end for half if your pistons and rods are fine.

I didn't touch the head as the previous owner put in a new one a few years back. In your case, check to make sure its flat, uncracked and not warped. That's the weak point of these heads. Once they warp the around of money you can drop fixing it up and do I,g a valve job outweighs just getting a new Clearwater. If yours miraculously checks out, a quick $50 mill at the machine shop, a diy valve lap with some rockauto closeout valves, a jet valve elimination kit, and fresh headbolts, done for $100.
Posted By: Malykaii

Re: 4g54 Rebuild - 05/02/15 10:19 PM

Normally I like to make clear and coherent posts. Right now I'm lazy, and it's to much to type up well... So yeah, typos and stream of conscience writing. I didn't even proof read. Good luck. Oh,and do the head bolt retorque procedure correctly. Previous owner of mine didnt, and fail enaured for me.
Posted By: BSRJIRONMAN

Re: 4g54 Rebuild - 05/04/15 04:39 PM

Thanks for the replies!

The owner replaced the head a couple years ago, but I'm not sure if they eliminated the jet valves or not. Way to identify without removing it?

Also, regarding the balance shaft, What are the benefits to eliminating? Less failure points? Are these prone to issues?
Posted By: heathdogg

Re: 4g54 Rebuild - 05/04/15 04:47 PM

Pull the valve cover and look. On the intake side, near the rocker arm, It will have a big valve spring and a little valve spring if it has the jet valve. I'm at the same point myself. put a crank and rod in my 2.6 or go get a wide block 2.4 from the u-pick-it here.
Posted By: JohnnyBfromPeoria

Re: 4g54 Rebuild - 05/05/15 03:42 AM

IronMan, the balance shafts were there for a reason. The technology was licensed by other manufacturers, including Porsche...for a reason. Some will say they cannot tell the difference when they are eliminated, but there will be a balance problem that is inherent with a four cylinder engine. I'd always choose to keep them.

Heath, while the 2.4 is a great engine, keep in mind that it's not always as easy as it seems to swap one in. I've never fully integrated mine into my '86 Montero, and I wish I had just pulled the 2.6 and sealed it up and left it alone. Seriously. Even though that truck had the early 3-speed auto, at least it was a complete running vehicle, while it is not as it sits (and sits) now. The truck has been in the east valley at LordTrunk's house for a couple of months now and it still has a list of things to be done to it. Not the least of which, the a/c compressor for the Montero does NOT bolt up to the 2.4, so that whole system has to be grafted; an expensive and extensive conversion that also seems sort of essential here in Phoenix.

John B.
Posted By: Malykaii

Re: 4g54 Rebuild - 05/05/15 04:28 PM

I'm not going to exactly answer the pros and cons of balance shafts or jet valves. A quick Google will get you hundreds of threads on the topic between here and starquestclub alone.

Its a case by case choice. I deleted the shafts as I was doing a supper budget rebuild all without pulling the engine. I found my bearings were in bad shape. Changing them would add expenses, and you can't do it without pulling the engine. Hence my choice. All I'm saying is at the very least pull your shafts out and inspect.

Jet valves are rebuildable and even for sale new. Some guy's like them. Me, budget build. Hence the cheaper option.
Posted By: heathdogg

Re: 4g54 Rebuild - 05/05/15 09:06 PM

My a/c is 2x65. 2 windows at 65. <img src="/forums/images/graemlins/smile.gif" alt="" /> I've gotta do a crank and at least a rod. Plus side of the 2.4 is fuel injection. And if they close the woods for woodcutting again this summer, lots of free time for me on the weekends.
Posted By: BSRJIRONMAN

Re: 4g54 Rebuild - 05/05/15 11:04 PM

Quote
IronMan, the balance shafts were there for a reason. The technology was licensed by other manufacturers, including Porsche...for a reason. Some will say they cannot tell the difference when they are eliminated, but there will be a balance problem that is inherent with a four cylinder engine. I'd always choose to keep them.

Heath, while the 2.4 is a great engine, keep in mind that it's not always as easy as it seems to swap one in. I've never fully integrated mine into my '86 Montero, and I wish I had just pulled the 2.6 and sealed it up and left it alone. Seriously. Even though that truck had the early 3-speed auto, at least it was a complete running vehicle, while it is not as it sits (and sits) now. The truck has been in the east valley at LordTrunk's house for a couple of months now and it still has a list of things to be done to it. Not the least of which, the a/c compressor for the Montero does NOT bolt up to the 2.4, so that whole system has to be grafted; an expensive and extensive conversion that also seems sort of essential here in Phoenix.

John B.


Thanks John. I'm always in favor of retaining engineered components/systems. I was just checking to see if there was something I missed in regards to efficiency, or well documented failures, etc.

I think I have a plan, and a clear path at this point. Only thing left to do is get the motor apart, and see what I'm working with.

Thanks to all for the helpful replies.
Posted By: ryany

Re: 4g54 Rebuild - 05/06/15 12:50 AM

Quote
I'm always in favor of retaining engineered components/systems. I was just checking to see if there was something I missed in regards to efficiency, or well documented failures, etc.


The balance shafts ARE a documented failure point, or at least the bearings are (probably because they're a PITA to replace and get skipped during a rebuild). Plan on installing new balance shaft bearings with your overhaul, as well as a new oil pump. You might also want to search for the thread on oil pump relief valve shimming as described by FastEddy - good knowledge there.
Posted By: Malykaii

Re: 4g54 Rebuild - 05/07/15 02:44 PM

The bearings indeed can be a failpoint. A guy on starquestclub has over 300k miles on his motor with original balance shaft bearings. His motor is meticulously maintained.

My motor has maybe 100k, and the bearing looked like crap. Case by case, check and assess what you have. Then make a call, but based on the motor your describing, I doubt the bearings will be ok as is.

I haven't ever heard of needing to replace oil pumps. From what I read, most of the time, it's still perfectly in spec.

I too should read Eddys article.
Posted By: BSRJIRONMAN

Re: 4g54 Rebuild - 05/12/15 09:40 PM

Got the motor out and mostly disassembled. This is what I've found so far;

between cyl. 1 and 2

[Linked Image]

between cyl. 2 and 3

[Linked Image]

Might be difficult to see, but there are cracks bridging the three small passages to the head bolt seat. Although these don't appear to be bridging the cylinders themselves, they look ominous. What are your thoughts?

The cylinder walls in #1 (cylinder with poor compression) look to be in good shape to me. No major scoring or gouges etc. Although the piston can "wiggle" a bit. Not sure of the tolerances here yet.
Posted By: BSRJIRONMAN

Re: 4g54 Rebuild - 05/13/15 10:28 PM

Another update:

two of cylinder 1's piston rings were destroyed. No major scoring on cylinder walls. Oil ring was ok. Block, crank, and head are at the machine shop to get cleaned, tested, and machined as needed.

Machinist doesn't think that the cracks will be a major setback. After testing the block, he will make recommendations.

One of the timing chain guides was bent. Because of this it was worn through to the metal backing.

Balance shaft is already deleted, presumably by the previous owner's mechanic.

Head looks to be in good shape, and all jet valves are intact. We'll see what the test results reveal.
Posted By: Malykaii

Re: 4g54 Rebuild - 05/14/15 03:51 PM

Well then... Looks like your one of the better off ones, you had the balance shaft out and never even noticed excessive vibration. I didn't either.

Lets see what the machinist says.
Posted By: BSRJIRONMAN

Re: 4g54 Rebuild - 05/14/15 04:34 PM

Well, there definitely was vibration. But I'm unsure as to what the greatest cause of vibration was; no balance shafts, or one cylinder not working... <img src="/forums/images/graemlins/lol.gif" alt="" />
Posted By: BSRJIRONMAN

Re: 4g54 Rebuild - 06/16/15 09:44 PM

Thought i'd update...

Machinist said everything was a GO, the cracks around the head bolt seats weren't critical, and that the block is sound otherwise. So I had him bore it out (.040), deck it, and install new brass expansion plugs.

The head also checked out, so I had him install new valve seals, valve job, surface it, etc.

Crank just got a polish.

Got all the new parts in; Pistons, timing components, gaskets, bearings, rings, etc.

Everything went together as planned. I continuously second guessed myself, because everything was just so simple (in comparison to other projects i've done in the past). I primed the oiling system by removing the spark plugs, and cranking it over for a few minutes. Then fired it up... or attempted to. It hadn't occurred to me that the distributor is not "keyed" like most newer cars. It's been a while since I've worked on something this old smile After a few backfires, I figured it out. Sorted it, and it fired right up.

After running it a while I took it for a gentle test run. All was well, aside for a little necessary carb tuning. Then a coolant leak developed from somewhere. It was very difficult to track down, as it was dripping from the bell-housing. Long story short: I have an exterior crack in the block on the passenger side, connecting the front-most and middle expansion plugs.... Gotta love it.

Still waiting on a call back from the machinist...

In a desperate attempt, I took the recommendation of my wife to find a "special glue" to patch it up. I went down to the local NAPA and got a bottle of Blue Devil block sealer...

Now let me preface this by saying that buying and trying something like this, is the absolute last thing I would ever resort to. I'm always a proponent of fixing something the correct way, or not at all. But in THIS case, I thought I had done just that, only to find that due diligence was not thoroughly performed.

So I follow the directions, get it in my cooling system, and it starts seeping from the crack. After about fifteen minutes or so, the crack turns greenish white (from blue), then white. And the leaking ceases! I shut everything down and check the coolant to make sure that this hardening is not systemic. Everything flowing good.

It's been two days now. Coolant level static. Temps good and cool (even on highway). unbelievable... But I don't yet trust it to hold for good.

In the meantime I'm researching possible repairs, and I've come to stitching (due to the block being cast iron). Anyone have experience doing this? Looks pretty straight forward, but more research is needed.
Posted By: Mudraider

Re: 4g54 Rebuild - 06/17/15 01:49 AM

Dude, have a similar situation in the 88. Before disassembly, I decided to try a product called Steel Seal. Alchemy I say. The 88 is living in TX, and I ran the crap out of it. Still runs cool, no leaks nothing. Better living through modern chemistry.
Posted By: Struc

Re: 4g54 Rebuild - 06/17/15 04:04 PM

Wow... That's horrible man. A machine shop should have caught that - unless they caused it during the machining process at some point.

Those stop leak type products can work, surprisingly, but I'm with you in doing it correctly. You might be able to find a good core block and make the machine shop re-do the work on the core block for free, and just swap everything over. There are also specialty welding shops that would weld the crack for you. There is also a process called pinning (probably the same thing you called stitching) that works. All just depends on what YOU want to stick into it effort and $$$ wise.
Posted By: BSRJIRONMAN

Re: 4g54 Rebuild - 06/17/15 04:36 PM

Quote
Better living through modern chemistry.


you ain't lyin'

Quote
there's also a process called pinning...


yea I believe this is the same "stitching" process. I'd go with this, but I cant find anyone local that offers this service. welding cast iron seems to create more problems than it solves. Even cold-welding.
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