|
Post by austing on Nov 2, 2012 21:38:35 GMT -5
Hi,
My '88 justy is in need of new Connecting rod bearings, and until I am able to do a complete overhaul/rebuild on the engine; I was wondering, what is the procedure for replacing the rod bearings through the oil pan? I have seen this mentioned in another thread here on the forum, but without much detail.
I would rather burn through a set of bearings between now and the time I have the money/time to do a full over haul, than to blow a rod through the block.
Any help is greatly appreciated, Thanks!
|
|
|
Post by Cañon Carver on Nov 2, 2012 21:47:15 GMT -5
I will be watching this thread...
|
|
|
Post by Armageddous on Nov 3, 2012 0:16:01 GMT -5
It's fairly simple, you need to remove the oil pan to access the rod bearings, then you need to replace them. Chances are your engine lost oil pressure so you will need to discover why that is if you have any hope of putting any mileage on the new bearings.
Also if a bearing has spun (worn to the point of moving in the rod) then chances are the crank will be too damaged to even accept a new bearing.
I'll go by memory on disassembly to get at the rods:
- Disconnect battery - Jack up car, support it on jack stands. - Drain engine oil. - Remove lateral cross member - two bolts at the front, two at the back and 2 for the lower motor mount - Remove the front exhaust pipe. - Remove the lower motor mount (3 bolts on the bell housing) - Remove the 2 bolts securing the flywheel dust shield/inspection plate - Remove the oil pan
Once the pan is off you will need to rotate the engine to gain access to each rod, you can usually just push on the flywheel with a screwdriver/pry bar.
You will need a torque wrench to properly install your new bearings, I believe the spec is 36ftlbs.
Undo the 2 12mm nuts securing the rod cap, take note of it's orientation to the front of the engine. You may need to hit the protruding rod studs with a plastic object to get the cap to seperate. Drop the old bearing out, lube up the new bearing caps with clean engine oil, and push into rod. The new bearings should fit snug and nearly click in to place, if they don't chances are your rods are out of spec.
With the crank surface exposed check it for scoring, unevenness etc. Hit it with some high grit emery cloth if you feel it necessary just make sure you clean it well after.
Install the rod with new bearings, lube up the rod nuts and torque them to spec. Jiggle the rod in place, there should not be any up and down movement. The clearance between the bearings and the crankshaft will not be enough for you to feel, or very very slight.
Lather, rinse, repeat for the rest of the connecting rod bearings.
Install a mechanical oil pressure gauge and before you go driving make sure your engine makes good oil pressure or you will be doing the job again in a couple days.
Terry
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 3, 2012 0:32:38 GMT -5
Hi, My '88 justy is in need of new Connecting rod bearings, and until I am able to do a complete overhaul/rebuild on the engine; I was wondering, what is the procedure for replacing the rod bearings through the oil pan? The act of replacing the bearings is pretty simple, but the situation is not as simple as it seems. For the record it's not really recommended to just slap new rod bearings in, but it is possible that it might be done without major issues. So, obviously pull the pan and you'll probably want to remove the oil pick-up tube. Pull your spark plugs so you can rotate the crank easily. Do one rod at a time. Rotate the crank so the piston is at it's lowest point. The rod will have two nuts holding the cap on. You need to remove those nuts and remove the cap. The cap is essentially the bottom of the rod; it's u-shaped and one half of the bearing fits inside the U. Pop the rod off the crank. It should resist you, but if your bearings are sufficiently worn it might come right off. Remove the halves of the old bearing from the rod and cap and replace with new. You will notice a little divet on one side of either bearing half. There is a corresponding divet in the rod and cap, so make sure they all line up. If you install the new bearings in the rod and cap and notice that the roundness of the bearing doesn't match the roundness of the cap or rod, then you have a problem. It means your rods are probably shot from slapping back and forth on the crank for too long. This can be the case even if they look fine. The problem with putting a new bearing on a rod like this is that it is more likely to spin or just self-destruct. In this case it's almost better to leave the old bearings in because they have conformed to the shape of the rod as it was beaten out of round. If you have access to a good set of calipers, bolt the cap back to the rod while it is disconnected from the crank and try to measure the roundness of the hole. To reassemble, put some assembly lube or vaseline on the inner surface of the bearing and do the reverse of disassembly. Torque the nuts to 29-33 ft-lbs (according to the FSM). Like I said before I caution against doing this, but I know a full rebuild is involved and expensive. If you dig into it, post up what you find and take it one step at a time. [Looks like Terry and I were responding at the same time]
|
|
|
Post by Cañon Carver on Nov 3, 2012 10:09:48 GMT -5
I will be doing this whenever my new parts arrive I will be sure to post up pics and such when I am done. It is not worth my time or money to rebuild the stock engine when I am just going to swap in the turbo engine down the road all rebuilt. -Jamie
|
|
|
Post by austing on Nov 3, 2012 11:43:40 GMT -5
Thank you very much Arm., and Ferox,
Directly after I arrived home from the cross country trip, I installed a new valve cover gasket, and while there is still a little oil around the distributor, the level on the dipstick has stayed the same week to week. When I installed the new Valve cover I also changed the oil (I had only been topping off before since it leaked so bad) and filled with Lucas and 20w-50, since then the knock has been very faint, and is hardly noticeable after the initial start/warm up period. I can't imagine that the oil pressure had been very good with the amount of oil that was leaked around the old valve cover
I realize that I should follow your advice, ferox, from the other thread in which you suggested the full rod bearing/machined crank, procedure; but being where I am right now, I want to just take off the oil pan and see how it looks; after the advice from both of you kind folks, I am confident that I can do it myself.
Thanks
|
|
|
Post by Armageddous on Nov 3, 2012 19:17:26 GMT -5
[Looks like Terry and I were responding at the same time] Almost like we both have done this before. Terry
|
|
|
Post by austing on Nov 30, 2012 21:09:19 GMT -5
Well I went ahead and replaced the connecting rod bearings; they really weren't that worn, compared to some of the pictures of bearings from knocking rods which I have seen members post here.
on top of that, it sounds just the same as before; however, one thing I did notice was a chain on the dipstick side of the oil pan, I saw it and thought imediately "Wow, that chain looks rather loose" so I touched it, and indeed it was very loose. I have a hunch that the slaping/tapping sound actually has something to do with that non-taut chain.
Is it possible to replace this chain without removing the engine? After a couple of searches, I am led to believe that the chain in question is the "Ballance shaft chain"?
|
|
|
Post by Armageddous on Nov 30, 2012 23:31:12 GMT -5
That is a debatable question. Tension is applied to the chain by the crankshaft pushing up against the chain guide. Really, the crankshaft needs to come out for the chain to be replaced, however I have heard of people pulling the chain sprocket off the crank and doing it that way.
If it were me I would say just pull the engine, you were only a few bolts away already when you had the pan off. You and a friend with a 2x4 can probably lift the engine out.
Terry
|
|
|
Post by Cañon Carver on Dec 1, 2012 9:58:52 GMT -5
I am doing this all by myself if it makes anyone feel any better -Jamie
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 1, 2012 20:31:22 GMT -5
Is it possible to replace this chain without removing the engine? After a couple of searches, I am led to believe that the chain in question is the "Ballance shaft chain"? If you don't have the oil pan all buttoned up, you can loosen the crank so that it drops down a bit but isn't fully removed. That should give you enough clearance to remove the chain from the sprocket. You really need to replace the chain guide along with the chain. I think the guide is dealer-only these days, but aftermarket chains were still available last time I checked. Admittedly that was a while ago. It would be way easier to do this with the engine removed. You could also try to carefully drop the engine down a bit to get better access to the crankcase plate.
|
|
|
Post by austing on Dec 1, 2012 20:54:10 GMT -5
Thanks for the responses everyone!
I believe Dusty justys has both the ballancing chain and chain guide.
|
|
|
Post by austing on Dec 1, 2012 21:08:55 GMT -5
Also: Ferox, do you think it is possible to change the guide, as well as the chain, by dropping down the crank?
All the help has really been appreciated folks, the advice I have received has greatly aided me in saving money by utilizing my own mechanical abilities.
|
|
|
Post by Armageddous on Dec 1, 2012 21:39:02 GMT -5
If your car is an automatic you can't drop the crank down as it will bend the pump input shaft for the transmission. If it's a manual then you should be okay.
Terry
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 1, 2012 22:49:25 GMT -5
Also: Ferox, do you think it is possible to change the guide, as well as the chain, by dropping down the crank? I don't know that dropping the crank will help much on the guide removal and install other than making a little more room to try to get a tool in there. It's been a while since I have done it, but I think you are going to have to pull the crankcase plate to access the bolts holding the guide to the block. If you can get a tool on them from underneath then you might be able to do it, but it would be a pita. It's worth a try at least. If I were doing it and I was short on money, I would probably start stockpiling parts as I could afford them and would pull the engine and replace the chain, guide, oil pump, water pump, and new crankcase plate gasket. The crankcase plate area is where all the maintenance action is going on, so if you are going to go through the trouble you might as well get maximum value for your efforts.
|
|
|
Post by Armageddous on Dec 2, 2012 11:06:37 GMT -5
Amen. Do it right and you'll do it once.
Terry
|
|
|
Post by Cañon Carver on Dec 2, 2012 12:07:14 GMT -5
I am doing it right this time. I probably destroyed this crank by doing a bearing swap only last go around
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 2, 2012 17:55:56 GMT -5
Just to clarify, the crank won't "drop" very much with the engine still attached to the transmission. I don't want to mislead, "dropping" the crank is probably suggestive of a more movement than you will actually get but you should be able to get a little more clearance to work the chain off the sprocket, especially with a stretched chain.
|
|
|
Post by austing on Dec 3, 2012 11:32:16 GMT -5
Another question Ferox: I just bought another white '88 justy 2 days ago (same as mine other than its having 4wd, as opposed to my FWD), I was told that the only problem it had had was that its ecu stopped working; so my question is: Do you see any problem with swapping the guide and chain from the parts car to mine? I also plan to buy new oil pump components and swap the front cover between cars while I have the engine out.
Anyone know where an ECU can be obtained?
|
|
|
Post by madmatt on Dec 3, 2012 13:37:55 GMT -5
Austing,
Have you already pulled your block? Because i'd swap blocks before i'd swap parts from a known good block to known problem one... then rebuild yours as time permits.
My 2 cents...
|
|