|
Post by Paul Hayden on Oct 20, 2011 1:38:15 GMT -5
My 1990 Justy engine is making a faint knocking noise, and I'm not sure what to do. The oil light flickers every once in a while, but there's plenty of oil in it. I do have to add more oil periodically. I've fixed a bunch of other stuff on the car, but I've never done any engine work. I need the car to get to work, so I'm thinking about just continuing to drive it, keep checking the oil and hope for the best.
I searched the forum and people with the knocking problem seem to think it's the rod bearings.
Is there anything I can do to fix this without having to take out the engine? Maybe it won't get any worse if I just drive her gently.
|
|
|
Post by justyjuggler on Oct 20, 2011 8:50:44 GMT -5
Is there anything I can do to fix this without having to take out the engine? Maybe it won't get any worse if I just drive her gently. The oil pump can be measured and changed with engine in place. So can the rod bearings and mains, to some extent. Unfortunately, it's a half-ass job as the crank usually shows damage once knocking occurs, and requires grinding to match with over sized bearings. Meanwhile, use a higher gear to keep revs up and engine torque lower for any given load. But beware, the increased velocity of the rods encourages a 'block punch' should a big-end ever seek freedom.
|
|
|
Post by madmatt on Oct 20, 2011 9:45:13 GMT -5
As justyjuggler, said, indeed you can patch it up with the motor in place.
Almost for sure the knock is bearings if you oil light is coming on. Remember the light flickering has nothing to do with oil volume, it is pressure, and you can have a full oil sump and low pressure or vice versa (although low oil gets dirty quicker... leads to wear... bla bla)
Bearings are cheap, and if the knock is light, I'd get a set in there quick even if you can't do the crank right now. Otherwise you'll be experiencing the "punch"...
Get a real oil pressure gauge, either t it off so you still have the light, or just hook it up directly. That will tell you what the real pressure is. Order up some standard bearings, drop the pan and replace. Find another motor to build, or plan a week or so in the future to remove and grind the crank if you're planning on keeping the car.
Matt
|
|
|
Post by Paul Hayden on Oct 20, 2011 11:35:02 GMT -5
Thanks for the quick responses!
Will I be able to get both the top and bottom of the rod bearings from the oil pan? One person said to get the top ones I must remove the head.
I can't seem to figure out what "main" bearings are. What are they connected to? And can you recommend an oil presure guage?
|
|
|
Post by madmatt on Oct 20, 2011 12:59:26 GMT -5
Yes, with the pan down, you will remove the rod end bolts and then both the rod and the rod end cap will be accessible to change the bearings in each.
You will not be able to change the crank "main" bearings.... but they are rarely the issue. These are the bearings that hold the crank in place within the block.
Any cheap mechanical oil pressure is fine. Autozone, pepboys, whatever... It's accuracy is not the issue, you want to see trends and know that you have more then 10 lbs of pressure!
For fun, I would get the gauge in first, run the car until it's warm (take it for a drive...) and record the pressures. Then go change the bearings and check again. If still low, get an oil pump kit.
Matt
|
|
|
Post by madmatt on Oct 20, 2011 13:04:37 GMT -5
Oh... and be careful torquing the old rod end bolts... really you should get new studs, but they can be hard to find (and I'm not giving up my last set). They can stretch, and if they do you will end up with loose end caps = too much clearance = bearing failure = i2.photobucket.com/albums/y44/DoItSidewayz/mattsmotor.jpgMatt
|
|
|
Post by justyjuggler on Oct 20, 2011 13:35:14 GMT -5
One person said to get the top ones I must remove the head. One person is right. To get to the 'top ones' or wrist pins, the pistons need to be removed; they only can go up, after head removal. But really, wrist pin failure is unlikely. Rod bearings are easy with engine in place, mains are harder with extra points awarded for sneaking in rear mains while gearbox is attached. Get any cheap-o gauge, like Matt suggests, just be sure the range is 0-50 or 60 psi, or so.
|
|
|
Post by madmatt on Oct 20, 2011 13:39:39 GMT -5
Okay, okay, yeah you can do mains in the car... I wouldn't get the extra points! (I'm too lazy...)
|
|
|
Post by Paul Hayden on Oct 20, 2011 19:04:05 GMT -5
Thanks for all the good information and advice! I feel much more confident now.
|
|
|
Post by Paul Hayden on Nov 12, 2011 16:51:47 GMT -5
Order up some standard bearings, drop the pan and replace. Dropping the pan.... I finally took a look at that. Looks like I gotta get the exhaust pipe out of the way first. I hope I can work around the crossmember.
|
|
|
Post by Paul Hayden on Nov 14, 2011 20:29:16 GMT -5
Well, I got it all apart. The old rod bearings and oil pump parts don't look that worn down to me. I'll see if the new ones make a difference tomorrow. Maybe I'll switch to 20w50 too.
|
|
|
Post by Armageddous on Nov 14, 2011 22:44:29 GMT -5
You're bearings are showing copper on the thrust side. Copper is part of the internal construction, while the grey is babbitt, which is whats actually used for the contact surface on the bearing. This all adds up to low oil pressure of course, and my concern is your crank may be under size. If that is true, putting new bearings in could make your situation worse. Maybe snap a picture of the crank surfaces? Your old oil pump rotors look trashed. All those lines and grooves are not supposed to be there, and indicate that hard material has passed through the pump and chewed up the surfaces. A good sign of poor maintenance or excessive crud in the engine. Make sure you clean the pickup screen and oil pan thoroughly inside and out before reassembling. There is an o-ring gasket between the pickup tube and front engine cover where it mounts, make sure you REPLACE THIS, and give everything a liberal coating of clean engine oil or assembly lube when installing, or else you will have difficulty getting oil pressure from a dry start. Terry
|
|
|
Post by Paul Hayden on Nov 15, 2011 0:52:59 GMT -5
Thanks for the information. I'm actually kind of glad you noticed some damage. I was thinking I might have done all this for nothing!
I only got as far as putting the oil pan back on today, so in the morning I'll take it off and get a picture of the crank surfaces while I'm replacing the o-ring you mentioned. However, I REALLY hope the crank is okay because I'm broke and I need to get her up and running ASAP. I may just have to roll with the crank as-is regardless. I'm currently driving my wife's Ranger, which gets horrible gas milage--a lose/lose situation!
|
|
|
Post by Paul Hayden on Nov 15, 2011 11:54:40 GMT -5
Here's the crank surface under one rod with the top half of a new bearing in place. It looks like a good fit to me. What do you think?
I took off the bolts for the pickup tube, but it doesn't seem to want to budge. Is there something I'm missing?
Also, the Chilton guide said to pack the oil pump with petroleum jelly to get a good vacuum. Should I do that too?[/b]
|
|
SeattleJusty
No, a boxer will not fit in a Justy.
Posts: 1,587
|
Post by SeattleJusty on Nov 15, 2011 15:56:38 GMT -5
In reverse order: yes, pack the pump with petroleum jelly, that much is a good idea. Now concerning the "looks like a good fit to me", with all due respect, that is insanity. Here is a snapshot from the Fuji manual and I believe the bearing clearances are supposed to be pretty tight, like .0008"-.0026" .0026" is less than the thickness of notebook paper. The human eye cannot appreciate that let alone eight-tenthousands. You need to get some plastigage fast and find out what kind of clearance you've really got because if there's say five thou. . . have mercy it's gonna be bad news when you start that thing up.
|
|
|
Post by Paul Hayden on Nov 15, 2011 20:30:51 GMT -5
Thank you. I did the measurement and it appears that I'm just under the limit. I got the oil pickup tube off, too. I just had to turn it back and forth to slide it off.
|
|
|
Post by justyjuggler on Nov 16, 2011 10:28:22 GMT -5
Looks good! Oil pump condition is determined by its shaft wear; they tend to taper just below the inner rotor and also slightly near the drive end.
|
|
|
Post by Paul Hayden on Nov 17, 2011 1:08:38 GMT -5
I'm very frustrated now. I got everything back together with new rod bearings, new oil pump rotors, cover and o-ring, new oil pickup tube o-ring, and 20w50 oil. But my oil pressure has barely improved at all. At cold startup it's around 40 psi. Once the car is fully warmed up, my oil pressure is about 18 psi on the freeway, 10 around town, and around 3 idling. I wonder how accurate my oil pressure gauge is. I bought the cheapest one they had. I don't know what to do. Any ideas? Also, what can I expect if I keep driving it like this? I drove it for a year the way it was. Maybe it'll be okay for a while longer. I work full time and I don't have a garage, so maybe I'll just keep changing the oil and hope for the best.
|
|
|
Post by redmavis12 on Nov 17, 2011 8:02:53 GMT -5
Paul, Is the knocking noise gone? I wouldn't sweat those pressure gauge readings...that's about what mine reads. I attribute my low readings to oil leakage due to all my seals being shot. Probably your main bearings need replacing or crank journals are worn. You've done everything you can short of engine overhaul.
|
|
|
Post by Paul Hayden on Nov 17, 2011 9:56:21 GMT -5
Thank you. That makes me feel better. Yes, it sounds better now except for some rattling coming from the exhaust, which was there before. I'll worry about the rest if and when I do an overhaul!
|
|