Low Oil Pressure at Hot Idle

[RattFink]

I JUST got my project car of six years running and driving. I've put about 50 miles on it. I let it warm up, then took it for a drive this morning, only about 6 miles. It was running very good with no issues. I came home to double check some things and planned on going for a good long drive since it's so nice out. At idle in the driveway, the low oil light came on. Revved engine and light went off. Shut off car, hooked up my OTC oil pressure gauge, started car and let idle. Hot idle oil pressure was low, 3-4 psi. Revved the engine and oil pressure shot up to 50/60 psi. Now, when snapping the throttle I am pretty sure I heard a rod knock upon the initial snap, but the noise went away as pressure shot up. It was a very sharp, metallic, double knock. I snapped the throttle again, I heard it again although not as bad as the first time. This is a stock 1986 T1 in a Shelby Charger. The engine came out of a 1986 Lebaron that was wrecked in the early 90's with 36,000 miles on it. I picked up the engine in 2010/2011 after it had been sitting for YEARS. Shortly after I bought the engine, I tore it down. The rotating assembly was left in, but everything else removed, inspected, cleaned. Oil pump was removed, cleaned, installed per service manual. Intermediate shaft was removed, inspected. Crank and rod bearings were plasti-gauged and all within spec. Everything looked good. Now this was all 5 years ago, but this is the last problem I expected to have with first getting this car on the road. Any input?

[Vigo]

Look for bearing material in the oil. If you don't find any, run thicker oil. That's what i would do if i didn't want to take it apart again. I've had single-digit hot idle oil pressure on most of the 8v's ive ever checked it on. But if the oil pressure is changing because something is letting go, it's only a matter of time before you take it apart one way or the other.

[iTurbo]

Does it have the oil restrictor (pressed in deck surface of block?)

[RattFink]

The oil restrictor is in the block, was never removed, and triple checked that it was there before assembly. The oil pump was installed with anaerobic sealer, and an o-ring was used on the pickup tube. The engine looked great inside, could tell it was low mileage. I probably should've just replaced the bearings, but they all measured fine... There seems to be some bearing material in the oil. Looks like the oil pan will be coming off next. I guess this is why we call them project cars. Hopefully it's nothing serious and I can be driving it again soon...

[minigts]

If there is bearing material in the oil, there will be more in the pan. I can say from experience that I have been able to take bearings that were REALLY worn, put in stock bearings and the car ran for a good year after without issues. Not saying you should let it ride, but sometimes it's the easiest fix. Just make sure there is no scoring on the crank or rods. If you spun a bearing it more than likely it has already. Good luck and post pics of what you find.

[85glht]

If you do take it apart, check the inner intermediate shaft bearing. I ran into the same situation after I had a machine shop go through the whole block.... The inner bearing was shot and they missed it. I was able to replace it in the car..... It was a PITA but possible. Good luck.

[Gaboon]

If all looks okay, either change to a heavier oil or add half a bottle of Lucas heavy duty oil stabilizer.

[RattFink]

Oil pan off, oil very very grey metallic looking, but no large chunks. Removed oil pump, large chunks of metal in oil pump gears, and larger chunks below the oil pump gear caked on the oil pump housing. It doesn't look like bearing material though, it looks like oil pump/intermediate shaft gear chunks.

[minigts]

Pics would be good, assuming you can see the intermediate gear though? That's not uncommon to fail. FWDP sells them, maybe TU too? Best to ensure you have a good one and replace it and the pump. If there are metal shavings in the pump at all, I would count it suspect.

Not 100% sure, but I think that CAN be caused by the timing belt being too tight. There is a tensioner tool you can get online, eBay and what not, that will set the tension correctly.

[RattFink]

The timing belt was riding toward the outside of the cam pulley. I had planned on adjusting the tension, but dang I only put 50 miles on it! I'll get pics later tonight. A few questions:

Can the intermediate shaft be removed with the engine still in the car?

Can intermediate shaft bearings be replaced with the engine still in the car?

I have the original engine on a stand with the intermediate shaft and oil pump in it. Best combo of new and used parts to make this last?

[minigts]

The timing belt was riding toward the outside of the cam pulley. I had planned on adjusting the tension, but dang I only put 50 miles on it! I'll get pics later tonight. A few questions:

Can the intermediate shaft be removed with the engine still in the car?

Can intermediate shaft bearings be replaced with the engine still in the car?

I have the original engine on a stand with the intermediate shaft and oil pump in it. Best combo of new and used parts to make this last?

I think that is indicative of a tight belt. If you put any load on the motor, that may have been it or it simply could have been weak and gave out. The IS can be removed with the engine in the car, you'll need a pneumatic to remove the gear for the IS and then 10mm to remove the retaining race bolts (3). After that it will slide out fairly easily. The bearings only need to be replaced if they are worn, but wouldn't hurt to do while you're there. The bearings can be replaced, but be EXTRA careful installing the new ones. You have to press them in, but if you're not careful you can damage the new ones by flaring the bearings depending on what you use to press them in. DodgeZ has a tool he made or had made that worked like a champ for me, but not sure if it's something he bought. Basically it was in the shape of an intermediate shaft with a seat for the bearings that was flat so the bearing would have equal and flat force as it was pushed into the slot. He may see this thread and post a pic of the tool. I think you can use the IS to push in the larger outer bearing, but not the smaller inner one.

No idea what combo to go with, just as long as the new one has no damage. Cordes will know what tool to use when setting tension for the belt, but the rule of thumb is to be able to turn the belt 90* on the front side of it easily, but taught at 90*. If it goes beyond that easily, it's too loose and if not to 90*, it's too tight. You will figure it out as you do it, but the tool is a better idea if you can find one.

[Vigo]

I've replaced the intermediate shaft in the car after my teeth stripped in the middle of Harris Hill raceway in front of everyone and i had to get towed in.

I've found one good way to keep from screwing up bearing surfaces with driver tools is to wrap the tool in a good layer of teflon tape before driving the bearing.

[crusty shadow]

You should definitely pull the engine and tear it down completely. If the oil has the grayish color you describe that means metal particles are acting like a slurry everywhere inside the engine- especially the lash adjusters. If the IS bearings are toast it is possible to replace them in car but its a lot of work and a much higher chance of not getting them installed correctly vs doing it with the engine on a stand.
expect to have to replace the the IS bearings, the lash adjusters ( there is no way to clean them out once they get full of metal- trust me they are trashed) the IS itself and the oil pump. hot tank everything and replace the crank bearings too.

I know thats not what you wanted to hear but anything else is really a band-aid patch and the problem will reoccur later on down the road, and you run a very real risk of damaging the cam bores in the head due to the metal particles that will keep showing up in the oil.

[cordes]

You can find them a lot cheaper than this if you can find the generic version of the tool. You'll be amazed at how little force is required when you use one for the first time though. I'm fairly certain a guy could use his hand to twist the tensioner if the motor were on a stand. It's really not that much.

http://www.toolsource.com/timing-bel...-p-114273.html

- - - Updated - - -

ETA: I picked mine up a few years ago, but I paid about $15 shipped for the tool I have.

[RattFink]

It's all apart. Intermediate shaft bearings look OK, not perfect but the shaft spun nice and smooth without the oil pump or distributor in. The largest chunks of metal were all caked on the oil pump, right below the drive gear. Like parts of the intermediate shaft/oil pump gear were falling straight down and settling there. Absolutely no large chunks of metal in the pan. I haven't pulled any rod caps yet. Pics of the intermediate shaft/oil pump will be up soon. I can get better pics tomorrow. I thought the gears would look worse than they do, but I don't have good ones to compare them too.

[RattFink]

[minigts]

I don't think that is your problem. I'd look elsewhere. That shaft looks fine to me.

[black86glhs]

I don't think that is your problem. I'd look elsewhere. That shaft looks fine to me.

I agree with Jon, it looks fine. How do the main and rod bearings look?

[RattFink]

I haven't pulled them yet, that will be tomorrow's project I suppose. I was hoping to get more done on it this weekend, but I haven't really been feeling well and have been taking it easy. I'm kinda bummed out right now and am looking for 2.4 engines I could buy LOL.

[minigts]

Rods you can check just by removing the caps, but the crank bearings will require more for the end ones. You could probably move the rods up and down by hand and tell if any are gone. I know I did that with one that went bad. Swapped out all 4 and put it back together and just drove it until I got the new motor in. It's not ideal, but it will work if you need to be able to drive the car. Otherwise, I'd get the whole bottom end rebuilt.