Hydraulic roller cam 318 low oil pressure

[Frazzlesnap]

This issue has been vexing me for a few months, now. I had a lifter collapse on my flat tappet hydraulic cam, so I upgraded to a hydraulic roller. The clearances for the lifter bores all checked out fine. I used to have 65psi of oil pressure at cold idle with the old setup, and about 45psi hot. With the new setup, I have... 65psi of oil pressure, cold. But it drops precipitously as the engine warms, to the point where I only have about 10psi when it's idling for a protracted interval in traffic on a warm day. Revving the engine immediately raises the pressure. For example, I get 60psi hot at 3000rpm. I'm using the same Valvoline Synpower, 10W-30, as always. I have two mechanic friends who are baffled. The flow rate is fine, and it's draining back down to the pan okay, so I'm not experiencing starvation. I am considering redoing the whole bottom end, with a stroker crank, all forged components, and a Milodon 7qt baffled pan, high volume pump, etc. I don't want to do anything aggressive until I have the oil pressure sorted out. Only the top of the motor was touched. I've got Edelbrock Performer RPM heads, oiling through the shaft like stock. I apologize if this is something obvious that I should already know. I've rebuilt brakes, a three-speed manual transmission, and performed general work on motors, but I've never built one myself, and am somewhat clueless as a result. Thanks in advance.

 

[Davea Lux]

What is your idle RPMs? If you put in a big loping cam you may be idling too low to get adequate oil pressure. Have you checked you gauge to be sure it is accurate? With a manual transmission you should idle at at least 750-800 RPMS. Next what thermostat are you running? Should be 180 degrees for most applications. A 195 degree thermostat will drop the oil pressure at idle about 10psi at idle with 10-30 oil. Going to 10-40w or 15-40w might help also as these older engines usually did better with more viscosity. Have you pulled the oil filter and drained the contents to check them for metal. If you see lots of shiny stuff in the oil from the filter, that is wear metal and something is failing. Run a magnet into the drained oil to see of any iron shavings stick to the magnet. If so there may be a problem with the cam shaft, or crank shaft. If the shiny stuff in non magnetic, it is probably bearing material indicative of failing bearings.

I would also run a compression check on all cylinders, if you have one or more that is low, that can be a further indication of a failing camshaft. If you installed a comp cams roller unit, they have had issues with the cross links breaking, that will run the cam instantly flat and put metal into the oil. It can also cause the lifter assembly to pop out of the bore with a resulting drop in oil pressure, although I do not think that is likely in this case because you still have some pressure.

Run these checks and report back.

Dave

 

[Mr onetwo]

Have you got the right pushrods and lifters?Did you make sure that the rocker shafts, ect. are installed correctly?

 

[70bigblockdodge]

Pushrod length.

 

[twostick]

Probably the roller lifter itself allowing more oil to pass. You didn't say what lifter you are using.

If it still runs 60 psi revved up, I wouldn't be too concerned about the idle pressure if the ONLY thing different is the roller cam. Try some 15w40 Rotella and see what happens.

Kevin

 

[Frazzlesnap]

Thanks for the replies. I paid a mechanic to go through the top end and verify all the fitment, and he and I both contacted Edelbrock and Comp Cams for extensive chat sessions. The only thing that seemed plausible to me, which the mechanic and Comp Cams said wasn't the case, was that the lifter bores might be too short, so the lifter(s) were losing pressure. The mechanic said he checked the bores while rotating the engine, and there wasn't anything abnormal. He verified the bores before installation. The parts were ordered after a long discussion with Summit Racing. Comp Cams tried to sell me a Big Mother Thumpr cam, which I said would be ridiculous in this engine, especially since I still needed decent low range torque. The pushrods are hollow, which I know isn't necessary, since the shafts and galleys in the block supply oil. I don't know why the mechanic ordered hollow pushrods, but that shouldn't be a problem, right? He's proven himself competent according to a lot of other folks, but he'd never worked on an LA Mopar motor for this kind of retrofit. I ordered everything except the valve springs, guides, retainers, and pushrods, so anything aside from those is totally my fault!
Part numbers:
lifters Comp Cams 8920-16
pushrods Comp Cams 7808-16
rockers Comp Cams 1622-16
cam Comp Cams 20-810-9
The springs and such are Edelbrock parts.
I was also wrong about the hot pressure at 3000rpm. It's only 52psi.
Again, thanks to everyone who has offered information and advice! This community is great!

 

[Davea Lux]

Some roller cams use the hollow push rod to lubricate each end of the push rod and the rocker. There is also an oil passage thru the head that pumps oil into the rocker shaft to lubricate the stock rocker shaft on the LA series engines. The Magnum series used hollow push rods, the rest mostly did not. If you are double oiling the top end of the of an LA engine, that could be causing drop in oil pressure as you added 32 oil leaks from the ends of the 16 push rods. Most builders block the oil passage in the head to restrict oil flow to the stock passage when converting to hollow push rods as is is no longer needed. Did you use the stock rocker shafts?

Here is an article about the different oiling systems on the 318 engine:

Mopar Engine Performance Guide: Valvetrain - Mopar DiY

Dave

 

[Mr onetwo]

do some reading in this thread over on FABO, might help. Low oil pressure?

 

[Big_John]

This issue has been vexing me for a few months, now. I had a lifter collapse on my flat tappet hydraulic cam, so I upgraded to a hydraulic roller. The clearances for the lifter bores all checked out fine. I used to have 65psi of oil pressure at cold idle with the old setup, and about 45psi hot. With the new setup, I have... 65psi of oil pressure, cold. But it drops precipitously as the engine warms, to the point where I only have about 10psi when it's idling for a protracted interval in traffic on a warm day. Revving the engine immediately raises the pressure. For example, I get 60psi hot at 3000rpm. I'm using the same Valvoline Synpower, 10W-30, as always. I have two mechanic friends who are baffled. The flow rate is fine, and it's draining back down to the pan okay, so I'm not experiencing starvation. I am considering redoing the whole bottom end, with a stroker crank, all forged components, and a Milodon 7qt baffled pan, high volume pump, etc. I don't want to do anything aggressive until I have the oil pressure sorted out. Only the top of the motor was touched. I've got Edelbrock Performer RPM heads, oiling through the shaft like stock. I apologize if this is something obvious that I should already know. I've rebuilt brakes, a three-speed manual transmission, and performed general work on motors, but I've never built one myself, and am somewhat clueless as a result. Thanks in advance.

Am I the only one that looks at this and says "Hmmm... Why did the lifter collapse?" and then says "I wonder if it was a drop in oil pressure".

This makes me wonder if the new problem really isn't a new problem.

 

[Frazzlesnap]

Am I the only one that looks at this and says "Hmmm... Why did the lifter collapse?" and then says "I wonder if it was a drop in oil pressure".

This makes me wonder if the new problem really isn't a new problem.

Oddly enough, the oil pressure was reading about 60psi when the lifter collapsed. I figured it was defective. Maybe not?

 

[Frazzlesnap]

do some reading in this thread over on FABO, might help. Low oil pressure?

View attachment 381834

Thanks. I'll check it out.

 

[Frazzlesnap]

Some roller cams use the hollow push rod to lubricate each end of the push rod and the rocker. There is also an oil passage thru the head that pumps oil into the rocker shaft to lubricate the stock rocker shaft on the LA series engines. The Magnum series used hollow push rods, the rest did mostly did not. If you are double oiling the top end of the of an LA engine, that could be causing drop in oil pressure as you added 32 oil leaks from the ends of the 16 push rods. Most builders block the oil passage in the head to restrict oil flow to the stock passage when converting to hollow push rods as is is no longer needed. Did you use the stock rocker shafts?

Here is an article about the different oiling systems on the 318 engine:

Mopar Engine Performance Guide: Valvetrain - Mopar DiY

Dave

I knew about the oiling differences between the LA and Magnum engines, at least in general. I was told, perhaps erroneously, that the hollow pushrods wouldn't matter, because the rocker shafts were of stock design, so there shouldn't be double oiling. Comp Cams and Edelbrock both said it wouldn't matter. It was the first thing I asked them when I found out that the pushrods were hollow. I know that the shaft serves to lubricate the rockers and their tips, but... I think I just confused myself! If you're right, then maybe I just need solid pushrods. I hope that's the case. Thanks!

 

[twostick]

I knew about the oiling differences between the LA and Magnum engines, at least in general. I was told, perhaps erroneously, that the hollow pushrods wouldn't matter, because the rocker shafts were of stock design, so there shouldn't be double oiling. Comp Cams and Edelbrock both said it wouldn't matter. It was the first thing I asked them when I found out that the pushrods were hollow. I know that the shaft serves to lubricate the rockers and their tips, but... I think I just confused myself! If you're right, then maybe I just need solid pushrods. I hope that's the case. Thanks!

If it has lifters that will oil through a hollow push rod and you have those kind of push rods, that's where you oil pressure is probably going. No need to change push rods tho, just get some lead shot and plug the push rod. If your oil pressure comes back, you'll have your culprit.

Kevin

 

[70bigblockdodge]

Your oiling the valve train 2 different ways, pick one or the other, as long as it is through the shafts. Solder or braze the end of the pushrods shut and the oil pressure will come back.
This is provided that the lifters are correct for a LA engine and not AMC retrofit stuff. Which Comp Cams seems to be peddling slot lately. UTG/Lunar outlook garage, my brother in law, and our local Mopar machine shop guy have all been burned by thier non Mopar spec lifters.

 

[twostick]

Your oiling the valve train 2 different ways, pick one or the other, as long as it is through the shafts. Solder or braze the end of the pushrods shut and the oil pressure will come back.
This is provided that the lifters are correct for a LA engine and not AMC retrofit stuff. Which Comp Cams seems to be peddling slot lately. UTG/Lunar outlook garage, my brother in law, and our local Mopar machine shop guy have all been burned by thier non Mopar spec lifters.

The OP is running a hydraulic roller. I don't know if he's running stock Magnum roller lifters or aftermarket but the Magnums for sure will be set up for push rod oiling and I'd be surprised if aftermarket ones weren't that way also.

I don't think heating a push rod hot enough to braze or solder it is a good idea. Using lead shot or a BB to plug the push rod solves the problem without risk of messing with the heat treatment.

Once the shot or BB is in there, it can't go anywhere.

Kevin

 

[70bigblockdodge]

The OP is running a hydraulic roller. I don't know if he's running stock Magnum roller lifters or aftermarket but the Magnums for sure will be set up for push rod oiling and I'd be surprised if aftermarket ones weren't that way also

Agree, his are retrofit, not sure why you would want to spend that kind of coin on a teener, but to each his own. If they are comp pushrods there is no heat treating, just a tube with two ends. Apparently comp decided that they would only carry AMC spec lifters now which the cup is deeper in the lifter, which is fine, but they don't spec different or warn against using stock type push rods.
It's yet IMHO Comp being your friend if you have a TV show or magazine. Everyone else ca-ching see you later, sorry about your problems.

 

[Frazzlesnap]

Thanks to everyone for the advice and information. I've checked the top end while running, and I can't see any oil coming out of the pushrods. Since the lifters are under pressure, if they were designed to alternatively be able to oil through the pushrods, wouldn't there be oil seeping out the top? My mechanic friend ordered a set of standard pushrods, so I'll try those. As has been notedl, I've spent way too much money on this thing already. I've just been determined to try and get something out of the original block. I'm seriously wondering if the lifters are just too tall to stay sealed against the bores through the whole reciprocating process. If they are, then it would be easy for the pressurized oil to seep out, wouldn't it? Sorry if I'm being obtuse. Again, thanks for the information.