Priming Oil Pump (Dizzy-Driven) - Gurgle and Air Bubbles??

[StangGT5]

I am trying to prime the oil pump on my 92 RRC with a Gems-based 4.6 after a top end rebuild. I installed an aftermarket cooler (Derale) in the front grill via 8AN lines, and had the timing cover off for a new chain and gears as well.

I get resistance when spinning the pump, but hear loud gurgles from the distributor hole like a trucker who ran into a rest stop after taco bell. There are air bubbles coming from the rocker shaft too. Please see a video below.

I already tried replacing the oil pump gears with Rovers North parts and packed the hell out of them with assembly grease, with no real difference. I also checked the cover bolts to make sure they're tight. The gears that came out looked fine, and the engine was very quiet before disassembly.

Given that the sound is coming up from the timing cover through the distributor hole, is it possible that the timing cover gasket shifted on installation and the pump is struggling to pull a vacuum on the oil journal/pickup?

I know removing the timing cover, oil pump, and installing a cooler created a lot of variables, but I'm not sure where to start. I guess pull the cover and install a new gasket more carefully?

 

[terryjm1]

Did you do anything with the oil pick up tube / assembly?

 

[StangGT5]

Did you do anything with the oil pick up tube / assembly?

No. I replaced the oil pan gasket, but didn't touch the pick up.

 

[terryjm1]

I know you are a more experienced mechanic that me and you have likely already considered everything I would. However, one way to rule out or possibly give evidence to it being a pick up tube problem is to overfill the crankcase with oil so the level is above where the pick up tube connects to engine and try to prime it.

Also, i wasnt paying enough attention one time I had the timing cover off and used a 3.5/3.9/4.2 timing cover gasket on a 4.0/4.6 engine. I realized it before I tried to run the engine. From memory, I am pretty sure oil passage openings are a bit different.

Also, to eliminate it as a possibility, I’d take the oil cooler out of the mix and route the inlet and outlet together at the oil pump. I did this on the last engine I built until I confirmed it had oil pressure.

Furthermore, those gaskets for the oil pump housing are pretty easy to damage. Maybe that’s it?

My current last thought… I had a BMW 2.4 TD engine that wouldn’t prime. The oil pump is in the crankcase. Using very light compressed air i pressurized the inside of the engine (risky, I know for seals and gaskets but the next step was pulling the engine) and it primed very quickly. Maybe a little light pressure (and perhaps some smoke) and you might find where the air is being pulled in when the air pressure leaks out.

 

[p m]

Also, i wasnt paying enough attention one time I had the timing cover off and used a 3.5/3.9/4.2 timing cover gasket on a 4.0/4.6 engine. I realized it before I tried to run the engine. From memory, I am pretty sure oil passage openings are a bit different.

I believe the timing cover gasket is the same from late 1993 to the end of RV8. I can't even say the break is between V-belts and serpentine belt engines.

 

[StangGT5]

I know you are a more experienced mechanic that me and you have likely already considered everything I would. However, one way to rule out or possibly give evidence to it being a pick up tube problem is to overfill the crankcase with oil so the level is above where the pick up tube connects to engine and try to prime it.

Also, i wasnt paying enough attention one time I had the timing cover off and used a 3.5/3.9/4.2 timing cover gasket on a 4.0/4.6 engine. I realized it before I tried to run the engine. From memory, I am pretty sure oil passage openings are a bit different.

Also, to eliminate it as a possibility, I’d take the oil cooler out of the mix and route the inlet and outlet together at the oil pump. I did this on the last engine I built until I confirmed it had oil pressure.

Furthermore, those gaskets for the oil pump housing are pretty easy to damage. Maybe that’s it?

My current last thought… I had a BMW 2.4 TD engine that wouldn’t prime. The oil pump is in the crankcase. Using very light compressed air i pressurized the inside of the engine (risky, I know for seals and gaskets but the next step was pulling the engine) and it primed very quickly. Maybe a little light pressure (and perhaps some smoke) and you might find where the air is being pulled in when the air pressure leaks out.

Well I'm pretty inexperienced with distributor-equipped Rovers. I pretty much stick to Bosch and newer LRs.

You are right, there are different gaskets for the v-belt 3.9 and newer 4.6s. Lucky me, because the truck has a RPI 4.6 with a 92 3.9(?) timing cover. I bought the truck heavily modified, and the guy I bought it from did not build it. Not sure which gasket it should have. I likely used a 4.6 cover gasket because I have a bunch laying around.

Good idea on looping-out the cooler and overfilling. I pumped a bunch of oil through the oil sending unit port after filling to spec when I noticed it would not prime. I am probably a inch high over max fill on the dipstick now.

EDIT: Comparing the two timing cover gaskets, I used a P38 4.6 timing cover gasket. There are some minor differences, and I am thinking this may be my issue. The engine is a GEMS based 4.6, but the pump and cover are 3.9.

 

[terryjm1]

EDIT: Comparing the two timing cover gaskets, I used a P38 4.6 timing cover gasket. There are some minor differences, and I am thinking this may be my issue. The engine is a GEMS based 4.6, but the pump and cover are 3.9.

I did the opposite. I suspect you need the gasket that is for the timing cover, not the engine.

 

[StangGT5]

I did the opposite. I suspect you need the gasket that is for the timing cover, not the engine.

I guess I will find out soon enough. I will pull the belts and cover, install the 3.9 gasket and go from there. I noticed the coolant outlets are differently shaped as well, so I would likely have had a nasty coolant leak even if the oil ports lined up exactly.

 

[terryjm1]

I guess I will find out soon enough. I will pull the belts and cover, install the 3.9 gasket and go from there. I noticed the coolant outlets are differently shaped as well, so I would likely have had a nasty coolant leak even if the oil ports lined up exactly.

Good luck. I wish I could remember exactly where the problem was with the gasket not lining up. I was looking at it after putting it together and noticed an obvious gap betweven the cover and engine where there should have been gasket. It was still on the engine stand, fortunately. I used a little hylomar to hold the gasket on the engine while I installed the cover to help assure it stayed in the right place. When I took it off it revealed to the full extent how “off” it was. Moving forward I will always place the gasket on the cover first to assure it is correct. I have a tote full of gaskets leftover from previous projects, That is where that gasket came from. I should have marked them before they went in the tote.

On a related note, I have been using a really sticky red color engine assembly lube when I put together oil pumps, It’s obnoxiously sticky and works great. It is like is a thinned version of red and tacky general purpose grease. Unlike petroleum jelly, it doesn’t get pushed out until after a good amount of oil has circulated. My thought for using it was that if there was a failure in priming it would stay in there until it did prime. Having to repack oil pump gears is no fun. I might try the regular red and tacky grease on the next one. It seems it should work even better in that specific application.

Currently, I am battling death wobble on a D1 front suspension that has all new bushings and tie rods. All wear items have been replaced. Only 55,000 miles on the axle itself. As such, I do not think it is the source of the problem. So, I am going to swap around wheels and tires next to if that helps. It is the one that got that low mileage engine you pulled from the flood salvage white one.

 

[StangGT5]

Good luck. I wish I could remember exactly where the problem was with the gasket not lining up. I was looking at it after putting it together and noticed an obvious gap betweven the cover and engine where there should have been gasket. It was still on the engine stand, fortunately. I used a little hylomar to hold the gasket on the engine while I installed the cover to help assure it stayed in the right place. When I took it off it revealed to the full extent how “off” it was. Moving forward I will always place the gasket on the cover first to assure it is correct. I have a tote full of gaskets leftover from previous projects, That is where that gasket came from. I should have marked them before they went in the tote.

That is funny, because I do it the same way and thus made the same mistake. I put a thin film of hylomar or black rtv on the gasket and tack it to the block before installing the cover. With this hybrid engine I erroneously assumed the timing gaskets were the same. It was only when I laid them over one another that I noticed the differences. Then I looked at the one on the engine I saw the gap you're talking about. Luckily I did use hylomar on this one, and it's easier to clean off the mating surfaces.

The only thing I know about death wobble on birfield axles is that there is some adjustment to the end pins. It it's not right you can get a nasty death wobble. I'm not well versed in that adjustment, so I would've done what you did (tie rod links, bushings, and steering stabilizer).

I usually use "Driven" brand assembly grease for the pumps and Comp Cams 102 paste/lube for everything else. What's the name of the red grease you use in the pump?

 

[terryjm1]

Permatex 81950 Ultra Slick Engine Assembly Lube, 4 oz. , Red​

It is annoyingly sticky and worked great for the GEMS oil pumps I have put together. They primed very quickly. I use it for the bearings, lifters, and camshaft as well.

My next engine project will be for my TR8 that uses a distributor driven pump. I am aware of several instances of having trouble getting this type of pump to prime and lose its prime after long periods of inactivity. It’s not a great design although it was used for decades. I’m kicking around the idea of trying Lucas “Red and Tacky” general purpose grease mixed with the Permatex assembly lube to make it a little thicker and help assure it doesn’t leak downward out of the pump but also if there was a failure to prime it wouldn’t all be pushed out and stuck just above the pump. The possibility to leak downward toward the oil filter on the distributor driven pump is the only potential downside I can see to using the Permatex assembly lube alone in the pump. (It doesn’t leak out of the GEMS pump.) Before I make the decision to add the grease to the lube I will put the assembly lube in the pump (off the engine) and see if gravity causes it to leak down. if it doesn‘t, I will abandon the idea of adding the grease.


The Lucas Red and Tacky grease is typically for wheel bearings and u-joints, for example. It is also annoyingly sticky like the permatex assembly lube. Im sure most wouldn’t suggest this as a good idea as it isn’t ”listed” to be used in engines. Some would probably say it is a bad idea. However, it seems to have all the qualities you would want to assure an oil pump primes. That being said, I haven’t tried it yet and wouldn’t recommend it until I have that experience.

I learned a lot about building engines from a really old machinist when I was between ages 16 and 18. He was very old school and developed a lot of his own methods. That was over 35 years ago. A lot of his “philosophies“ rubbed off on me. This is exactly the kind of thing he would do. Although, I think he used regular general purpose grease to assemble engines. He would have said, engine assembly lube was just marketing to get more money out of your pocket. At the time, in St. Louis, he was “the guy” people wanted to build engines. He was a cranky yet funny old guy and I really liked working with him. He could call you a moron and make you laugh.

While I wouldn’t recommend the Lucas Red and Tacky general purpose grease for the reasons mentioned above, I fully recommend the Permatex assembly lube. It works great and is designed for that specific use. It is also fairly inexpensive.

 

[discostew]

I think it’s gotta be the pickup tube or the front cover gasket. What else could it be? It’s sucking in air someplace.

 

[StangGT5]

Houston, we have oil pressure.

I replaced the timing cover gasket with a 3.9 part, inspected the pick-up tube, replaced the pickup gasket and oil pan gasket. Upon refilling, I had no oil pressure. So I pulled the pump cover to re pack it with grease, and actually inspected it this time.

This truck ran super quiet, so these gouges may have happened the first time I tried to prime it without grease. Live and learn (and have a bunch of spare gaskets) I guess.

I planed the housing with 120, 320, then 400 grit to remove gouges, cleaned it, and reinstalled it with greased gears. It almost immediately started pushing oil out of the rocker shafts.

 

[Greg_M]

Thanks for posting the resolution.

 

[terryjm1]

Glad you got it figured out and followed up. I’ve seen worse with these oil pumps still producing oil pressure. I suspect you are correct the damage was caused after the pump pushed the lube out without being primed due to the air leak. All is well that ends well.

 

[StangGT5]

Thanks for pointing me in the right direction. I have been pretty lucky that I have not had to tear into the distributor-driven Rovers, so I never ran into this issue before. I was pretty relieved when it primed....mostly because I threatened the truck with a Chevy engine if it failed to prime this time and I'd have to follow through on the threat.

 

[StangGT5]

Just wanted to follow-up and say thanks to everyone that helped me figure out the oil pump issue. I just got the truck running again and am excited to have it moving under its own power. The first start went well...other than a massive fuel leak thanks to a rolled injector o-ring. I was a little unsure about how to make the DUI distributor work with the factory EFI, but it ended up being a simple two-wire install. I am not crazy about the fitment of the distributor or the live wires. This truck already had a relocated ignition module, so it likely wasn't worth the install.

Anyway, here's what a RPi 4.6 V8 sounds like with Rimmer Bros stainless headers.