Lotus Elan and Lotus Elan Plus 2 Forums

The twincam stock engine was rebuilt and original starter re-installed. The engine turns nicely with the plugs out, but doesn't get oil pressure. With plugs in, it will hardly turn over. Battery is new and fully charged. Any ideas where I should explore for the problem? Thanks.

I'm just starting on this path with my first rebuild so am no way an expert , but I would think reading other posts the oil pump should be packed with vasalene to get it to prim with the plugs out.

Also did you use a rebuild grease on the bearings , and just my thought but some light oil on the rings or cylinder walls.

Just ideas

Steve

Thanks Steve, I am not too concerned about the lack of oil pressure. It has oil in the oil filter, and I have pressure filled the oil pump from the gauge line. I have also packed the oil pump with assembly grease. My concern is the lack of sufficient starter rpm with plugs in. It's just painfully slow.

I don't understand why people pack oil pumps with Vaseline. Before you fit the pump all you need to do is trickle some engine oil into the pump inlet whilst rotating the skew gear by hand to ensure the rotors are covered in oil and also to fit the filter prefilled with engine oil.

That's the pumps normal operating mode. It never requires Vaseline to get it started in normal operation so why should it require it during initial assembly? I've never used anything but plain engine oil for prefilling pumps and never had a problem with the pump priming.

CG901 wrote:Thanks Steve, I am not too concerned about the lack of oil pressure. It has oil in the oil filter, and I have pressure filled the oil pump from the gauge line. I have also packed the oil pump with assembly grease. My concern is the lack of sufficient starter rpm with plugs in. It's just painfully slow.

After rebuilds I always insist on getting oil pressure before firing the engine. Although I fill the pump and filter during assembly, I often need to backfill the oil system through the oil pressure gauge tapping with an oil filled grease gun. To get the pump working, turn the engine with the plugs out, and the oil pressure gauge plug removed, until you get oil coming out there (messy, but effective then replace. The engine should be spinning over at a good rate.

I think the slow turnover with the plugs in is an unrelated problem. Did you check the crankshaft was free as you progressively tightened the main and big end bearings ? Have you tried changing the starter ?

2cams70 wrote:
That's the pumps normal operating mode. It never requires Vaseline to get it started in normal operation so why should it require it during initial assembly?

In normal operation the pump both the suction tube and the pump remain air-tight and full of oil. However, after an initial assembly the pump suction tube will be dry, and the suction side of pump will also be more or less dry

I will try priming the oil pump whilst turning the engine over with plugs removed. I am not certain this addresses the larger problem of sluggish turnover with plugs in.

CG901 wrote:Thanks Steve, I am not too concerned about the lack of oil pressure. It has oil in the oil filter, and I have pressure filled the oil pump from the gauge line. I have also packed the oil pump with assembly grease. My concern is the lack of sufficient starter rpm with plugs in. It's just painfully slow.

Compared to others on here I'm a complete novice but I would suggest trying a different starter motor, if only to rule it out. When I first got my car it was a bugger to start (cranking until the battery was flattened). It was returned to the garage 3 times, who fixed a bad earth, replaced the coil, condenser, rotor, HT leads, fuel pump and eventually fitted electronic ignition which improved things but didn't fix it completely. Eventually the problem diagnosed itself, as the starter pinion started to jam in the ring gear. Replacing the starter with a refurbished Lucas motor transformed the car. Much faster turn over, no more flattened batteries, and no problems since.

Incidentally, I revisited the starter motor issue a few weeks ago. When getting the replacement starter motor I bought two on ebay. One from a company that refurbishes starter motors*, and another from a private seller which was a NOS Lucas factory refurbished starter. I fitted the former motor as it arrived first but a couple of weeks ago I fitted the factory starter while replacing the engine mounts. The supposedly NOS motor turned over slowly and jammed in the ring gear. Taking it out and connecting it to a battery with jump leads, it ran slowly and drew so much current the insulation on the leads melted...

* The picture on ebay was a Lucas starter motor, but they supplied an Indian-made repro. I eventually got a refurbished Lucas starter but it took a bit of aggro. I bought the other motor in the meantime.

Check all your grounds. Battery to chassis, and the braided strap from the chassis to the block. Pull each one, clean the surfaces to bare metal, then reinstall.

Pull and remake each connection between the battery and the starter solenoid, then to the starter.

Make sure your battery is fully charged or attach a second battery with jumper cables.

If it still no better, then try replacing the starter.

Foxie wrote:In normal operation the pump both the suction tube and the pump remain air-tight and full of oil. However, after an initial assembly the pump suction tube will be dry, and the suction side of pump will also be more or less dry

Don't agree I'm afraid. It's one of those urban myths. Oil pumps were never "packed with Vaseline" on the engine assembly line by Ford and the pump isn't air tight. The oil drains back each time the engine is stopped. A viscous fluid like Vaseline could cause hydraulic locking. It's an oil pump not a grease pump.

+1 never used vaseline in oil pump, only engine oil. Filter bowl filled with engine oil and gears in pump oiled.
When vaseline arrives in bearing shells it's not an engine lubricant and too thick.
Alan

2cams70 wrote:I don't understand why people pack oil pumps with Vaseline. Before you fit the pump all you need to do is trickle some engine oil into the pump inlet whilst rotating the skew gear by hand to ensure the rotors are covered in oil and also to fit the filter prefilled with engine oil.

That's the pumps normal operating mode. It never requires Vaseline to get it started in normal operation so why should it require it during initial assembly? I've never used anything but plain engine oil for prefilling pumps and never had a problem with the pump priming.

Vaseline or grease is more likely to stay within the pump in a decent quantity - this helps if the engine is rebuilt and then not run for a while. Pretty much the same as using Graphogen to rebuild an engine - if the engine is laid up Graphogen doesn't go anywhere so is still there when the first start-up occurs.

I've tried both methods with oil and grease in the pump (ie fully primed) and it doesn't ever work as well as grease.

I agree with Graphogen because it's an engine lubricant but imho vaseline isn't an engine lubricant.
Maybe it's possible to use ep gearbox oil also.
I have used stp engine oil additive for rebuilding with no problems.
Alan

I'm with Stresscraxx. Eliminate poor connections. Use jump lead from battery negative all the way to the engine metal to bypass negative path. See what happens with starter rpm. You could also do the same to the positive path from bat pos to solenoid feed terminal. Being careful not to flash/short anything.

If you do have bad joints you will also have heat. A few have had heat on the negative chassis connection in the boot or trunk connection. Someone burnt his fingers as I recall. I have also had starter solenoids that have failed to connect properly when energised causing lazy cranking (due to age and too many operation). Again some heat. Try another solenoid if all the conductor test prove nothing. Solenoids only have a certain life as it is a tough duty and they can fail. I have also had lazy starters and they do tend to fail with load (plugs in). Swap job. Othertests are less intrusive and worth eliminating first.

Mike

I would NOT use gear oil in your engine. I had to strip an engine and replace all the bearing shells after using it to prime. It seized up due to dragging all the white metal away. Costly lesson that one!