Slow Engine Turnover

[Chancer]

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.

You say slow with the plugs in but you dont precise whether the ignition system is connected, too much static advance will slow the starter motor to a crawl, the distributor positioning on a rebuild is normally just a best guess until the engine iis running to time it.

[alan.barker]

Sorry i meant just on the gears in the oil pump only
Alan

[normand]

Had same trouble with starter with 10 tooth pinion, same starter with 9 tooth works perfectly!

[alan.barker]

The starter on my sprint sometimes jammed. I removed it to check and found the oil lite bush was worn next to the bendix. I bought a new bush very cheap and fitted it and it was 100%. Also changed bendix.
Now it's good for at least another 10 years
Alan

[StressCraxx]

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!

I completely agree. In addition, the gear oil has a totally different additive package for gear wear properties. The reaction between different additives can cause some strange substances to form and plug the oil filter.

Painful personal experience.

[CG901]

Thanks for all the great advice. I am testing voltage at the solenoid, and various points on the chassis for a good 12.7V. So far, getting good voltage reading. Easy to suspect the starter as its original. It does turn over the engine fine with no plugs. If I rule out low current to the starter, it might require a new high torque starter.

[john.p.clegg]

Testing for and getting a good 12.7 Volts doesn't really tell one anything , apart from continuity , if there is a resistive fault the idle state voltage readings will look good but the current flow will be reduced , hence slow starter speed/power.
Difficult I know but best to check voltages while the starter is in use.

John

[CG901]

Agree with John that testing voltage under load is best method to determine if there is resistance in the circuit or starter.

[john.p.clegg]

It may be worth taking the starter motor off and removing the end plate ( just two screws? ) and checking all four carbon brushes , if only one is down on length or sticking you'll be on half-power..

John

[CG901]

Yes, thank you John, will check the brushes.

[Craven]

Come on John, you know better than that! Brushes are COPPER in a starter motor, and have welded connections quite difficult to change.

[john.p.clegg]

Yes,but the braided copper leads are easy ( easier ) to crimp/solder..

John

[Chancer]

Not copper, a sintered conductive material, copper coloured and may have some in there together with other metallic powders in the mix.

Probably more carbon than copper nonetheless.

[john.p.clegg]

OK,ok , i'll edit to say

Yes,but the braided leads are easier to crimp/splice.

John .

[William2]

Being a rebuilt engine it is inevitably going to be tight initially so the starter motor is having to work that much harder. I had a similar issue with my car and wasn't happy with the quality of new/recon Lucas starter motors. I bit the bullet and bought a high torque Wasp starter from Sue Miller and never looked back. Much more torque and less strain on the battery. Money well spent in my opinion.