Trouble Cranking Engine After Rebuild

[William2]

I have just tried to start my engine after restoring my S4 Elan and found that the starter motor is struggling the crank the engine over at all! Engine has been rebuilt to SE spec. Starter motor, solenoid and wiring is all new. Battery is fully charged. With the plugs removed the engine will turn over at sufficient speed to prime the float chambers and register oil pressure on the gauge. I know that a rebuilt engine is tight at first and the oil, etc is thicker on a winters day.
Has anyone else experienced this situation and have any ideas?

[dougal9887]

Ignition too far advanced?

Dougal.

[Grizzly]

I know you say the battery is fully charged but is it a decent battery? (the 2 seater battery is usually quite small with lowish CCA which never helps) my plus 2 used to struggle if it didn't catch first time as it takes some effort to turn a high compression motor over.

Some thing else that doesn't help is the Carbs, if you crank with the Throttles fully shut it struggles but if you hold the throttle open slightly as you crank it does tend to turn over easier.

Of course that's all assuming you have a good ground strap to the engine/starter? if its poor you will end up cooking the smaller grounds going to other things.

[gus]

will it crank with the ignition defeated and plugs in?

will it crank with a jump start?



a new engine may be marginally harder to crank, but unless something is very wrong, it should not be noticeable

[StressCraxx]

Check your battery to chassis ground and your grounding strap from the chassis to the engine at the motor mount. All should be clean and bare metal.

Regards,
Dan

[Mick6186]

I recently rebuilt my +2 engine and had the same symptoms as you describe. Fast cranking with the plugs out, but a real struggle with the plugs in. I tried a change of starter to no avail. Jump leads to my diesel car battery, with the donor car running made no difference. I believed my old battery was ok, but decided to change it for one with the highest CCA I could find. Massive improvement, with the engine starting with no problems

[TroonSprint]

I'm impressed that you can get oil pressure using just the starter. Mine won't achieve that. My rebuilt engine is fitted with a modern pre-engaged high torque starter and it spins away merrily, even with the plugs in.

Can you measure the voltage drop when you are cranking with the plugs in? Have a look at this web page. http://www.mgb-stuff.org.uk/electricstext2.htm#heavy Paul Hunt is an MGB enthusiast who has written probably the most comprehensive practical web site on all aspects of those cars. Since many Elan components and systems are identical to MGB ones, it is well worth looking in mgb-stuff for answers to all sorts of problems.

Dougal's comment on ignition timing being too far advanced is worth considering too, but I bet it's a large voltage drop issue.

Mike

[alan.barker]

i had this problem and i had fully charged the battery. I tried a known good different battery from my TVR and hey presto super. The battery in my Elan Sprint was knackered with no force.
It's easier to try a different battery than faffing about
Alan

[William2]

Gentlemen, thanks for your help. I have ordered a 550CCA battery off Ebay as the first way forward. If that fails I will try a new 240Amp positive copper core battery cable. There is a company in Bristol that makes them to order.
I have also bought a 10 tooth starter motor spare in case my "made in India" one is dodgy!! The battery earth cable, engine braid link cable and solenoid to starter cable are all new and I made sure that the metal to metal contact was good when I put the car together.

[ericbushby]

I know this has been covered many times, but I believe the starter pinion should be 9 teeth for our twin cam engines. That is what I bought on the recommendation of a local Lotus specialist and reading this forum.
Eric in Burnley
1967 S3SE DHC

[William2]

I tried fitting a new larger capacity battery today but even this will hardly turn the engine over at all with the plugs in. However, what I didn't mention was that the starter has been making awful grinding noises which I new wasn't right.
I removed the starter motor which was made in India as it happens and it looks like the pinion casing has been rubbing on the clutch housing I presume. This obviously explains the mechanical grating noises and may even explain why the starter motor is not doing what it should. Tomorrow I will shine a torch in the bell housing/flywheel area and keep my fingers crossed that there is no damage to ring gear, etc. It has occurred to me that maybe the pinion has been manufactured slightly oversized but I have just stumbled across an old form thread where someone else also experienced this same problem.
I have sourced an original Lucas Mini 10 tooth starter from Ebay and will measure the pinion diameter and compare the two. The thought of having to remove the newly installed engine depresses me, so if needs be I was thinking of removing the pinion and getting a machine shop to skim a bit off the pinion casing.
Who would have thought that an issue like this would arise, but it would appear I am not the only one who has had this problem.

[Chancer]

I dont know what number of teeth your ring gear has but what you describe is exactly what happens when you use a 10 tooth pinion where a 9 tooth one is required.

When you hear the music of the properly engaged pinion, see how fast the engine cranks over and how easy it starts you will be kicking yourself.

The next time you hear another car with the same affliction you will wince!

I am wincing just reading your posting

[alan.barker]

when you rebuilt the engine did you change the Clutch pressure plate. The outside diameter of the pressure plate could also be oversize. Imho the problem is not the difference between 9 or 10 tooth bendix gears.
Alan

[ericbushby]

It may have been my post which you read about the bendix sleeve rubbing.
In that case it was sufficient to reduce the diameter of the sleeve a little with the bench grinder. It only needed about ten thou` to clear.
Later when the engine was out I removed some metal off the edge of the pressure plate where it had been touching using an angle grinder.
Later still, I fitted a modern pre-engaged 9 tooth starter, which works on the other side of the starter ring clear of the pressure plate, although that wasn`t the reason for fitting it.
Should your starter ring be damaged, that is an option for you. While you have the starter out just check that the ring teeth are chamfered both sides, they usually are.
Best of luck,
Eric in Burnley
1967 S3SE DHC

[alan.barker]

with a pre-engaged starter you do not need the chamfer the other side.
Alan