69 2.0L engine very slow turning over.

[murray]

2.0L 911T engine recently honed bores, new rings , rebuilt Weber 40 carbs now really reluctant to turn over at any speed. New battery fitted so have checked the timing...seems ok, lots of fuel in the carbs, new plugs, points, leads. Tried another battery from a new Audi...same problem, really sluggish.

Not sure if I am missing something so would be glad for someone to suggest where to check next. ( Cannot bump start as slightly uphill ! )

[Lightweight_911]

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Have you checked/cleaned the main earth connections to the 'chassis' ?

[KS]

I assume the engine's just been apart? Does it turn over easily by hand?

[bjmullan]

Have you tried taking out all of the plugs and turning it over with the starter, could be a lazy starter.

[murray]

Thanks to you all,

I have not tried turning it over without the plugs in ... I will do it and report back soon.

Turning it over on the crank by hand is still quite stiff but I put that down to the new rings etc ?

I have cleaned the earth from the gearbox to the chassis and the main battery one.

thanks, Murray

[RobFrost]

Did the engine work increase the compression? And did you do anything which might cause valves and pistons to meet? I'd do a compression test - make sure it's not too high. Are you sure the engine's well-oiled? Also, is it sucking and blowing in the right direction on all cylinders? It's possible engine work has simply improved compression and exposed an already weak starter. I had an old Volvo p1800 with poor compression and the cylinders flew around.

[murray]

Thanks Rob, I have not checked the compression since the work was completed but it turns over well without the plugs in and I am sure that there is nothing "touching ". Seems to be sucking and blowing correctly.

Beginning to suspect the starter !!

[RobFrost]

Thanks Rob, I have not checked the compression since the work was completed but it turns over well without the plugs in and I am sure that there is nothing "touching ". Seems to be sucking and blowing correctly.

Beginning to suspect the starter !!

I'd check all the high current leads - engine earth, battery both leads, ensure battery terminals are tight. Add a 2nd battery / jump leads. Also, did you fill the engine with heavier oil than was taken out? Also, after a piston change did you measure your new compression ratio before reassembly?

[RobFrost]

On the question of excessive compression, also consider the possibility you took out an oversize gasket / cylinder shims if it wasn't you who assembled the engine on the previous occasion.

[murray]

Thank you all, I have checked and cleaned all the leads and will be trying a second battery . engine oil is much lighter at present ( 5/30) as the previous was gloopy and unknown. Did not measure the new compression before re-assembly.

There did not appear to be any unusual gaskets or shims when taken apart but not sure of exact measurements.

[RobFrost]

I'm really curious to learn how this is or was ultimately resolved so please follow up when a solution is found.

[murray]

thanks Rob, engine now out as there seems to be a tight spot every revolution when turned by hand...will update after more dismantling !!

[RobFrost]

oh dear sorry to hear that