stiff engine

[cadetchris]

recently rebuilt the engine in my moggy, and used copious amounts of oil to lube up all the parts nicely.

however, i have put it in the car and i can barely turn the thing over, the handle is very very very stiff and the starter motor dosent have the umpf to turn it over, i just get a click as the teeth engage and thats it.

filled the sump with oil, so it has oil.

with the engine being so stiff, i cannot start it at all.

any ideas how i can fix this?

i really dont want to have to have to re-rebuild the engine as i haven't had the car going for 3 weeks now, and the novelty of the scooter is getting very thin now

[PSL184]

Did you turn the engine over by hand as you were rebuilding it? ie after each bearing cap was torqued up and after the head and valve gear were fitted? If was OK then it should be OK now. If it really is "that" tight then it will have to come out to find out why it is binding up.

[cadetchris]

thats what i did, once each bearing was tightened up, i rotated the engine to move the oil around abit. i also put in each piston without the rings, just to check that they moved without binding.
when it was on the bench, i could just about turn it with the spanner, once in the car it would turn on the motor (with abit of effort) and now the starter just click and dosent turn the engine.

what could of changed in the past few days?

[PSL184]

I would expect it to be tight after just been rebuilt (from what you say it sounds OK) - are you sure the battery is charged up? Make sure you have attached all the cables to the starter and battery securely too.

[cadetchris]

battery is definitely charged, i put it in mums car and gave it a further good run around, just to make absolutely sure, so yes the battery is all good. all cables connected and clean, earthing straps connected.

[PSL184]

Check the starter is not jammed on the flywheel. Put car in 4th gear and rock it to see if it clears.

[bmcecosse]

" on the bench, i could just about turn it with the spanner " - That's far too tight - you should have been able to turn it (spark plugs out) with your two hands on the belt drive pulley. You take a big risk if you start it without checking. You should have asked us about it being tight while it was still on the bench! Can you list exactly what has been done to the engine ?

[mike.perry]

At what stage in the rebuild did you last turn the engine over? Have you turned it over with the head on and the plugs out?
Go back to that last check and then check everything you have done since. It could be something as simple as a long bolt fouling on a component.

[PSL184]

I've known some rebuilds to be very tight as described above.... If it turns by hand (and I mean full turns, not just about moving) then the problem is with the starter or wiring....

[cadetchris]

i have replaced the piston rings, con rod bearings, oil pump, swaped the timing chain for a duplex version and renewed all the gaskets.

it would turn with the head on and plugs in (with some resistance)

i am inclined to think either the starter has got stuck on the flywheel or i have burnt out the starter owing to the resistance from the engine

[mike.perry]

If you take the plugs out you should be able to turn it over on the handle or with a spanner. Check that the starter is not jammed.

[kennatt]

If its very stiff as you describe on the handle(it should be easy to turn on the handle with the plugs out ,should turn,even after a rebuild,very easyily) then sorry to say but chasing the starter motor is not going to be the solution,as bm says its a pity you didn't post at the bench stage of the rebuild,you may have to take the engine out and have a look at the bearings etc.I would suggest that under no circumstances try to start it,(You could by Towing) but don't be tempted,if its that stiff now something is out of place or torqued up wrongly,and you could cause a lot of damage,like a bent con rod or crank shaft. Sorry but I would be having the engine out and the sump off and then repost for advice on what you find.

[PSL184]

Just a thought - was this the engine you had trouble lining the gearbox up with? Make sure that the clutch is disengaged properly?

[cadetchris]

the very same engine. i whipped out the gearbox and bolted the two together and then reinstalled the lot. i completly renewed the clutch and it has been disengaging far better than it was before.

i have ordered a sump, head, rocker gaskets, as well a few other bits, so i am going to leave the engine in and whip off the head and sump to see whats going on.

when i was rebuilding the engine, their was quite abit of resistance from the pistons when i was putting them in, even though i used copious amounts of oil. one of the piston skirts was broken and i replaced it with a new one. could the other pistons be slightly damaged? i didnt notice any, they where in pretty good nick my all accounts, maybe that could account for the unsual stiffness? well ill do all that tomorrow, as i have work and the snow here is pretty cold.

[PSL184]

Was the block bored out? Are the pistons the correct size ie not oversize pistons in a standard bore?

[IslipMinor]

Simple thing to do first - assuming that the clutch is all connected up, press the clutch pedal fully down a couple of times. If the centre plate was not quite aligned, it needs releasing. Might work!!

[bmcecosse]

You can certainly do a good check with the engine still in the car. I would drop the sump - and take out the 'new' piston you got - then see if it turns easily. If not - take out another piston, and so on until it either turns easily or you have all 4 out. Hopefully at this stage it turns easily ?? As in really easily - able to spin it round and round with one hand on the starting handle! If that's so - then the main bearings are ok - you need to look at each big-end - were the caps on right way round - were the conrods in right way round - and were the piston rings all correctly assembled and fitted nicely in the ring grooves - none had 'escaped' as you fitted the pistons ? Just a point - when you fitted the duplex - did you countersink the two holes on the front plate -and fit countersink head screws ??

[katy]

Quote: their was quite a bit of resistance from the pistons when i was putting them in

Did you check the end gap on ALL the rings before you put them on the pistons?
It sounds to me like you didn't and that is the propblem, the rings are too tight.

[cadetchris]

presuming that i have standard pistons, standard bores and standard rings (which i do) measuring the end gaps of the piston rings would merely academic and serve no use.

[bmcecosse]

If you say so Chris - if you say so.......... There is obviously a serious problem with your engine - yet you don't seem to accept that ? The rings may NOT be right - the way to check - is to measure the gaps! You haven't come back about the duplex gears - why did you fit that ? And did you countersink the two holes and use c/sunk head screws ???????