Block assembled - won't turn over by hand properly?

silent running

Over on Projects I'm doing a build which I've almost finished. I just got the timing belt on last night but it seems to be 'sticky' when turning over and at once point it just stops. I don't want to force it at all. I wound it back to the start position and it jumped a tooth on the crank sprocket. There are a number of reasons I can think of why it might do this:

• Harder to turn the four cams as well as the crank all on one belt?
• Pistons hitting the heads?
• 'Stiction' at the turnover point around TDC and BDC?
• Knackered tensioner

Help! I've already ordered another tensioner anyway, but any ideas will be appreciated.

dj219957

have you tried a search mate? i seem to remember somone with a simular problem not long ago and it was solved.

silent running

I tried one but it didn't come up with anything. I must have tried the wrong search terms

merlin24

If you think the engine is locking up -
Line the timing marks back up and drop the cam belt off again.
With the cam pulleys "off cam" - can you turn the cams by hand freely ??
If they turn ok,you know its not a tight cam cap.
With the cams in the "off cam position (all valves closed) - can you turn the crank ok or does it lock up in a certain place.

Mick

silent running

Right Mick, I'll get on it right now. Good thinking. Am I getting the timing belt on and off in the right place, i.e. lining it up on the four cam pulleys and fitting it over the crank sprocket and the tensioner last of all.

samcowrx

Some people have had the problem of oil squirters hitting the back of pistons?, i dont know if this applies to your block or pistons?

__________________
2.1 forged build underway-20G

silent running

**** I hope not. I don't think that can be happening as it turned over pretty well without the heads on. IIRC...

OK I've just been and removed the timing belt. The four cams turn fine, smooth as silk off cam, ping off the cam when you push them a bit further. None have any particular sticking points that I could feel.

Then I put all four cams at rest and turned the crank. No problems at all, goes round and round perfectly smooth.

Soon as I put the belt back on, after maybe half a turn it just stops dead, same whether you go clockwise or anticlockwise. If you try to turn it any more it just tightens the already tight crank pulley bolt in, or jumps a tooth. I could see the tensioner pivoting upward just before it jumped, I'm sure. So there's got to be something holding things back.

Is it just me being a pansy and not wanting to force it round? Presumably turning four cams and a crank is going to be noticeably harder than each on one its own?

Mo.k

are the spark plugs in the head? could it be compression your feeling???

adzer

i'm just taking a guess but could the heads be on the wrong sides? would cause the timing to be out badly wouldn't it? i've never seen a head off the engine so not sure if they can be fitted wrongly.

but on some engines i've turned by hand i've came to points thats got sticky/hard to turn but i just put more pressure on it and it turned fine then would stick again. car started and run fine.

silent running

No, plugs are out, and the heads can't be fitted wrongly. Well I suppose maybe they could be, but it would be really obvious! THanks for the suggestions though. I wonder whether I should stick the crank pulley on as well and then tighten the bolt down into that so at least I won't worry about stripping the thread in the crank.

scooby(puppy power)

have the block or heads been skimmed and to much took out,

Mo.k

I just use an old hub nut instead of the pulley or a big washer so you can see whats happening.
does it feel like its hitting metal, can you tap against it as you rock it near the tight spot using a big bar but being gentle.
Mo.

Mo.k

just seen the picture on your project thread, turning the engine over like that will damage the thread on the bolt as you are in too far and the end is being squashed put in a washer or old hub nut then you will get correct torque but check the thread on the end of the bolt first.
mo.

silent running

They have been skimmed but CR is still right and there's a decent thickness of gasket in there. Without the belt everything works fine individually. I've fitted the old crank pulley on there and did that up, went for 120Nm for the time being. Turning on that, I can get the crank 3/4 of the way round i.e. from 12 o' clock to 9 o'clock then it stops. Whatever force it needs to get it further, it's more than 120Nm.

Bollocks. What can it be?

overlord

are you turning it the correct way when i did mine the manual said your only supposed to turn it one way.
Also if it turns over ok without the belt but wont turn over with the belt fitted are the correct cams in the correct places??

silent running

Well that's what I'm wondering. Each cam has a notch in it for the pin to go into as you tighten down the pulley. I wonder if one has gone wrong somehow? Or maybe I need different pulleys for STi3/4 cams?

dazdavies

Sounds like your valves could be coliding.

You did turn the cams opposite to each other on the left hand side when lining up the notches didn't you?

silent running