See page 2 : TDC problems with timing belt change

[e30onBBSs]

In the future, it's good practice to set the head to TDC, then rotate the crank back about 45 degrees or so so all the pistons are down in the cylinders. This makes it so if you have any trouble putting the head back on, you won't have any chance of scraping the top of either piston 1 or 6 because one they will both be at TDC even though 6 isn't on compression.

Then once you get the head on, turn the crank to 45 degrees back to TDC for cylinder one and put the belt on. ofc make sure the head is still at TDC, which it should be. Tension the belt then crank the engine around a few times to make sure everything is smooth.

[JeLani]

In the future, it's good practice to set the head to TDC, then rotate the crank back about 45 degrees or so so all the pistons are down in the cylinders. This makes it so if you have any trouble putting the head back on, you won't have any chance of scraping the top of either piston 1 or 6 because one they will both be at TDC even though 6 isn't on compression.

Then once you get the head on, turn the crank to 45 degrees back to TDC for cylinder one and put the belt on. ofc make sure the head is still at TDC, which it should be. Tension the belt then crank the engine around a few times to make sure everything is smooth.

I have had trouble putting it on before and wondered if it was on correctly but it was on correctly the whole time because of the corners of the block that fit into the bottom of the head on opposite sides confused me to think it was on wrong.

[e30onBBSs]

I have had trouble putting it on before and wondered if it was on correctly but it was on correctly the whole time because of the corners of the block that fit into the bottom of the head on opposite sides confused me to think it was on wrong.

sweet, good job :) Just a tip that may save some scratches

[JeLani]

sweet, good job :) Just a tip that may save some scratches

Thanks man. And for it to sync with crank movement will it have to be bolted down? Im going to bolt it anyways .


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[JeLani]

Never mind the belt just has to be on..


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[e30onBBSs]

Never mind the belt just has to be on..


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Yea it shouldn't have to be bolted, might be worth putting in a couple of the center head bolts for peace of mind.

It's funny you ask that, at school I'm working on a 3.0 m57tud (some weird name) a diesel out of an e70 x5. I was thinking like an e30 where the head bolts are in the middle. Put the cams back in, get the timing back together which was a biiiiitch because we don't have the tool to hold the tensioner back. Then we are like hell yea! And my teacher is like bro how are you gonna put the head bolts in XD so now the cams are out again lol

[JeLani]

Bumping an old thread here. But lets fast forward to now.

• the head is back on and everything.
•camshaft sprocket is at TDC
•Crank at TDC
•New tensioner set in place
•using a spring and pin this time ( there wasn't any before) note: i feel its a pain in the ass to install anyways but i want to do it right or not at all.
On to my problem now : going to bolt up my tensioner.. Last second the crankshaft will have the tendency of moving straight past TDC. Does anyone know how to prevent/deal with this? It is the only thing in the way of my re-assembly and should be the easiest part.





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[e30onBBSs]

If the belt is on you are okay, the cam and crank are connected in time by the belt so if it moves it's fine

[JeLani]

If the belt is on you are okay, the cam and crank are connected in time by the belt so if it moves it's fine

Really? It wont hurt my valves?

[e30onBBSs]

See page 2 : TDC problems with timing belt change

Really? It wont hurt my valves?

And if the belt is on and the crank moves a tiny bit, the cam will move a tiny bit as well, but might not be noticible because the cam turns half as much as the crank. So a 2° turn of the crank would only be 1° of the cam.

Either way- definitely put the tensioner in and loosen the bolt so the belt is tensioned once you have the belt on.

That being said, as long as neither the crank nor the cam moves while you are putting the belt on, you are good. Once the belt is on and both cam and crank are at tdc still, they will stay in time.

I do the tb around the bottom half of the engine, then around the cam pulley. It's hard to move the crank or the cam by hand, so don't worry too much about it. You will feel if one of them moves. As you know, make sure they are both still at tdc to be safe!

Once the belt is on, loosen the tensioner bolt so the tensioner applies pressure on the belt.

Then spin the crank 720° and make sure the cam and crank both line up to tdc. If they don't, you are probably a tooth off. Tighten the tensioner again, take the belt off, and repeat.

Pics of the tensioner may help to make sure everything is set up right


Good luck!

[JeLani]

And if the belt is on and the crank moves a tiny bit, the cam will move a tiny bit as well, but might not be noticible because the cam turns half as much as the crank. So a 2° turn of the crank would only be 1° of the cam.

Either way- definitely put the tensioner in and loosen the bolt so the belt is tensioned once you have the belt on.

That being said, as long as neither the crank nor the cam moves while you are putting the belt on, you are good. Once the belt is on and both cam and crank are at tdc still, they will stay in time.

I do the tb around the bottom half of the engine, then around the cam pulley. It's hard to move the crank or the cam by hand, so don't worry too much about it. You will feel if one of them moves. As you know, make sure they are both still at tdc to be safe!

Once the belt is on, loosen the tensioner bolt so the tensioner applies pressure on the belt.

Then spin the crank 720° and make sure the cam and crank both line up to tdc. If they don't, you are probably a tooth off. Tighten the tensioner again, take the belt off, and repeat.

Pics of the tensioner may help to make sure everything is set up right


Good luck!

This is the exact way i imagined id to it the other day! counter clockwise right?? ive tried it this way but i couldnt even turn the crank 45 degrees but i guess that was because only the crank would turn and not the cam because of the belt not being tense enough then! and the bolt ur referring to is the top one or the lengthy looking one? either way i understand what ur saying and thanks

[JeLani]

still have problems.. crank just won't stay put. when i do turn the crank with correct tension , the cam timing i feel is over delayed

[jeffnhiscars]

Puts your spark plugs in.mthe compression will help the crank stay put

[JeLani]

They are in. The were in when i slapped the head on. Should i try taking them out and putting em back in?

[JeLani]

I hate to say.. Im still stuck. I was told to compensate the camshaft movement for the crank movement. But how to do that precisely? ...