Thread: Thought i had joined the broken crank club but NO!

Originally Posted by Bulletman

I rotated it with injectors out so i should be able to do as you say..

Im a bit confused as to if i can rotate with all the valves closed how does that tell me its timing not a valve ?

Appreciate the suggestion which i will try..

Cheers Bulletman

If the cams are out it should turn over. Because none of the valves are down. You measured the stem Heights and they were all the same. When you lock the engine on number 1 look in the hole or confirm that the piston is on tdc.

When you set the cams up the opposite cylinder to number 1 (I can't remember the firing order) should have its exhaust valve and inlet valve both slightly open. Exhaust will be nearly closed and inlet starting to open.

Turn the engine without cams first. Then with them again. If it stops again, look to see which cam is opening a valve

Originally Posted by loanrangie

My LH exhaust camshaft was slightly bent ,not enough to lock up on rotation but enough that you could feel the resistance.

I did replace both cams on the side that had all the damage .. they werent new but they came from an engine that didnt suffer a major failure so i was told..

This is a definate lock up not just resistance..

I did rotate the engine with the cams out when i was trying to lock the flywheel and i would have definately rotated it 360 degrees as it took a lot to find the hole in the flywheel that lines up with the locking tool.

Im wondering can the crank be 1 rotation out ? It takes 2 rotations to do a full cycle so im wondering can that possibly be the issue..

Ive never worked with overhead cams and been a long time since i was on the tools doing this type of stuff so im struggling with how this timing works

Cheers Bulletman

Originally Posted by Bulletman

I did replace both cams on the side that had all the damage .. they werent new but they came from an engine that didnt suffer a major failure so i was told..

This is a definate lock up not just resistance..

I did rotate the engine with the cams out when i was trying to lock the flywheel and i would have definately rotated it 360 degrees as it took a lot to find the hole in the flywheel that lines up with the locking tool.

Im wondering can the crank be 1 rotation out ? It takes 2 rotations to do a full cycle so im wondering can that possibly be the issue..

Ive never worked with overhead cams and been a long time since i was on the tools doing this type of stuff so im struggling with how this timing works

Cheers Bulletman

The crank turns twice for one rotation of the top end. You can’t get the bottom in the wrong place. If you’re sure you’ve got the bottom at top dead centre (locked in place and timing marks aligned, then the options are
- a valve is being extended and is getting stuck, hitting a piston - interference
- something is binding up, feeling like interference
- the timing of each cam to each other versus the cams to the bottom end is wrong

I assume you have the manual and have followed precisely how to time everything together?

I’d go back to the start and check everything.

Originally Posted by DiscoJeffster

The crank turns twice for one rotation of the top end. You can’t get the bottom in the wrong place. If you’re sure you’ve got the bottom at top dead centre (locked in place and timing marks aligned, then the options are
- a valve is being extended and is getting stuck, hitting a piston - interference
- something is binding up, feeling like interference
- the timing of each cam to each other versus the cams to the bottom end is wrong

I assume you have the manual and have followed precisely how to time everything together?

I’d go back to the start and check everything.

When i was trying to initially lock the flywheel thru the locking hole above the starter there were several holes in the flywheel that didnt line up then when i continued to rotate the crank 1 hole does line up and you can lock the flywheel... enough to remove the crank bolt and fit a new bolt to correct tension.. so from everything i have read and have seen without physically seeing the piston crown then i belive #1 is at tdc... but i will check thru the injector hole today..

As you say i will start again but everything i read assumes that the engine has already been timed and you are setting the timing to do a belt change ..

I will go back and check it and also see if i can follow it from the firing order and proceed from there..

Thanks all for your time and imput .

Cheers Bulletman

Use a long rod down the injector hole on cyl 1. Ensure as you rotate clockwise that it hovers briefly then goes down. You could also measure each cylinder to see where there are all at in their strokes to compare.

I am sorry but your engine has suffered a major event and many things could have gone wrong that are not obvious. I would be pulling the top end/heads off and inspecting everything with a fine tooth comb including the pistons.

The way things are going I can see you fixing the engine and the finding further issues down the track.

Originally Posted by 101RRS

I am sorry but your engine has suffered a major event and many things could have gone wrong that are not obvious. I would be pulling the top end/heads off and inspecting everything with a fine tooth comb including the pistons.

The way things are going I can see you fixing the engine and the finding further issues down the track.

I've seen straight valves get away with this before.

So todays fun and games... removed the cams on the drivers and 1 cam on the passenger side .. loosened the other cam.. the reason i couldnt remove it is because it has the fuel pump gear on it and unless you hack the back of the fuel pump plastic cover you need to remove the pump gear to loosen or remove the back cam cap...

So with that cam loose enough to rotate so the lobes arent pushing on the valves and the other 3 removed i rotated the engine half a dozens times without issue.. i did have rods down each injector hole so i could follow the firing order plus i was a bit worried i may have had a broken crank but each rod went up and down in the correct sequence so i can only assume that
1- i dont have a broken crank
2- its unlikely i have broken bits on the piston crowns or valves that arent seating correctly..

So bolt it back up checking that timing is correct which im 100% sure it is... and low and behold its now locking up in a diffent spot.. and not close to where it was before going on the firing order where it did it before and now..

So im thinking the side that i never replaced the cams on has a bent cam or 2.. does this make sense to others ?

Next step is to pull that side again and see if its possible to get to the fuel pump gear for removal.. the heads i bought have the gear still on it and its held on by 1 centre bolt which isnt keyed so if i can manage to get a socket and bar in there.. if not its plan 256..

Im not having as much fun as it sounds like either
Cheers bulletman