VR6 timing issue.

[Toad 0]

Good morning,

 

I know that there is a good guide in the Wiki and another good thread on this, but I had some problems over the weekend whilst fitting some cams to a VR.

 

Firstly, we timed the engine so that the tdc notch on the crank pulley aligned to to mark on the crank case*, and found that the cams fitted appeared to be a tooth out, so rechecked the crank pulley before removing the cams, fitting new ones with cam locking tool, and turning the engine over by hand to check the timing was correct.

 

Again, it appeared that the cams were 1 tooth out, unfortunately at this point one cam jumped a 2 teeth or so, so rather than struggle and try to work out which way to turn the cams, I removed them so I could turn the bottom end over with no risk of piston-valve interference, set the crank pulley to the TDC mark, checked that the notch in the intermediate shaft was pointing up toward me (as shown in the bentley), and I could make out that the small pointer on the intermediate shaft was pointing upwards, as I would expect. The plugs were out, and we could see that No. 1 and 6 were at TDC. I refitted the cams with the locking tool, then began to turn the engine over again by hand to make sure everything was aligned properly. Unfortunately after about 1/2 a turn the engine came up solid, as if No. 2 or 3 (??) had hit one of the valves, now I cant see how this would happen, but decided to stop at that point.

 

Surely if the engine is at TDC, the intermediate shaft is correct and the cams are fitted with the locking tool, then it must be timed correctly?

 

The car has had chains and tensioners done in the past, but must have been set to TDC before, the flywheel and crank pulley can only fit one way round, so their marks must be correct, but I'm rather confused now...

 

*I've not got a picture of the crank pulley marks, but there is a small notch on the inside of the aux belt pully which lines up with a raised line at around 5 o'clock on the end plate.

[dirtytorque 0]

maybe 180 degrees out ???? :shrug:

 

Is there a tdc mark on the fly wwheel ?

 

Totally ignorant on this engine but worth a poke.

[Toad 0]

maybe 180 degrees out ???? :shrug:

 

Is there a tdc mark on the fly wwheel ?

 

Totally ignorant on this engine but worth a poke.

 

There is a mark on the flywheel, but you can't see it with the gearbox fitted, hence the mark on the aux pulley. The Bentley does tell you to use the tooth on the starter ring, but you just can't see it.

 

The cams can only fit one way round, as the notch for the locking tool is offset.

 

I did wonder if it had previously been set wrongly, hence the issues now.

[steve @ 0]

I had a slight issue when fitting my 268's. The rear cam (near the exhaust manifold) didnt quite line up, like it was half a tooth out. It was all set to TDC and like you using the cam locking tool. It couldnt have been a tooth out as this would have trown the timing off too much either way. So in the end we refitted every thing and she's been fine ever since.

[fla 9]

Tom, when i timed my car admittedly i had the gearbox off. However, it does look as though it is half a tooth out. Also, as there is no oil circulating you will reach a point where, due to teh slackness in teh chain it appears that the pistons are 'stuck'. Gnetly push it beyond this. If it absolutely will not move then you are most likely 180 degrees out. did you see the slot on teh aux pulley from the top of the chain cover? You seem to also have used the notch on the crank pulley so by all accounts the lower chain is in the correct position. However, try this - fix the cams in the correct position using teh cam locking tool and turn the crank pulley to line up the lower chain. You might find it needs to move approx 1 link. If not turn it through 180 degrees and try again. Then manually turn the engine over and see how it lines up. Then check this with the three timing points (locking tool, crank pulley mark, intermediate pulley slot).