Thread: 300tdi cam timing

I reckon you would be spot on with your assessment.
And since you mention a bent push rod, would pay to check them all plus the holding down studs for the rocker arm shaft.
Pistons hitting the valves (timing out) hard enough to bend the pushrods may have stretched the aforementioned studs or partially stripped the threads in the cylinder head.
llandro

It does look to be a whole tooth out

And yes i would imagine that may have something to do with your lack of oomph but the bent push rod I dont know as once it's all set it doesnt move so you would think it would have bent all of them not just 1.

Sounds like it may have had a timing belt failure earlier on which you didnt know about and this caused the bent push rod and you just stumbled onto it doing the head gasket.

The thing with only slightly bent push rods is that sometimes you can take up the difference in the tappet adjustment......I wouldnt recomend it but if it was to get rid of the car a car yard or some mechanics may not be a ohnest as some.

The belts do go slightly out of time when worn due to them seating ever so slightly in toward the pulleys which I have heard be called stretch but these belts dont stretch and they dont seat/bed in that much.

When you get it right then you should have more go then.

Thanks for the replies.

I checked the rocker assembly and all the pushrods when I found the bent one - all was good. Seems strange to only bend one though.

If the engine has been running with the cam timing advanced by one tooth of the belt, I would have expected more symptoms other than being just a bit sluggish. I've only driven one other Tdi Disco, and that was a real slug compared to mine, so I thought mine wasn't too bad.

Will see how it goes when I get it back together.


Paul

Originally Posted by awabbit6

Thanks for the replies.

I checked the rocker assembly and all the pushrods when I found the bent one - all was good. Seems strange to only bend one though.

If the engine has been running with the cam timing advanced by one tooth of the belt, I would have expected more symptoms other than being just a bit sluggish. I've only driven one other Tdi Disco, and that was a real slug compared to mine, so I thought mine wasn't too bad.

Will see how it goes when I get it back together.


Paul

The symtoms for the cam being out one way is bad fuel economy and really slow and sluggish and the other way is things getting bent.

I cant remember which is which but thats what Ive seen and been told by my LR mechanic mate.

Hope that helps

If memory serves me correct there is a set of bolts in the centre of that gear/pulley for the cam and if you loosen them off fine adjustment can be made to the camshaft timing to make up for any minor misalignment like the above picture shows.
The previous belt I believe was fitted to the nearest tooth without any fine adjustment done because the person who done it didn't know.
It would only cause minor performance lost and not much more.
Why would the motor only bent one push rod and not all of them if timing was a problem with the valves.
The most likely problem for a one off bent push rod or broken rocker is the case hardening failing on the the valve stem caps and the cap coming out and taking up all the valve clearance..........this is a common TDI 300 problem.
Take the rocker gear off and check the valve stem caps for the case hardening flaking or the the caps missing and replace them.

Originally Posted by 101 Ron

If memory serves me correct there is a set of bolts in the centre of that gear/pulley for the cam and if you loosen them off fine adjustment can be made to the camshaft timing to make up for any minor misalignment like the above picture shows.
The previous belt I believe was fitted to the nearest tooth without any fine adjustment done because the person who done it didn't know.
It would only cause minor performance lost and not much more.
Why would the motor only bent one push rod and not all of them if timing was a problem with the valves.
The most likely problem for a one off bent push rod or broken rocker is the case hardening failing on the the valve stem caps and the cap coming out and taking up all the valve clearance..........this is a common TDI 300 problem.
Take the rocker gear off and check the valve stem caps for the case hardening flaking or the the caps missing and replace them.

The fine adjustment is on the pump, I dont remember mine having adjustment on the cam pulley......there is no need for it any way.

As far as the caps losing their temper and causing a bent push rod, that is pretty unlikely as it would make the gap bigger not smaller than what it was.

The most likely cause is a bodgy repair or it just wasnt noticed if the timing belt had broken before or maybe it had a minor hydraulic after a swim but that is unlikely as well, more likely to kill a conrod than a push rod.

Originally Posted by 101 Ron

If memory serves me correct there is a set of bolts in the centre of that gear/pulley for the cam and if you loosen them off fine adjustment can be made to the camshaft timing to make up for any minor misalignment like the above picture shows.

There are three bolts on the cam pulley, but there is also a square drive on the inner hub of the pulley that the outer pulley fits into. There is a bit of movement there, but not much. I don't really want to dial in the cam from scratch though for a simple belt replacement. I'll see how it fits up tomorrow.

Originally Posted by mcrover

The most likely cause is a bodgy repair or it just wasnt noticed if the timing belt had broken before ...

I agree that it is probably a bodgy "that'll do" repair that it has had in the past. Possibly it wasn't noticed or deliberately ignored. I found it pretty had to miss when I pulled it out.



Paul

I have had a broken rocker to prove that the caps when they come out or try to come out do strange things.(take up all the valve clearence)
My timing on the camshaft was half a tooth out and it corrected it with the adjustable bolt set up on the cam sprocket .
It was a while ago now and the exact way I done it is now fuzzy