Camshaft timing

[Quattrofrank]

Hi

I`m in the process of replacing the head gasket on my car. After setting the bottom to tdc and taking the camshaft covers off it looks like the timing on the inlet camshaft is off.
Can anyone have a look at the pictures and verify?
If thats the case, how do I fix it? Do I need to take of the front cover and redo the timing chain or how is the process?

Exhaust camshaft


Intake camshaft

[mgcjag]

Hi Frank....how do you know you are at TDC...have you just turned the engine till the pointer is on tdc on the crank pulley or have you taken piston No1 up to the top of its compression stroke (divide by 2 on the crank pully when the piston stops on its up stroke and starts on its downstroke) thats the TDC process for setting Cam timing is in the workshop manual, page B27 best to follow it step by step......not too difficult.......you will need to do it anyway when you replace the head......will also be much easier with head off to set tdc mark with crank pully whilst turning engine to find top point of piston

[Quattrofrank]

When I was adjusting the ignition timing I used a micro gauge to verify that the timing marks on the crank pulley was correct.
So this should be spot on :)

Have ordered the camshaft setting tool so that it will be correct when re assembling.
Have taken the head off now and I realize that it is possible to rotate the camshaft and keeping the timing chain steady. So either something has moved or it was a bad job done by previous owner

[abowie]

That's f#$%ing miles off! The slot should be exactly in the middle at TDC. The exhaust cam is a weeny bit off too perhaps.

I suppose it's possible that someone did this deliberately, but your cams to eye look like stock parabolic ones as far as can be told from a photo. They do however seem to be only 2 hole cams whereas I would have expected 4 hole ones on a series 2, I think. They might be the intermediate cams, but I thought they were only on 1968 cars...dunno.

If I had to guess I would think that whoever did this didn't tighten the upper chain properly while installing the head or that maybe somehow the chain has jumped a tooth. Lord only knows.

Here's one on my bench at the moment, set to TDC.
Both cams:


Inlet cam:


Exhaust cam.

[abowie]

The process for setting the cams is in the manual.

If you wanted to fix this in situ...

You will need a camshaft setting tool, the timing chain tensioning tool and some lockwire. I like 32 thou/0.8 mm soft stainless.

NOTE: I have reread and edited this about 100 times to make sure it is as clear as I can make it. If anyone thinks I have made an error PLEASE speak up.

Basically:

1. Start with the engine accurately set to TDC (you have done this already).

2. Remove the bolts holding the cam to the sprocket. THIS IS THE ONLY TRICKY BIT.

From your pictures I can't see any holes on the cam flange so there are probably only 2 of them. They should be lock wired in place.

The next bit is CRITICAL. READ it all first or you'll damage valves. YOU CAN'T EVER ROTATE THE ENGINE WITHOUT BOTH CAMS FIXED IN PLACE BY BOLTS.

One bolt will be inboard and one will be outboard, at 3 o'clock and 9 o'clock, and you can't get to them both at the same time.

SO. Rotate the engine clockwise until the bolts exchange positions and the inboard bolt is accessible. Remove it. Now rotate the engine forwards to TDC again. The other bolt will be back at 3 o'clock. Remove it too.

Be REALLY careful not to drop them into the timing cover recess; stuff a cloth in there.

3. Loosen the top timing chain adjuster; to do this you will need to remove the breather housing.

4. Remove the large circular spring clip and then withdraw the adjuster from the sprocket. Remove the sprocket from the cam flange by gently tapping it forward. The chain will at all times remain on the sprocket.

5. Now carefully rotate the camshaft back into the correct position. DO NOT DO A FULL REVOLUTION OR YOU WILL BEND A VALVE. Just use a plastic mallet or a bit of wood and a hammer on the side of the lobe of #5 (second lobe from the front) and tap it back until the slot is vertical relative to the cam journal cap at the front of the cam, where the cam gauge goes. Confirm position with cam gauge.

6. Now put the sprocket back onto the flange; making sure it is sitting square.

7. Tighten up the timing chain so it is firm. It tightens anticlockwise.

8. Replace the adjuster into the sprocket so that the bolt holes line up perfectly and put in the one bolt you can. Do the bolt up tight.

The adjuster must sit flat, not be cocked. This can be tricky and may take you a while as the adjuster has many tiny teeth to allow it to engage the sprocket. You need to fiddle and ensure it is perfectly aligned. If necessary rotate the adjuster 180 degrees. Do not force it. It will go in eventually.

Once the adjuster is in flat and the bolt is in tight you can rotate the engine around so you can access the other bolt and put it in too.
REMEMBER YOU CAN'T EVER ROTATE THE ENGINE WITHOUT BOTH CAMS FIRMLY FIXED IN PLACE BY AT LEAST ONE TIGHT BOLT.

Replace the large circular spring clip.

9. Double check that the upper cam chain is tight.

10. Replace the lockwire.

11. With the engine back at TDC recheck the cam positions with the gauges. They should be spot on. If necessary, repeat the above on the exhaust side too.

[Quattrofrank]

Thank for an excellent guide.
Took the head off and went to have it skimmed, after testing the valves I found out that one the exhaust valves was sligthly bend and 3 of the inlet valves did not held vaccum very well. I guess that explains why the enigne was working like a bucket of crap.
It looks like the teeths on the inner part of the spocket for the timing chain is worn out and thats why the cam moved. It looks like there is part available to get this fixed.

I also have a spare engine, so I tought maybe that head was better (with bigger inlet valves, its a 8l engine). But when take the cam covers off I realized that the engine had lost a few tappet guides (they where grinding against the cam).

So I`m not sure what to do now, probably best to use the original head and get bigger valves, new seats, valve guide etc (complete rebuild and tuning). Or should I use the 8l head since that has already bigger valves? Guess both of them need a total rebuild. I`m concerned that the 8l head has been to hot because of the tappet guide loosening and some of the tappet guide parts might be somewhere inside the head and could cause damage a later point.

[David Oslo]

My money would be on fixing the head that came off the engine, not the spare one. There's a few engine builders in Oslo, and of course Sarpsborg Motor, but when I checked prices 2 years ago (for my TR6) I thought they were all a bit pricey. So tracking down Kjell Kirkebakken i Ski (closed now) I found Musangen Motor, which is a one-man shop run by an ex-Kirkebakken employee. Really nice guy, knows his stuff and teaches at local college, and has all the right machine tools. Balances cranks & flywheels too. Nice price too if you know how to ask.