Timing chain setup

[jaymanek]

Hi all!

So I got tired of waiting for my trusted mechanic to have time to replace my valve guides and as it is summer here in the uk I decided to have a go myself.

I took the head off myself and had an engine shop replace the guides, seals and give the head a general going over.
They seemed to have done the job many times before and had it done in 48 hours. They mentioned its an identical setup to some ford engines of that era?!

Anyway, I was very careful to mark my chain and cam sprocket but I think when I was adjusting my valve clearances, I may have let the chain slip as upon reassembly the engine would not turn by hand past a point. So I have now setup the chain again with the aid of this forums literature.

Currently my crank is at tdc but my cam is just slightly off it's marking. The engine turns freely. Both cylinder 1 valves are shut with cam lobes at around 3 and 9 I clock if I remember correctly (although I may be wrong on the exact positions as I'm not near the car now)
I don't think it's possible to get the crank at tdc and my cam exactly on the Mark as if I move the chain even by one notch, the timing goes much further out.

So is it normal for the markings not to match exactly? I assume it's to do with the head having had some skimming and of course an engine that's done 60k miles and 40 years old!?

I just need some pointers as although I'm pretty handy, I have never done a full head gasket myself and there is no way I'm risking starting the engine without being sure,

Also is there any chance ive disturbed the fuel timing? I really hope not as it's another think that's a bit before my time as all of my other cars have ke jetronic injection.


Thanks in advance for the help

Jay

Ps this club has some amazing resources which have helped me with this.

[Naj ✝︎]

Hi, Jay,

Have you taken up the slack in the chain by priming the chain tensioner?

May be an idea to change the 'O' ring seal on the tensioner while you have good xs.

Naj

[jaymanek]

Hi,

Changed the O ring, thanks, got it with the kit from SLS.

I havent primed it yet but will do after reading about it last night, its just a case of pour a little oil down the pickup and work the tensioner a few times?

However, i doubt that would affect the position of the timing marks?

[merrill]

what were the position of the crank and cam before you removed the head?

Did you line up the crank, cam, distro before you removed the head?

IE,  crank tdc, cam notch lined up and distro rotor pointing to the #1 mark?

Checking the timing before the head was removed would help diagnose if you have a worn chain vs something else.


If you get everything back together and it is still off, it is possible to check the degrees the timing is off using a dial gauge and then use an offset key
on the cam sprocket.    If you need to the job # to check the timing using a dial gauge let us know

[jaymanek]

Thanks all,

I put everything back together after speaking to my technicians (we have a garage) who were all of the opinion that an agine of this age will never line up 100% and that i was being too fussy!

Anyway I started the car and she runs perfectly, just as before... I will just check that nothing else has gone off like ignition timing etc and re torque the head bolts, then im ready to roll for hte summer, hopefully without a cloud of smoke behind me!

[glenn]

Offset keys(for cam sprocket) are available to get the crank and cam shafts in perfect harmony. ..

[jaymanek]

Thanks I never knew such things existed, where can I get these?   Thanks

[merrill]

you can get the off set keys from MB or the MB classic center.

using the proper technique to measure the degree your timing is off you can use the key to get the timing very close if not dead on

[jaymanek]

Thanks,

I see my problem is not a new one then, a quick google revealed all sorts of solutions!

Well before I start going overboard im going to see how the car runs when i get a little time.

If there is any indication the timing needs to be altered then i think i would probably need a 2 degree key at most.

We have just had a baby boy so this has to go on the rear burner for a little while!

p.s. After starting, the top end seems a little noisy to me, its as if the camshaft has a bearing gone, sort of like a worn wheel bearing type of noise.. Its not loud but I honestly cant remember if it was there before I took the engine apart.
I dont think its an immediate issue but wondered if anyone else has experience this or indeed if its normal.

[knockmacool]

A baby boy? That will do wonders for your timing ! Congratulations!

[graphic66]

If you overtighten the valve cover it can possibly rub on the cam and make a bad noise.

[ja17]

Hello,

Yes it is normal that that the cam and crank timing is off a bit on a older engine.  Make sure that the cam is right on or a bit late when the crank is at TDC "0".   Having the cam timing even a bit advanced will cause issues. One chain link equals 18 degrees. In other words, your chain is not off one link unless you are 18 degrees off !

the BBBs indicate that going to the trouble of installing off set cam keys will not make a noticeable difference in how the car runs. If you use the off set keys remember offseting the key one way changes the cam timing the OPPOSITE way.

When a cylinder head is taken off and cut, the chain timing is changed. For instance............. If the head is cut 0.5mm the chain timing is changed (0.5 X 2)  by a full 1.0 mm.    

Chain stretch is not actually stretch. Most lengthening is caused by minute wear on each pin in the chain multiplied 134 times !

Changing the timing chain every 100,000 miles is usually adequate protection to avoid catastrophic failures.

The most critical sprocket on the engine is the main crankshaft chain sprocket. It has a fairly small diameter and works hard driving the cam shaft, injection pump, distributor etc. Always replace this sprocket during an engine overhaul.  It can be changed without removal of engine but it is very difficult and the sprocket will usually last the life of the engine unless it is damaged.

[jaymanek]

Thankyou for that excellent answer Joe, the reassurance I was after!

I also had my mechanic pop by last night who says I have done everything right and now just  need to set the ignition timing and re torque head bolts.

The bad news is that the very top (small) radiator hose connection has sheared off!
So now I have to remove the radiator to have it soldered back properly.
I was going to change the complete radiator until I checked the prices, even aftermarket ones are 600 EUR +

A local radiator specialist seems confident they can solder a new connection in place with no fuss.

[ja17]

Hello,

That little tube is easy to knock loose on the radiator.  I usually solder them in place without removing the radiator.  Getting everything super clean is most the work. Someone good with a propane torch and solder should make short work of it.  See if your radiator man can just have you drive the car over so he can fix it in place. Or find a good plumber who is good with solder and torch !

[jaymanek]

Thanks,
He wants to solder it from behind as well so may as well do the job properly... I hate to know things arent right as knowing my luck ill be on a european drive when the thing decides to burst!

[jaymanek]

JA17 - I went with your suggestion for the radiator tube... my handyman came around with his kit, some of which sounded like it should be used to go back in time, and had it properly fixed within a few seconds. The repair seems solid, i have given it a good tug and doesnt seem to be going anywhere...

The car is all done, I have retorqued the head bolts - I opted to replace the bolts one by one as a few of the heads were starting to look like they could strip the next time.

I am just waiting for a timing strobe and then I will set the ignition timing...

[ja17]

Hello,

Yes, this should be a lasting fix if done correctly. I do it all the time.

[jaymanek]

If you overtighten the valve cover it can possibly rub on the cam and make a bad noise.

Good job I remembered this post. I was re checking the valve clearances tonight and upon start up I heard a loud ticking... your post rang in my head and i slackened the centre bolt off a quarter turn and the noise dissapeared!