Engine problems & cam timing dial

[Miss Marple 1954]

Hello folks!
I can't get my freshly built 1098ccm to run properly; the engine runs mechanically smooth, but a bit bumpy, as if one of the four doesn't really know what to do and when.
The spark plugs, cables etc. ignition (123 ignition), ignition coil, fuel and fuel pump, air have been checked several times - everything is great there.
The timing chain is also on point, but now I want to check the timing and the valve lift, maybe one of the markings on the new timing sprockets is wrong?
I had already spoken to the technical supervisor of the German Morris Register a few times - I now only have to check this position.

There was a great "cam timing dial" from Declan as a pdf that I would like to use - can someone please tell me where I can find it! Or tell me where I can download it?

Thank you and best regards
dirk

[philthehill]

If you want to time the camshaft to the crankshaft correctly you not only need a timing disc but also two Mercer dial gauges so as to measure when the piston and crankshaft are at TDC and the camshaft is at full lift.

Timing the cam 1.jpg (217.63 KiB) Viewed 4282 times

You can adjust the camshaft timing with offset Woodruff keys (of which I am not a great fan) or use an adjustable camshaft gear set up.
This is the timing disc you need:
http://www.minispares.com/product/Class ... o%20search
The link to Declan's pdf seems to be lost
But here is a similar item that you can print off:-
https://www.blocklayer.com/degree-wheel
Here is a link to some useful information regarding timing the 1098cc camshaft.
viewtopic.php?p=608511#p608511
Have you inserted the distributer drive shaft correctly? Before doing anything you need to check that the shaft is timed correctly. See the BMC wksp man for details.

[MikeNash]

Greetings Dirk.
I hesitate to be at odds with "m'Learned Friend" Phil but if you want only to determine your valve timing you can do this solely by "feel". When the valves are closed the pushrods are free and easily rotatable by finger pressure and so if you turn the engine you can feel the pushrods become fixed (in rotation only) as they begin to lift the valves and, of course, become rotatable as the valves go back onto their seats. A little practice will show all.

Regarding the timings that you'll see I think you should read this old thread
viewtopic.php?f=4&t=37425&p=573883&hili ... ng#p573883

And regarding Declan's timing disc let's hope he'll be along soon and give us a new link. I've found my copy indispensable. And please let us know your results.
Regards from MikeN.
PS Your engine's ignition timing is correct, isn't it?

[Miss Marple 1954]

Hello Phil and Mike.

Thank you for your answers and the tips and hints - I checked again today to see how the status is up to date.
I'm slowly becoming unsure

I hope I write it clearly ...

Here my results:
Timing chain - if both points on the sprocket gears are correct (as in the photo above), cylinder 4 is on TDC and both valves on 4 are closed (firing) and loose.

Then I removed the distributor to check the drive shaft. The shaft is positioned so that the slot is not correctly on the 20 to 4 position - it's a bit later The larger part of the shaft points upwards...

A more precise positioning to the 20/2 position is not possible. The distributor then points to cyl. 3, now it shows cyl. 1 pass forward. (Pictures)

Do I already have an error there or is the shaft installed correctly?

Confused greetings from Osnabrück
Dirk

[philthehill]

Withdraw and rotate the drive shaft anticlockwise one tooth and rotate the distributer body to suit.

[Miss Marple 1954]

Hi Phil,

yes - that's exactly what I did - I turned the shaft one tooth anti-clockwise yesterday, this is photo 3 from yesterday evening.
Then the distributor points between cylinder 2 and 3 ...

[philthehill]

Then turn it back another tooth until it corresponds with the diagram Fig A.A.28 and Section A.A.28 in the Minor wksp manual.
When you have the shaft right all you can do is turn the distributer body till the rotor arm corresponds with the correct distributer cap contact.

[Miss Marple 1954]

Ok - thank you - I'll take a closer look tonight and then I'll be back

[panky]

Can't seem to get it any bigger sorry

[Miss Marple 1954]

HI.

So - last night we checked again - until we finally found something - it just wasn't noticed until now!

If the markings on the sprocket gears match, the marking between the pointer and the cover does not match (image 1) ... oh man!
Then roughly searched for the TDC with a screwdriver (and found it!), Surprise - then the marking at the bottom of the TDC pointer (Image 2) fits - great, but the two points on the spur gear do not match. (Image 3) Roughly at least 1/2 tooth - more towards one tooth.The lines in Image 3 are just a rough guide

There - I just didn't look/pay attention to the point; when assembling about 2 years ago.


-Is the duplex chain kit incorrectly manufactured, is the groove milled incorrectly - whether cam or crank is wrong or both to each other? I guess its the crank that's out ...

-Could it be that this is why the engine ran / rumbled / shook so unsteadily?

-Has anyone had this before...?

- Or is there another point I need to check now ...?

Thanks ...

[philthehill]

Unless you use two dial gauges and the timing disc you will not know if the camshaft/valve timing is correct.
Using a plunger down the plug hole to determine TDC is not accurate enough as the piston remains at TDC whist the crankshaft can turn through several degrees.
The timing marks appear to be half a tooth out.
As the cam gear rotates at half the speed of the camshaft you could try moving the camshaft gear one tooth.
When turning the engine to determine the timing always turn the engine clockwise as any slack on the return side of the chain can effect the relationship of the timing marks. There does seem to be some slack on the return side of the timing chain in the photo above.

[Miss Marple 1954]

Hello Phil,

Yes exactly - I agree with you!

Yesterday - with the screwdriver was just a troubleshooting tool - a bit like "field repair"

Tomorrow evening I will pinpoint the error with my buddy and eliminate it hopefully - with dial gauges and a timing disk.

Oil pan and sprocket wheels off - and then, as you say, offset the camshaft by probably a tooth.

Yes - the timing chain is really loose on the return side, although the engine has worked a maximum of 600 mls since the rebuild.
Then I'll do "happy screwing" tomorrow evening - I'll report back

Thank you very much!

[Miss Marple 1954]

Hi everyone.

at the weekend we measured and checked everything - exactly according to WSM (chapter "General data 12") valve timing - with the values we then measured exactly - after a while (it really takes a while to determine the correct values - if you don't do that every day) we came very, very close to the values from the "Book of Words".

The result is - we had to reposition exactly one tooth on the camshaft sprocket.
It looks like the mark on the camshaft sprocket seems to be set correctly but on the crankshaft sprocket it is out by ½ a tooth.

But no matter - now I have to put some things back together again and then I can test how it works, I hope it's really good!

A quick question on a note to Phil that we didn't understand - what is Fig.AA.28 supposed to show us about the problem? Maybe I have a different WSM than YOU? (see photo 5)

Many thanks to all - I will keep you up to date

Dirk

[philthehill]

Oops
Sticky fingers again.
It should be Fig A.A.20 and Section A.A. 28.
Fig A.A. 28 was to make sure that you were paying attention

[Miss Marple 1954]

I almost thought of something like that ... a test.