Timing problem

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stevelemoir
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Timing problem

Post by stevelemoir »

4yrs ago I renewed my single timing chain and cogs. I also renewed the 2 rubber tensioners.
When setting the timing with a strobe the dimple was static where as before it was moving about all over the place.
I have only done a few thousand miles since the replacement but now when dynamically setting the timing the dimple is moving about again!
I tried to set the timing statically using a multi-tester and for 2 plugs the setting was fine but for the other 2 it was retarded by about 10 degrees.

The distributor has been reconditioned by 'The Distributor Doctor' so should be OK.
My old distributor is behaving in the same way.

Can the chain or tensioners be worn already?
I am considering fitting the Mini cam chain tensioner.
bmcecosse
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Re: Timing problem

Post by bmcecosse »

Of course it has worn....the real answer is indeed the Mini simplex chain with tensioner. But don't waste time strobing the timing - since you have no idea what setting to use...just swing the dizzy at idle for best/smothest idle - and then road test to check it isn't pinking. DO check the vacuum advance is working as it should - and twist the rotor arm to make sure it springs back correctly.
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stevelemoir
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Re: Timing problem

Post by stevelemoir »

I made a mistake in my description of the static timing. I should have said....
I set the static timing on the compression stroke of cylinder 1 to the 5 degrees pointer
using a multi-tester to accurately show the points opening.

However I noticed that on the non compression stroke on cylinder 1 the timing is retarded.
I know this doesn't matter but can anyone explain it?

Thanks for the advice, I will check the vacuum more carefully, so far I have just checked that it is not blocked.

Engine seems to run OK on this static timing but I will do a few test drives and possibly do as you say and just go for the best idle.....when the rain stops!
bmcecosse
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Re: Timing problem

Post by bmcecosse »

Any slight eccentricity on the dizzy spindle will throw the timing out. I know you say the dizzy was 'overhauled'... but to what standard I wonder. Try another dizzy if it bothers you!
Last edited by bmcecosse on Sat Feb 08, 2014 3:56 pm, edited 1 time in total.
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katy
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Re: Timing problem

Post by katy »

Remove the distributor cap and rotor, is there any sideways slop in the shaft?
Talk slow, think fast!
stevelemoir
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Re: Timing problem

Post by stevelemoir »

Just to update from this post.
I have the engine apart and the distributor drive is very worn.
I think this may have contributed to the odd timing results between the 4 cylinders.
I'm annoyed with myself because checking the distributor drive with the engine in is quite simple.
I hope you can see how bad it is from the photo. The gears are worn to points and must have been close to failing!
IMG_0638.JPG
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stevelemoir
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Re: Timing problem

Post by stevelemoir »

Just to update from this post.
I have the engine apart and the distributor drive is very worn.
I think this may have contributed to the odd timing results between the 4 cylinders.
I'm annoyed with myself because checking the distributor drive with the engine in is quite simple.
I hope you can see how bad it is from the photo. The gears are worn to points and must have been close to failing!
IMG_0638.JPG
philthehill
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Re: Timing problem

Post by philthehill »

I found the same problem on a recently stripped 948cc Minor engine which I reported on here.

viewtopic.php?f=4&t=69684

Whilst the camshaft skew gears were not worn enough to cause me concern you do need to examine the camshaft skew gears because if you do not and they are worn - fitting a new distributer drive could take you back to square one very quickly.

Phil

stevelemoir
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Re: Timing problem

Post by stevelemoir »

The camshaft screw gears are totally unworn. When I saw that the distributor drive was such a mess I did think that the cam would be knackered but it Is fine.
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kennatt
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Re: Timing problem

Post by kennatt »

Had exactly the same with an mgb,after fitting a so called new distributor, came to conclusion that the drive was not exactly cut to the same as the cam, same old problem of copy of a copy etc. the cam shaft is obviously harder.
philthehill
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Re: Timing problem

Post by philthehill »

Glad to hear and see that the camshaft is ok.
I would suggest that you fit a new distributer drive shaft and not a used one.
The new skew gears on the drive shaft will match and mate to the camshaft skew gears with less overall wear.

https://www.moss-europe.co.uk/spindle-d ... soc=137991

I have included this link as it makes reference to the timing scatter:-

http://www.minispares.com/product/Class ... o%20search

stevelemoir
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Re: Timing problem

Post by stevelemoir »

I’m fitting a NOS distributor drive supplied by Club Spares and now there is just a tiny bit of play. I guess this is to accommodate oil.
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