41 replies to this topic

[Clubber Lang]

Had a problem i thought was with the clutch. Taken the clutch/flywheel off and couldn't see a problem. I then found the primary gear was stiff to turn and thought this may have been the problem as it should be easy to turn. I then undid the bolts to the transfer cover and went to tape up the spline to stop the seal getting damaged and found the primary gear spinning like it should even though i had not moved the transfer cover? I have now removed the cover and cannot find a problem. Anyone got any ideas at all?(I had expected to find a problem with the bearings or one of the transfer gears.)
When i fitted the engine and box i drove it round the block no problem then my son took it round and couldn't get the gears. It seemed a bit intermitent but it would go into gear with the engine turned off which i thought was the clutch hence taking it apart (after checking hydrolics to the clutch.).
I think the problem is to do with the transfer cover or transfer gears or bearings but now it seems o.k. i am a bit worried that i will put it back together and find it happen again. One thought is that the transfer case could have been tightened to much or the gasket to thin (minispares gasket) but i doubt it (though am considering this?). Anyone got any ideas/experience on this?
Why would the transfer gears being tight affect gear change/clutch?
Any ideas or opinions gratefully received as i am at a loss here. cheers Steve

[Dan]

As I said in your other thread, I suspect you pushed the seal too far into the casing. I read your other reply and I don't think the seal is meant to be flush. There is a step in the face of the fitting tool but I can't remember if the seal sits below or proud of the surface. I'll have to look at the tool. Another possibility is that your transfer housing was not aligned properly, causing the seal to rub on the primary eccentrically. The dowels do a reasonable job of aligning it but there is a special tool to sit on the crank tail or primary (can't remember which) that aligns the case perfectly with the crank. Nobody uses that tool though so if that is the problem it's certainly unusual. Did you fit the transfer case yourself? Does it have both dowels in place?

By the way, please don't start several threads about the same problem.

[Clubber Lang]

Sorry Dan, as the other thread was more about removing the transfer cover with the engine in i thought i would bring my findings/problem to a new thread as it was getting lost.
Thanks for your advice and i understand where you are coming from and have not yet ruled this out but having checked the seal and the amount of resistance that was on the gear i would be suprised (though pleasantly suprised as easy fix) if this turns out to be the problem. If the seal was in to far i would have expected to have seen some wear on it? would it not block the oil holes in the primary gear if it was in too far and cause problems with that as well? Also i had removed the big c washer at the front of the primary gear before i touched the transfer cover and i could move it out a little?
I am still at a loss as to the cause but before i put it back in i will again replace the seal without pressing in as far. I have replaced one on a previous engine with no problem though.
I have looked inside the primary gear and there is a slight split in the brass bush/bearing which i am not sure should be there so will take a photo and post to see if it is supposed to be there.
Regards Steve

[Turbo Nick]

what have you been doing in there? could it be that the new gasket you have fitted is thinner than the old one and the idler gear is being nipped up too tight hence making the primary stiff to turn?

[Clubber Lang]

Photo inside primary gear, it is turning freely?

Attached Files

•  bearing_001.jpg   64.07K   33 downloads

[Clubber Lang]

Hi bud, yes that could be an answer, the gasket was out of a gasket kit from mini spares so i don't know to be honest, maybe i nipped it up to tight? i also put a bit of gasket sealer on both sides. Is the tolerance that tight that this could be the problem? regards Steve

[Stevie W]

Hi Steve,

The running tolerance on the idler gear is quite tight and there are thrust washer/shim sets that contain different thickness washer to correct the running clearance.

Also the drop/transfer gear casing gasket thickness can vary and if your idler gear was running on bottom tolerance a thinner gasket would or could cause the 3 drop gears to lock up. As the engine and box warm up this clearance will close up and make matters worse!

Unfortunately the proper way of checking the running clearance is with the gearbox off the engine so you can get a DTI or feeler guage in there. However just measuring gasket thicknesses and selecting a thicker gasket should free things up.

Hope this helps!

Steve

[Stevie W]

Just looked at the photo of the primary gear inner bush, I can't tell for sure but the bush looks as though it maybe cracked at the top which wont help matters!

Steve.

[Dan]

If the bush has cracked it's a sign it may have been too tight on the crank. I can't see what would have caused that though if it's the original primary that's been there all along. Different gasket thicknesses cause problems for the idler gear rather than the primary but as said above this would lock the whole gear train. When you fit a new gasket of a different type or when you don't know what type was previously fitted you are supposed to measure the idler clearance and re-shim it if needed but that's not practical in the car. The tollerance is indeed just a few thou but using a smear of gasket sealer is normal practice so shouldn't be a problem.

[Clubber Lang]

Thanks for the replies folks, i didn't realise how close the tolerance was. I would think it highly probable that it was to tight against the idler gear causing it to tighten the whole lot up. I will try a thicker gasket if i can get one. The gear selection was indeed worse once the engine warmed up i think as it was o.k. for the first 5 minutes then got difficult albeit a bit intermitently. There is indeed a split in the bush inside the primary gear, if you look at the leading edge it isn't aligned perfectly. This may or may not have an effect? it turns quite freely. Could i use an primary gear off another engine or is this not a good idea?
One thing to note is the fact that this is a metro engine i bought which had apparently done 17000 miles but the clutch was burned out and there were small surface cracks in the flywheel face so i changed the flywheel/clutch assembly for another one i had.
Keep the brainstorming going people as i am learning a bit more each time. Thanks Steve

[Dan]

That bush is realistically beyond use now. Using a second hand one is fine if it fits and the bushes are in tollerance and in good condition. You could always re-bush it, they are available. It means some machine work but it can then be reamed as an exact fit to your crank and so will be as oil tight and well-fitted as possible.

[mickyh]

I have found this interesting I am still having problems slecting gear and we have just put in a new gear box and clutch, you can't seem to get gear properly and then it will jump and not go back in. However when the clutch pedal is raised you get a whirring noise which disapears when you push the clutch in I have been told that this due to worn primary gear bushes.
I toook the clutch off to check evertinhg was correct and replaced it all for one last go before I take the transfer housing off. I noticed however that there appeared to be plenty of movement in the primary gear and still some when the lock washers where applied.

I will try driving tomorrow, and if no joy its new primary bushes for me at the weekend!

[Clubber Lang]

Hi Dan, any idea where i can get this done? engine is still in the car though, regards Steve

[Clubber Lang]

How do i know if a replacement primary gear (used) is within tolerance? I am begining to feel out of my depth here as i am a builder not a mechanic or engineer. kind regards Steve

[Dan]

You need to measure the crank tail and the bush diameter. There is a published tollerance but I can't remember what it is just now. You will need some accurate measuring tools, the tollerance is only a couple of thou. Most decent motor engineers could re-bush and ream the primary for you, Yellow Pages is your friend.