Ring gear

Post by **andypocock** » Wed Mar 18, 2009 6:05 pm

I'm in the middle of sticking a 1098 in place of an expired 950 so I'm going to use the 950 flywheel on the new engine but I noticed that the ring gear is well chewed up.

I've got a brand spanking ring gear for a 1098 which I was going to stick on the 950 flywheel but when I checked the suppliers I see that they list a different gear for each engine size.

Does anybody know if I really do need a 950 ring gear or will my 1098 one be OK on the 950 flywheel.

Many thanks

Andy

Post by **PSL184** » Wed Mar 18, 2009 6:14 pm

The diameter of the 948/1098 flywheels are the same but I have never had the ring gear off to see if the mounting depth is different - That's the only thing I can think of which would stop you using 1098 ring gear....

Post by **PAULJ** » Wed Mar 18, 2009 8:43 pm

Could it be the profile of the teeth thats different? it may be worth checking that the starter motor will mesh with it

Post by **PSL184** » Wed Mar 18, 2009 9:12 pm

948 and 1098 use the same starter so doubtful.....

Post by **andypocock** » Wed Mar 18, 2009 10:19 pm

Thanks for your thoughts chaps. I'm inclined to think it can only be the depth as the only reason I'm changing is that the 1098 flywheel is a smidge thicker.

I think I'd better bite the bullet and get a 948 ring gear in as I'll regret it if I get over to the car and then find that I can't get away with my 1098 part.

Andy

Post by **bmcecosse** » Wed Mar 18, 2009 11:14 pm

Is there no way to measure them - and compare? Teeth should be the same. Although I haven't done the job myself - I believe you just need to heat the ring gear up to max domestic oven temp - and then drop it on the cold flywheel. Just be sure to drop it on right way up!

Post by **andypocock** » Thu Mar 19, 2009 12:17 am

Unfortunately I don't have them here or else I'd get measuring. I just thought "Oh not to worry I have a new ring gear at home".

It was only when I checked the suppliers websites that I saw different ones listed

Wish I hadn't looked really but then I don't want to turn up ready to go on Saturday and find that my ring gear is a non starter.

Andy

Post by **Kevin** » Thu Mar 19, 2009 12:31 am

Is it advisable to use the 948 flywheel with the smaller clutch behind a 1098cc though.

Post by **bmcecosse** » Thu Mar 19, 2009 12:36 am

If using the original 948 box - he will have to !

Post by **andypocock** » Thu Mar 19, 2009 1:20 am

Yep using the original box which is why I was swapping to to the old 948 flywheel with the knackered ring gear.

It's just that I have a 1098 ring gear that I bought for my (1098) car but didn't use and I was hoping to save £25 (and time) by using it on my sister's (948) car.

Andy

Post by **sirrom** » Thu Mar 19, 2009 7:37 am

I believe there is a difference both have the same number of teeth ie 104 and outside dimention is the same (265) but inside dimention there is a slight difference (1098 = 236) (948 = 233) doesnt sound much but ....

Post by **bmcecosse** » Thu Mar 19, 2009 11:55 am

That would certainly make it un-useable on a 948 flywheel. Alterantive would be to weld up the badly worn teeth - and file/grind them back to correct profile!

Post by **andypocock** » Thu Mar 19, 2009 5:40 pm

Thanks Sirrom. 3mm or a metric 1/8" would leave the 1098 gear ring a little loose

I've ordered a new 948 gear ring. Welding and filing 104 teeth didn't sound all that an attractive way of spending my weekend.

Thanks all.

Andy

Post by **bmcecosse** » Thu Mar 19, 2009 8:35 pm

I'm sure you wouldn't need to file ALL the teeth - were there not just a few that were damaged ? Would be great if you could come back when you have the two ring-gears side by side - and confirm the differences for us !