Looking for guidance on IMS gear set up.
 

Hello, I am new to the Porsche world but quite experienced mechanic. I have been gathering parts for a 1972 911 build, and currently focusing on the lower end of the engine.last September I picked up a 993 crankshaft off the forum. The crankshaft lacks the gears and shims that press on the end. Last week I picked up a 964 intermediate shaft with a steel gear, which I gathered is pertinent for the larger stroke motor. So here’s my questions; first what is the part number of the crankshaft timing gear. How or what is the procedure for spacing the gear so it meshes correctly with the IMS gear. Last where can I source the gear and the shims needed. I believe 993 crank gear is going to be in a category of its own. Thanks Pio

The IM gear on the crank does not have shims to set up. The IMS gear and the crank gear are a matched set. The number stamp on your IM gear will determine which crank gear you need. I believe there are however different thickness circlips, it must be a tight fit.. I’ll post a pic of the circlip table. I would get the gear from Porsche but there’s probably others on this forum that have some experience with the aftermarket steel gears hopefully someone will give some advice there.

Once you get your crank gear you will need to check the backlash between the new crank gear and the old IMS gear.

Thanks, for your input. I did watch a 3 min YouTube video by Mike desilva showing how to check the back lash. I wasn’t sure if there was a depth setting as well.

Does anyone know if the crank gear from an earlier motor like a 3.2 will work? I believe the 964 and 993 crank gear is aluminum instead of the IMS gear like the earlier models. I was hoping to set this motor up with steel gears as another Pelican member had posted.

I covered what works recently. You need a matched 993 gear set or 996 Turbo or GT3.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/1127973-what-steel-intermediate-shaft-gear-people-using-these-days.html#post11820460

I just placed an order on 996 turbo IMS a little cheaper than the 993 but it all seems to be the same based on Evan’s post.

996-105-911-70Intermediate Shaft
900-041-025-01Circlip
900-118-010-00Woodruff Key
901-105-125-04Timing Gear
993-105-275-52Intermediate Piece Cap
900-041-026-01Circlip

The PET porsche parts catalog has all the part numbers, qty you will need.

So I’m still trying to locate the gear that presses on to the crankshaft. The gear I need has 35 teeth, all the ones that I can find has 29 teeth which was used with the aluminum IMs gear. I’m starting to come to the belief that the steel gears can only be used as a match set like a ring and pinion. Has anyone ever put a motor together with a used IMs gear and a new crank gear, and was it successful? I have replaced similar style gears in transmissions and it was never an issue.
Also, how do I determinate if the case is “0” or “1” if I don’t have any of the original internals? Thanks

Check this video out. It explains the IMS gear and case numbers.

https://youtu.be/wJKEm2S9jEQ

I just watched that video, and it appears that there is a stamp inside the case below, the IMS bore. I still am quite not sure if it’s acceptable to use a set of gears that came from separate sources. Other words using the used steel IMs gear with the correct 35 tooth crank gear,setting a dial indicator and getting the proper backlash, will it chew up the gears and ruin the motor?