top-mount starter on late model rotary???
top-mount starter on late model rotary???
what's crackin', people!!!
I'm working on a rotary-based project and am exploring options to overcome space constraints - getting kinda tight!!!
Has anyone heard of adapting an early Mazda top-mount starter(RX-2, RX-3, etc.) to a 2nd gen RX-7 drivetrain?
I haven't found much info regarding tooth count on early flywheels, ring gear offset(early RX compared to 2nd gen RX-7).
All input would be greatly appreciated.
I'm working on a rotary-based project and am exploring options to overcome space constraints - getting kinda tight!!!
Has anyone heard of adapting an early Mazda top-mount starter(RX-2, RX-3, etc.) to a 2nd gen RX-7 drivetrain?
I haven't found much info regarding tooth count on early flywheels, ring gear offset(early RX compared to 2nd gen RX-7).
All input would be greatly appreciated.
Old [Sch|F]ool
Joined: May 2001
Posts: 12,862
Likes: 568
From: Cleveland, Ohio, USA
I know someone who is in the process of using a topmount on a newer engine.
What he found was that the starter needs to have its holes ovalled because the ring gear is further from the engine on the bottom-mount engines. 1/4" sounds about right.
All nonturbo engines (except RX-8 and I think REPU - need confirm/deny on this) use the same diameter ring gear.
If you're using a transmission made for a bottom mount, you will have to do some hacking to the trans to get the starter to fit, but the engine should have the mount pad for the starter.
What he found was that the starter needs to have its holes ovalled because the ring gear is further from the engine on the bottom-mount engines. 1/4" sounds about right.
All nonturbo engines (except RX-8 and I think REPU - need confirm/deny on this) use the same diameter ring gear.
If you're using a transmission made for a bottom mount, you will have to do some hacking to the trans to get the starter to fit, but the engine should have the mount pad for the starter.
Mods shut me down B 4 I could finish...
Anyways, good look on the info. Stretching those holes is better than spending $500 on a trick flywheel or flipping the ring gear on the flywheel around(even possible on the "7"?).
After seeing a top-mount starter(it's been a while), I kinda figured I'd have to butcher the bell but wanted to get some confirmation B 4 committing.
I appreciate the help, folks.
-turb'd
Anyways, good look on the info. Stretching those holes is better than spending $500 on a trick flywheel or flipping the ring gear on the flywheel around(even possible on the "7"?).
After seeing a top-mount starter(it's been a while), I kinda figured I'd have to butcher the bell but wanted to get some confirmation B 4 committing.
I know someone who is in the process of using a topmount on a newer engine.
What he found was that the starter needs to have its holes ovalled because the ring gear is further from the engine on the bottom-mount engines. 1/4" sounds about right.
All nonturbo engines (except RX-8 and I think REPU - need confirm/deny on this) use the same diameter ring gear.
If you're using a transmission made for a bottom mount, you will have to do some hacking to the trans to get the starter to fit, but the engine should have the mount pad for the starter.
What he found was that the starter needs to have its holes ovalled because the ring gear is further from the engine on the bottom-mount engines. 1/4" sounds about right.
All nonturbo engines (except RX-8 and I think REPU - need confirm/deny on this) use the same diameter ring gear.
If you're using a transmission made for a bottom mount, you will have to do some hacking to the trans to get the starter to fit, but the engine should have the mount pad for the starter.
-turb'd
Old [Sch|F]ool
Joined: May 2001
Posts: 12,862
Likes: 568
From: Cleveland, Ohio, USA
Oh, it won't work for a TII, much larger flywheel.
You may be able to fabricate a spacer to get the starter further outboard, though. You'd definitely be forging new ground here.
You may be able to fabricate a spacer to get the starter further outboard, though. You'd definitely be forging new ground here.
Oh, I forgot to mention, I'm using the smaller N/A flywheel.
Also, got the starter today and it fits up perfectly using the N/A flywheel, check it out:
Teeth mesh nicely, though, I'll need to chamfer the flywheel teeth so they don't thrash since they'll be engaging from behind... I guess I better get to grinding.
Also, got the starter today and it fits up perfectly using the N/A flywheel, check it out:
Teeth mesh nicely, though, I'll need to chamfer the flywheel teeth so they don't thrash since they'll be engaging from behind... I guess I better get to grinding.
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