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-   -   Key broke, how do you remove pulley? (https://www.miataturbo.net/general-miata-chat-9/key-broke-how-do-you-remove-pulley-77939/)

Preluding 03-11-2014 03:27 PM

I JB welded mine on an old miata I had...as long as surface is prepped then it should hold up fine...I'd probably swing for a new Timing gear and Key though...

I've also heard of people making more marks in the cranks and gear so there are 2-3 more key ways for durability...they had access to machining equipment though.

hornetball 03-11-2014 03:34 PM


Originally Posted by IcantDo55 (Post 1110710)
As I got the car with out the AFM or crossover intake pipe and crank looks like this I bet your right. Header was heat wrapped. All pointing to hotside SC in its past.

Gotcha'. I thought this was on your turbo car. A SC would definitely explain this damage.

IcantDo55 03-13-2014 03:34 AM

2 Attachment(s)
So anyone ever "pin" a crank pulley? I see its popular in the SC crowd on LS motors. Just drill out a hole like a key way and drive a roll pin in there. I dont know how easy it would be to remove again but it should never let it slip regardless of the stock key. I would loctite the stock key in too.

My SC Mustang has machined two keys in to the crank but that was high dollar high HP build (800) and a bug blower using a 10 rib belt.

One below had two but I think one would do it.

Staffah 03-13-2014 11:44 AM

Its already F'd so how many more times do you think you want to dick around with this engine (i.e. replace the timing belt)? Pin it, weld it, or JB it and then drive until you are ready (or forced) to swap in a good motor.

FAB 03-13-2014 12:05 PM


Originally Posted by IcantDo55 (Post 1111358)
So anyone ever "pin" a crank pulley? I see its popular in the SC crowd on LS motors. Just drill out a hole like a key way and drive a roll pin in there. I dont know how easy it would be to remove again but it should never let it slip regardless of the stock key. I would loctite the stock key in too.

My SC Mustang has machined two keys in to the crank but that was high dollar high HP build (800) and a bug blower using a 10 rib belt.

One below had two but I think one would do it.

This is surprisingly not common in the Miata community. It's probably because most owners don't even think about the problem until they have already started to blow out their keyways.

I don't see why this wouldn't work as a quick fix in your situation. Certainly better than welding. The only problem I see is again keeping things even as the Miata configuration is not a press on pulley.

Sounds like you should give this a shot considering your crank is already beyond the point of return and unlike welding - this is at least an easy fix to un-do if/when it comes time to replace the crank.

EDIT - Whatever you do - keep an eye on it for the first few hundred miles. An unbalanced pulley is worse than not having one at all.

shlammed 03-13-2014 12:11 PM


Originally Posted by IcantDo55 (Post 1111358)
So anyone ever "pin" a crank pulley? I see its popular in the SC crowd on LS motors. Just drill out a hole like a key way and drive a roll pin in there. I dont know how easy it would be to remove again but it should never let it slip regardless of the stock key. I would loctite the stock key in too.

My SC Mustang has machined two keys in to the crank but that was high dollar high HP build (800) and a bug blower using a 10 rib belt.

One below had two but I think one would do it.

I did this with a Honda I had.

the issue I could see with a Miata is that the crank face isn't flush with the pully. so you wouldn't be able to get the hole started with a drill in a place that would help.

Solution though might be putting a solid rod in the pully off the engine and drilling the hole centered on the ID of the pully, slip it on then drill the crank for it after. Could be a serious pain though.

FAB 03-13-2014 12:16 PM


Originally Posted by shlammed (Post 1111440)
I did this with a Honda I had.

the issue I could see with a Miata is that the crank face isn't flush with the pully. so you wouldn't be able to get the hole started with a drill in a place that would help.

Good catch :squint: I knew there had to be a better reason why this is not a more popular solution for our poorly designed crank pulley setup.

hornetball 03-13-2014 12:47 PM

TDR adds pins on all their SC installs. Friend of mine just had an M45 installed by them.

Personally, I think the solution is easy. Use a turbo.

IcantDo55 03-13-2014 10:22 PM


Originally Posted by shlammed (Post 1111440)
I did this with a Honda I had.

the issue I could see with a Miata is that the crank face isn't flush with the pully. so you wouldn't be able to get the hole started with a drill in a place that would help.

Solution though might be putting a solid rod in the pully off the engine and drilling the hole centered on the ID of the pully, slip it on then drill the crank for it after. Could be a serious pain though.


I'll gust shim it flush drill and then remove shims.

FAB 03-13-2014 10:50 PM

It's shallow in the wrong direction. The pulley face is proud not the shaft. Maybe remove the timing gear from behind the pulley boss and do it...?

Landrew 04-22-2017 11:12 PM

Any pics of the TDR pinned sprocket ?


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