# Eagle crank timing gear issue



## Jared (Apr 19, 2013)

Someone else must have run into this.

My short block was built with an Eagle stroker crankshaft. I had some extra time today so I decided to test fit parts to prepare for assembly. The timing gear will not slide onto the shaft. I tried fitting the gear that came off the old engine and that one doesn't fit either. I still have the broken crank that came out of the old engine and both timing gears fit on that one. I used a caliper to measure and the Eagle crank is maybe 1/100 or 2/100 of a cm bigger round than the original one was. I have a digital mic at work that I can borrow to get a more accurate reading on it.

Has anyone else run into this? If so, what's the solution? Do I need to have the timing gear machined or can it be cleaned up by hand using emery cloth to fit?

As always, thanks in advance.


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## Old Man Taylor (May 9, 2011)

It isn't unusual to have the snout as much as 0.003" too big. I would take the crank to a crank shop and have the whole thing measured and turned to spec.


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## Jared (Apr 19, 2013)

Old Man Taylor said:


> It isn't unusual to have the snout as much as 0.003" too big. I would take the crank to a crank shop and have the whole thing measured and turned to spec.


I would but the crank is already in the engine. Building the bottom end was a bit past my talent so I started with a short block.

I bought the timing set through Butler and they indicated that the bottom gear may need to be honed to fit after market crank shafts. This lines up with what you said. I borrowed a digital micrometer from work and measured the old and the new cranks and came up with under 0.1 mm difference (~0.003 inches). Yesterday, I reached out to Butler, explained my situation, and asked them how they suggested I hone the lower gear. They said they use a ball hone to do this in their shop.


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## PontiacJim (Dec 29, 2012)

Jared said:


> I would but the crank is already in the engine. Building the bottom end was a bit past my talent so I started with a short block.
> 
> I bought the timing set through Butler and they indicated that the bottom gear may need to be honed to fit after market crank shafts. This lines up with what you said. I borrowed a digital micrometer from work and measured the old and the new cranks and came up with under 0.1 mm difference (~0.003 inches). Yesterday, I reached out to Butler, explained my situation, and asked them how they suggested I hone the lower gear. They said they use a ball hone to do this in their shop.


Probably could also use a small wheel cylinder hone - 3 flat stones spring loaded like a cylinder hone and would most likely get you a better and even hone in my opinion.

I would also fit it with the crank keyway out just to eliminate the potential of the gear hanging up on the keyway, which can happen, and then you'll keep honing away when in fact it was the keyway hanging you up.


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## Jared (Apr 19, 2013)

PontiacJim said:


> Probably could also use a small wheel cylinder hone - 3 flat stones spring loaded like a cylinder hone and would most likely get you a better and even hone in my opinion.
> 
> I would also fit it with the crank keyway out just to eliminate the potential of the gear hanging up on the keyway, which can happen, and then you'll keep honing away when in fact it was the keyway hanging you up.


Thanks Jim. Keyway is already installed too. I had read where the keyway can be tight to too big too. I'll gauge it up to that point and give it a slight file if needed. I plan on being very careful on this. The new and old gears will just make it past the beveled inner side before they get stuck so it'll be pretty obvious when I hit the sweet spot. Worst case is I have the old gear to use as a backup if I mess up the new one. While I wouldn't want to reuse anything from the old engine, I have that as an option.

I am probably going to take a couple days off from work this coming week and get this project going. I have three weeks on the books and I reload time in June so time to burn. I'll probably start a new thread and post as I go.


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## Jared (Apr 19, 2013)

As a follow up. The ball hone worked. I worked in 3 - 5 second increments and stopped as soon as the gear would slide on tight. Took me a bit of time to do and I went through an entire can of brake cleaner in the process. I wanted the gear as clean as I could get it for each test fit.


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