Author Topic: Fox 35 50th anniversery case smaller diameter crankshaft? (Read 2144 times)

Dennis Toth · « **on:** August 20, 2019, 08:09:39 PM »

Guys,
I have just started to set up a Fox 35 in a new 50th anniversary case and the standard crankshaft doesn't fit? It seems the older 40th anniversary case has a larger diameter crank by about 0.006". Is this just this case or was there a change for the 50th case?

Best, DennisT

RandySmith · « **Reply #1 on:** August 21, 2019, 09:05:46 AM »

Quote from: Dennis Toth on August 20, 2019, 08:09:39 PM

Guys,
I have just started to set up a Fox 35 in a new 50th anniversary case and the standard crankshaft doesn't fit? It seems the older 40th anniversary case has a larger diameter crank by about 0.006". Is this just this case or was there a change for the 50th case?

Best, DennisT

That is typical with the FOX 35, I have seen that many times , I have also sw this the other way

Randy

Dennis Toth · « **Reply #2 on:** August 21, 2019, 01:11:12 PM »

Randy,
Besides sending it to MM is there a simple way to get this to the proper size?

Best, DennisT

GERALD WIMMER · « **Reply #3 on:** August 21, 2019, 02:49:47 PM »

Hello We are spoilt these days with CNC made engine parts back in the day when engines were 'hand' made and fitted many parts did not interchange on a lot of different manufactures engines and I think Cox were famous for how parts even pistons would swap between motors. I particularly remember this with the Davis Charlton diesels were parts would not fit without reaming, lapping or machining and you were always swapping out rods and cranks after frequent breakages.
Regards Gerald

RandySmith · « **Reply #4 on:** August 21, 2019, 03:44:28 PM »

Quote from: Dennis Toth on August 21, 2019, 01:11:12 PM

Randy,
Besides sending it to MM is there a simple way to get this to the proper size?

Best, DennisT

If it is a tiny amount you can lap it, if it is a couple of ten thousands it really needs to be reamed, They make adjustable reamers, That is what I use, so without seeing it I would say send it off to be fitted

Randy

Dennis Toth · « **Reply #5 on:** August 21, 2019, 05:30:07 PM »

I measured the new case at 0.429" and another case that the shaft fit nicely at 0.433". I have a few of these so I think I should just pick up an appropriate ream. What is the brand and make of the reamer that I need to get? I have Grainger, Harbor Freight nearby that I could pick one up at. When I looked on line it looks like Grainger has one that is a hand adjustable reamers 13/32" with max size of 7/16" which covers the size range. Is this a good one?

Best, DennisT

Dan McEntee · « **Reply #6 on:** August 21, 2019, 09:38:03 PM »

Of course they can make a very precise hole. It all depends on the nut on the handle! You can screw up a perfectly good hole with a hone also. You can ream it close, and then lap to a final clearance and fit. For a Fox, being just a tad sloppy is sometimes desirable for some people. I would measure the bushing and then the crank, and see which is closer to the OEM spec, and then work the other for the fit you want. Then you have a chance of these parts fitting something else if need be, or other parts fitting this engine. It may be "just a Fox, but even after all these years, they aren't making them any more.
Type at you later,
Dan McEntee

Brett Buck · « **Reply #7 on:** August 21, 2019, 10:09:07 PM »

Quote from: Motorman on August 21, 2019, 09:24:13 PM

Ah yes, the notion that a reamer can make a very precise hole. I hear this every now and then.

There you go, Randy.

Oy gevalt...

Brett

GERALD WIMMER · « **Reply #8 on:** August 22, 2019, 05:03:35 AM »

Hello

This also reminds me of an E.D Miles Special my brother brought new from England in the 1990's at great cost . It had a reverse tapper bore

yes tight at the bottom of the stroke and loose at the top and generally rough machining work all over... something went wrong there, not at all like the original ED engines that were generally well made

He also got a new Irvine 40 Diesel that went clunk when you attempted to turn it over and only had about 270 degrees movement of the shaft before something hit, don't know why it left the factory like that? At least this was brought locally and was easily exchanged for a good engine.

Regards Gerald

RandySmith · « **Reply #9 on:** August 22, 2019, 10:57:43 AM »

Quote from: Motorman on August 21, 2019, 09:24:13 PM

Ah yes, the notion that a reamer can make a very precise hole. I hear this every now and then.

I have a good quality adjustable reamer, that i have used on many engines, among them FOX 35s, and McCoys, some have been rebushed
I have had zero problems making a round straight precise hole, That does not mean that someone could not screw up a busing with a reamer, but it is far better than using some other means, Stay away from drill bits, and you need to get it close before it could be lapped
you also have to be very careful setting the reamer

Randy

Dennis Toth · « **Reply #10 on:** August 22, 2019, 01:29:57 PM »

Randy,
What is a good brand and type for the ream? I know this has to be done carefully and if it gets messed up it is the guy setting up/ turning the ream and not the tool.

Best, DennisT

RandySmith · « **Reply #11 on:** August 22, 2019, 04:03:51 PM »

Quote from: Dennis Toth on August 22, 2019, 01:29:57 PM

Randy,
What is a good brand and type for the ream? I know this has to be done carefully and if it gets messed up it is the guy setting up/ turning the ream and not the tool.

Best, DennisT

https://www.mscdirect.com/product/details/02239002
the above should be what you need, FOX used a 7/16 reamer for the bushing, Set this one at the minimum and it should cut to .4375
check to see if that is opened enough, then adjust from there
If yours is smaller as stated then get the next size down, I just measure 2 FOX cranks at 4375

so we have differant cranks
I will post the smaller one too

below is the smaller one that will fit your size case bushing

https://www.mscdirect.com/product/details/02230993
Randy

RandySmith · « **Reply #12 on:** August 22, 2019, 04:22:32 PM »

Dennis

I just measured 6 FOX 35 Cranks that are all new, and from different decades The went from small of .4365 to .4375
I measure a couple of NEW fox 35 Cases they are from 437 to 438
I do not know where you got a 433 one?? that seem very small
maybe recheck again

Randy

RandySmith · « **Reply #13 on:** August 22, 2019, 04:25:06 PM »

Quote from: Dennis Toth on August 20, 2019, 08:09:39 PM

Guys,
I have just started to set up a Fox 35 in a new 50th anniversary case and the standard crankshaft doesn't fit? It seems the older 40th anniversary case has a larger diameter crank by about 0.006". Is this just this case or was there a change for the 50th case?

Best, DennisT

I have an undamaged NEW 40th case here that is .436 measured top to bottom on the bushing, and .4375 when measuring from side to side, so it is a slightly oblong distorted bore

Randy

Dennis Toth · « **Reply #14 on:** August 23, 2019, 06:31:22 AM »

Randy,
I checked again and still got 0.433 - 0.434" on the case bearing. I check two other cases that has had a crankshaft in it and they are same as yours 0.435 - 0.436". Thanks for the information on the ream, they are similar to the Grainger - Adjustable Blade Hand Reamer, Fractional Inch, 13/32", 7/16", High Speed Steel, Item # 4LGR5 Mfr. Model # 4LGR5 Catalog Page # 2257 UNSPSC # 23171610 $20.19 for the smaller size.

Best, DennisT

RandySmith · « **Reply #15 on:** August 23, 2019, 08:44:30 AM »

Quote from: Dennis Toth on August 23, 2019, 06:31:22 AM

Randy,
I checked again and still got 0.433 - 0.434" on the case bearing. I check two other cases that has had a crankshaft in it and they are same as yours 0.435 - 0.436". Thanks for the information on the ream, they are similar to the Grainger - Adjustable Blade Hand Reamer, Fractional Inch, 13/32", 7/16", High Speed Steel, Item # 4LGR5 Mfr. Model # 4LGR5 Catalog Page # 2257 UNSPSC # 23171610 $20.19 for the smaller size.

Best, DennisT

Hi Dennis

That should work for you , let us know how it comes out

Randy

Dennis Toth · « **Reply #16 on:** August 30, 2019, 10:24:36 AM »

Guys,
OK got the Grainger - Adjustable Blade Hand Reamer (Fractional Inch, 13/32", 7/16", High Speed Steel, Item # 4LGR5). I had an old case that I used as a test fit. Once I got an understanding of how to adjust the size (on this ream moving the cutters down increase the diameter) I started slowly increasing the diameter (moving down about 1/8 turn of the collars) and test fitting a crankshaft. For my ream in seemed that turning it counterclockwise was smooth and that's the way I did it. I did use some airtool oil as a cutting fluid (on line they indicated that cutting oil used for steel is not suitable for softer metals like bronze/brass/aluminum). As it got close the front started to fit and I needed to work on the back. It seemed the venturi hole area was a little tighter so I slowly worked from the back side and got it so the shaft just slipped in a little snug. Once the shaft was in (with a little oil) I put on a prop and spun it a bit and it spins very smooth. I think a little break-in and we should be good to go.

Thanks for the help and guidance from the group.

Best, DennisT

Author Topic: Fox 35 50th anniversery case smaller diameter crankshaft? (Read 2144 times)

Dennis Toth

Fox 35 50th anniversery case smaller diameter crankshaft?

RandySmith

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

Dennis Toth

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

GERALD WIMMER

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

RandySmith

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

Dennis Toth

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

Dan McEntee

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

Brett Buck

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

GERALD WIMMER

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

RandySmith

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

Dennis Toth

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

RandySmith

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

RandySmith

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

RandySmith

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

Dennis Toth

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

RandySmith

Re: Fox 35 50th anniversery case smaller diameter crankshaft?

Dennis Toth

Re: Fox 35 50th anniversery case smaller diameter crankshaft?