[Fot] Center main support

[tr4racing at googlemail.com]

Interesting photos.

I’ve never thought about this. All my cranks need a little straightening after some use in race engines.

The machine shop says, that is normal. Many race engines warp cranks during usage.

As long the bearings are okay nothing to do they say.

My mains never developed a problem…..and I’m running larger main bearing clearances to compensate crank flexing….all seems fine.

On the other hand, I’m running smaller rod bearing clearances.

 

Cheers

Chris

 

 

Von: Fot <fot-bounces at autox.team.net> Im Auftrag von Phil Gott via Fot
Gesendet: Sonntag, 24. November 2019 04:11
An: Tony Drews <tony at tonydrews.com>
Cc: Friends Of Triumph <fot at autox.team.net>
Betreff: Re: [Fot] Center main support

 

Here are some photos:




 

 

 

Sent from my iPhone





On Nov 23, 2019, at 12:23 PM, Tony Drews <tony at tonydrews.com <mailto:tony at tonydrews.com> > wrote:

 

I agree, that sounds like overkill.  Mine only requires the top of the cap to be machined flat, no other block mods.

Regards, Tony

On 11/23/2019 5:42 AM, Phil Gott wrote:

Thanks again, Tony: 

The one we have, built by the late Bill  Throop, in addition to reinforcing the cap itself, has the block machined internally to accept the sides of a strap, then the strap  is cross bolted from the sides, through the block from outside.  I’m wondering if this is a bit of overkill. Based on your recommendation, it seems to be.

Maybe I can send some pictures later today, as we are pulling the engine today for other work.

Phil

Sent from my iPhone





On Nov 22, 2019, at 10:56 PM, Tony Drews  <mailto:tony at tonydrews.com> <tony at tonydrews.com> wrote:

 

I run that setup, it was an uncle jack trick.  Here's what he wrote about that (on my engine building tips page):

"I also like to strap the center main to add rigidity to the bottom end.  To do this, mill off the cast face of the main flush with the surfaces for the head bolts. Get a front strap for a Chevy 400 block. You must enlarge the holes in the strap  and you must use longer bolts.  Some  builders feel that this is totally unnecessary, but since starting to do this, I have never had a main bearing deteriorate faster than a rod bearing, which is something that happens more frequently than you would expect."

Regards, Tony Drews

 

On 11/22/2019 3:58 PM, Phil Gott via Fot wrote:

Has anyone seen the need to add extra support to the center main on the TR wet sleeve engine? We have an engine that has a steel bridge cross-bolted underneath and supporting the center main cap. Is this needed? Just took 3 factory cranks to the machine shop and all three were bent about .002 in (.002 run out at center main when supported on first and last mains.) Two of these were raced, the third was removed from a tired street engine. note: None of these cranks came out of the engine with extra support at the center.
Curious as to the need for the extra support.
Thanks,
Phil Gott
114 TR4A
 
Sent from my iPhone
_______________________________________________
fot at autox.team.net <mailto:fot at autox.team.net> 
 
http://www.fot-racing.com
 
Donate: http://www.team.net/donate.html
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/tony@tonydrews.com
 
 
 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/fot/attachments/20191124/ddbfe696/attachment-0003.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 976982 bytes
Desc: not available
URL: <http://autox.team.net/pipermail/fot/attachments/20191124/ddbfe696/attachment-0009.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image002.jpg
Type: image/jpeg
Size: 1056459 bytes
Desc: not available
URL: <http://autox.team.net/pipermail/fot/attachments/20191124/ddbfe696/attachment-0010.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image003.jpg
Type: image/jpeg
Size: 664537 bytes
Desc: not available
URL: <http://autox.team.net/pipermail/fot/attachments/20191124/ddbfe696/attachment-0011.jpg>