Carrillo Connecting Rod Axial Clearance

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Nigel Cousins
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Carrillo Connecting Rod Axial Clearance

#1 Post by Nigel Cousins »

Hi,
I am looking for some guidance and shared experience regarding the axial clearance on Carrillo rods.

I have a new set of PR-R912-1HS-5352B4S Cam Clearance Rods, on doing a dry set up to check clearances, set TDC etc. I found that the axial clearance between the rod and crankshaft was 0.457mm = 18thou. which is +6 thou (0.157mm) outside of the axial clearance spec of 0.10mm - 0.30mm.

After measuring everything to double check, the Carrillo rod width which incidentally matches the Carrillo specification drawing is 19.53mm, measuring 4 original Porsche rods for comparison R616.013.101.01 rods, they measured 19.78mm.

My questions are; is there a reason for the smaller rod width? and has anybody had experience in running with this amount of axial play?

Many thanks
Nigel

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John Clarke
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Re: Carrillo Connecting Rod Axial Clearance

#2 Post by John Clarke »

Hi Nigel What a good question!
And are the bearings supplied with the Carillo Rods also short on the width? Any less Rod Bearing Footprint isn't good. I don't unfortunately have the answers for You but look forward to our experts Input
Kind Regards Jay
 

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C J Murray
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Re: Carrillo Connecting Rod Axial Clearance

#3 Post by C J Murray »

That clearance is not a problem. Sometimes the extra clearance is used to improve oil flow through the rod bearing.

Are you using a stock crank or Scat etc crank? Make sure you have adequate axial clearance between the bearing and the crank. Trim the bearing if needed.
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Martin Benade
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Re: Carrillo Connecting Rod Axial Clearance

#4 Post by Martin Benade »

That must not be a critical dimension, Vic has said he clearances them with a belt sander when needed.
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Nigel Cousins
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Re: Carrillo Connecting Rod Axial Clearance

#5 Post by Nigel Cousins »

Thank you Jay, Martin and C.J. for responding so quickly.

For your information the rod bearings measure at 15.86mm wide which is narrower than the rod axial surface.
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Are wider shells available? I checked another standard set from another manufacturer and they were 15.90mm wide.

The Crank is an IKE knife edge counter weight design. IKE are a UK race parts supplier and machine shop.
IMG_0064.jpeg
The IKE crank rod Journals measure at 52.750mm diameter and 20.01mm wide. I had the journal reground as I was not happy with the tolerances out of the box.
As a double check to ensure the crank had not be made wrong. I measured 3 original Porsche cranks I have, to compare journal width and they ranged from 19.97mm - 20.01mm, so not a problem.

Thank you again for any thoughts, I feel it is better to seek advice and question, especially when something comes up out of spec.

Kind regards
Nigel

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