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+60 flat top race pistons for 1275 A series

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Derbyshire, UK   GBR
Hi all,
In the UK the lightweight Omega race pistons have reduced size 18mm gudgeon pins (wrist pins?). On strip down after three short races we noticed there was some wear on the piston pin bores, we wondered if this is due to the smaller contact area taking greater load per square inch? This leads me to look for lightweight forged pistons with standard size pins.....any leads Stateside please?
Peter

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Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
Peter we have had no issue with smaller pins and often use 19mm pins. I mostly use JE and they with make anything you want brother, manufacturing is excellent, you can probably run these forged piston tighter in the bore than any other brand. The only downside is their sale techs, all the good old guys have retired, know what you want, fill out your custom order sheet, because they are clueless. I have a couple of custom tops on file with JE, you are welcome to use if needed.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com


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fast-MG.com Gold Member Dave Headley
Cortez, 4 corners, Colorado, USA   USA
One of the features JE offers are pin oilers. Drilled holes from the inside of the oil ring groove to the pin bores


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Dave Headley, dba FAB-TEK offers full service race car parts and preperation for MGB & MGA race cars, SCCA and Vintage. Dave is a mechanical engineer and has raced MGBs since 1963.
Derbyshire, UK   GBR
Thanks for the info Hap, do you have any flat top +60 slipper piston dimensions on file with JE?
Dave, thanks for the info. The Omega pin bores on the slipper pistons we have two elliptical grooves, one each side of the pin bore at about the 2 o'clock and 10 o'clock positions. I do not feel it is a supply problem.
Peter

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fast-MG.com Gold Member Dave Headley
Cortez, 4 corners, Colorado, USA   USA
Peter, with JE's pin oilers, oil is pumped to the pin bores from behind the oil ring as the ring moves in and out in the groove. What is the source of oil in the pistons you reference?


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Dave Headley, dba FAB-TEK offers full service race car parts and preperation for MGB & MGA race cars, SCCA and Vintage. Dave is a mechanical engineer and has raced MGBs since 1963.
Derbyshire, UK   GBR
Interesting Dave. We only use JE in all the Bs and have no problems. The pins are splash fed in our A series engine.

I have asked around and folk think the engine owner may be an 'animal', however, we have been building his engines for his Midget since 2003 or so and have never seen this problem with him running standard size pins.

Peter

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Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
In reply to # 3641271 by Peter Burgess Thanks for the info Hap, do you have any flat top +60 slipper piston dimensions on file with JE?
Dave, thanks for the info. The Omega pin bores on the slipper pistons we have two elliptical grooves, one each side of the pin bore at about the 2 o'clock and 10 o'clock positions. I do not feel it is a supply problem.
Peter

Peter JE will automatically do a slipper unless you tell them not to. This is a MGB dome piston, but it shows the JE slipper rather well. The second piston is a CP piston for a 1275, which looks alot like the type design used in engine like a NASCAR cup engine, so major slipper and skirt surface not much bigger postage stamp.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com



Edited 1 time(s). Last edit at 2017-12-09 07:57 AM by Speedracer.


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others

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Derbyshire, UK   GBR
Hi Hap
We have been using the JE FSR MGB ones for a couple of seasons and very pleased.
The CP one looks good.
Peter

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fast-MG.com Gold Member Dave Headley
Cortez, 4 corners, Colorado, USA   USA
Hap's second picture clearly shows pin oiler holes in the oil ring groove.smoking smiley


Member Services:
Dave Headley, dba FAB-TEK offers full service race car parts and preperation for MGB & MGA race cars, SCCA and Vintage. Dave is a mechanical engineer and has raced MGBs since 1963.
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