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MG TD TF 1500 - XPAG con rod & main bearing

After a complete disassembly of engine of my 1953 mg td, I take a look to the connecting rod and crankshaft bearing set. The con rod bearing is marked 0.020 and the crankshaft bearing is marked 0.010.
So, I have measured the diameter of the crankshaft to check for wear and I am very surprise.
The diameter of crankpin journal is 44,96 mm.
The diameter of crankshaft main journal is 51,72 mm.
The diameter of main bearing seem ok but the crankpin journal seem near standard size then it is marked 0.020 on bearing ...
What did you think about that ???
Didier
Roussel Didier

Hi Didier,
check that the bearing is not marked O.OO2O it was possible at one time to get bearings in O.OO1 increments for worn crankpins.
Ray TF 2884
Ray Lee

Thank you for answer Ray, but the bearing is marked 0.020. See pictures attached.

Roussel Didier

And the crankshaft bearing (0.010)

Roussel Didier

Hello Didier,

You can use a plastigauge to measure the real clearance of each bearing. here are the instructions.


http://www.plastigaugeusa.com/how.html

John
J Scragg

Thank you John for the information. Do you know the clearance for the XPAG engine for the con rod and main bearing ?
Roussel Didier

Didier,

The clearances are:

Main bearings

0.0008 - 0.002 Inches
0.03 - 0.08 mm

Con rod bearings

0.0005 - 0.001 Inches
0.02 - 0.04 mm

All this information is found in this document

http://www.iot.ntnu.no/users/oddk/mg3/downloads/XPAGEngine.pdf

I suggest that you download it.


John



J Scragg

Many thanks John for the clearances and the document (I have immediately download it on my computer and ipad).
I have also ordered the plastigauge (red one) and when I will received it, I will mesure the real clearance of each bearing.
Didier
Roussel Didier

If the journals are really 44.96 then my guess is that the shells are NOT TD ones but for some other engine where the -0.020 size for THAT engine is the same as standard for the TD
Chris at Octarine Services

Yes Chris, it is a possibility thatI had not considered. I try to find the bearing model on the web with the reference but without success. If someone have an idea ...
Roussel Didier

Do they have a makers mark - like AE ?
Chris at Octarine Services

Yes, the makers mark is CLEVITE.
And you can read on them (see 1st pics) :
.020 10 63
CB 326
Roussel Didier

After research on the web, I found that Clevite make bearing for american car. Perhaps the model marked .020 on my engine is not for a MG TD ...
Roussel Didier

This thread was discussed between 15/08/2013 and 18/08/2013

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.