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Weigh your pistons.

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Mitchman2 Avatar
Mitchman2 Mitchell Andrus
Mills River, NC, USA   USA
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I'm helping a buddy rebuild his TD engine. He's gotten a new set of Aerolite pistons from Moss... Should be a matched set, right?

In grams: 390, 393, 398, 399. This is not even close. You cannot shave 9 grams (the weight of 2 quarters) off of the heaviest piston(s). He's sending them back.

Always weigh your pistons. They should be within a half gram out of the box. Some builders will demand under a tenth of a gram difference.



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Aridgerunner Avatar
Aridgerunner Bill Bussler
Montoursville, PA, USA   USA
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1956 MG MGA 1500 "The A"
1959 Triumph TR3A "The Mistress"
1977 MG MGB "Sweet B"
The next set might be worse. Why not take them, and the rods, to a good machine shop and have them balanced?



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Mitchman2 Avatar
Mitchman2 Mitchell Andrus
Mills River, NC, USA   USA
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I did. the shop said the rods are perfect. The pistons don't have a lot of meat on them. Easier to get a set properly matched out of the box.

The second set arrived - all within 1 gram.



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'30 Model A Ford Town Sedan
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'53 XK120SE OTS
'58 MGA roadster
'66 Series 1, 4.2 Jag E-Type OTS

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riley1489 Avatar
riley1489 Gold Member Bruce H
Great White North, QC, Canada   CAN
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1953 Jaguar XK120
1959 Riley 1.5 "King George"
1973 MG MGB
In reply to # 3645063 by Mitchman2 The pistons don't have a lot of meat on them.

did you weigh or swap the gudgeon pins about?

B



Life's most persistent and urgent question is, "What are you doing for others?"

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Mitchman2 Avatar
Mitchman2 Mitchell Andrus
Mills River, NC, USA   USA
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In reply to # 3645095 by riley1489
In reply to # 3645063 by Mitchman2 The pistons don't have a lot of meat on them.

did you weigh or swap the gudgeon pins about?

B

With, of course, just as you weight the connecting rods with their hardware.



The Flat Earth Society has members from all corners of the globe.

'30 Model A Ford Town Sedan
'48 MGTC Q Special
'53 XK120SE OTS
'58 MGA roadster
'66 Series 1, 4.2 Jag E-Type OTS

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riley1489 Avatar
riley1489 Gold Member Bruce H
Great White North, QC, Canada   CAN
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1953 Jaguar XK120
1959 Riley 1.5 "King George"
1973 MG MGB
In reply to # 3645440 by Mitchman2 With, of course, just as you weight the connecting rods with their hardware.

I was not questioning your abilities. confused smiley and yes measured with respective hardware of course. I always measure things, rods end to end etc.

I was asking were you able to weigh the gudgeon pins? was there a difference between them? and would swapping them about have helped?
I recognize this a moot question as all is now well with the replacements.

B



Life's most persistent and urgent question is, "What are you doing for others?"


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Mitchman2 Avatar
Mitchman2 Mitchell Andrus
Mills River, NC, USA   USA
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In reply to # 3645461 by riley1489
In reply to # 3645440 by Mitchman2 With, of course, just as you weight the connecting rods with their hardware.

I was not questioning your abilities. confused smiley and yes measured with respective hardware of course. I always measure things, rods end to end etc.

I was asking were you able to weigh the gudgeon pins? was there a difference between them? and would swapping them about have helped?
I recognize this a moot question as all is now well with the replacements.

B

Quite honestly it never occurred to me to swap the pins around.



The Flat Earth Society has members from all corners of the globe.

'30 Model A Ford Town Sedan
'48 MGTC Q Special
'53 XK120SE OTS
'58 MGA roadster
'66 Series 1, 4.2 Jag E-Type OTS

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