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Wiegh 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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fast-MG.com Avatar
fast-MG.com Dave Headley
Cortez, 4 corners, Colorado, USA   USA
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For road use on an inline 4 banger, you can pair the pistons and balance in pairs. Pair the 390 with the 399 for 1 & 4, and the 393 with the 398 for 2 & 3. Then you only need to lighten the 2 & 3 pair by 3gms. As far as 0.5gms out of the box on cast pistons, I would not expect that. The very good quality race pistons I use are usually within 1 gm. I often buy two or more sets at a time and select for balance among them.

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LaVerne Avatar
LaVerne LaVerne Downey
Fruita, CO, USA   USA
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1954 MG TF "Green Hornet"
1969 MG MGB "The Beater"
1979 Triumph TR8 "Turd 8"
This close enough for you ? smoking smiley


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Mitchman2 Avatar
Mitchman2 Mitchell Andrus
Mills River, NC, USA   USA
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Yea, not bad for out of the box.

We can do better with about 20 minutes and a Dremel.

I feel a contest coming on.......



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'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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LaVerne Avatar
LaVerne LaVerne Downey
Fruita, CO, USA   USA
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1954 MG TF "Green Hornet"
1969 MG MGB "The Beater"
1979 Triumph TR8 "Turd 8"
That's with the rods...both out of the box.

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Hawkmonster Avatar
Hawkmonster Joe Policastro
Flagstaff, AZ, USA   USA
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LaVerne I do not think you and Mitch are comparing apples to apples. His were out of the box from a normal supplier. If I remember yours were custom made by a high end racing supplier to get that fine of a difference.

Dave thanks for the tip. I am helping a friend with his TD rebuild and will use that technique with his normal supplier pistons.

Joe

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LaVerne Avatar
LaVerne LaVerne Downey
Fruita, CO, USA   USA
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1954 MG TF "Green Hornet"
1969 MG MGB "The Beater"
1979 Triumph TR8 "Turd 8"
You are correct Joe. I was just giving him a hard time.smoking smiley


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TD4834 Avatar
TD4834 Bill Chasser
Sacramento, CA, USA   USA
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1950 MG TD
1951 MG TD
1951 MG TD MkII
1952 MG TD MkII    & more
Yep you get whatcha pay for.
I dumped all my old pics off my phone or I’d give my bragging rights as well

Bill Chasser
TD-4834



Bill Chasser
TD-4834
TD-5779
TD/c-8151
TD/c-16920
TD-19408
TD-24060

TF-8200

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LaVerne Avatar
LaVerne LaVerne Downey
Fruita, CO, USA   USA
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1954 MG TF "Green Hornet"
1969 MG MGB "The Beater"
1979 Triumph TR8 "Turd 8"
grinning smileysmileys with beer

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TD4834 Avatar
TD4834 Bill Chasser
Sacramento, CA, USA   USA
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1950 MG TD
1951 MG TD
1951 MG TD MkII
1952 MG TD MkII    & more
Nice coating on your piston skirts LaVerne

Bill Chasser
TD-4834



Bill Chasser
TD-4834
TD-5779
TD/c-8151
TD/c-16920
TD-19408
TD-24060

TF-8200

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about 3 weeks and 1 day later...
Hawkmonster Avatar
Hawkmonster Joe Policastro
Flagstaff, AZ, USA   USA
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This thread was of interest to me since I am in the last stage of gathering parts for a TD engine rebuild. A huge thanks to LaVerne for helping me find a matching pair of rods. I sent of my rods and Pistons to be balanced by Dave Headley in CO at FAB-TEK.

Results. 0.3 grams spread on the rods and 0.2 spread on the Pistons. Very nice balancing job by Dave. For those of you in the need for this service and others you can not go wrong with his experience, service, turn time and fees.

Joe

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fast-MG.com Avatar
fast-MG.com Dave Headley
Cortez, 4 corners, Colorado, USA   USA
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Joe, you're making me blush!grinning smiley

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