T-Series & Prewar Forum
Wiegh your pistons
Posted by Mitchman2
Topic Creator (OP)
Dec 13, 2017 08:37 AM
Joined 9 years ago
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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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'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
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.
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
fast-MG.com
Dave Headley
Cortez, 4 corners, Colorado, USA
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Dec 13, 2017 09:08 AM
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Joined 15 years ago
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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.
Topic Creator (OP)
Dec 14, 2017 12:54 PM
Joined 9 years ago
3,100 Posts
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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.......
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
We can do better with about 20 minutes and a Dremel.
I feel a contest coming on.......
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
Hawkmonster
Joe Policastro
Flagstaff, AZ, USA
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Dec 17, 2017 10:19 AM
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Joined 12 years ago
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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
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
Dec 17, 2017 10:33 AM
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Joined 16 years ago
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You are correct Joe. I was just giving him a hard time.
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TD4834
Bill Chasser
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Dec 18, 2017 02:14 AM
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TD4834
Bill Chasser
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Dec 18, 2017 06:05 PM
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about 3 weeks and 1 day later...
Hawkmonster
Joe Policastro
Flagstaff, AZ, USA
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Jan 10, 2018 01:05 PM
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Joined 12 years ago
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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
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
fast-MG.com
Dave Headley
Cortez, 4 corners, Colorado, USA
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Jan 11, 2018 12:06 PM
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