curse st EBA #2

[big job]

I have 7 perfect and one like 20grms (light) one on right see the ridge 'turned'
is like 20+ grams lighter. I can not find one= they want to sell me a set.
So fellow machinist ; turn a shoulder on the other 7 pistons????
factory defect my thought


can you see the turned ridge? as I thought they dropped it ; then made it good: (green arrow)
Perfect Circle shame ? Best I can describe I anint no book writter I do hands on.

[J Franklin]

Why not send them back for a better matched set? That seems the easiest way to solve your problem. These things happen.

[51 MERC-CT]

Looks like two different manufacturers/brand of piston.

[BILL WZOREK]

I am not a engine builder by any means / Have put a lot of Diesel engines together
Got boo coo miles out of most.
But is 20 grms that much to worry about in a street engine.
could we average the weight of the pistons and rods & pairing them up so that they are as close as possible to each other worrying more on left side of engine to right side of engine spinning mass weight.
I can not believe that all these flatheads that survived till now that they were all put back together with this much meticulous details ( By no means am I saying the details don't matter because they do to a point ) But can the difference be felt in the seat of the pants on a street engine with only 20 grms on one piston ???

[JSeery]

Wouldn't it be better to drill the inside of the other pistons just like normal balancing?

[Binx]

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Originally Posted by 51 MERC-CT

Looks like two different manufacturers/brand of piston.

Totally agree. Fwd notch and fwd arrow. Not the the same production obviously.

Lonnie

[big job]

I agree with everybody. problem is I've had the 'unopened piston box' for two months,
due to other jobs so I hate to be a haunt I'll call the vender again. I still think it was
buggered up and was dressed up. I just may turn the other 7 to match, another
solution is to weigh a piece of alum. plunge with a endmill weigh that for the amount
needed (reset dro's) time consuming, but while in the bowels of the job, may as well do it correct
so I can sleep at night. Hey Binx, Notch and Arrow or Friday or Monday production?

sam

[JWL]

The "notch-arrow" thing indicates the castings were poured in different molds and might not be from the same manufacturer.

Frankly I don't know where 20 grams could be removed from a piston?? That is really asking for allot. From those pictures I cannot determine the different machining? I wouldn't even attempt to remove 20 grams from a piston unless there was a very obvious casting thickness variance.

[LOWRIDER]

Could you take the extra weight out of the wrist pin? That's how my guy balanced mine. They were press fit pins in mine, don't know if it could be done on yours that way.

[Ronnie]

Take a pic from the side and the inside.

R

[johnboy34]

2 months, call the vender anyway and explain, I'm sure he wouldn't use the set that way!

[Bored&Stroked]

Return them - the set is 'defective' from the start. These look like two different brands of pistons. I wouldn't spend any time screwing with them.

B&S

[Mart]

They are completely different. The "front" marking is different. The one with the turned area did not start out like the others.

The seller sold you a defective set of pistons. In fact they did not sell you a set, as such.

Mart.

[big job]

Originally Posted by LOWRIDER

Could you take the extra weight out of the wrist pin? That's how my guy balanced mine. They were press fit pins in mine, don't know if it could be done on yours that way.

I suppose so in this case is to add weight to this odd ball, a phone call is
in order

sam