Balancing 63DT NPR Pistons

[BogusSVO]

I have to assemble a couple of stock rod 6 bolt short blocks, both .50mm or .020 over.

I know the closer the weights of the parts, the smoother the engine runs.

So since both short blocks are getting the same part number pistons and the same size, I can mix and match as needed.

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Box #1 Was 1.9g from lightest to heaviest

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Box #2 Was .8g from light to heavy , I can live with that If I had too.

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I swapped 2 pistons around from box to box and got them closer.

With a touch of grinding, I worked both boxes so the high to low was .2g

Also, the EngineTech pistons and rings are NPR, just reboxed.

 

[ColtiXim]

Good idea.
Have you a picture about the grinding area ?

Thanks

 

[BogusSVO]

Good idea.
Have you a picture about the grinding area ?

Thanks

I need to get one, I take for granted at times most all know what I talking about.

You just start with the cast flashing on the inside of the piston. Some shops drill the underside ow the crown.

 

[BogusSVO]

Good idea.
Have you a picture about the grinding area ?

Thanks

I think you jinxed me asking that!!

Just had to balance a horrid box of pistons... off by 4g high to low.

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The light one is on the left, the heavy is on the right.

 

[ColtiXim]

Wow, still NPR brand ?

Edit: Not NPR, these piston look to be have an snap ring groove ...

 

[BogusSVO]

I can not confirm if this set was NPR, good chance they are tho, same supplier.

Yes they have the wrist pin clips, this set is for a Mazda 1.8L BP engine.

 

[ColtiXim]

mizumoauto ?

I need to weigh control my 1G set, funny results i hope

 

[BogusSVO]

mizumoauto ?

I need to weigh control my 1G set, funny results i hope

No, not mizumauto, They are just a parts seller, like topline or enginetech or Rock

 

[dsmcurse]

I can not confirm if this set was NPR, good chance they are tho, same supplier.

Yes they have the wrist pin clips, this set is for a Mazda 1.8L BP engine.

Man, you always work on all the cool $hit dont you? Couple a years back for a DD I had a '95 Mazda MX3. Lil hatchback Mazda, man i wanted to swap the NA Mazda dohc cam for the turbo japan BPT version so bad. Couldnt justify the expense on a lil gas saver work car tho

 

[BogusSVO]

Yep I do get some fun stuff from time to time.

I have a 434 SBC that I have to go thru, it fried 5 of the 8 pistons and damaged the heads, seems someone messed with the nitrous timing retard box.

 

[YZFR1]

Yep I do get some fun stuff from time to time.

I have a 434 SBC that I have to go thru, it fried 5 of the 8 pistons and damaged the heads, seems someone messed with the nitrous timing retard box.

BogusSVO, could you please elaborate some more on how retarding the timing too much would cause a damage like that? I was always under the impression that it was mostly bad for the exhaust components rather than pistons themselves because the combustion would move away further from the chambers. Kind of curious about that. Thanks

 

[BogusSVO]

YZFR1.. Yes you do want to remove some timing when the nitrous sprays.

Just like you do when you get into boost.

In the case of the 434, somebody played with the knobs on the box, changing the amount of timing pulled.

Be about the same as someone getting into your DSMLink and changing the timing maps.