Don's (vwlover77's) Engine Build

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vwlover77
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Re: Don's (vwlover77's) Engine Build

Post by vwlover77 » Sun Jan 12, 2020 8:46 pm

I measured the weights of my new Brazilian Mahle pistons (with wrist pins installed) using a digital postal scale. The results were identical after 4 repetitions of measurements:

1. 684 grams
2. 686 grams
3. 684 grams
4. 686 grams

Good enough for a stock engine?

Also, is there any need to make any measurements on the pistons or cylinders? All 4 pistons are marked as "93.97 Sp 0.03"
Don

---------------------------
78 Westy
71 Super Beetle Convertible Autostick

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SlowLane
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Re: Don's (vwlover77's) Engine Build

Post by SlowLane » Tue Jan 14, 2020 8:48 am

vwlover77 wrote:
Sun Jan 12, 2020 8:46 pm
I measured the weights of my new Brazilian Mahle pistons (with wrist pins installed) using a digital postal scale. The results were identical after 4 repetitions of measurements:

1. 684 grams
2. 686 grams
3. 684 grams
4. 686 grams

Good enough for a stock engine?
Boy, I'll say! I think you lucked out there and got a "pick of the litter" set. When I measured mine, three were in close agreement, but the fourth one was 10 grams lighter. 10 grams is a lot of aluminum, so I didn't even think about lightening the others to match. The engine runs just fine.

While you are getting all this machine work done, be sure to get your connecting rods checked for straightness and roundness, get new bushings pressed into the small ends and reamed to fit your wrist pins, and get any big end that fails the roundness test re-sized.
'81 Canadian Westfalia (2.0L, manual), now Californiated

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asiab3
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Re: Don's (vwlover77's) Engine Build

Post by asiab3 » Tue Jan 14, 2020 9:01 am

I would pair the piston weights in horizontal groups. For example, put the 686g pistons on cylinders 1 and 3, and use the lighter pistons on 2 and 4.

Not an advertisement, I've just had all good experiences: John at aircooled.net offers a $50 balancing service, and he will open another box if you order a balanced piston set and one is too far out to reasonably balance. This way you won't get three good ones and one dud. ;)

Robbie
1969 bus, "Buddy."
142k miles with me.
319k miles on Earth.

Jivermo
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Re: Don's (vwlover77's) Engine Build

Post by Jivermo » Wed Jan 15, 2020 5:03 am

Rough to hear about your case being broken in shipping. During our current, on going rebuild, we have had two shipments of new pistons and cylinders arrive with broken piston cooling fins. Bus Depot’s source supplier does a miserable job of packing these delicate parts, even when better packing is requested. It’s frustrating to open the carton, and find damage that could easily been avoided with some minimal care.

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