Datsun Roadster Forum-311s.org

So recently I noticed quite a bit more blowby so did a Compression test to find all 4 cylinders down from time of rebuild. Pulled all four pistons to find all four broken top comp rings. Mighta been detonation as I found the distributor lockdown bolt loose and timing very advanced. Car was jerking something bad during a drive and I wasn’t even thinking that it could be that. Pistons are in great shape, just very little scuffing where the rings broke. These were Hastings that come with Deans kit. Should I just get another plain cast iron ring set or look for one with moly coat? Bores will clean up nice with a flex hone. Just looking for a set that will seat in short time. Hastings don’t have a moly coat for U20. Any recommendations on a particular make?

I used Hastings #2C4212, Made for an ISUZU Diesel. For reference my engine is bored 2mm, (.060) over.

Referenced it in this thread.
viewtopic.php?f=3&t=15064&p=116485

137cu. in. GENERAL MOTORS 1984-85 Diesel GMC 4ZC1 ISUZU-Japanese 2238cc 1983-On Diesel 223, 4ZC1 Chrome Sleeves use 4212 only

FYI
2 mm over is .080
1.5 mm is .060

fj20spl311 wrote: Mon Jul 26, 2021 3:14 pm FYI
2 mm over is .080
1.5 mm is .060

I don't know why I misremembered it but I checked and confirmed my >misteak<, ha!

I’ve decided to go stay with Cast Iron as before. Seat faster and I’ll just have to keep eye on timing. Hastings are hard to find for U20.