Head# Cam# oversized rings

Discussion forum for the venerable 510, and its non-US counterparts, the Datsun 1600 and Bluebird.
Posts: 2
Joined: Sat Dec 05, 2015 6:11 pm
Car: 240z 620 510 RX-7

Head# Cam# oversized rings

Postby Speedracer906 » Sat Dec 05, 2015 6:30 pm

I have a couple L20b questions:

I was just gifted a l20b head that had the #s filed off or didn't have them in the first place.
The numbers around the timing inspection plate say #70 and 12-23 other than that it looks simular to a U67.

Also on this head of mine, it has a Crane cam with the numbers DA 2722 10 C and 62 5 below.Does anybody know anything about Crane #s and what it is that I have?

Last one, this engine was locked up and I've had it for 20 yrs. I finally have a project 620 and decided to open it (l20b) up to see what I've got. The front cyl was rusty; perhaps this engine blew a head gasket. The rust in the cyl is enough to bore out instead of just hone. Any idea how many thousands can be removed while still useing oversized rings?

I'm going to call the machine shop on Monday but was just trying to plan ahead.


Posts: 1011
Joined: Mon May 04, 2009 5:32 pm
Car: 2000 Nissan Wingroad, 85 Datsun 720 Pick Up.

Re: Head# Cam# oversized rings

Postby flinterman2000 » Fri Mar 18, 2016 7:40 pm

Can not tell you about the L20B as they are rare here and I do not know anything about crane cams but rust in the cylinder can be dealt with easily depending on the level of pitting on the wall. I had a Z20 with No1 piston frozen in the cylinder. Bought a set of liners and brought the cylinders back to stock. I also had a Z18ET with rust in cylinder 2 & 3 and honing did the job and used 10 thou oversize rings. So a visual of the cylinders and a test hone would give you an idea on what to do. Hope this helps.

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