15 August 2015

LZ18 cam followers showing cracks...Datsun 120Y LZ18

It's been a while since I last blogged. What have I been doing? I was arranging for the restoration of a Datsun 120Y LZ18 powered.

I had earlier on in the blog mentioned about a Datsun 120Y with a later version of the LZ18. The cylinder head was taken off and sent to Australia for a rebuild in the nineties. The head was then assembled back on the engine block and left as is till today in 2015.

The LZ18 of this B210 Datsun 120Y has had a history of racing in the city of Bandar Seri Begawan's ex-airport racetrack in the 70s and was subsequently sold away to Malaysia in the 80s after motor racing in Brunei was stopped.

Cam followers were immediately diagnosed as showing cracks and I was informed to replace them...with what? This was in the late 1990s if I remember correctly.

Engine had seen 10,000 rpm whilst in my hands and I'm not proud of it. I should have been more careful to limit it to 8500 rpm perhaps on an L18 stroke of 78mm. Fortunately, cam followers did not fail yet as I can imagine it would have destroyed this rare cylinder head in an instant if any of them did.

It was decided that cam followers from the FJ20 was the closest match and a set was sourced and resurfaced with the follower bores on the LZ18 increased in diameter from 32.5 to 34mm to match. Today in 2015, I would have gone for Supertech's excellent range of cam followers. See here at: https://www.supertechperformance.com/cam-followers-p5922

Cam followers weights varied wildly with the three samples I measured. I was surprised. 

These followers were also not so accurately machined, IMO, from back in the 1970s thus causing the variations in weights. Today in 2015 I am sure machining would have improved.

No comments:

Post a Comment