Cam etching/engraving decipering

Engine, Transmission and related drivetrain.
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zKars
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Cam etching/engraving decipering

Post by zKars » 17 Jan 2018 13:53

This may be fruitless, but anyone recognize any of this engraving on the back of a cam I have in an U67 head?
IMG_3214.JPG
IMG_3214.JPG (232.32 KiB) Viewed 484 times
The cam appears essentially stock looking to me base circle wise. Lift computes to 0.45 in at the moment, nothing special, just curious if anyone has seen these engravings.

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Re: Cam etching/engraving decipering

Post by datzenmike » 17 Jan 2018 16:49

260 may be the duration. L4s are rated at 428 degrees but most cams are rated at 0.050" lift so I imagine the factory cams are 220 or so really.

Most L4 are 0.413" lift some early L16s were around 0.390"

if 260 and .450" lift that's just right and not too radical..
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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Re: Cam etching/engraving decipering

Post by zKars » 17 Jan 2018 19:07

There I go again assuming shee-it. I'm thinking stock Z cam lifts when I thought .45 was pretty close to stock, but clearly not.

And when I look at the rest of cam, it's actually a CWC casting not Nissan. Duh. It's in good shape now, the springs are stock, so it should hold up for now.

The head itself is in pretty crap shape valve wise. 2-3-4 all have leaking intake valves. #3 is noticably sunk into its valve seat. Time for a valve job I suppose. Anyone with a nice stock l20B head that's all ready to go?

On a related subject, what does one do with 87mm bores for a head gasket? Seems that bottom end of this thing is a bored L20b with Z22 crank and pistons. (87mm bore, 92 mm stroke, suspicious 4 valve reliefs in each slightly dished piston...). The thing had a stock L20b 85mm bore headgasket and it pretty much hangs into the bores just a bit too much for my liking. Cometic makes head gaskets to spec is all I can think of.

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Re: Cam etching/engraving decipering

Post by Byron510 » 18 Jan 2018 03:00

Sounds like Z22 pistons were used on a re-bore. These had the four valve reliefs which you mentioned. Sure it’s not a Z22 block? Is there an engine stamp pad on the drivers or LH side of the block - the opposite side of the oil filter?

As for which gasket to use, for many years I have used the NapsZ 2.2 head gasket, trimming off the front timing cover section at the front edge of the block. Then I canablize an L series head gasket just for its front timing cover section, sealing the two with a dab of silicone where they meet. Done this on many engines for myself and others when building 2.2 LZ motors. I believe this is pretty standard practice. I have heard that others have simply used a good bead of silicone around the front, but have not tried this myself.

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Re: Cam etching/engraving decipering

Post by zKars » 18 Jan 2018 07:56

It is an L20b block, checked that.

Will get the 2.2 gasket and do a little splicing.

Thanks!

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Re: Cam etching/engraving decipering

Post by datzenmike » 18 Jan 2018 17:25

There were two L20B heads. Square exhaust '74-'77 and U67 and round exhaust '78-'80 W58. I would assume you are using the U67 as the L16 exhaust fits it better.

U67 head makes a 9.84 compression on a Z22 block... again... very nice.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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Re: Cam etching/engraving decipering

Post by zKars » 19 Jan 2018 11:30

Yes, it's a nice package. Even with the crappy head it runs very strong. Even came with a light (10lb) aluminum flywheel. The head is an early square port.

It has 150PSI static compression across the board. When I got it, the compression on #2 was 0, while the others where all a perfect #150. The valves on #2 were adjusted with negative lash, so much so that the intake valve was being held open. Incredible, who does that? With proper lash #2 came back in line with it's neighbors.

The beast burns oil, I'm hoping it was the head, guides or valve seals. With that kind of even compression, hard to imagine it's rings leaking. The bores all look fresh and cross-hatchy.

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Re: Cam etching/engraving decipering

Post by Byron510 » 19 Jan 2018 19:30

Actually it may not be as strong as you think.
I'm not sure what the duration is on the cam you have, as that can affect a compression test.
My motor is a stock 2.2 bottom end like yours with a slightly milled head. I measured the CR on mine to be 10.7:1 with an early U-67 head. Compression was 185 across the board with the Shadbolt 445 cam, but 170 with the higher lift/longer duration Engle M14 cam. The head was not removed to change the cam, so truly everything else is the same.
But yes it's fun. It 'only' puts 150 HP to the ground, but it keeps a smile on my face.

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Re: Cam etching/engraving decipering

Post by datzenmike » 20 Jan 2018 12:02

zKars wrote:Yes, it's a nice package. Even with the crappy head it runs very strong. Even came with a light (10lb) aluminum flywheel. The head is an early square port.
ALL L series were square exhaust port heads. Only the '78-'80 W58 head L20B has round ports.

The U67 is a great head in that the earlier L16 cast iron header fits it. Large valves and intake ports. The only draw back is that the U67 had co-joined intake and exhaust manifolds and used hot exhaust to 'warm' the intake. This can be remedied by throwing them away and using L16 exhaust and later W58 intake which has larger diameter runners than an L16/18 intake. Drill two holes for coolant flow into the intakes and a little plumbing and you're good. Now the intake warms rapidly from the heated coolant, but also 'cools' it when very hot. Keeping the intake air charge withing a tolerable range winter and summer makes for predictable economy and performance and easier tuning.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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