gundee

Here on BaT. https://bringatrailer.com/listing/1972-datsun-240z-48/

I actually have a pair of 'C' spacers.

Wow that exhaust valve sure does look to sit deep into its seat but I am no head expert for sure. Just never saw one ground like that assuming new valves and seats. An old stock head with a couple past valve jobs, then yes. The valve seats look to be so tight fit that there is no interference fit between them. See what the head experts say.

On March 2nd I mentioned maybe pulling the head. I would say this is a must now. I think this head has some machine work issues. Nothing more can be done up top. IMO.

Here is what I got back from their Tech support: "We have been selling that damper for a very long time and I have never heard of anyone having an issue with it not going on the crank. We do not have any facilities for machine work here so there is nothing we can do. My suggestion is to have a machine shop hone it out until it fits. You are aware that it is a press fit onto the crank? Sometimes submerging the damper in boiling water for about ten or fifteen minutes allows it to expand enough to go on the crank. Make sure you have some kind of hand protection if you attempt this to keep from burning yourself."Jim DavisTech Support

Looks to be in Kansas. Needs much work. https://kansascity.craigslist.org/cto/d/1970-datsun-240z-numbers/6534809566.html

You could try this guy. Warehouse full. Hannibal MO. https://quincy.craigslist.org/pts/d/datsun-new-parts-added-240z/6501838309.html

Is that a parking meter in photo?

David solved my issues. He knows them inside and out. I am guessing by performance he means overall drive ability. If I am on the track at WOT all the time then I would want HP max. I do not like Webers because I never saw anyone that really understands them like David knows Mikuni. Webers just have waaaayyyy too many variables.

I suppose you do not have a build sheet with the springs they used. Did you notice if the cam towers have been shimmed and if the springs were shimmed to match? Weather you call Schneider or Isky, either is good, tell them your cam and get their opinion if that cam is even usable for the street. It would be interesting what they say. Also let them recommend a spring. Do not just buy some yourself and guess.

Now I remember. Powerforce may have fixed this by now. When those first came out they fit so tight no one could install them. Me included. I returned it and got one from another supplier. Same thing, No way in hell was that going onto the crank nose. I took it and my stock pulley to the machinist to mic the ID of each. The Powerforce was .001 smaller ID. He said he did not have a keyway hone to enlarge. So it went back into the box on the shelf. When I turn in my scrap metal next I just may toss that Powerforce in for added weight.

My belt sits high similar to that. I may have used a 240Z crank pulley when I installed the L28 engine. I thought the pulleys were the same at the time but the L28 pulley must be wider. I have been driving it this way for a few years now. I upgraded to the ZX alternator so the belt fits flush there. I did buy one of those Powerforce single groove but never got around to installing it yet. I guess I will have the same issue if I use the Powerforce pulley.

This is a good buy for the early 240Z owners especially. If I did not already have my original 1972 head rebuilt the same way I would consider this one.

Did this really come from California Datsun? Is that what the previous owner said?

This engine looks to be a rather expensive build as that sheet shows. I would be surprised if California Datsun had anything to do with this build. He is better known as fast and dirty rebuilds a cheap as possible. I believe he may have purchased it from someone, maybe on Craigslist and flipped it. And it was likely built some time ago, which is no issue. You see FAR performance (camshaft) has been gone for how long? 30 years? Don Potter died in 2009. He was ill for quite awhile and likely had not done much well before he died. I would think this is a really strong fast motor. I just don"t know what is going on. I do not believe Panama heat has much to do with it.

Won't we all be surprised if it was not a SU setting problem after all. SU"s are so simple. With my 240 SU"s and all the British cars I had, if they were just set in the Goldilocks zone it plain ran good.

I would agree that those lash pads do seem too tall for those retainers. Really do not see why the head was built with that spring/retainer combination. Part of cam kit or mix and match set up? Who,s springs are those I wonder. If mine I would remove and replace all with Schneider spring and retainer kit. My builder prefers those over Isky for the street.

blodi if this motor was a spare race engine as stated, do you mean spare never run or used but pulled as a back up engine. This motor may have been run very hard previously. If so I might think about pulling head to have it checked out. I know thats a lot of work but as long as it still Winter time.....

You would use that blue machinist fluid when setting up new. But as it has been run a lot since then, you can see the wipe pattern that is already evident. So not real necessary but does not hurt anything if you want to.

Always good to check rather than assume. But we still don't know why that pad came out. Also as long as your doing this check to see if you are getting coil spring bind at full lift. That would be a problem right there.

I read that you got a new lash pad before and machined it down to .170in. Is that what the broken one measured? I would pull all rockers to check wipe pattern. Then make note of thickness of each corresponding lash pad. Start checking everything as if you were assembling a new head.

This is the same valve as last time? Hmmmm. Interesting. I don't see anything obvious. The wipe pattern on rocker arm looks real good.

Without seeing it, sounds like its the set up where Datsun mounted their rear sway bars starting in 1973. I have a Bob Sharp rear bar that mounts like that.

My 72 came with that bracket and the wiring installed. I just figured all the 72's here came that way.

OK. This is a compromise method that I think works better anyway. Hold assembly hanging as shown. Tip just enough to touch but not depress needle valve. Take measurement.