Help Z-pilots...240Z Head Thickness

[spawpoet]

I checked the FSM, and I can't find the original spec in there. Does anybody know the original spec from the factory for the head height in 240Zs? I found a number (I think it was around 4.245") in the How to Modify manual, but I'm not confident it's correct as I have two heads that are thicker than this spec. Can anybody verify how thick the 240z heads were stock? Thanks!

Chris

[pballance]

Chris, I looked in 4 different manuals, Factory '71 and '72, Haynes, and Chilton's and could not find a head thickness spec. All I could find is the flatness spec.

Paul

[spawpoet]

Chris, I looked in 4 different manuals, Factory '71 and '72, Haynes, and Chilton's and could not find a head thickness spec. All I could find is the flatness spec.

Paul

Thank you for looking Paul. The flatness spec was all I could find too outside of the numbers from the How to Modify Your Datsun book which had conflicting specs of 4.248" and 4.218"in different places. I did have a guy on Hybridz that also quoted the 4.248 number. Still weird since I have a half dozen heads that measured thicker. I got lucky, and when I called Riley for some valve springs I asked if he knew the spec, and he repeated the same 4.248" number, but clarified that that's the factory minimum spec for the head, so for IT we should not be going below that if I remember correctly. He said there never was a published thickness from the factory, and since I have several that measured right at 4.265 my guess is that's probably original thickness. Again thank you Paul. I hope you've had a great race season.

[pballance]

Good to know that Riley had the answer with a minimum thickness.

I have had a good year, got my oldest son out of college, younger son back in, and managed to get a new-to-me engine and quaife in the car and make Barber where I wasn't DFL (but close) .

If things go well I will make it to the ARRC this year, as a driver and not as crew. You going to make it north Chris?

[spawpoet]

I wish we could, but it probably won't be in the cards until 12' at the earliest. I don't have enough track experience to feel comfortable running RA yet, and we currently tow with a Pathfinder which is fine down here where it's flat, but I don't think it would do well in the hills. I'm hoping to upgrade the tow vehicle sometime in the next 18 mths, and by then I'll have more than one regional race weekend under my belt. RA and Sebring were my sportscar meccas growing up, so when I feel ready, a can't wait to get a crack at the track, and for that matter, any track with elevation changes. BTW, I would imagine you run Barber a lot. It looks like a lot of fun on TV. How does Barber stack up to the other tracks in the SE? Congrats on a productive year/race season. I hope it works out for you making it to the ARRC, and good luck running there Paul!!

[spawpoet]

Paul, I had another question that you might be able to answer. How many hours do you race on a set of valve springs??? We are planning to change them every 20 hours or so, but I really don't know what the service life is for them under racing conditions.