Eddy67

I hope you guys have the patience for a few more questions along the way. I measured my heads height every 6" or so all the way around the head and noticed different measurements, so obviously they are only machining one side of the head meaning that the cam holders are all at different heights, so the question is why aren't the flipping these heads over and grinding the other side also to insure that the cam holders are all at the right height and that the head is truly parallel top and bottom?

Diseazd Gezzz I am glad I let you guys know the rest, I did not know about the valve clearing the cylinder walls Jeff G 78 I did go back and read what it cost you to do the valve job, I should have looked first before asking the price, I think this is the better way to go, unfortunately there is no time to buy the right books on redoing datsuns, I am sure I will need read it several times being dyslexic and all, and due to the time left to do this job I figured it best just to talk to you guys. madkaw There's a lot that I need to consider at this time with the move coming up, the time that's left to do this job and money is kind of tight right now, I did not want to bore you guys with all of that. Plus I picked up a pretty nice virgin 1970 510 I need to prepare for the tow back also. Automotive machining is a bit on the expensive side in Canada, so I think its worth while to spend a little more than I wanted too now and have the valve seats replaced and have it done right then there will be no need to take this engine apart later. I do have access to another engine back home that I can make a little more high performance at a later date, but I still want this one done right, so I will do the E31 and have the valves done at the same time Sorry for the confusion Thanks

The rest of what story?

So I did order the valve seats a few days back, any idea how much they are to put in? I guess if I do this it will make for a reliable head that should go for a long time. The bottom end is very tight, no play in the pistons, no ridge ring at the top of the cylinder either.

Awesome I think this may be the way to go for now.

Well I am not to worried about the performance, but if one option gives me a little more I will go for that. The car is heading back home to Canada with me after being here 16 years. We cannot get these cars up there any more, they were already scrap 25 years ago when I bought my first one all very badly rotted out. As far as the ports on the N47, both intake and exhaust are round, whats the difference between them?

So performance wise is it better than a stock E31?

So one last idea for you guys, I also have an n47 head which I hear is the least desirable, it has never been machined down and its only .003" out, which is still in spec. What are your thoughts on this head? I really only need to be able to drive this car 2500 miles where it will be restored and I can then think about which option to go with on my e31 heads.

Wow .050? I will have to find the book you are talking about. Thanks for everyone's input

Cool I will take the head to the shop for pressure testing and to have it machined flat

Anyone,,,, I really want to send this head out and have it pressure checked and ground if I am still within limits of doing this. It could be when all is said and done I may need up to .040" shims is this doable?

Its the L24 motor, what is the most you can take off the bottom of the head and the thickest cam shims that can be used. I ask because I would like to have this machined flat so it will remove a little more off the bottom of the head. That said it is only out by .006" maybe it does not need machining this may still be in spec. I read that .002" per cylinder on an aluminum head was ok not sure about the 240z head

So adding .030 shims or what ever it takes to get it in spec is ok to do? what it the most you can go or am I at the limit now?

Can this head still be used with a head shim? Or is a thicker head gasket better? This head even has a 3 angle grind job

No I don't have it

Heres a pic of the holes they look fine, there's one other thing I forgot about, the cooling jacket with the red arrow on it was completely plugged with this hard clay/sand type mixture almost like cement. I chiseled it all out, it went in some 3/4 inch or so, I could swear this was the sand from when the head was cast and all of the sand did not come out, interesting enough that it was near that cylinder in question.

madkaw I thought you meant what is the serial number of the head, the damage is on the 4th cylinder ajmcforester For this head I will need to take it to the pros, I am going to remove and replace the bronze seats on the other head myself. I was going to chuck this head out that is in the pic but I may keep it for now. I also have another E31 head that has the 280 valve seats in it but it is already .030 under spec, not sure if its worth anything I guess I could go with a thicker gasket and cam shims if need be, anyone have any thoughts on it?

where do I find that number? On the end of the head firewall side, there a number sign and under it is says 1, is that it?

So you think there was a water leak in this cylinder?

Anyone know what temp is safe to take the head up to?

I believe its detonation, the rest of the head looks almost brand new, I don't understand why just one cylinder would be like this.

Its an E31

Its a shame, this one has never been machine down, still lots of thickness to it, and its straight

Is it too far gone?

What are your thoughts on this head?