Yes, I'm registered for the Canby show is in two weeks.


I would measure the combustion chambers. Instead of trying to measure the the unmeasurable.

I don't necessarily want to shave the head, I'm wondering about clearance because I don't know if it's been done already hence my wanting to figure out what original head thickness was thenI could measure this one & know if it'd been milled down & how much.

are you going to Canby next month?

I doubt if you will have valve clearance problems with dished pistons. But the rule is, when custom maching, measure the clearance. Why do you want to shave the head?

I wouldn't buy a cam 'around here'. I'd buy from a grinder that can do custom grinds, not limited to just few grinds. Tell them what you want, or get their recommendation. Try the legendary isky cams.

I stuck a digital caliper on the inside of the bore at the top of the cylinders and they were all 76.50 MM give or take a few MM's at the very top so I guess its not as large a CC's as I thought. Just found this - MM to 1/1000" conversion - 30 = 0.76, I guess i should measure the pistons to find their exact size as well.

so can anyone answer the valve clearance question, that seems rather important doesn't it?

I had issues with my 79mm bore a15, the headgaskets wouldnt last,
Cracks in bores on hot days (happened twice between 1st and 2nd),
Maybe walls flexed at certain loads and some other issues.
It went like a rocket with quad keihins, mystery cam, elec ignition
and extractors but in the end the bore damage ate too much into my pockets.
If I had to do it all again I would offset ground the crankpins
to 86mm stroke (like most modern engines) use motorbike rods and
77mm pistons. 1600cc without the headaches and heaps of grunt for
the street from any gear.

Thanks for the input. Actually I'm going to use a different head, its the one on the right...

H72 head w/37MM & 30MM valves, had to have new exhaust guides installed, heads OK though.



I do need to figure out if this heads been milled down, what about valve clearance, I noticed the chamber on the stock A15 head is pretty deep as opposed to my H72, how do I determine that I have proper clearance & not worry about slapping the piston if the heads been shaved too much? the pistons come right up flush with the top of the block.

Also, what about a head gasket ,which one would you use, stock, Nismo or what?

Thanks ,Evan

I'd VERY storngly reccomend have the cylinder head pressure tested, and hardness checked. If the frost plug had rotted out, and the head gasket had blown, you've no way of knowing how hot that motors been. Becuase they are so hard to kill, they can run very hot for a very long time. This can bugger the heads, I've had more than my share that were cracked/and or lost their hardness. Also check the clearance in the ring grooves to see if they are inside usable tolerances. And also inspect the piston skirts for vertical lines. When a motor gets hot, the piston swells up in a bore and forces the oil out from between the bore walls and the piston skirt. If you get too much wear there, the piston it's really reusable. But even if you reuse parts that are past it, it should still go. These motors are pretty hardy old girls.

Thanks for the input. You both confirmed what I thought in the first place, that most of the machine work isn't really necessary & a good cleanup should do the trick. I have a small auto/marine parts store (Edmonds Auto Parts) around the corner that has a small "semi"-machine shop, no real block work anymore but he's got a parts cleaner/washer that I can have him clean it up for about $60. Then I'm planning on knocking out the freeze plugs & start putting it back together.

polishing the cranks probably not a bad idea & checking the big ends as well, I'm planning on leaving the pins/bushings alone, figured I'd throw the pistons into the parts washer as well then scrub off the remaining surface rust. Hey, do I need to replace the oil pump, I know its probably good insurance.

Honestly, this is the first time in 20+ years I've completely torn a motor down so the memory's a little foggy when it come's to all this stuff, I end up feeling like this a bit... I did manage to muddle my way thru the 60A 5 spd. rebuild properly, it now goes into all gears including reverse - all new bearing, syncros & shifter fork!

David, where else around here would you look for a cam grind, delta said their 4 profiles ranged from stock to "Nascar" grind, well maybe he didn't say Nascar grind but you get the idea. I could just have it cleaned up & brought back to stock. So what kind a grind are you referring to ?

So i guess I've got the 1608 cc version now if its already bored out to 30 over - wow big block power!!! I'll have to put some
496 HiPo badges on the side of the car

BTW - what about the head gasket - if its 30 over do I need the 79MM Nismo gasket or will a stock one work or just blow again? I read a post thread in the tech wiki last night that discussed this.

Thanks guys, really appreciate the info

Given the fact you are going to get new rod/main bearings, you might as well get the crank linished. Typically it removes around 1/10,000 (1 tenth of one thousandth) or thereabouts, so won't have any real effect on bearing clearance, but it does tend to maximise bearing/crank life vs just replacing bearings. Based on local prices it wouldn't be enough to break the budget, I can only suspect it'd be similar elsewhere cost wise.

As far as honing goes - just give it a light 'dress up' and the important thing is to actually move the hone in and out (assuming you are using a normal handyman style electric drill which doesn't let you run it at low rpms) of the bore pretty darn quickly - as the rpms are usually so high that it makes it hard to get a suitable angle on the cross hatch pattern. It can help to duct or gaffer tape down an old head gasket to help prevent the hone angling out at the top of it's travel and leaving too much of a chamfer on the top of the bore. you don't really need much material removal at all - just a quick 'touch up' so to speak and the rings will bed in fine.

Probably goes without saying, but after honing, debris will (not might, not can, definitely -will-) lodge inside the cross hatch grooves. And scrubbing with solvent won't do the job. You really need (do it first with solvent) to get in there with a massively stiff nylon brush and hot soapy water. And clean the bores until the stage where you can run a clean lint free cloth through the bore, drag it up and down the bore and not get _any_ dirt/change in colour on the cloth. Stop short of that, and that debris ends up accelerating ring wear, and can cut into the longevity of a rebuild of this sort (and is probably where the idea of 're-ringing' an engine got a bad name and why so many think they need to bore to the next oversize). Looking at those bores though, there's no significant ridge, you'll do particularly well with just a quick hone!

These motors seem to be fairly indestructible, but just for peace of mind, I'd suggest getting someone to measure the con-rod big ends for size and ovality. I'd be particularly surprised if they were out of tolerance, but for the sake of about 5 minutes work to measure them, it can't hurt.

If you decide to clean the rods at all, use an up and down motion rather than across, if that makes sense (*not that a quick skim with a wire brush should damage them either way, mind you)

The head gasket itself doesn't look bad - I'm wondering if all the rust is purely because of where it was stored (possibly with a plug or two removed) and it got hit with rain a few times. If the gasket was bad, I'd be tempted to get the block decked (just minimally to ensure it was straight) but looking at the pics, I'd be inclined to leave it as is (just with a clean up of course)

Ya iall that machine work is not need
A14 dont; crack

Delta cam has four profiles. SKip them there are four stock profile
Go with some one with custome probile, modern high lift grind is what you want. Izky or Cran.