Closest safe quench?

[FirePowerMinis]

OK, experienced slant-blockers, what's safe piston to head distance on these rascals? I'm used to setting up at .030 on my OHC's, but they have a steel rod. I'm a firm believer in the benefits of tight quench, but don't want the slug polishing up the head. lol I've mocked up and the piston is .040 in the hole. I can swith to a +.020 rod and .010 gasket, and be at .030 sans-cutting. Or???
I'm planning a ZOT flat-top for the "stocker" and a Wiseco on the billet rod.
I set the .5mm over ZOT up at .002 clearance, is that OK? Forging will be at .003.

Stock rod, <4k revs?
Billet rod 7k revs?

 

[Newoldstock]

sounds good with 30

 

[walker32]

Yes .030 is about as right as I would run with aluminum rod

 

[Newoldstock]

Yes .030 is about as right as I would run with aluminum rod

Not like you have a choice lol.

The block expands at about the same rate as the rods.
There is room to go tighter but you need to consider machining defects and clearences of sthiongs slinging around.

If the over all engines was much tighter I would run a tighter quench too.

 

[FirePowerMinis]

Is it worth it to dowel a few more cover bolt holes?

How aboot moving the head a few MM "up" the deck, to get the valves away from the wall by getting nearer the bore centerline, and more equal quench pads?

And, has any one switched to a smaller plug, moved closer to the valves? I have a 160 Honda 14cc with a stripped plug hole and am gonna try a 10 or even 8mm Iridium plug, and fill in that side of the chamber, bath-tub chamber. I think I can get 10-11cc chamber and still keep HP decent, have good BSFC. Maybe?

First attempt...

 

[Newoldstock]

I don;t think so.
Just fill the stock ones with epoxy to stiffen them up and use good 8.9 bolts and you shoudl be fine.

I don't know what you would gain from trying to shift the head over.

I do like that head even though the Intake is bigger than I could use....
I would not pass up the oppertunity to see if I could make it woork for you lol....

 

[FirePowerMinis]

Haa. I do have parts on loan, from Anehiem to Adelade, so it's not out of the question. I just stuck a half dozen projects I completed but don't have time to mess with, on FB. If I live to be a hundred, I'll never finish all the silly ideas... This one or the bathtub? This is only 30/25. Since the tub will be welded, it'll get new seats, maybe real big. Or, maybe I'll fill some of the exhaust port and make it a governor build with 27/24's?

Moving the head would get the valves in the wider part of the chamber, allowing the tall short turn to really add to the filling, esp if much bigger valves were used. This one has epoxy in the cavern behind the guide, but I'll weld V2 since alcohol softens the A-B so I'm stuck on C12 here