Head milling results.

Ray III · Jul 17, 2004

My engine is the 89 2.3, the one with the single plug heads. Cleaned up one of the chambers with a wire wheel and stuck a sparkplug in and measured 58cc of liquid into there. I don't know what the given head volume is though.

While it was at the jobber I had them mill .060" off it. Measured the volume again, this time I got about 54cc.

Assuming the stock head volume was 58cc, we know that the displacement is 2300/4=575cc, divide that by the compression ratio (pre 91) of 9:1 and there should be about 6cc of dead space between piston and head. So with a 54cc head + 6cc = 60cc, 575 divided by that yeilds about 9.6:1. I'm notoriously inaccurate, but something like that.

Of course compression goes up a bit more if you got an overbore; I calculate about 9.7:1 for .020" or .030" over.

Bolted the head to the block with no gasket and a piston at TDC, with a ratchet on the crank bolt to observe any movement. Then I spun the camshaft a few times. Crankshaft didn't move. Considering that the head gasket will increase piston to valve clearance, we can conclude that this is still a noninterference engine.

NOW we shall see how it runs. (If at all.)

351wcoupe · Jul 17, 2004

Ray III said:
Bolted the head to the block with no gasket and a piston at TDC, with a ratchet on the crank bolt to observe any movement. Then I spun the camshaft a few times. Crankshaft didn't move. Considering that the head gasket will increase piston to valve clearance, we can conclude that this is still a noninterference engine.

everything sounds good up to the "setting the head on the engine" part. Remember the results you got may be misleading because without the engine warm and having oil pressure the lifters aren't pumped up(doesn't open valves as far). Its good to try it without the head gasket but I would have done it with an old head gasket and use clay to see how close the valves get to the pistons.

Touring23 · Jul 18, 2004

Ray, be sure to cut the locating dowels back appropriately so that they won't lift the head. I had problems with gunk in the dowel bores, suggest a toothpick and Q-tips to get them totally clean. Actually had to go back in to fix that little oversight.
Here is a compression ratio calculator. I've been told to use .042" for the gasket thickness and 3.87" for the gasket bore (reference available by PM); that's for the Fel-Pro blue, as I recall all of the gaskets measured were in the .042"-.045" range.
Hope this helps. Good luck!

Ray III · Jul 18, 2004

hmmmm I forgot about those stupid lifters. I'll have to put my old ones in the vise and figure how much they would have collapsed, I don't think it would have been more than gasket thickness. They seemed pretty damn tight when I put them in anyways.

those gasket numbers are about right... as for the dowels I lost one of them anyways I watched the one I put in to make sure it seated; the block was also hot tanked so there was no debris in it anywhere.

bhuff30 · Jul 18, 2004

The circle track people say that each .007 milled off is approximatly 1cc, so that should be about 8.6cc less volume in the head. That alone would give you 10.1:1 compression, which is all the higher I would go on a street car. That should still allow you to run 87 octane.
I think taking out the headgasket was a bad idea. You need to seal it somehow. I would highly recommend putting some "form a gasket" or something of that nature on at least. Anyway, taking out the head gasket takes out another 7.7cc, so that put your compression ratio at 11.3:1 compression, which you may not be able to get away with on the street.

mr_woodster · Jul 18, 2004

bhuff i think he had the headgasket off just to check clearances ..i could be wrong

Bearded Forever · Jul 18, 2004

Oops.

bhuff30 · Jul 18, 2004

mr_woodster said:
bhuff i think he had the headgasket off just to check clearances ..i could be wrong

Ahh, gottcha. If that is the question, then I have some answers. I milled .090 and didn't break anything when my timing belt snapped. It will remain a non-interface engine. Notice how the valves are streight above the pistons... even in the piston does hit the valve, it will simply compress the valve springs. On the other hand, think about a DOHC honda or something. They have valves coming in at all kinds of wierd angles (nearly perpindicular to the pistons), so when the piston hits the valve, it tears stuff up instead of compressing the valve spring like our engines.

Ray III · Jul 19, 2004

yes there is a gasket

I dunno about that 1 cc for every .007", I was aiming for something near 10 to 1 in any case but I doubt my cc numbers are that far off. Even a retard can operate a syringe and see exactly where a thin liquid comes flat with the head surface.

what kind of power gain was there from .090" off? If I had figured my math better beforehand I probably would have tried something like that, but I'll prolly be happy with it

the valves are actually canted, just not to the extreme of other engines. Hitting the valve would not compress the spring (works the other way around) but I guess the lifter could collapse.

bhuff30 · Jul 20, 2004

Ray III said:
yes there is a gasket

I dunno about that 1 cc for every .007", I was aiming for something near 10 to 1 in any case but I doubt my cc numbers are that far off. Even a retard can operate a syringe and see exactly where a thin liquid comes flat with the head surface.

what kind of power gain was there from .090" off? If I had figured my math better beforehand I probably would have tried something like that, but I'll prolly be happy with it

the valves are actually canted, just not to the extreme of other engines. Hitting the valve would not compress the spring (works the other way around) but I guess the lifter could collapse.

I beleive the 1cc/.007 rule. I read that from the circle track guys, and it says that 75% of the area of the head is open. that seems about right just be looking at the chamber of the head.
when I milled it .090, I put in dish pistons, which lowered my compression ratio a bunch. that is why I milled it so much. That put my at just under 10:1 compression. As for the results, I can't say for certain how much of my gain came from the compression, but even with the big exhaust and moderate cam, I didn't lose any low end power, which could have only been made up for with the higher CR. According to dyno2000, I should have gained 7hp, and 8 ft/lbs of torque which is a very nice gain on a 100hp 2.3.
As for a retard opporating a syrenge... I havn't perfect that art. If you look closely, the water climbs up the walls or can pool well above level. I was never successful at measuring my chambers.
Whatever the case may be, I think you will be very happy with the extra power. You will notice it everywhere in the power band.

Ray III · Jul 20, 2004

use diesel fuel not water.

Head milling results.

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