Thread: Thoughts on a full race motor setup

Ashtonser, after building 40-50 Built SR motors ( maybe more) over the years, there are a few things that I have learned to stick with on what the factory manual says for specs, and others that I have learned to "modify" and "adjust" and others i've learned to ignore. The head TQ specs i listed will work better, hold more power, keep non factory headgaskets from leaking, and just plain last longer.

If the machinist did not use a TQ plate to bore the sleeves after installation then the sleeves can lift up higher than the deck surface while boring, and when the block is decked ( assuming it was decked) the sleeves are not bottomed out in the bores. So when the engine is assembled and running the sleeves are "loose" in the block and are not sealed FIRMLY against the head gasket.

If the sleeves are tapered fit into the block then it may be salvageable. They could be pressed back into the block, the block could then be milled just enough to create a flush surface on the deck as needed. But this depends on how the block was machined as such.

I would also recommend going to 91-92mm bore next time. The Mazworx gasket can support that large of a bore. Its the same cost as a 90mm, but you get extra displacement for free. Specing out the pistons for another $250-350 and take some weight off of them and get some of the better "goodies". There is cheap HP built into piston design, Most people use shelf pistons or just stock but larger bore.

Either way, good luck with the motor, hope it works out. Keep us informed.

-Ted

The touring car headers are nice, but they are spec'd more for those setups and also the exhaust has to go over the transmission. The 4-2-1 was also because those motors needed not just top end power, but the earliest HP peak as possible and as broad a powerband as possible, and not just WOT. Those motors were also built to last HRs on end as well and also the RPMs were limited to about 8000rpm.

I do know what header design works wonders on a C6M cam motor ( overall depends on the displacement and head setup) so i'm curious to see pics of your design. Its rare to see custom headers in the SR20 world due to the complexity and the cost. Your setup does sound quite interesting I must admit.

-Ted

The satcar headers run under the car like conventional headers. Which is why I am considering using them. I think 4-2-1 headers are more forgiving than 4-1's which seem to be very sensitive to the setup of the motor.

here are some pics of the temporary 4-1 I'll be using. I had this made up for under $200. It's mild steel.

They probably aren't the perfect header, but they should give me a good base to start from.

44mm stepped to 48mm. Overall lenth is 79-82cm accross the board, so within about 1-1.5" of each other.

im really interested in what specs a good 4>1 header should be built with, for say an sr20ve with n1 cams, 3" exhaust, cam gears and the usual other modifications.

I want to have a custom set built for me over here, but would like some guidelines to pass onto the builder as it will be the first sr20ve motor he's ever done.

I would love for you to elobrate a bit more on this cheap horsepower and piston design. You've hinted at it a couple of times in this thread but you keep leaving us hanging
I understand if you don't want to share though. Knowledge is a valuable thing.
On a side note to that, if cheap horse power an be design into pistons how come these aftermarket piston manufacturers design them into their pistons, thats the sort of thing that puts their product ahead of the competition

Thats what i was thinking may have happened, Due to the fact they didnt use a torque plate the sleeves may have done just that, The block was decked after sleeve installation was completed. So i would be safe to bet thats what happened. Again it possibly could be salvaged but i would just feel safer going with mazworx if we had to go back and redo it. Being both the block and head were resurfaced once already. Although the mazworx gasket is pretty thick and probably more than covers that material taken off. But i would just feel better if we went that way, And im thinking 92mm bore next time as well. I think my buddy is going to just get that de motor and swap most of these parts onto it. Should still make over 200whp with the mods and cams we have. I know he was well up there over that mark with this motor when we were tuning it. Id say 225whp or so. For a car that weighs 300lbs more than mine to accelerate like mine maybe faster with 180whp its up there. But we never made it to a dyno. So close, haha

The Mazwox gasket I think is thinner than the stock gasket by .1mm.

If you have a motor that has a stock gasket of say 1.2mm and you use the same gasket of 1.2mm once you have decked a block and shave a head the gasket can not make up the diffrence you took off.

The Mazworx gasket can not cover the amount of material taken of the head and the block because it is no thicker than stock.

True as far as keeping your valve to piston clearance the same, but as far as sealing goes it should not matter what the thickness of the headgasket it, Both surfaces are flat and smooth. It should have sealed easily. No problems, No questions asked. But the fact that it didnt and on all four seems more like a sleeve problem than a gasket problem. Especially the way the sleeves were installed and procedures used. So we will find out. The head might already be off if not definetly by later today. Oh and another thing is i was not getting any coolant into the oil or vise versa. Which tells me all other passages on part of the factory block, not the sleeves, was sealing perfectly. There was no oil leaks around the edges or inside. Compression even with a leak at the cylinder seal was 250 psi on all 4. So again i doubt it was anything to do with gasket. I just dont see that happening. I will try and have pics up later once we know for sure.

I don't know what Teds piston secrets are but when i got my 90mm pistons I took a dremel to the sharp valve relief cuts and grinded them down smooth. I didn't want any potential corners to create hot spots.

Thats a great idea. I did the same to my pistons and then ceramic coated the piston to keep the heat out.