EJ22 Turbo pistons

[oab_au]

Originally Posted by SVXelerator

Mr. Harvey,
I understand what you are saying, from a metalurgical standpoint. Question - how do you explain the popular 350 cu in. stroked to 383 cu in. small block Chevy engines that have been around for years and are taken up beyond the SVX's normal 6500rpm redline rotational speed on a regular basis?
Thanks.

Well I don't know that I can explain What they do with Chev engines "horses for courses". But if you can understand my reasioning from a metalurgical standpoint, then you just need to look at the two crankshafts to understand my reasioning for not stroking the SVX crank.
The V8 crank is very short and stout, it has 5 main,and 4 bigend journals for a total of 9. The SVX has 7 main and 6 bigend journals, a total of 13 in approx the same length. This makes the V8 crank torsionaly stiffer than the Svx, so it does not suffer the same torsional vibration, as the much longer SVX crank. It is this sort of flexing that causes cracking, unless it is harmonicaly damped. To remove the metal grain flow from the bigend, and replace it with random deposited metal, can only weaken the crank and make it prone to cracking.
I can't back this up with SVX examples, It is just Automotive common sense for me, to realise that this is a recipe for disaster.

Harvey.

[oab_au]

Originally Posted by SVXRide

How about a pin-side view to see if the piston compression height is the same? The centerlines of the pins don't look like they're identical (but then that could just be due to the washing machine's lid not being perfectly flat )
-Bill

The turbo piston will have the top ring lower that the NA piston. I think thats why it looks different.
The dish in the turbo piston is about 28cc + 11cc for the gasket = 39cc + what ever the head cc is???

Nearly there.
Harvey.

[OBI]

The pistons are different castings. the pins are different. you must use the 2.2 pins. The eg33 piston has a raised crown which is good news for us since it suggests that the cumbustion chambers are pretty close on both motors and the compression will be eightish to one

[oab_au]

The turbo piston pins are longer. I doubt that the combustion chambers are the same. The Turbo only has 31mm inlets, the svx is 36/37 I believe, so I would expect the svx chamber to be bigger.

Dieingsvx is going to tell us soon, when he measures it.

Harvey.

[SVXelerator]

Originally Posted by oab_au

Well I don't know that I can explain What they do with Chev engines "horses for courses". But if you can understand my reasioning from a metalurgical standpoint, then you just need to look at the two crankshafts to understand my reasioning for not stroking the SVX crank.
The V8 crank is very short and stout, it has 5 main,and 4 bigend journals for a total of 9. The SVX has 7 main and 6 bigend journals, a total of 13 in approx the same length. This makes the V8 crank torsionaly stiffer than the Svx, so it does not suffer the same torsional vibration, as the much longer SVX crank. It is this sort of flexing that causes cracking, unless it is harmonicaly damped. To remove the metal grain flow from the bigend, and replace it with random deposited metal, can only weaken the crank and make it prone to cracking.
I can't back this up with SVX examples, It is just Automotive common sense for me, to realise that this is a recipe for disaster.



Harvey.

Mr. Harvey,
Thank you for your response! What if the SVX crank was internally balanced and heat treated after offset grinding?

[svxfiles]

Originally Posted by SVXelerator

Mr. Harvey,
Thank you for your response! What if the SVX crank was internally balanced and heat treated after offset grinding?

And/or, what if it was not welded, but just offset ground and Nitrited (sp?)

Going down in size to get "just" an 1/8" more piston travel?

Or, would it be better to get it bored out, liners installed instead?
Boring and liners $600, new pistons, $600+.
Crank offset ground $250, new connecting rods $500...

What to do...

Did you ever feel, Harvey, that you were taking a busload of kindergarden age kids on a field trip to the circus?

[OBI]

I hope that the svx chamber is not bigger( less than 8 to 1 would suck). looking at the the big difference in both piston's volumes, it seems to me that the pistons are mainly responsible for the difference in compression (8 to 1 2.2L and 10 to 1 3.3L) we already know that the bore and stroke is the same and that the piston hight is the same so the only influencing factors left are the piston volumes and the combustion chamber volumes, the difference in the head gaskets would be little if any. We are just gonna have to see till we cc both heads. Anyone got a pic of the svx cc? Please post it.

Originally Posted by oab_au

The turbo piston pins are longer. I doubt that the combustion chambers are the same. The Turbo only has 31mm inlets, the svx is 36/37 I believe, so I would expect the svx chamber to be bigger.

Dieingsvx is going to tell us soon, when he measures it.

Harvey.

[drivemusicnow]

Just thought I'd note something that I saw.

The valve reliefs on the SVX are slightly larger. this makes sense due to the fact that the valves are larger. a SLIGHT bit of machine work may be required when swapping over.

Most easily noticed here:


The turbo pistons have a very slight line for valve relief, however compare the distances of the outer edge to that valve relief compared to the equivelant on the SVX piston.

Like I said, not a big deal, however it may be more important with cams that have higher lift.

[SilverSpear]

That does assure that both 2.2 and 3.3 engines have different size valves. unfortunately

[oab_au]

VT subie say the head cc at "about 52cc". That makes it 7.07:1. Too low. I think we need to go with the NA 2.2 pistons to get the ratio that we need.

Harvey.

[oab_au]

Just checked, if we used the NA 2.2 pistons we would have 8.13:1, that would be OK. As the 2.2 turbo pistons are not forged, we will still have to get the NA 2.2 forged, if we are going to boost hard.

Harvey.

[TomsSVX]

that site that Chike posted about the 2.2l pistons. They had turbo pistons that raised the CR to 9.0 and they were forged... what CR would that leave us with??

Tom

[oab_au]

Originally Posted by TomsSVX

that site that Chike posted about the 2.2l pistons. They had turbo pistons that raised the CR to 9.0 and they were forged... what CR would that leave us with??

Tom

Who, where, what.???????????
Harvey.

[TomsSVX]

slowboy racing I think has 9 to 1 Compression 2.2l tubo pistons available. They raise the compression bu they are forged. So say we used these 9-1 pistons in place of the 8-1 would that make an 8-1 CR if these pistons were used in the Eg33??
Tom

[longassname]

Harvey you did your calculation using the cc of the dish from that guy who did the airplane engine and the cc of the head vtsuby said, right?