94AWDcoupe

iTrader: (125)

when you pin up in piston 6mm the rod comes very close to crown. you cant move it up farther without sacrificing crown thickness. moving the pin up 9mm is not a good idea at all. the pin would come very close to second ring as well. if you use high compression you can get around problem one. but from all the custom pistons I have seen I wouldnt move pin more than 6mm.

mega-z

iTrader: (13)

Great thread!

l2r99gst

iTrader: (2)

Is there such a thing as a piston with a closed pin design? Meaning, that the pin doesn't slip through the piston, so that it can be placed high inside the piston and not interfere with any of the rings?

I think with some clever design, this may be doable. Has this ever been attempted or exist today?

Ted B

iTrader: (6)

That would seem difficult given that a seam in the plane of piston motion would present a weak point in the worst place. When one wraps his head around the G forces that must be withstood by the piston assembly, it's understandable why over revving the bottom end can literally end up pulling the pin straight through the underside of the piston. I've seen it!

As for the Ti rods, Oliver has discontinued its Ti machining operation - just not enough activity to account for the trouble. No worries, I am going through the 'back doors' of a few other possibilities...

R/TErnie

iTrader: (32)

Well I called Carrillo today and I called R&R…

Carrillo H-beam 150mm is 567grams(TOTAL) 396grams(BE) 171grams(PE)
Actual weight of the Carrillo @ 574grams (measured by Kouzman)
Price: 1312.00 w/CARR bolts @ 6weeks

R&R H-beam 150mm is 571-575grams(TOTAL) 403grams (BE) 172grams(PE)
Actual weight of the R&R as measured by Mike on the last set that was shipped @ 571 grams
Price: 1012.00 w/625 custom aged bolts @ 6weeks

The R&R A-Beam 150mm is 612grams(TOTAL) 415 (BE) and 197(PE)
Price: 860.00

R&R H beam has a strong case. I focused most of my attention to the PE (wrist Pin End) weights more than the (BE) weights (standing for Bearing End) and the overall weight (which is the first step)

JohnBradley

iTrader: (30)

Crown thickness on the 162mm rod 94mm stroke combo piston is 7.8mm at its thinnest right under the pin. You get forced to run a 10:1 though to maintain that. The 156 would allow a little more but its not as bad as you think it would be. Minimum engineering from JE is 6mm and an off the shelf crown measurement revealed they have it at 6.2mm. Crown thickness due to raised pin height is not a problem. If you build a steel rod motor you have even more room above the pin that can be added into the crown thickness anyway.

R/TErnie

iTrader: (32)

AAAAAHHHH.

It's looking like R&R Rodsand JE pistons... Aaron do you have a weight on the piston with the pin height of 1.012"? I'm curious how much less it weighs than the 1.13" piston.

I'm really leaning towards a 4G64 block due to the r/s benefit and the fact that I can start building the new engine without needing components from my current longblock

Lucas English

iTrader: (12)

315g for the piston, 138g for the pin.

aaron

R/TErnie

iTrader: (32)

Assuming that the wiseco's gain 8-9 grams per .5mm in bore size increase that makes an 87mm Wiseco 1.13" compression height piston right at 326grams to 328grams.

That makes the JE 1.012" CH piston 13 grams lighter win win. Now it just depends upon how heavy the wrist pin and ring pack is.

R/TErnie

iTrader: (32)

UPDATE: Sourced a 4G64 Block from Aaron @ English Racing

Looking for 88mm crankshaft

Decided on R&R Steel Rods and Ross Custom Pistons.

Waiting for work to repay my travel expenses so I can start ordering parts.

JohnBradley

iTrader: (30)

I gotz a crank ninja.

R/TErnie

iTrader: (32)

JB always making it happen!

R/TErnie

iTrader: (32)

After talking with JB for a while... I'm 99% sure of my stroke now.

4G64
94mm Eagle Crankshaft

I've got three ideas for rods/pistons...

159mm Rods w/ 1.13"CH Pistons
uses a semi-"stocked" rod with a stocked stroker piston
1.69 R/S ratio

OR...

Custom 161mm Rods w/1.062"CH Magnus Shelf Pistons
uses a custom rod and a stocked Magnus piston.
1.713 R/S ratio (stock is 1.704)

I know that JB ran a 162mm rod with 10:1Rc Pistons... so I'm curious how running higher compression (like 9.5:1 or 10:1) changes the crown thickness.

Std 162mm Rod w/ 1.012"CH (High Rc)
Shelf Rod/Shelf Piston
R/S Ratio 1.723

I guess its time to talk to the piston mfg and see what they say about the different compression heights. I'll talk to Marco and Aaron as well. Like I said before... R&R lightweight H beam with Ross custom pistons.

Ted B

iTrader: (6)

I recommend staying with the 159mm rod. That combination won't leave much compression height as it is. Trying to use a longer rod with that particular combination seems kind of like wanting to wait longer to pull the parachute ...

R/TErnie

iTrader: (32)

Ted,
How much crown thickness do I pick up by raising the compression .5 Rc? Do you have an estimate? I tried to work backwards with an Rc calculator, but I really couldn't determine what it would be because of the cc's changing due to more valve relief and less overall dish in the piston I had in mind.

Best I could tell was that I could increase the thickness by .030" or .762mm going from 9:1 to 10:1 Pistons. So about .015" per .5Rc

My thoughts then are... the 159mm rod with the std 1.13 CH piston is the most simplistic solution that will be "semi" off the shelf from R&R and Ross.

My other thought is if I use the STD magnus 1.062 piston (I assume 1.072) and make it a high Rc piston I can assume that my "effective" CH will move to around 1.102" and have very similar crown thickness to a 1.13 std stroker piston.

Am I way off here? Or are you going to tell me about splitting hairs in an expensive fashion? To me... they're all going to cost the same amount of money. The wait time will be the same as well. I'm not too concerned about down time since the car isn't DD'd and I'm not in a competitive racing series that wouldn't allow me to have the car down for 6-8 weeks.

Thank you for your time and comments Ted, you've been helpful and insightful. -Eric