Jim Green's 90q 20vt - 636whp 07k

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audifreakjim
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Post by audifreakjim »

:woowoo: Just got a phone call that the pistons are in! I might actually get this thing going before Christmas :-D
noriceforyou

Post by noriceforyou »

audifreakjim wrote::woowoo: Just got a phone call that the pistons are in! I might actually get this thing going before Christmas :-D


freaking awesome Jim! Now if "Santa" would only deliver that dang axle for my Nissan! ;)
Toxcheap

Post by Toxcheap »

:stupid:
Sweet get some pics up so we can see :-D
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audifreakjim
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Post by audifreakjim »

Here's some pics of the pistons.

Attachment ( 2768 ) : P1010094.JPG


Attachment ( 2767 ) : P1010092.JPG


Attachment ( 2766 ) : P1010089.JPG
SEStone
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Post by SEStone »

Interesting skirt shape on the sides there!

Sam
Sam Stone
Derracuda
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Post by Derracuda »

yeah jim, you got a nice skirt there :-D
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Audilard
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Post by Audilard »

I thought those were gold plated for a second. :P
Darin
1989 80 20vt
JShadzi

Post by JShadzi »

Hey Jimmy, interesting pistons, check out my pistons, here is what I did (or how my pistons turned out):

Image

The dish on your Weisco's looks really big, you sure its 13cc's? Also, the valve reliefs are really big, any reason for it?
RSCoupe
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Post by RSCoupe »

I noticed that on Jim's Wiseco's that the sharp edge between the valve pocket and the edge of the piston has been removed, whereas on Javad's JE's, it's there. There were some reports on the S2Forum that this thin "edge" can become a hot spot, potentially causing detonation, and in some, it even melted. Those that have gotten JE's since, have ground away this sharp area.

Any thoughts? Javad?

My new JE's are scheduled to arrive Wednesday.
Thanks Javad! :-)
Mark Siggelkow
'90 CQ-R - NASA GTS-4
'12 TT-RS (Wife's DD)
'00 A4 1.8TQ (My DD)
'62 356B (vintage racer)
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Toxcheap

Post by Toxcheap »

Well can't be much different than these areas!!

Attachment ( 2770 ) : P10100891.jpg
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audifreakjim
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Post by audifreakjim »

The dish on your Wiseco's looks really big, you sure its 13cc's? Also, the valve reliefs are really big, any reason for it?


Yea, that's why I sent you that email. It looks like on your pistons they just shaved it off and didn't really dish it? These maintain the compression hieght all the way around, which would cause the dish to look bigger in the middle.

I noticed that on Jim's Wiseco's that the sharp edge between the valve pocket and the edge of the piston has been removed, whereas on Javad's JE's, it's there. There were some reports on the S2Forum that this thin "edge" can become a hot spot, potentially causing detonation, and in some, it even melted. Those that have gotten JE's since, have ground away this sharp area.


It looks like that's what they've done to me.

I might try and get some clay to see what these actually are. before these go to the machine shop tomorrow.
olsonjus

Post by olsonjus »

They look really nice. I noticed the piston looks like it does maintain the compression height all the way around. This should help with detonation on pump gas. They look like quality pieces. Let us know if you do cc them.

Regards,
Justin
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audifreakjim
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Post by audifreakjim »

Well, just taking the major diameter of the dish and not figuring in the fairly significant camfer in the dish at 7cm and .35 cm deep would give 13.5 cc's. I'm not sure if the valve reliefs are included in the calcs or not, but it looks good to me.
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audifreakjim
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Post by audifreakjim »

Ok, spent all day messing with a bum engine hoist and a centerforce PP that's .4in shallower than the 7A PP that worked perfect. The AAN CF PP causes my slave cyl to bottom out so it looks like I'll be jimmy rigging the clutch with a slave cyl extension since I'm all tapped out of money for the car. Needless to say I didn't CC the pistons, but after did the calcs this morning, it's not necessary.
JShadzi

Post by JShadzi »

RSCoupe wrote:I noticed that on Jim's Wiseco's that the sharp edge between the valve pocket and the edge of the piston has been removed, whereas on Javad's JE's, it's there. There were some reports on the S2Forum that this thin "edge" can become a hot spot, potentially causing detonation, and in some, it even melted. Those that have gotten JE's since, have ground away this sharp area.

Any thoughts? Javad?

My new JE's are scheduled to arrive Wednesday.
Thanks Javad! :-)


I wouldn't call these areas "sharp" on my pistons, they are dimensioned exactly like the stock pistons, the areas are quite rounded over and I don't anticipate any hotspots becuase of the valve relief areas. I haven't seen Jim's pistons up close so I can't comment on those.

Yea, Jim, must be a visual illusion from the pics, and the large ring land rise makes up the difference.

And for referece to others that have mentioned it, the 20vt head's only quench area is right above or adjacent to the intake valves, or basically the "unmachined" area or "raised portion" on my pistons, the rest of the combustion chamber is completely open to the piston and simply makes up the hemispherical combustion chamber.
pkw

Post by pkw »

with the stock mc bore the material gets pretty thin, (i have cut mine down a bit on my mc pistons for my 7a/mc combo) with an 83 mm bore like javads it would be fine. imho.........worse case, the problem would fix itself :P
dets

Post by dets »

jim, kinda OT , but what size exhaust do you run? compared to the 20v?



TIA.
zepmoreau

Post by zepmoreau »

looks like I'll be jimmy rigging the clutch with a slave cyl extension


Jim, you should be good at "Jimmy-ing" anything.... let's rephrase this.... you're going to "Green" the slave with a slave extension... just so we're clear on this! :D :P
87turboquattro

Post by 87turboquattro »

JShadzi wrote:
RSCoupe wrote:I noticed that on Jim's Wiseco's that the sharp edge between the valve pocket and the edge of the piston has been removed, whereas on Javad's JE's, it's there. There were some reports on the S2Forum that this thin "edge" can become a hot spot, potentially causing detonation, and in some, it even melted. Those that have gotten JE's since, have ground away this sharp area.

Any thoughts? Javad?

My new JE's are scheduled to arrive Wednesday.
Thanks Javad! :-)


I wouldn't call these areas "sharp" on my pistons, they are dimensioned exactly like the stock pistons, the areas are quite rounded over and I don't anticipate any hotspots becuase of the valve relief areas. I haven't seen Jim's pistons up close so I can't comment on those.



i don't know if you guys have looked at the pistons after running.but i had the same thing on my bbc weisco pistons,i like javad,rounded them over because from the factory they were sharp.when sharp,they melted away and disappeared down to a certain level.the rounded ones stayed put.neither engine had a detonation problem.engines are still running strong and haven't been pulled apart for 2 yrs of beating on the water.
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audifreakjim
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Post by audifreakjim »

dets wrote:jim, kinda OT , but what size exhaust do you run? compared to the 20v?


I'm sticking with the same 3" system, It should work just fine. Hell, I think Javad is still running 3" at 600 whp.
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audifreakjim
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Post by audifreakjim »

:woowoo: The head's ready, there's a 83mm HG coming from Javad, we might have a running motor soon!
olsonjus

Post by olsonjus »

Take a picture of that head gasket when you get it. I'm curious what they look like.

Regards,
Justin
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audifreakjim
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Post by audifreakjim »

Don't worry, I'll have lots of pics to post. :-)
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audifreakjim
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Post by audifreakjim »

A little update, the bottom end and head are assembled, I was supposed to get the stupid thing in the car tonight, but I forgot my Bentley and needed a bunch of torque values, so now I get to update my thread and clean the bathroom. :frustrated:

ARP Fasteners, 034 rods.

Image

Mmm,,,

Image

Ported Head with water manifold machined in.

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Image
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Electric PS pump. :woowoo:
Image
Wizard-of-OD

Post by Wizard-of-OD »

Love the PS Pump Location!
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