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Discussion Starter · #1 ·
I got that set up and i just got everything torqued down and when i turn the motor over (flywheel nut) when the intake valves open its hitting the piston. i doubled up on oem basegaskets. was this not enough or is my problem somewhere else?
 

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QUOTE (Blackedyfz450 @ Feb 28 2009, 12:53 PM) index.php?act=findpost&pid=752126
I got that set up and i just got everything torqued down and when i turn the motor over (flywheel nut) when the intake valves open its hitting the piston. i doubled up on oem basegaskets. was this not enough or is my problem somewhere else?[/b]

what kind of piston? what kind of cams?
 

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It is either the Cylinder Works Gen 1 or the Athena that doesn't have the same deck height as the OEM cylinder. I can't recall which one but this problem matches a deck height being off. I have heard of people running...ron woods base gaskets b/c they are thicker then other base gaskets (I believe) and possibly a stock bask gasket on top of it to make everything spec out correctly.



Someone correct me if I am wrong but that is what I recall.
 

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i used two metal base gaskets from cometic. stacked with copper spray. venom 14.25:1 piston, hr+3mm, athena cylinder and hot cams intake and exhaust cams. i also had the thicker ron woods base gasket, but chose not to use it due to the fact i was afraid it would compress too much when torqued. maybe that happened to your build. being your gaskets aren't metal, and there's two fiber type, maybe they squeezed out/in when torqued and compromised deck height?
 

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^^^+1 for misse


I thought if you ran an athena cylinder and HR +3 you had to run there piston so it would clear. shorter piston.
 

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I thought if you ran an athena cylinder and HR +3 you had to run there piston so it would clear. shorter piston.
[/quote]

it can be done with other pistons you just have to pay special attention to deck height and squish.
 

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the athena cylinder is shorter, if my math is right you will at least an .030 base gasket to make this build work. we dont deal much in athena cylinders. get a hold of terse he will be able to help you out.
 

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I do recall the Athena Jugs being shorter than stock.... causing clearance issues....

there are many possibilities here for error, piston backwards, cam timing off, etc....

i would double check your work, and clay check the setup when you get it correct.
 

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IMO the cam timing is off.

I ran two metal Cometic base gaskets with the exact Venom 98mm and Athena jug and it was perfectly fine.

Please make sure the piston is in right. 3 intake valves 2 exhaust. Don't laugh.... I've seen it done before.

Yes Athena jugs are shorter then OEM by .45mm with out a base gasket. Each of the metal Cometic base gaskets I had measured .54mm... and 2 = 1.08mm

OEM jug = 77.20mm
Athena jug = 76.75mm

Total = minus .45mm

Needing +.45mm or 1 extra (2 total) Cometic .54mm base gasket to make up for the .45mm shorter Athena jug. This also gives .09mm lower TDC and a little extra room for piston rock.
 

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Discussion Starter · #13 ·
I tore it back down and put it back together again this time after torqueing it was fine turned over how it should. i think the timing was off somehow. thanks for all the quick replies!
 

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You need to check piston to valve clearance. It may turn over but you may not have enough clearance. It would be bad for a valve to hit the piston at 9K rpm. You need at least .080" clearance also check the clearance between the valve and the sides of the piston relief especially if you have larger valves
 

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P/V clearance is more then enough... even for the largest lift "drop in" cam out, the Venom pistons are good for atleast +1 valves, and possibly +2mm.... piston valve pocket depth is more then plenty......


But all that aside... you are correct all that should be checked.
 

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It should be good but we dont know if the head has been milled or how far the piston is in the hole. It is always best to check piston to valve clearance never chance any thing.
 

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Discussion Starter · #17 ·
To answer a Few questions-Stock Cams (cam-mod) Venom 14.25, HR+3, 3 oem base gaskets. head has not been milled. the intake valves are hitting the piston when intake valves come all the way open. when everything is set into place with out torqueing it does not hit the valves only after being torqued. what im getting out of what eric said you need .054 to get it right?

ok im getting a little pissed off. i put it in the frame and now it hits again so i pulled it out again and ive taken some pictures to show that the timing is on and the triple base OEM gaskets. i want more opinions thanks you
hard to tell but the timing marks are lined up


both cams showing cam-mod position


Intake Cam


Exhaust Cam
 

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I guess I don't see how you can have that many base gaskets on, stock lift cams, and cam mod and the valves hit the piston. Are the oem base gaskets squishing out or spreading apart or something?

Have you measured your cylinder? Maybe it is real short.

Like I said... when I stack a base gasket they are metal ones, not oem fiber ones.

Are you absolutely sure your piston is in the right way?

OEM jug = 77.20mm + OEM base gasket .63mm = 77.83 total jug height.

Athan jug = 76.75mm + 2 metal Cometic base gaskets 1.08mm (each gasket = .54mm x 2 = 1.08mm) 77.83mm total jug height

^^ With 2 metal Cometic base gaskets and a shorter Athena jug you have the same jug height as stock. The exact 501cc combo you have I built (Hot Cams) it ran perfect even on 40shot of nitrous. You have other problems.
 

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something is wrong with your cam timing.

with 3 base gaskets the exhaust cam dot will be closer to the head than usual (even with the cam mod done) and the intake cam dot will be slightly higher, like it is in the pic.

plus...you only have 12 dots between the pins...i think you have the exhaust retarded one too many teeth

ditch the 3 gaskets...they will only end up leaking anyway. go back to 2 metal base gaskets.
 
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