will flat top pistons hit valves with b303 cam?

les1 · 04-10-2001, 05:39 PM

i have a brand new f9 block and i put flat tops in it for more power but am i going to be sorry? i want to put a b-303 cam in it but have heard valves will contact pistons but i need to know for sure no speculation. the heads are ready to go on just waiting on this one last thing all help much appreciated. thanks

NO SLO PK · 04-10-2001, 05:50 PM

The B is a mild lift cam (.480) but it really depends on a lot of things like the heads you are using and the valve sizes. Were reliefs cut in the new flat tops? What is the deck height of the pistons at TDC? Are you advancing or retarding the cam? I guess what I'm saying is that there are a lot of variables with a custom built engine and it's best to check the P/V clearance with clay to know for sure. I wouldn't leave it to chance.

------------------
Russ L
'91 LX
Procharger, 3 row intercooler, extrude honed Cobra intake, Mac full Length Headers, 30# inj., 73mm C&L, 75mm tb, E303 cam, 289 rods, ported E7 heads, MSD, T-Rex w/255 lph Walbro, 5 lug conversion, Cobra R wheels, 3.27 gears and Moser Axles.

[This message has been edited by NO SLO PK (edited 04-10-2001).]

les1 · 04-10-2001, 11:13 PM

heads are ported e7t's and yes the pistons have valve reliefs but ive never seen a piston that was totaly flat on the surface.

NO SLO PK · 04-11-2001, 10:16 AM

Sounds like it should be okay. But if it were me, I'd still invest the $20 for a spring removal tool, $2 for a light spring, $3 for play-doh and check the clearance anyway. It's cheap insurance.

------------------
Russ L
'91 LX
Procharger, 3 row intercooler, extrude honed Cobra intake, Mac full Length Headers, 30# inj., 73mm C&L, 75mm tb, E303 cam, 289 rods, ported E7 heads, MSD, T-Rex w/255 lph Walbro, 5 lug conversion, Cobra R wheels, 3.27 gears and Moser Axles.

04-10-2001, 05:39 PM	#1
les1 Registered Member Join Date: Mar 1999 Location: seattle Posts: 76	will flat top pistons hit valves with b303 cam? i have a brand new f9 block and i put flat tops in it for more power but am i going to be sorry? i want to put a b-303 cam in it but have heard valves will contact pistons but i need to know for sure no speculation. the heads are ready to go on just waiting on this one last thing all help much appreciated. thanks

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04-10-2001, 05:50 PM	#2
NO SLO PK Registered Member Join Date: Mar 1999 Location: Arcadia, CA, USA Posts: 731	The B is a mild lift cam (.480) but it really depends on a lot of things like the heads you are using and the valve sizes. Were reliefs cut in the new flat tops? What is the deck height of the pistons at TDC? Are you advancing or retarding the cam? I guess what I'm saying is that there are a lot of variables with a custom built engine and it's best to check the P/V clearance with clay to know for sure. I wouldn't leave it to chance. ------------------ Russ L '91 LX Procharger, 3 row intercooler, extrude honed Cobra intake, Mac full Length Headers, 30# inj., 73mm C&L, 75mm tb, E303 cam, 289 rods, ported E7 heads, MSD, T-Rex w/255 lph Walbro, 5 lug conversion, Cobra R wheels, 3.27 gears and Moser Axles. [This message has been edited by NO SLO PK (edited 04-10-2001).]

04-10-2001, 11:13 PM	#3
les1 Registered Member Join Date: Mar 1999 Location: seattle Posts: 76	heads are ported e7t's and yes the pistons have valve reliefs but ive never seen a piston that was totaly flat on the surface.

04-11-2001, 10:16 AM	#4
NO SLO PK Registered Member Join Date: Mar 1999 Location: Arcadia, CA, USA Posts: 731	Sounds like it should be okay. But if it were me, I'd still invest the $20 for a spring removal tool, $2 for a light spring, $3 for play-doh and check the clearance anyway. It's cheap insurance. ------------------ Russ L '91 LX Procharger, 3 row intercooler, extrude honed Cobra intake, Mac full Length Headers, 30# inj., 73mm C&L, 75mm tb, E303 cam, 289 rods, ported E7 heads, MSD, T-Rex w/255 lph Walbro, 5 lug conversion, Cobra R wheels, 3.27 gears and Moser Axles.