Cam & Rocker Lift Help!!!

-FoxBoy- · February 14th, 2010, 04:25 PM

Ok if i have a 518/518 lift cam an i use 1.6 0r 1.7 RR will that make the cam lift bigger? will i have to worry about pistion to valve issuse ? using keith black flat tops 2.02/1.60 relief cuts. heads are gt 40 with 2.02/1.60s . springs are good for 550 lift

RDY4WAR · February 14th, 2010, 04:44 PM

You could use the 1.7 rockers for a higher lift. I recommend that you always check piston to valve clearance. It's one area that you can't ignore, always check it when installing new valvetrain, even if it's basically stock. One thing to make sure of is the cam timing. Over time the cam can move out of time due to inbalance. The stock damper is weighted on the outside with a rubber seal on the inside. Over time the rubber seal can lose grip and make the cam go out of time slightly. I've seen quite a few 100k mile 302s that are having vibration issues and it's due to the timing being 3-4* out of spec. If going that much higher over stock, I would recommend getting an aftermarket damper that is weighted on the inside.

JBIGBOOTSY · February 14th, 2010, 07:52 PM

Originally Posted by -FoxBoy-

Ok if i have a 518/518 lift cam an i use 1.6 0r 1.7 RR will that make the cam lift bigger? will i have to worry about pistion to valve issuse ? using keith black flat tops 2.02/1.60 relief cuts. heads are gt 40 with 2.02/1.60s . springs are good for 550 lift

Odds are you'll need more spring. Allways measure for ptv clearance.

93mustank · February 14th, 2010, 09:50 PM

Originally Posted by smithboy76908

The stock damper is weighted on the outside with a rubber seal on the inside. Over time the rubber seal can lose grip and make the cam go out of time slightly. I've seen quite a few 100k mile 302s that are having vibration issues and it's due to the timing being 3-4* out of spec. If going that much higher over stock, I would recommend getting an aftermarket damper that is weighted on the inside.

This is 100% false ........ A spun balancer does not affect cam timing

RDY4WAR · February 14th, 2010, 10:00 PM

Originally Posted by 93mustank

This is 100% false ........ A spun balancer does not affect cam timing

an out of balance one does...

93mustank · February 14th, 2010, 10:02 PM

Originally Posted by smithboy76908

an out of balance one does...

Explain

RDY4WAR · February 14th, 2010, 10:07 PM

The spin balancer is made of two parts, an outer and an inner part. There is a rubber seal in between the two. On the OEM balancer, it is weighted on the outside part. Over time, the rubber seal can crack and start pushing outward. When this happens, it causes the weight on the outer part to work against it and it actually slips on the inner part since it's not sealing off. I've personally seen it bad enough that the cam was actually off 4 degrees despite the balancer showing dead 0. I've really only seen this on heavy track run cars. Putting on an aftermarket balancer that is weighted on the inside part can prevent this issue.

JBIGBOOTSY · February 14th, 2010, 10:19 PM

That's ignition timing, the cam sprocket is attached directly to the crank.

-FoxBoy- · February 15th, 2010, 12:04 AM

very true

February 14th, 2010, 04:25 PM	#1
-FoxBoy- Newbie 91 coupe Engine rebuild Join Date: Jan 2010 Location: Tampa,Fl Posts: 25 iTrader: 0 reviews	Cam & Rocker Lift Help!!! Ok if i have a 518/518 lift cam an i use 1.6 0r 1.7 RR will that make the cam lift bigger? will i have to worry about pistion to valve issuse ? using keith black flat tops 2.02/1.60 relief cuts. heads are gt 40 with 2.02/1.60s . springs are good for 550 lift

February 14th, 2010, 04:44 PM	#2
RDY4WAR I Post Entirely Way Too Much 07 Turbo Focus 12.93 @ 105mph Join Date: Feb 2010 Location: Glen Burnie, MD Posts: 6,073 iTrader: 0 reviews	You could use the 1.7 rockers for a higher lift. I recommend that you always check piston to valve clearance. It's one area that you can't ignore, always check it when installing new valvetrain, even if it's basically stock. One thing to make sure of is the cam timing. Over time the cam can move out of time due to inbalance. The stock damper is weighted on the outside with a rubber seal on the inside. Over time the rubber seal can lose grip and make the cam go out of time slightly. I've seen quite a few 100k mile 302s that are having vibration issues and it's due to the timing being 3-4* out of spec. If going that much higher over stock, I would recommend getting an aftermarket damper that is weighted on the inside. __________________ 2007 Focus - 230/215, cams/head/manifold swap done, new #s soon ...going E85! 1985 Bronco - 351W & 4WD 1986 Mustang LX - 351W build in the works! David Michael Smith, 07/25/1956 - 12/08/2011 ...R.I.P dad! I miss you dearly! Last edited by RDY4WAR; February 14th, 2010 at 04:47 PM.

February 14th, 2010, 10:07 PM	#7
RDY4WAR I Post Entirely Way Too Much 07 Turbo Focus 12.93 @ 105mph Join Date: Feb 2010 Location: Glen Burnie, MD Posts: 6,073 iTrader: 0 reviews	The spin balancer is made of two parts, an outer and an inner part. There is a rubber seal in between the two. On the OEM balancer, it is weighted on the outside part. Over time, the rubber seal can crack and start pushing outward. When this happens, it causes the weight on the outer part to work against it and it actually slips on the inner part since it's not sealing off. I've personally seen it bad enough that the cam was actually off 4 degrees despite the balancer showing dead 0. I've really only seen this on heavy track run cars. Putting on an aftermarket balancer that is weighted on the inside part can prevent this issue. __________________ 2007 Focus - 230/215, cams/head/manifold swap done, new #s soon ...going E85! 1985 Bronco - 351W & 4WD 1986 Mustang LX - 351W build in the works! David Michael Smith, 07/25/1956 - 12/08/2011 ...R.I.P dad! I miss you dearly!

February 14th, 2010, 10:19 PM	#8
JBIGBOOTSY MM Fanatic 1990 LX hatch Join Date: Aug 2006 Location: Hobart Indiana Posts: 4,392 iTrader: 0 reviews	That's ignition timing, the cam sprocket is attached directly to the crank. __________________ Bolt-on Abraham Lincoln Log motor. With extra wiring.

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February 15th, 2010, 12:04 AM	#9
-FoxBoy- Newbie 91 coupe Engine rebuild Join Date: Jan 2010 Location: Tampa,Fl Posts: 25 iTrader: 0 reviews	very true

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