valve lift ?

[Lee Thompson]

With iron production heads (un cut ), what is the max. valve lift at the valve, before the exhaust retainer hits the guide? Assuming the heads are stock and no seals on the exhaust guides. Thanks

 

[FJM568]

Wouldn't it coil bind before the retainer hits the guide???

 

[Lee Thompson]

Coil bind first? Possibly, I don/t have any extra heads to check with. I know the exhaust guide is longer. At one time I had my guides cut down to give more clearance. This was when my machinest thought the exhaust must get seals. I no longer run seals on the exhaust.

 

[FJM568]

Lee, I just went to the garage and checked an old head that I pulled off my 87 T...Untouched head, never been off the car before I took them off, to my knowledge...

I've had the valve spring removed off of the exhaust side and I put the original used/abused/burned valve in and installed the retainer and keepers...Pulling up on the retainer and using a dial caliper from the bottom side of the stock retainer on the small diameter closest to the valve stem and to the top of the valve guide on the head, I measured about 0.508...I also checked it with a new, untouched GM exhaust valve that was purchased from Brian Weaver(Bweavy) and Jesse(Intercooler), and measured at about .496...

Keep in mind, this is on a well used and abused head, but has never had a valve job or anything done to it...A valve job would change that some depending on how much material they take off of the valve seats and the valves itself...

I hope this is what your looking for...Lemme know if you need anything else...

 

[Lee Thompson]

?

That is exactly the info I was looking for. Thank you very much. You went to a lot of trouble.----Lee

 

[6PacktoGo]

I've got a half dozen sets of 8445s, and the dimension varies from .48" to .50", on stock heads with no valve job.

 

[FJM568]

Not a problem, Lee...I had already had the valve spring off, so it was just a matter of sticking the retainer and keepers on the valve and measuring...

hmmm...Just how big of a cam are you plannng on putting in your motor???

 

[Lee Thompson]

valve lift

FJM586- one of my bestest friends wants to replace his cam. I like the Schneider 208-224, but it has close to .500 lift on the exhaust side and he doesn/t know if his exhaust guides have been cut. He lives in another state so with this info I don/t know what to tell him. On my own car, I have my original 85 heads. With the work done on them, right now I am using a 218-224 with .500-.520 lift. (steel billet roller)

 

[6PacktoGo]

Re: valve lift

Originally posted by Lee Thompson
FJM586- one of my bestest friends wants to replace his cam. I like the Schneider 208-224, but it has close to .500 lift on the exhaust side and he doesn/t know if his exhaust guides have been cut. He lives in another state so with this info I don/t know what to tell him. On my own car, I have my original 85 heads. With the work done on them, right now I am using a 218-224 with .500-.520 lift. (steel billet roller)

Lee, I'd say nothing much over 0.460" lift without machine work ie cutting the top of the guide. I prefer 0.030" clearance, and I know at least one I measured was only 0.480". I measured at least a dozen on three different sets of heads. By the way, it is any easily measured dimension even on the car with the spring off. A regular dial vernier caliper (6" or 8" version) will fit right in.