PDA

View Full Version : F engine Cam question


Air Randy
12-22-2008, 09:15 AM
I have the pan off and am making good progress getting the rings and rod bearings replaced.

Looking up from below I can see the cam lobes pretty clearly. Looks like there is a fair amount of pitting on the lobe surfaces. How much of this is OK before you need to replace the cam & lifters?

How tough is it to replace the cam with the block in the chassis?

Looking at the MAF website they have either stock or RV re-ground cams with resurfaced lifters. The RV cam is only $40 more than the stock grind. Can I use the RV cam with stock valve springs? I just had new ones installed on my rebuilt head. If I need to replace the cam, any suggestions on where to get it from or is MAF as good as any?

RicardoJM
12-22-2008, 10:33 AM
Randy, I seem to recall RougeLeader having just gone through this sort of thing with his engine rebuild. I couldn't find the post on the board so it probably happened on the e-mail list while the forum was down. Unfortunately I must not have save the e-mail thread. Of course I could be recalling a dream and none of it ever happened. Perhaps Sean will chime in when he sees the thread.

treerootCO
12-22-2008, 10:40 AM
I use the red-line of my 2F to smooth down my cam lobes. :hill:

Rzeppa
12-22-2008, 11:20 PM
I have the pan off and am making good progress getting the rings and rod bearings replaced.

Looking up from below I can see the cam lobes pretty clearly. Looks like there is a fair amount of pitting on the lobe surfaces. How much of this is OK before you need to replace the cam & lifters?

How tough is it to replace the cam with the block in the chassis?

Looking at the MAF website they have either stock or RV re-ground cams with resurfaced lifters. The RV cam is only $40 more than the stock grind. Can I use the RV cam with stock valve springs? I just had new ones installed on my rebuilt head. If I need to replace the cam, any suggestions on where to get it from or is MAF as good as any?

You can replace the cam without yanking the engine, but it's a fair amount of work:

http://rzeppa.org/tech/cam.htm

I have mixed feelings about "RV" cams. They normally require a fair amount of tweaking in carb and ignition to get to work properly, and normally give something else up, such as other areas of the power band, idle, and cold running etc. They can give better power at certain RPMs, but IMHO the stock geometry is an excellent balance between the various trade offs for these engines.

As to your first question, that is REALLY subjective. Without either clear photos or a personal look-see I really can't answer that. Obviously pitting is bad, but on these engines, if the actual contact surfaces are well hardened it may not make much difference in longevity.

Uncle Ben
12-23-2008, 12:22 AM
If you go with an RV can go with fresh billet as a reground tend to have to steep ramps which causes very rapid opening of the valves which promotes valve float. 2F's really respond well to RV grinds but you will want headers/exhaust, recurved distributor and richer carb jetting to realize the full benefits.

Air Randy
12-23-2008, 11:38 AM
I've decided 2 things:

1-I'm going to hold off for now on replacing the cam & lifters. I'm sure it needs it but this isn't my DD so it should be OK for a little while longer. Then I can tear into it next summer without having to do much more work than if I do it now.

2-I'll go with a stock cam. Not enough benefit from the RV cam to justify the extra work to get everything right.