Hey guys, Am I nuts in contemplating on putting in a mechanical roller cam shaft in my existing engine? I know there is a trade off in using mechanical lifters such as constant valve lashing. How often will this needed to be done on a vette that might be driven for 2 hours every day of the summer? I am not afaid of extra maitenance but to an extent. if its like every two days then forget it, but I can live with every 1-2 weeks. I would like to try to push the envelop on my engine a bit more and take advantage of the nice heads I got with huge valve springs, good for up to .65" lift. I was thinking of using comp cams 280AR: 280 duration int/exh, 236 @.50" ,.550 lift, 110 deg lobe sep. Engine has trickflow twisted wedge heads and yeilds 10.2 compression. Super chevy did almost the same motor in sept. 1998 :
Displacement: 355 cu. in.
Carburetor: Holley 750
Heads: Trick Flow Twisted Wedge
Intake: Edelbrock Victor Jr.
Camshaft: Lunati mechanical street roller, with 294° of duration and 0.620 in. of lift.(Corrected valve lift with 1.6:1 rocker arms is a lofty 0.661 in.)
Rockers: Summit roller, 1.6:1
Pistons: forged
Rods: forged
Crank: steel
Timing: 35°
Comp. Ratio: 10.0:1

MAX HP: 455 @ 6100
MAX Torque: 435 @ 5000
I dont wanna do this high of lift cam, but I will be using 1.6 roller rockers for the 280AR. I'll get the stall converter I need later. I got 3.55 gears and 700r4 trans. What do you guys think?

|UPDATED|12/19/2004 11:49:24 PM (AZT)|/UPDATED|

Any one got a car that has a mechanical(solid lifter) cam?

I replied, but for some reason it never posted.
Anyway, we have a few guys here at work that run mechanical cams on the street. Mostly back and forth to work, around town on the weekends and weekend warriors at beech bend raceway.

I think most of them only check and make adjustments about every 3 or 4 months depending on the abuse they are subjecting to the engine. If you were going to do a lot of cruises and rack up a lot of miles I would say you would need to only adjust every 6 months or so possibly only once a year.

Personally i think they are noisy and too much hassle. There is a reason that most of the OE's never used these except in their very high performance appliccations. If your wanting to make more power and want more cam lobe ramp speed and lift I would suggest going to a hyd roller setup. I think you would be much happier.

Either way if your going to use extreme lifts just make sure you check your piston to valve clearance. If it gets too close you may need to machine notches in the tops of your pistons. There are several tools on the market that will allow you to do this with the engine in the car. It basically requires removing the heads and removing the valves. The machinging tool uses the valve guides in the head to machine the notches in the right spot. Just need to make sure you leave no material in the cylinder bores or on the head.

After Shark said:Personally i think they are noisy and too much hassle. There is a reason that most of the OE's never used these except in their very high performance appliccations. If your wanting to make more power and want more cam lobe ramp speed and lift I would suggest going to a hyd roller setup. I think you would be much happier.

I concur.. the performance increase between an SR and an HR is miniscule.. too many drawbacks, not enough benefit.

When I was a kid in the 60's and if you liked racing on the street on Fri and Sat nights and wanted the girls to go for a ride afterwords the only type of cam you ran was a solid lifter cam, the hyd cam still hadn't com of age yet,you could wind a 11 to 1, 327, 4:56 rear to the moon, setting rockers is no big deal for me, I like the sewing machine sound myself, but things have changed alot since then, lifter tech has come a long way since then, if you want to build a roller motor and want roller lifters, go with a hyd. lifters unless you plan turning 7K or more.

|UPDATED|12/21/2004 6:07:14 PM (AZT)|/UPDATED|

Thanks guys for the opinions, I was just thinking about it cause I see alot of mechanical roller lifters sell on ebay for real low prices. Hydrallic rollers though are still pretty expensive. I did a clay test on my engine to check for valve interferance with my .470 lift cam and could not see any impressions into the clay and it was on pretty thick, I dont think a .550 lift will be a problem. I would still need to by new pushrods and a thrustbutton and a expensive roller cam. It might be worth the significant boost in hp though. Hmmmm...