roller cam?

[mopar_nocar]

can a person replace the roller cam in a 318 with a flat tappet?

sb

[dwc43]

Yeah, you can, but why. That's a step backwards. Loss of power and more friction with flat tappets over rollers.

[mopar_nocar]

Cost. Cam costs twice as much. or more. are the pushrods the same? can you reuse the lifters? that might be the deciding factor.

sb

[dwc43]

You need longer push rods and you have to have new lifters to match your cam.

[John Kunkel]

Factory roller cam engines lube the top end via the pushrods and lifters, if changing to a flat tappet cam you need to run AMC lifters and drilled pushrods which have provisions for top end oiling.

[rumblefish360]

Even on pre-Magnum motors?

[dwc43]

No, not on pre magnums like mopar_nocar is running. THey oil through the head and rocker shaft just like all LA engines do.

[mopar_nocar]

in essensce i am trying to get a feel for how to attack this. i don't want to spend a ton of dough (don't have it really) but i would like to get some extra oomph out of this little 'teen.

i've never messed with the roller engines before....what are the factory cam specs on the roller engines? did mopar take advantage of the roller to increase lift rate? would i be better off with the stock cam than say a summit 204/214 duration cam for the flat tappet?

in the end the engine will be in an a body/auto/3.23 (or 3.55) gears running a 205/70-14 tire.

sb

[dwc43]

The cam does use the lifter to it's advantage. I don't have the factory specs in front of me right now. You'ld be better off with another roller. It will cost you just as much to change over since you will need new cam,liters,push rods and springs.

[DartGT66]

Even the roller factory grinds are very conservative, they do not take advantage of the possibilities. The only purpose is to lessen the friction and get better fuel economy + free a few more horsepower. If you install a REAL aftermarket hydraulic roller cam, you will gain over any aftermarket flat tappet. The cheapo summit cams may be a performance advantage over the factory roller, but there are a lot better flat tappets on the market than those.

[madmax2]

can use a solid roller lifter with a hyd roller cam?

[George G. Leverette]

Roller cams are quite different than a cam cut for roller lifters. If you want to make more power then go to a power provider like Hughes Engines, Comp Cams or straight Line Performance and discuss the expected power levels you want to acheive. The cost of the cams give some assurance that they are not regrinds off a xx year old casting with inferior hardening techniques. There have been numerous cam failures during start-up on cams recently. How valuable is your time, how long can the car set without use? New cans require new lifters unless you use Schubecks. Making power is a slippery slope once you get on there is no way off until you hit bottom, the cost of oil just went to the highest ever today!!!!!!!!!!!!!!

[mopar_nocar]

factory roller specs are

.391/.391 lift and 240*/240* adv. duration. that makes it about 192* @ .050

so, stick a set of roller 1.6 ratio rockers on there and you've got about a .420 lift cam and an ALL roller valve train. sounds like a method to make decent (not great) power, plenty of torque and get decent fuel economy, too. should be a smooth running little engine. push rods seem to be the big sticking point on this, which is easily surmountable.

zero deck the block, stick some 1.88/1.6 valves into the head and have some fun.

what do you guys think?

sb

[RAM1500]

Why not see if you cant use a hydralic roller cam in that motor like the magnum motors have?

[RAM1500]

If you go with the flat tappet cam dont buy one because its priced dirt cheap. A couple years ago we bought two flat tappet cams for the Cuda from Skoggins Dickey that were supposedly Mopar cams, but they were cheap compared to Jegs and Summit and it took four passes and two scrapped cams to see why. At first i figured it might've been the alcohol but no, then we checked the lifters out and they were ok too.

[mopar_nocar]

point is decided. i found some 1.6 rockers from midwest motorsports (i think, the link is at home) and i'll get some pushrods from the local IAPA outlet. deck it down and ride.

sb

[72Challenger]

Well then you'll get great mileage, but this thread should be moved out of the Performance Talk forum and into the Economy forum.

192 @ .050? Bet you can get it to idle at 400 RPM in gear!