Cam question

[4onFloor]

I've got a 350 that has a flat lobe on my cam. In order to save a little $, i was thinking about using a cam that i pulled out of a 305. The problem is that the 305 had roller lifters and my 350 doesn't. is it ok to use non-roller lifters on a roller cam? I'm gonna buy new lifters but i cant afford rollers.

[1992RS]

You might wanna just scratch that whole Idea. YOu can't use a roller cam with flat tappet lifters. The design of the cam is completly different for rollers. And as far as buying roller lifters, even if you had the money to buy them you would have to get your engine machined to except them. Your best bet is to buy a new cam and lifters. You can get a brand new cam and lifter set on ebay for the price you'd pay for just the cam or lifters at jegs. But if you do what your talkin about it's not gonna be perty.

[4onFloor]

even though i cant afford roller lifters, i though you could get roller lifters that would work in non-roller engines. i thought that had pivot bar across 2 lifters that kept em from spining. that's the only reason i questioned a roller cam with flat lifters, cause i know roller lifters arent supposed to spin, and flat lifters are. i didn't know if the cam was ground at such an angle that it spun the lifters.

[1992RS]

Now that you mention it I do recall seeing those retrofit roller lifters which would work, but you might want to ask around and find someone who has done this and see if they've had any problems with them. It's not really so much about spinning lifters as much as getting the lifters to lift. The roller cam has kind of a flat lobe that works well with the roller lifters, and the other has more of a pointy lobe to that helps get the flat tappet lifter started on the upward assent and then smoothly back down again. If you use the roller cam with flat tappets your it's not going to want to go up and is going to cause a lot of friction. Plus if I remember correctly the roller cam is ground smaller because the rollers on the lifter make the lifter longer..so you won't even get the lift that you want. So I would hold of on the roller cam untill you can get the roller lifters.

[4onFloor]

i think i'll just save up a little and get a kit that comes with a new cam, lifters, and assembly lube.

[4onFloor]

your right, the lobe on a roller cam is shorter, but only by about .010 Roller lifters are taller, but they use shorter push rods. the push rods make up the exact difference. if i remember right, roller lifters in a stock 305 are .6 taller than a flat tappet lifter, and the push rods from a flat lifter engine are .6 taller.

[dcatkin]

Originally Posted by 4onFloor

I've got a 350 that has a flat lobe on my cam. In order to save a little $, i was thinking about using a cam that i pulled out of a 305. The problem is that the 305 had roller lifters and my 350 doesn't. is it ok to use non-roller lifters on a roller cam? I'm gonna buy new lifters but i cant afford rollers.

It may be a good idea just to trash that whole idea, if you put a cam in it sould be brad new out of the box, and what's more the roller lifters have a different lifter boss. I'd just wait untill you can afford the new cam and lifter setup. Before you put a brand new cam in you'll want to check you valve springs for pre load pressure and height, also check the cam bearings for burning and other wear.

Check out the info on my site about engine building, http://hp-car.com/engine/building/index.html

http://hp-car.com/engine/valve.html


David C. Atkin

Editor

http://hp-car.com

[Vlad_Tepes]

92RS

Its purdy not perty =)

[1992RS]

I'm sorry Vlad, what was I thinking? I'll be more carefull next time...LOL

[Vlad_Tepes]

No worries mate.