slider cam in roller head

[Sundance 6g72]

I run non roller cams. I grabbed cams from a 87 caravan. They are more lift and duration than the stock cam. The car runs rich, but with the heads being ported like they are it hasn't seemed to be a big problem.

http://www.turbododge.com/forums/f11...ml#post2457735



really? I didnt think we could do this and if we really can, how much would it help? lol

[c2xejk]

The statement "the car runs rich" would need clarification. If the heads are flowing better, I would expect the engine to lean out. If it is idling rich because of low-vacuum (ie. side-effect of a big cam) then that likely can be solved by one of my ported lower intakes.

[Wiscoballer]

so this will or will not work?

[Force Fed Mopar]

The statement "the car runs rich" would need clarification. If the heads are flowing better, I would expect the engine to lean out. If it is idling rich because of low-vacuum (ie. side-effect of a big cam) then that likely can be solved by one of my ported lower intakes.

That divot or dimple or whatever it is you mentioned, what is it's original purpose, if any?

[c2xejk]

It is a side-effect of the casting process. It occurs where the bolt towers for the fuel rail are...

[Wiscoballer]

so yes this works, and it will up performance?

[c2xejk]

Yes. It removes turbulance in the runners.

[Wiscoballer]

Yes. It removes turbulance in the runners.

Sorry, meant the cam

[turbovanman²]

It can work but you better check the geometery before you button her up.

[c2xejk]

No guarantee that it will improve lift or duration. That would need to be checked.

[tryingbe]

User slider rockers with slider cam too.

I've seen a slider cam used with roller rockers at the junkyard, the cam has deep indentation of the rockers.

[sdac guy]

It is generally accepted that you can run a roller cam in an older head (slider head). But unless you take some precautions, you can't do it the other way around, as in your thread title.

The reason is the slider cam and followers need more lubrication, so the slider head has oil squirt holes cut into the cam tower caps. These squirt oil directly on the cam lobes so the slider followers have a good oil supply at the point of contact. If you run a slider cam in a roller head that doesn't have the squirt holes cut into the cam tower caps, the slider followers and cam lobes will not last very long.

Now the post you linked to on TD, the guy there states he is using a slider cam with roller followers, but he doesn't say which type of head he is running. The roller followers should be happy on any head (oil wise).

But using the roller followers on a slider cam might be a questionable practice as the lobes on a roller cam are designed for roller followers (valve lift/closure rate). And I am not certain the base circle of the cams are the same between the two types either. It may work fine in the short term but I don't know of anyone who has tried this for the long term.

Barry

[Sundance 6g72]

well the rocker ratio on the slider head is 1.5

the roller head is 1.6

when we run 1.5 solid rockers (still roller rockers, talking about the 1.5L 4cyl rockers brent tried) we have to run a bigger cam because with a smaller ratio the cam becomes "smaller"

but if you go the other way around... run a cam from a 1.5 ratio head in a 1.6ratio head, the cam should act bigger than it was in the 1.5 head.

but without the proper oiling, i wouldnt want to try this..

[Ondonti]

Slider head is 1.38 ratio.

That doesn't mean the cams are equal when multiplied by that ratio. As Barry mentioned, the profile is different. If you have looked at a slider cam, you will see that it has a super sharp peak instead of a wide fat peak. This means with roller rockers you will have much less duration @ medium and high lift. Who cares what your peak lift or advertised duration is when your valve is not opening/closing as aggressively as it did before.

My guess is that rich = less airflow and the car is running slower. Its pretty easy to state that having owned a set of slider heads. I still have everything but the cams which are junk in my opinion.

[Ondonti]

Looked. 89mph in lightened P body. I think my point is proven. What you have there is exaggerated claims based on E.T. that was improved with drag radials but trap speed tells the tale of engine performance. I ran 3mph faster in a heavier AA body with.....Diamantes. I E.T.'d slower but who cares? 88mph was my best auto trans MPH. Seen that one guy over there run the same trap with spray and auto trans, then deny his rebuilt transmission/converter is faulty and blame the engine for being impossible to make power with ("because my dad knows everything").

[5DIGITS]

There are several things going on here and it may be best to break them apart.

Rocker ratios:
The rocker ratio is not dictated by the the cylinder head.
With followers, the rocker ratio is a function of where the cam contacts the follower with respect to the valve-tip contact point and the pivot point.
(SLIDER) The slider cam rocker ratio is actually not constant because as the cam profile 'slides' across the follower the point of contact moves.
It is generally accepted that when the cam is at peak lift, on the follower, it is positioned such that the cam lift to valve lift generates a 1.5 ratio.
(ROLLER) On the other hand, the roller follower contact point remains relatively constant as the lobe travels across the roller.

Lubrication:
As Barry mentioned, there are provisions on a slider head to allow oil lubrication for the cam to follower contact point.
These are not present on cylinder head that was originally manufactured for a roller cam.
Running a slider without the lubrication holes will cause premature cam failure.

Running observations:
The rich condition and/or poor running condition is the result of 'everything wrong' between the the calibration and cylinder events.

Mixing roller and slider hardware:
Running a roller follower on a slider cam = Avoid !
Running a slider follower on a roller cam = Although, not recommended, it can be done at the expense of massive over-lap and digging trenches into the slider follower.
The roller lobes are too narrow and the localized loading on the follower has been significantly increased. With this, it should also be avoided!

I hope this helps someone avoid damaging an otherwise good engine.

[RoadWarrior222]

Running a slider follower on a roller cam = Although, not recommended, it can be done at the expense of massive over-lap

Hmmm, I thought a roller profile was "narrower" due to the roller effectively widening it, so you'd get more duration and/or overlap with roller follower on slider cam, but less duration/overlap and lift with a slider on a roller cam.

Also I had heard that ramp rates had to be shallower on a slider cam, so the slider won't dig in instead of lifting, whereas this wasn't so much a problem on a roller cam, thus it could have sharp ramps.

Anyhoo, from reading reports of folks who've mixed things up, it appeared to me that slider cams survive roller followers quite well when they are high mileage cams, not fresh ground or new cams. It would appear that they harden in use, in the original intended application. IDK why you can't case harden them in a BBQ or something if you feel like it though.

And yes, we could do with more detail about whether slider cams/roller followers are working in slider heads or roller heads.

I has an '88 motor with sliders running, and a '92 motor with roller on rollers for parts... plan ATM is to freshen the '92 heads, port them, transplant them onto '88 bottom end, then work on '92 bottom end....

[turbovanman²]

It can be done, others have piped up here that they've run slider cams with roller rockers on our 8 valve but I how long will it up hold up?

As others have said, roller cams are harder so the wheel doesn't dig into the cam, ramp angles are great as the roller allows the valve to be opened faster, do that with a slider and it digs in.

IF you don't care what happens, try it.

[5DIGITS]

Hmmm, I thought a roller profile was "narrower" due to the roller effectively widening it, so you'd get more duration and/or overlap with roller follower on slider cam, but less duration/overlap and lift with a slider on a roller cam.

Visualize the 'egg' profile of a slider cam lobe vs the near 'oval' shape of the roller lobe.
The area difference between the two lobes will cause a roller lobe to open a slider follower sooner and close it later.

Also I had heard that ramp rates had to be shallower on a slider cam, so the slider won't dig in instead of lifting, whereas this wasn't so much a problem on a roller cam, thus it could have sharp ramps.

The logic needs to be reversed in the above statement.
Roller = slower ramps, narrower lobe (in width) due to reduced friction and reduced ramp rate loading
Slider = faster ramps, wider lobe (in width) due to metal to metal contact and higher ramp rate loading

Anyhoo, from reading reports of folks who've mixed things up, it appeared to me that slider cams survive roller followers quite well when they are high mileage cams, not fresh ground or new cams..

The rounder profile of a roller lobe is that way for many reasons and one of these supports maintaining contact with the roller.
The slider profile is effectively a ski-jump for a roller-follower and with the production roller axles already on the small side, it is unwise mixing of parts.
The first person to realize axle failure and send debris through their engine might shed some light on why this is not smart.

IF you don't care what happens, try it.

Well said !!

[Ondonti]

Do I need to mention that this is the 3.0 Section. I don't care about the accepted slider ratio of some other motor.
The peak lift ratio is 1.38. That is all there is too it. Generally accepted by whoever else can't prove differently.

Ramp rates are lower for slider cams because roller profiles will cause excessive wear. I don't understand why people keep acting like roller rockers chew things up. Its all backwards in this useless thread.
Rollers are an improvement because you can run wilder cams. Slider cams are always wimpy in comparison. The only thing a roller rocker will accomplish on a slider cam is making the slider cam more aggressive then when the slider cam had slider rockers.

I have actually put both roller and slider rockers on a 3.0 slider cam head with slider cam. Who else posting has done this? Who else has put a dial indicator on that setup? Thank you. Force Fed has some some of this stuff on rollers so he is the only other person that I know who can share direct information about the 3.0.