318 roller cam

mpdave391

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Okay so I’m in the process of building my 76 318
I’m at across road tho
I’d like to go with a roller cam. But I’m confused I’m looking at the comp cam CL20-601-9 hydraulic roller cam. I have also looked at the. Howards CL718045-09 roller cam I was going to get the Edelbrock 60775 performer rpm heads. And Harland sharp s70025ke adjustable roller rockers.
Where I’m getting hung up is the rockers are oiled threw the heads correct how do the lifters get pumped up. I’m not trying to buy a bunch a parts and not have the right stuff or should I go with a solid roller cam or should I just stick with flat Tappet cam
I’m building this to be a hot street/strip car.
 

Duke5A

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You're going to spend a small fortune on retrofit roller lifters. Too bad it's not an 85+ block.
 

mpdave391

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Yeah I wish it was. Was a factory roller block. But this is something I have for a long time and had been completely gone threw I’d hate to dump it and start all over. I know I’m going to have 1200 or more in a cam and lifters I have been saving all my spare Pennie’s for it I’m ready to pull the trigger on it I just wanted make sure if I bought the retro kit from comp I could use the. Harland sharp rockers. Or if I would have to find something else
 

Camtron

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For the money you’re already spending, I’d get ahold of comp or Hughes engines, give them the drivetrain specs and intentions for the car and have them do a custom grind and set you up with all the hardware.
 

Aspen500

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Check also if you need pushrods with oil holes. When I put the PRW roller rockers on my BB, they required pushrod oiling for the pushrod ball socket and to oil the roller tips. The rocker pivots are still oiled through the shaft though.
 

M_Body_Coupe

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Okay so I’m in the process of building my 76 318
....I’d like to go with a roller cam. But I’m confused I’m looking at the comp cam CL20-601-9 hydraulic roller cam...I’m building this to be a hot street/strip car.

Alright, so that's a LOT of cam for a 318, but you did say "hot street/strip car", keep in mind, with the smaller displacement of a 318 you'll need plenty of converter (if runing automatic transmission) as well as good amount of gear - I'm actually thinking 4.10 to start off with!

Having said that, while the guys are spot-on in terms of recommending a roller block as a starting point, you can certainly accomplish what you want to do with a non-roller as well. The one thing I learned about this approach is the criticality of making sure your non-roller lifter bores are TALL enough to NOT expose the lifter oiling passage, let me explain this one.

Because the roller lifter is taller than a flat tappet (solid or hydraulic) it may expose the oiling band of the roller itself as the lifter rides up the cam lobe to it's max lift. When this happens the exposed lifter band basically dumps all the oil pressure that feeds the lifters, and that's a major NO-NO! (massive oil leak)

Now, how do you guarantee that it'll work? Well, it's a trial & error thing...basically you need your cam to be installed in the block, a pair of rollers tossed in there and then you turn it over to max lift and keep your fingers crossed to NOT see that oilding band on the lifter getting exposed.

Here is what my non-roller block with the current CompCams 8920 roller lifters look like. I am showing you two key things here:
1) the placement of the lifter in my block at cam base circle and how far into the lifter bore the top of the lifter is
2) the placement of the lifter in my block at max lobe lift and how far OUT of the lifter bore the top fo the lifter is
3) the NOT desired placement with the oiling band exposed (this is over-emphasized, but if that band - the dark part of the lifter - is exposed, the oil pressure that feeds all the lifters just causes that oil to dump into the lifter valley)

Hopefully that better explains the concept.

20230601_085512.jpg


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20230601_085709.jpg


20230601_085823.jpg
 

M_Body_Coupe

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Ohh...one more thing: the factory non-roller lifter bores that are most susceptible to this issue are those which show a deep chamfer of the lifter bore (so at the top), my block does not, in fact that was one of the things I looked for when shopping for the block.

Currently with my CompCams XR292HR cam, I am fine, but that's only a .365" lobe lift cam. I have a measured 0.200" room in my lifter bore before the lifter is out too far and the oiling band is exposed. For my purposes it is safe to say I will NEVER run a cam that big!!! LOL

There are some lifters out there that attempt to deal with this, Hughes is one of them, Howards is another.
 

mpdave391

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I’m starting to think I should just stick with a non roller cam lol. So on your cam shaft what’s the specs of the xr292hr
 

M_Body_Coupe

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I’m starting to think I should just stick with a non roller cam lol. So on your cam shaft what’s the specs of the xr292hr
Listen, don't let the feedback you're getting here de-tour your plans!

What we are all going to be pre-desposed to do is to highlight the challenges, after all, if you are aware of them BEFORE starting the job, you are more likely to avoid some of the same pitfalls.

If you can, I would check as much as what you have for the issues that have been raised in this thread so far.

I mentioned Howard's roller lifters because they are known to have a different lifter body (as compared to the Comp stuff) in order to help us Mopar SB guys deal with the engine block lifter bore issues. After years of reading on-line posts I believe these do a pretty good job of doing so. In fact I had picked up a set of these and was going to run them instead of the Comps, but I then ran into an issue with my W2 heads and the Howards placing the plunger higher up caused the pushrod angle (between the lifter and rocker arm) to get a little worse still, and that in turn ran into a head clearance issue.

Sooo....expect that you might run into such a problem. If you'd rather avoid dealing with such a possibility, than yeah I agree, flat tappet hydraulic is probably the safest way. Just remember, those have their own 'can of warms' (today's oil mix, lack of ZDDP, etc.).

I've attached the XR292HR cam card as well as the detailed grind specs from CompCams.

COMP_CAMS - XR292HR-12 - CUSTOM - E_8961-14 - Hydraulic Roller Cam Card.jpg


COMP_CAMS - XR292HR-12 - CUSTOM - Hydraulic Roller Cam Grind Spec Card.png
 

Mikes5thAve

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I'm guessing you've already thought of it but one big question is what do you plan on doing with the car?
It seems to happen a fair bit where someone sinks a bunch of time and money to get max performance out of a 318 when they would have been that much further ahead with a 360 and sometimes end up going that route once the 318 is done anyway.
Don't get me wrong I like 318s and if its going to be a fun regular driver that's probably the route I'd go because there's a drop in mileage going 360 (altho a hopped up 318 isn't always that great either) but you definitely notice the performance increase.

What have you already done to the engine? It might be still worthwhile switching over to a roller block if it simplifies running a roller cam and eliminates some of the lifter/bore issues.
 

mpdave391

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So I have set the car up to be a street/strip car as far as the the 318 goes. It’s been completely rebuilt. There isn’t but maybe 1000 miles on it. I hate to tear all the parts out of it. After I spend the money. On a roller block if I find a good one I was just wanting to put a better cam in it. Get maybe some more power out of it.
I’m looking to build a stroker out of a 360 But some key components are still on back order.
I haven’t bought the cam or heads yet so I can always go back to. A Non roller cam
I just thought that they where the way to go and figure I’d try it out on the engine I have complete
 
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