Comp Cam 23-707-9 Solid Roller Opinion.

[malex]

Have any of you guys ran this cam or have experience with it.

Specs are:
Comp 23-707-9
Grind: RX308R-8
657 Int / 659 Exh Lift with 1.6 Ratio
275 / 282 @ 050
108 LSA / Installed @ 108.
4500-7000 power range

Engine combination for this cam is 505, 12.56 CR, Victor Max Wedge, Indy NSS intake, 2-750 Eddies.
5000 Dynamic Converter, 4.10s. 3400 lbs.

This is Comps recommendation for this combination.
They say that it won't kill valve springs or lifters.

Any info, experience or recommendations is appreciated.

Thanks Guys.

 

[dvw]

I run the Comp. 471 RX lobe. 285 duration,1.7 rocker so .800" lift on 112LCA. Your motor is smaller so down sizing duration isn't a bad idea. Not Sure about the 108LCA, maybe 110. As you add duration the LCA needs to widen out to prevent excessive overlap. Mines more aggressive, big power. I've rotated springs and lifters. 150 passes on Comp 996 springs, 250 passes on lifters. I have a spare set of used Comp offset 829 lifters to sell. Comp rebuilds them for about $175. Swapping to Pac springs for longer life, we'll see.
Doug

 

[malex]

Doug, thanks for your knowledge. I raised the LSA with Comp when working with them questioning whether 108 was too tight. They said that it will be fine for the RPM range I want to run at. Having said this, I will think more on it now that you have questioned it too. I'm looking at running no more than 6300-6400 RPM. A 31" tire with 4.10s should be pretty close.

 

[dvw]

I'll bet that thing will like more rpm. I Wouldn't be surprised to see 6900-7100. The narrow lobe sep will help midrange on the street. My bet is any advantage is has will be beyond stall speed at the track. It might like more gear but I'd try it first. If there's a good port job on those heads it'll run pretty good.
Doug

 

[malex]

I'll bet that thing will like more rpm. I Wouldn't be surprised to see 6900-7100. The narrow lobe sep will help midrange on the street. My bet is any advantage is has will be beyond stall speed at the track. It might like more gear but I'd try it first. If there's a good port job on those heads it'll run pretty good.
Doug

Do you think that if this cam is installed at 110 instead of 108 it would raise the RPM curve? I believe I've heard it said that 2 degrees retarded is good for about 200 RPM? Does that sound right? This cam selection isn't a done deal yet, there might be something better out there.

Yes the Victors will be getting port work done but with the stock block, larger HP numbers makes me wonder about main webs cracking.
Main studs, aluminum caps and a girdle are going into the bottom end along with 7.100 H-beam rods, Icon Pistons and Ultra-lightweight crank. I'm hoping that reduced reciprocating weight will also help it live a long life. The lighter rotating assembly probably would like more RPMs.

 

[dvw]

You won't know unless you try. Every combo is different. Your motor looks like a smaller version of mine. Mine is in at 108 on the 112LCA. It runs more mph than most of the similar N/SS cars so I see no sense to retard it. Molnar has some of the lightest steel rods available 7.100" .990"/2.200" journal, 835 grams with Mopar big end width. Nicely finished good price. I have a set ordered for mine right now. http://www.campbellenterprises.com/molnar-technologies/molnar-connecting-rods.php
Doug

 

[malex]

You won't know unless you try. Every combo is different. Your motor looks like a smaller version of mine. Mine is in at 108 on the 112LCA. It runs more mph than most of the similar N/SS cars so I see no sense to retard it. Molnar has some of the lightest steel rods available 7.100" .990"/2.200" journal, 835 grams with Mopar big end width. Nicely finished good price. I have a set ordered for mine right now. http://www.campbellenterprises.com/molnar-technologies/molnar-connecting-rods.php
Doug

Very good information on the Molnar rods. After reading this I had to go out and check my H-beams. They measure .995. I decided then to check the throw width on this Ultra Light crankshaft and it measured 2.012. That leaves me .022 clearance. I think that I read .022 is ideal. My stroker kit is from 440 source and these Platinum series rods are obviously matched to the crank throw width.

Regarding the camshaft mentioned above, it turns out that the Comp Cam catalogue has an error. The catalogue says 657 / 659 with 1.6 ratio rockers. I ended up ordering this cam and all was good. Later that same day I googled and found a cam card for this specific grind. Checking it over I see that lobe lift is 439 / 440. I thought I would just calculate the total lift with 1.6 and it comes out to 702 / 704... What the hell, not what the Comp Tech advisors told me. My Icon Pistons are rated for about 700 lift and I want to stay below that. I contacted the Comp tech line and sure enough, they realized that they gave me the same incorrect information as in their catalogue. Back to the drawing board and the cam will be returned once it arrives, already was shipped.
We put together a custom grind now and these are the numbers, any opinions are welcomed.

Lobe design is the .420 High Tech. (Easy on valvetrain)
Lift with 1.6 rockers: 674 Int / 674 Exh
Duration @ .050. 274 Int / 282 Exh.
110 LSA

Thoughts?

 

[IQ52]

As I see it the 23-707-9 has .439/.440 lobe lift. Multiply that by 1.6 and you get .702/.704. Subtract the valve lash .026/.028 and you have .676/.676. Isn't that within your lift desires?

The HI-TECH .420" lift rollers are, and I quote, "Theoretical Valve Lift @ "0" Lash Rocker Arm Ratio" 1.6 is .672/.672 with the lobe numbers 4016/4032 (274/282 @ .050").......@ "0" lash.........you must now subtract the valve lash to get your net lift. I personally don't know what that lash is but I doubt it is less that .016". Therefor you have .656/.656 or less net lift with the new cam. S'okay if that is what you want.

 

[malex]

As I see it the 23-707-9 has .439/.440 lobe lift. Multiply that by 1.6 and you get .702/.704. Subtract the valve lash .026/.028 and you have .676/.676. Isn't that within your lift desires?

.

Hi IQ. That's correct on the calculation after lash. It would likely work but my preference is to build in some additional clearance at the start. With the Victors being milled to 63CC and .001 deck it will tighten things up, how much, I'm gonna find out. The wider LSA than 108 is also my preference with the larger cubes. IQ do you have any experience with the Comp .420 lobes by chance? They are supposed to be easy on the valve train but I'm not sure how it effects performance.

 

[IQ52]

As I look at the lobe profiles I don't see anything that will make much difference in valve train stress at your rpm levels.

63cc's? Does that mean you milled about .072" off the head? I only see about .006"-.010" maximum, maybe only .004" gain in piston to valve clearance with the cam swap. If you needed to add additional clearance with the first cam you'll need to do the same thing with the new one.

 

[dvw]

Duration affects piston valve more than lift. You'll find the tightest P/V is between 10 BTDC and 10 ATDC, no where near max lift. We've run .070"/.090" after lash w/o contact. Make sure to check with clay. Other wise you won't know the radial clearance ( I like .060"). Also advancing the cam will tighten up intake, retarding tightens up exhaust. Tighter LCA tends to reduce P/V. The more lift in your case the better in my opinion. Heck those heads and intake would like better than .850" lift.
Doug

 

[malex]

As I look at the lobe profiles I don't see anything that will make much difference in valve train stress at your rpm levels.

63cc's? Does that mean you milled about .072" off the head? I only see about .006"-.010" maximum, maybe only .004" gain in piston to valve clearance with the cam swap. If you needed to add additional clearance with the first cam you'll need to do the same thing with the new one.

You're close IQ. I recall that about .065 came off to get to 63cc.

- - - Updated - - -

Duration affects piston valve more than lift. You'll find the tightest P/V is between 10 BTDC and 10 ATDC, no where near max lift. We've run .070"/.090" after lash w/o contact. Make sure to check with clay. Other wise you won't know the radial clearance ( I like .060"). Also advancing the cam will tighten up intake, retarding tightens up exhaust. Tighter LCA tends to reduce P/V. The more lift in your case the better in my opinion. Heck those heads and intake would like better than .850" lift.
Doug

You sure run your engine measurements tighter than I would like to, you must be getting real close. I'm hoping to stay around .100 on the intake, more on the exhaust. I'll certainly be pulling out the clay when it's time too.

 

[dvw]

I currently run more but with the new pistons I'll tighten it up. The .070" was a 8000 rpm Hemi. It's amazing what can be had if the valve action is nice. I've read guys running .020"/.030" to 10,000 with light valve train with only light contact. Also .800" lift rollers with just over 100 psi on the seat. If we had access to a spintron we could as well.
Doug