Once I get my L88 dyno'd so that I have a baseline, I will probably change out the cam for something a bit more civilized. The 288R mechanical roller appears to have a lot of benefits. Sounds like the best of both worlds, reasonable low end plus a 7000 red line.

With the massive overlap of the L88 cam, I am doing very well regarding detonation or knock problems with only a little 100 octane (5 gallons per tank) for safety as I continue to sort things out. No doubt this will be more of an issue with the tighter numbers of the 288R cam and my 12:1 compression. If I have to use more 100 that is ok. it is not worth boring out my new motor .030 to get new, lower compression forged pistons. I don't want to replace my full floating rods either. I’m not really anxious to tear down the motor to have someone flycut and re-balance the pistons. The price of 100 octane gas seems like a better deal to me, for now. Also, I got such a deal on a big can of moth ***** :D

Any of you guys have any actual experience with this cam? Reliability, performance, behavior, etc.

Chuck

 

I ran it in my 427 for several years. I have had that motor for 20+ years in many different combinations and cams, and it was by far the best one Iever used in it overall.

Some of the more radical flat tappets put out comparable power, but with no where as near as good streetability.

It made 14" of vaccuum, idled well around 900 or so. I had 11.2 compression, ported Merlin oval ports (324 cfm), Team G single plane and 1050 Dominator. It ran low 11's anywhere at 123 mph through the pipes on pump gas.

On the chassis dyno it peaked at 5850 rpm on hp and around 4300 it seems like on TQ. Very broad power curve which made it great on the street. It didn't care where you shifted... it was always ready. Interestingly,it only lost 6 hp at 7000 rpm on the dyno. It was still hanging in there fine.

It had 195 psi cranking compression.

Hope this helps.


Jim

 

I have a comp cam 288R right now but can;t find the rest of the part number here at work. It is .623 lift, 112 lobe centers 236 intake and 244 exhaust at .50. I don't like the cam. It idles fine with lots of vacuum but lacks the mid range and high rpm of my old flat tappet cam. It falls down around 6000. If I didn't have $1500CDN in the valve train I would dump the cam. Maybe next year.

 

Ditto what 427 hottrod said. Am running the cam now
and have tons of vacuum. Using Sq port heads, factory trips, 10.5 cr
idles at 800 without loading

specs:
.623 gross lift
110 degrees centerline
244 @ .050

incredible response at any rpm range

 

Norval......Did you custom order that one?

Mine was the same as Gdaina's. 244/244 @.050 and .623/.623 on 110 LSA.

I think your short duration and wide LSA was not enough of a good thing. I can see how yours would run out of breath early.

Either way it's not a huge cam, but the one I had worked great in a 427 street motor.


Jim

 

Mountain Motor: Good point to consider valve clearance on big domed pistons at critical lift/timing points.

427 Hotrod & GDaina: That is the kind or encouragement and info I am looking for. By the way 427, with your old motor, were you using aluminum heads with that 11.2 compression on pump gas? This is also very encouraging! The power peak at 5850 kind of surprised me. I thought it would be higher; but if this remains within 6 hp to 7000 I would be very pleased indeed!

Norval: your negative experience is a good point to temper my potential unbridled enthusiasm for this cam. Is it possible that the cam is flowing more air and your engine is leaning out?

GDaina: Can you tell me how the car performs over 102mph? :lol:

Thanks again for such great replies!

Chuck

 

Lingenfelter did a article of big block chevy's and recommended this cam for a hot street motor. It is definitely not custom ground , is 112 lobe centers, 236 @ .050 intake and 244 @ .050 exhuast. It replaced my old .648 lift 256 @ .050 intake 264@ .050 exhaust and 108 lobe centers. This was a flat tappet cam that crane. That old cam had no idle vacuum but mid range to 7500 it pulled. My heads were not streetable then. Rectangular 346 cfm at .600. My present roller is definitly 288R something.
Have a nice weekend

 

I have a question that has probably been asked before, but here goes. How do you guys feel about the reliability of solid rollers? The benefits are obvious and the 288R just happens to be my prime choice of cams for a street driven 454. When I build this engine, I want to be able to take it on occasional trips (100 - 200 mi) without any worries of breakage. According to DeskTop Dyno, this cam is awsome. I haven't found any other cam profiles that does everything as well (combination of low end and broad torque along with max hp) as this one does. I'm glad that a couple of you guys have good things to say about the manners of this cam.

 

Chuckster......... :D

 

No worries here.......that's all I did last summer...cruised on the weekends and put on a ton of miles....glad I have stock in MobilExxon

 

Chuck, Comp also has a few similar cams that are a newer design. The XR286R and XR292R. They're similar, but with a dual pattern design. I'm thinking about the 292 for my new 540.

By the way, the "off the shelf" lift of the Comp rollers seems to run much higher than most of the other cam manufacturers. Sounds good for some free horsepower if you can fit it with your pistons!

-Joe

 

Flareside: I have the 292 Comp Cam in my 454 in my auto 73, I don't like the cam very rough idle, 11" of vacuum at idle, idle must be in the 1100 to 1200 or it will stall. If you have 4-speed it might work better, I have to put the vette in "N" at the lights and stop signs and the power brakes do not work very well.

 

73, I'm only considering the roller 292. Are you running the solid flat tappet? I would expect that solid to be pretty rough on the street, but the roller should be much milder. I'll also be running it with a 5 speed, EFI, and without power brakes, so I don't really need strong vacuum or carb signal. If I do go flat tappet, it will be milder than the 292.

Curtis, talking is all I can do right now ;) Between work and the house, I don't have time for anything else! Don't worry, I'm only *considering* the roller, not buying. Just wait until April... :lol:


[Modified by Flareside, 10:28 PM 3/15/2002]

 

No Girdles! *If* I do go with the roller, it will be complemented by the new Jesel SS shaft rockers for $700. Unfortunately, they are only available for Dart's right now, so they limit head choices. I look at the swing from flat to roller as a $1500 change, and that's why I haven't committed to it.


[Modified by Flareside, 10:30 PM 3/15/2002]

 

Ha, ha. So, is the first part me, or is the second part you :lol: Just kiddin', just kiddin'! My wife has called me both irrational and mindless at times :)

Heck, if practicality figured into this, I would have had to build a small block!

To get back on topic: Are you guys with the 288R running it without a girdle? It's hard to know where the line is here... I think the Comp recommended spring for that cam has around 175# on seat and over 400# open.

-Joe

 

Mountainmotor,

How much more likely will detonation or knock problems be with the cam changes you suggested as well as the 288R compared to what I have now? The approximate cam specs for the L88 are: .540i/.560e lift (valve lash subtracted); and, 262i/273e degrees at tappet (without lash subtracted) @.050 lift.

Chuck

 

I was using iron heads. I knew I was pushing it but it worked well.

If you have an honest calculated 12.0-12.5 compression, I'm actually a little concerned. But as long as you're used to running some race gas it should be OK. It will definitely be responsive!!

There is also a Crane street roller with around .636 lift that is around 250 (?) @.050 on 110 LSA that I have seen work well. When you talk to Crane, they typically say the .636 is about all they will use on street stuff and they just move duration out further for power.

It also seems that Crane allows for significantly less seat pressure. Of course they do this because of what MountainMotor said... long slow duration with relatively low lift. Nice gentle ramps.

I was using 190 seat pressure. Honestly, I had several rollers die after about three years. I can't really complain though. I bought the cam/lifters used from a dragster with a .740 lift cam. I had the cam reground for less duration and lift (still .725) and ran it for 1-2 years on the street. I then installed the same lifters on the Comp street roller, decreased the pressure to 190 and then ran it for three years before some rollers died.

I also had oiling restrictors in the motor. Bad deal for the street.

So long story short.... the Comp 288 AR cam is good. Use the 244* version at least. The Xtreme line I think takes it to the next level, but once again, the lobes aren't as gentle.

The only concern I have I guess, is I would think a "real" roller an a steel blank might last longer than the Austempered version. They did that to eliminate the dist, gear issue, but now you can easily get the pressed on gear cores.

With your compression I would look at the Crane also.

And I also agree.... Ultradyne is on the cutting edge on cam tachnology. Lots of real world work goes into their stuff.

I used Engle to grind the one in my 540. He was the most willing to talk about the combo I wanted. Mark Engle was very honest and straightforward about what he felt worked and what didn't.

Jim

 

No girdle here, and am using comp cams spring for the cam. This not a billet cam, and is ground out of the same stock as the flat tappet cams.
If you use higher spring pressure than recommended, you will snap the cam in half

 

Chuck - it's not that far from my roller cam. If I were you I would be a rocket man and think up my own. I just don't know how your bigger bore and compression reacts.

Earson cams is just down the road from me and they do custom grinds for $225 out the door. They use Crane cam blanks. It's where i'm having my next one done.

You have a low usage car. So I would go way into the 600 lift area. My springs are within a few pounds after 9000+ miles with .635/.644 So instead of a cam change i thought about using larger ratio rockers to hop it up. I have a stud girdle because i have so much deflection of the 7/16th ARP studs with my springs.

 

Mountainmotor,

Thanks for another detailed reply. I did polish the combustion chambers and piston tops before assembly. The heads cc'd at about 121, plus or minus within 2 cc's on all chambers. I wanted to make sure no sharp edges, minor flashing could become a flash point and that carbon would have a harder time sticking to the surfaces.

I was also told that using the factory cam would cause severe detonation on straight 92 octane, but it doesn't. It makes sense that filling the chamber with even more air should increase the static compression; but, is that true throughout the rpm range? I would think that the L88 cam is probably filling the cylinder just about as well in the 5000+ range. I'm not really looking for more power as much as broader power. The car idles ok at 1000, but seems happiest at 1200 where my vacuum is about 6". Above 2500 the car really begins to respond and sticks you to the seat hard above 3000. Previous posts stating idle vacuum in the 14 range seem very appealing!

The factory did have a .600/.600 lift cam spec's for my engine if used for CanAm racing, but I don't know for sure if .630 will work. I would have to get out my dial indicator and measure valve drop throughout the engine's rotation.

I am not desperate to change the cam at this point, but I know I can take advantage of better technology.

Thanks again all,

Chuck