StraubTech

Pump gas 10 to 1 build. Street Cruiser

.548/.530
237/243
108 Sep

3000 rpm 511#/ft
5000 rpm 503#/ft
3800-4000 rpm Peak torque 547#/ft

5800 rpm Peak HP 519.6

35 degrees
11" vacuum

keithinspace

Curious of if you have any video of that monster. I'd be curious what the ~240 duration sounds like at idle.

That's pretty impressive vacuum as well. I assume that is what you were trying to control with the less aggressive overlap?

To achieve that and still get 500+ numbers is pretty wicked. No replacement for displacement, I guess.

cv67

Nice Chris
These the old school AFR 190s? Did they have the CNC jobber or as cast?
They are one big heavy hunk of aluminum!

c3_dk

Nice engine, build cost?

bluedawg

Nice!

DO MA NEU!

StraubTech

Engine builder is my customer. I only supplied cam and lifter on this build. I don't have any idea.

The Money Pit

I run an Isky Z-35 flat tappet solid, (254@.050 .544 and 108LC 108ICL) ,and wonder just how it would compare to this. Never been dynoed, so all I can do is guesstimate. My idle vacuum is about 8 inches in gear, and it'll pull hard to 7000 rpms.

I am considering a roller in the future, once a few other projects are completed, and I think when I recam, I will end up down sizing a bit, for better "street manners". My concern is down sizing "too much", and leaving a ton of power on the table.

Is there any guideline for comparing a flat solid to a roller?

cv67

Had a few SFT in that size range having gone from those to a solid with similar size the difference was dramatic imo probably have better vacuum too. Downzing guessing the right guy grinds the cam you should have your cake and eat it too.

StraubTech

I down sized a 540 CID engine a few months ago. Took out 20 degree of duration on the intake and 30 degrees on the exhaust. Went from Soild roller to Hyd roller. Lift went down .100" also. Engine picked up at peak 16HP but picked up a 108#/ft of torque....sometimes downsizing can really be UPSIZING!!!

garygnu

any advantages of a hydraulic roller cam over a solid roller cam ? besides lashing valves ,which I miss doing .

cv67

Longevity/cost is less with the HR
buying a cheap solid roller lifter isnt the best plan

OMF

I have a Comp XR276HR 224/230 @.050 .535/.544 with 1.6 rockers in my 406, and seem to have alot of valvetrain noise. They are adjusted correctly and the rocker geometry/ pushrod length is all checked and correct. The only thing I've done to tame the noise is 20/50 oil.
I do understand that there are lots of complaints about the noise in this series of cams.

I'm curious about the valvtrain on this engine....is it noisy like an industrial sewing machine?

keithl1967

I have the XR282HR in my 406 (in my Camaro)--I am running the Comp aluminum roller rockers (1.5:1), and do not have any noticeable valvetrain noise at all... I do run 20/50, as recommended by my machine shop (I built the motor under their tutelage)

I am just starting the planning states of a 355 build for the 'vette...
Looking at the XR252HR (much milder build) and possibly just stamped, roller tips rockers (to stay under stock valve covers)...

c3_dk

That is amazing, great info here.......

StraubTech

On the street I feel the hyd roller is the best choice for anyone. Increased engine life with less maintenance.

Some guys like Friday night fender lean over valve adjustment. Nothing wrong with that. It is part of the roots of hotrodding.

StraubTech

A lot of it is lobe profile. How aggressive the lobe rate is.

bluedawg

How do you tell how agressive a lobe is?
Is there a formula?
DO MA NEU!

keithinspace

Regarding solid lifters: At the rate most of us drive our cars (2000 miles a year max?) you're talking about 30+ years to accumulate any type of significant mileage. I hear you on longevity and durability of hydraulic, but there WILL be other modes of failure and needs for rebuild either way before solid lifters become a problem.

Additionally, there are many 'tight lash' solutions out there that greatly decrease the amount of lash. This, in turn, decreases the degree to which things get "beat up" during regular driving. I'm running a Comp XR286 R-10 cam which is a 0.576/0.582 lift and 248/254 duration @ 0.050 on 110 degree. The adjustment is 0.016 and 0.018 on the lash. You can't hear ANY valvetrain noise on this engine.

I agree on the quality of the roller lifters. That is somewhere we did not skimp on my build.

Additionally, we're running the Comp rev kit. Folks have said that it is unnecessary for my build, but with the failure mode of these things almost always being the roller tips of the solid lifters, I didn't see any reason to NOT install it.

You can also get really nutty with the lobe profile on solids.

With the larger ARP rocker studs, the massive needle-bearing stainless steel roller tip rockers, and the poly-lock adjusters, I checked my valve adjustments 500 miles after the original build and they were 100% perfect.

I MAY add a stud girdle just for giggles...make me feel a little better about maintaining the valvetrain geometry in all conditions.

In the end, diving into the engine once in the spring and once in the fall to adjust valves is a lot of fun. A nice "3 beer project" that is best done with an interested friend.

The "roots of hotrodding" comment was very well taken. If someone thinks adjusting valves is a pain in the butt and should be avoided at all costs, then they don't 'get it' and are more suited to a hydraulic cam. Fine for some. Not for all. Of course, my engine builder mentioned that he WILL NOT build a solid engine for some folks because he knows they'll find a way to screw it up. It was a real compliment when he agreed to build me a solid lifter engine...

MotorHead

I have the same cam slightly modified for an extra $40 I played with the dur. lift and small base circle and the cam is billet steel. I don't know if Comp Cams is offering these changes so cheap anymore though.

The lobes on the cam are incredibly steep and I have no idea how the lifter follows them without jumping off the top. I have T & D shaft rockers and haven't had to make any adjustment in 2 years or more now. I will be honest and say there is some noise

keithinspace

As this cam that we have is extremely aggressive for the street and not as well suited to auto cars, my builder seldom gets to 'play' with them. That played into my builder's surprise when we unpackaged the cam and found that it was cast, not billet. He called Comp and they assured him it wasn't a problem. Cost savings. It saved us having to change the dizzy gear, of course. And we certainly haven't had any issues yet. VERY stable valvetrain geometry.

Regarding the steepness of the lobes, I totally agree. The benefit of a solid roller system. While the 160# valve spring seat pressure we're running certainly helps with ramp jump, the addition of the rev kit was a contribution that I made to the build.

The "compromises" we made for durability of the cam and the valvetrain system were to keep the valve spring pressures down, add the rev kit, and back off our "ultimate redline" of 7k RPM to 6.5k RPM. With all that taken into consideration, I'm pretty comfortable that the rollers should stay in contact with the cam.

Of course, I've gotten pretty accustomed to my 5,600 RPM rev limiter setting. I've only hit it once. The car is still pulling VERY hard when I shift at 5,500 RPM, but it really does feel like "enough". I'm not trying to set any records and just enjoy driving my car. Grenading my engine is NOT where I want to be. So unless the mood strikes me to move the limiter up to 6,000 RPM, I believe I'll continue "short shifting" at 5,500 RPM and have myself a VERY fast AND DURABLE time with my engine. Sounds great and feels great. Don't need any more...