What is the Max HP on a sealed GM 604

[robert1]

I've built many Briggs motors intentionaly lofting the valves. I've never seen any one intentionaly loft overhead valves. You would have to have the valvetrain designed around this to do it correctly. You can't change the cam enough to do this in this application and you sure as hell wouldn't do it by lessening the valve spring pressure. When these things lose 20 lbs of seat pressure they start dropping rpms. When you loft (float) this valve where is the intake centerline. Is it where it started or did you just retard the cam 10°? Everyone of these I know of start breaking parts i.e. spring locators when they get into valve float which is just above 6800. I guess you can buy a set of those moleculely alltered springs that are treated at the polar ice cap that will allow both valve float and 7800 rpms.

[autodoctor911]

don't the physics involved in spring oscillation only allow doing this at a particular rpm, where the frequency of the spring matches the frequency of the valve event?

oops, I was thinking of a spring that can return to an equilibrium state. the valve spring is always loaded. the valve never can get int o oscillation, so the force of inertia from the valvetrain would need to exceed the spring rate, and the frquency is not that important. but how do you do it so the valve doesn't close rapidly and destroy the seat, without making the duration longer?

[jed]

I dont think lofting the valves is anything new. Seems like I rember back in the 70 it was quite common.

Back then they called it controled valve float.

Mark (raceman14) is a very creative thinker. He not only looks at new technology and how he can use it but looks back
at what was being done and applies it where he can. Usually he can make it work even better.

I also build SPEC engines for several different venues, and as he mentioned about honing there is HP in just the way you finish the cylinder walls.
SPEC engines are especially sensitive to friction and any reduction there is a ++.

I have spent hours and days honing cylinders using different ring (oil rings especially) Just trying to get 3/4 to 1 Hp on 115 hp engine.

My SPEC engines run perty good and can win with a good driver but having talked to Mark he makes me look like a novice.
When i hang up the phone my head is spinning. Kind of like sending a highschool sciense teacher to area 51. I will blow your mind.

Pay attention to what he says, fuel curves, timming curves, acceleration rates, honing and ring packages and on and on.
YOU WILL RUN FASTER

[stockcar5]

mark is nothing more than a snake oil salesman whos antics have cost racers money. the folks on this board im sure are smart enough not to buy into his b.s

[autodoctor911]

I've built many Briggs motors intentionaly lofting the valves. I've never seen any one intentionaly loft overhead valves. You would have to have the valvetrain designed around this to do it correctly. You can't change the cam enough to do this in this application and you sure as hell wouldn't do it by lessening the valve spring pressure. When these things lose 20 lbs of seat pressure they start dropping rpms. When you loft (float) this valve where is the intake centerline. Is it where it started or did you just retard the cam 10°? Everyone of these I know of start breaking parts i.e. spring locators when they get into valve float which is just above 6800. I guess you can buy a set of those moleculely alltered springs that are treated at the polar ice cap that will allow both valve float and 7800 rpms.

I am still not sure yet if racer14 is on to some really good stuff, or selling a bunch of B.S. I am skeptical, but still intreagued. Is the valve loft on the 604 with a stock cam profile, or one that has been worked, but still meets lift measurement rule? Also, is it doable for endurance application, or multiple races on one build, or do all the valvetrain parts need to be replaced after one sprint race?

the setbacks you mentioned robert could be overcome: the cam timing could be modified, as well as the valve adjustment(no preload or minute lash) I want to know what rpms it starts at, and what kind of hp gains at what rpms can be achieved, and with what durability. I am interested in the application of this to a restricted lift, rpm and valve size application.

[CamKing]

the cam timing could be modified,.

That would be illegal. You can't move the cam timing from the stock location.
If you loft a hydraulic roller, the piston pumps up completely, and even if you zero lashed it, it wouldn't close the valve until it got all the way off the closing ramp.
Without being able to advane the cam, the opening would stay the same, and you would just increase the duration past BDC. So if the cam was on a 108 ICL, and you lofted the valve 20 degrees, you just moved the effective ICL to 118.

[jed]

Mike could you provide a cam and lifter and spring kit that would pass inspection. OH and run faster.

[autodoctor911]

That would be illegal. You can't move the cam timing from the stock location.
If you loft a hydraulic roller, the piston pumps up completely, and even if you zero lashed it, it wouldn't close the valve until it got all the way off the closing ramp.
Without being able to advane the cam, the opening would stay the same, and you would just increase the duration past BDC. So if the cam was on a 108 ICL, and you lofted the valve 20 degrees, you just moved the effective ICL to 118.

I am just exploring the possibility of the concept for other applications at this point. I just want to know if the concept has a useful advantage. the advantages desired are more than just bypassing a rule that limits lift and duration. I am sure those who have worked on it seriously have seen some benefits, one of which would be the change in duration and lift with rpm, similiar in effect to variable valve timing and lift. I would like to see any modification that can broaden the torque curve for a racing engine, making them more competitive, as well as easier to drive. I don't know if valve loft can work in a 604 and meet rules, butit seems it can at least work in a side valve 1 cylinder. so there must be something worth consideration.

mike: if youe were able to design a cam profile, that was only limited by lift(.550") for a class that allowed any lifter type, and were limited to 2.05/1.6 valves and restricted to 7000rpm, what kind of cam would you recommend. is a solid roller better, or one of those special high rpm hydraulic roller set ups?

[CamKing]

mike: if youe were able to design a cam profile, that was only limited by lift(.550") for a class that allowed any lifter type, and were limited to 2.05/1.6 valves and restricted to 7000rpm, what kind of cam would you recommend. is a solid roller better, or one of those special high rpm hydraulic roller set ups?

Sollid Roller.

[CamKing]

Mike could you provide a cam and lifter and spring kit that would pass inspection. OH and run faster.

Yes.

[autodoctor911]

I figured you would say that. a solid roller is going to make the most peak HP for sure. But, I was wondering if area under the curve from 3000-6500 could be had by using a rhoads bleed down setup? I am thinking it wouldn't add as much as rhoads says it does, unless you have a cam that is designed to peak too high for the application, but what if you do use more duration with the rhoads lifter. and since valve lift is measured at the valve with "zero lash", maybe could get away with an extra .035" of lift.

[CamKing]

I figured you would say that. a solid roller is going to make the most peak HP for sure. But, I was wondering if area under the curve from 3000-6500 could be had by using a rhoads bleed down setup? I am thinking it wouldn't add as much as rhoads says it does, unless you have a cam that is designed to peak too high for the application, but what if you do use more duration with the rhoads lifter. and since valve lift is measured at the valve with "zero lash", maybe could get away with an extra .035" of lift.

First off, most techs will pull out the hydraulic lifter, and put a sold in to check lift.
Second, the area under the curve you could get with an aggresive limited lift solid roller, would be much more then what you could get with a Rhoades style hydraulic.

[autodoctor911]

good to know. what kind of duration do you suggest, and what are the best lifters to use? I was thinking about using some .750 roller bigger bore lifters in a sbf. I still have no idea what the best heads would be yet, but was contemplating a canted valve like the yates racing design, but with a port job that would minimize the cross section to keep the low end torque. are there heads that will outperform these for this application? I am sorry, whoever started this post, to get off subject. If you would mike, PM me with an answer, or If you could respond on my topic: best engine for these rules?

[raceman14]

Still no answer on the Camshaft question??? How do you re-grind a stock GM 604 cam, gain 15hp and keep it legal ???

I like the comments on controlled valve float.

Lots of folks getting way off track, hydraulic lifters when pumped up act as solids, when they are taken apart they are 100% stock, because they are. The camshaft profile is not changed because National race winning cams are Adcole'd and that catches anything. Lobe lift and duration measured every degree. I have checked 100+ stock cams with a friend and we have not seen more than 1/2* one lobe separation and 1* on durations. Lift is near perfect every time as is Base Circle.

How can a cam be re-ground and still check with baseline within those parameters???

I can only address the things that I have done with the system I run.

The lifters that are run are the ones that come stock in the sealed engines, nothing is done to them. To insure that the retainers and locks don't crap out I run the stock ones thru a similar metallurgy process to ensure they will live. I have sold 600+ sets to NHRA, SCCA, UMP, Ne-Smith, Fastrak & ASA racers and engine builders. I have not discussed this system in full, until just recently as I had a 2 year non-disclosure with a OEM Distributor that was selling 40-50 sets per month.

Like I said earlier, if you have access to a dyno with an air bell CFM of air pulled with loft show significant gains in A-B-A testing. This has been done by multiple engine builders at their shops with my customers.

I understand the concern with lifter and cam damage but I have had 30+ of my own engines back in for re-fresh and the cams were in excellent condition and re-used in about 1/2 of the engines. I replace lifters every re-fresh because I don't want to chance a failure but the lifters look great.

As with many discoveries sometimes you just stumble across them while looking for something else. I was testing some GM lifters on the spin-tron, had about 10 flats of 144 in each box. An alarm would go off any time one of the 16 sensors detected harmonics. As I was separating out what I thought to be junk lifters I ended up with a set of 16, so I decided to put all 16 in the spinner engine and see what happened. I found 2 distinct harmonics a first order and 3rd order. Having built speakers and electronic in high school and college, I fell back on some old Helmholz Resonator formula's and started ciphering on a way to get those harmonics out of the system.

The only way to get them out of the system was to use heavier springs...OK not legal for dirt but ASA can use conicals so I went with that. Step two after confirming that was to go to the dyno and test it. Low and behold the conicals ran up to 7200 rpm before valve float and they made pretty decent power up there but the valve floating junk lifters made almost 20 more HP from 5000-6500.
Since ASA ran a 6600 chip I figured I was still in good shape...not really cause only about 3-4 ASA guys ran my stuff over the conicals.

I decided to concentrate on the dirt deal and a good friend of mine Kenny Harriss had a couple dirt cars. He was the guy that brought his cars in for the short TV show that ran out of my shop so it was easy to convince him to test this stuff for me. During that test year he ran thru 3 sets of springs which were re-treated every 5 races. His driver Royce Bray won the Fastrak National Championship, as well as my other test customer Bobby Dauderman won the UMP National Championship, we also had a couple Canadian Championships in 602 and 604 with the same products.

Rather than being accused of selling snake oil, I'll just say the folks that run my stuff are happy, they all pay a premium price for the parts and service and I have been keeping busy building, prepping and selling the stuff as fast as I can for the last 6 years.

[CamKing]