curiousity...roller cam question

[GS Kubisch]

Wondering what everyone is using for springs......
Also,what are you guys doing for rocker arms to clear said springs?


"Winter Boredom" brings this up,so bear w/me.......

[Jim Weise]

TA 1190 vasco jet.. cryo frozen/bead blasted

and a die grinder...:ball:

[GS Kubisch]

what diameter are we talking?
I've seen breakage after the die grinder work.....scared me into what I use.I'll have to take some pictures one of these days.

[Jim Weise]

They are 1.500 in dia..

Strength is no issue, the set I am working with ran on a .650 roller for a number of years, with no problems. There is plenty of meat left on the rocker. Of course, just like everything else in the world, I am sure someone out there has broken on at one time or another, but it's not a horendous issue. I don't know of anyone who has.

It would be nicer if the rockers fit the big springs, but oh well..

It does not turn out to bad, if you do it carefully, and artistically.

JW

[12lives]

Jim - what kind of improvement can one expect out of going to a roller? Also, Is it worth while on a street car?

- Bill

[Jim Weise]

How much is just the roller worth over a solid cam?

That's an interesting question, and one I wish I could answer. But since I have not had the occasion to dyno a motor with a solid, and then go to the exact same spec cam that's a roller, I cannot answer the question, based on personal experience. Speculation I have heard from others pegs it between 20 and 40 HP, but that could be an educated guess on their part, as much as anything.

Generally, a roller cam of shorter duration is used, than a solid would be, for the same application. This is due to the difference in design. For instance:

The cam in Mike Garrisions motor is only a low 250* duration cam. That's a 528 ci motor, so if you went to a solid, then almost certainly you would want a cam in the 270* duration range, to feed that motor. Most big HP buildups I have seen with solid cams recently are using a cam of this size.

The TA 308, which is a widely used race solid, is 268/274 duration, and is considered a healthy solid, but not a monster.. I have seen much bigger cams out there, and TA has several bigger ones on the shelf. The 267/276* roller cam in the 494 I have on the stand right now, is in fact considered a "big" roller cam. IT's actually my customer's old STG 1 Roller cam, and although not optimum for his new STG 2 TE heads, the concensus amoung Mike, Scotty, and I was that it should work ok, and there was no need to buy another expensive roller cam. We figured we would try it, and see what happens. It has way more exhaust than it needs, but we don't feel that will hurt the combination and application. If we feel the motor is lacking due to the cam, we may try a different grind, but then again, his car is still rather heavy for the application, and big dyno numbers don't always mean fast et's either, unless you have the right combo for it. Typically the real big rollers need a tunnel ram intake, and to be spun harder than I care to take the stock block/oiling system. I don't want to see any failed number 3 rod bearings.

I know that some of the GSE guys have went back to solid cams, due to lifter bore failure issues, and frustration with destroying their expensive motors. They should be able to chime in and talk about if they went with the same spec cam, or a bigger solid and if their combination improved or slowed down. I have seen very good power numbers from some solid cam motors lately.

As far as the street application, it's cost prohibitive, due to the cost of the parts, and the work required to make the motor live. In a hot street/ dual purpose motor, your better off with a solid cam.

If money was no object, then sure, put a small roller cam in.

[Staged70Lark]

Bill,

I looked into this subject a few years back when I removed my roller cam and went back to a solid grind for durability reasons.

Example:

Roller Cam (Custom Grind)with .670 lift, 268 int duration at .050, 192 intake duration @ .200 lift

Solid Cam (T/A 508S) with .620 lift 272 int duration @ .050 and 186 intake duration @ .200 lift

I talked with many cam grinders and the concensus is that 6 to 8 degrees of duration at .200 lift will net you anywhere from 10 to 16 hp.

My car ran low 9.50s with the roller and mid to low 9.50s without the roller. So.. I would say the above statement is a good guess.

Now what would be really nice!!!!! Is if the new blocks (T/As or Bureks) would be made to use the BB Chrysler lifter diameter. The larger lifter diameter would allow us to grind some solid lifter cams that would compare to our present day rollers.

Take Care

[GS Kubisch]

Jim
Have you ever seen the JESEL or T&D individual pairs?

I have the T&D and they are basically a SB Chevy rocker,I can use up 1.625 springs if I need.
Always wondered why Mike never offered these as they are the correct thing to do when committing to a roller.
I had to deal directly w/ T&D and I know there are a few people using these and know of another Buick w/ the JESEL set up.

What has Mike T used on his personal motors?
I know he's probably tried some aggressive rollers...

[12lives]

Reason I asked was a recent article in Hemmings Rods & Performance. They did a before and after dyno pull (engine in car type) with a "straight" swap from a hydraulic to a roller hyrdraulic and no other mods. This is in a 400 chevy. The gain was 44 HP and 51 FT-LBs. Impressive! Its seems to me its hard to compare grinds between roller and flat cams with the profiles so different!

- Bill

[Jim Weise]

GS Kubisch said:Jim
Have you ever seen the JESEL or T&D individual pairs?

I have the T&D and they are basically a SB Chevy rocker,I can use up 1.625 springs if I need.
Always wondered why Mike never offered these as they are the correct thing to do when committing to a roller.
I had to deal directly w/ T&D and I know there are a few people using these and know of another Buick w/ the JESEL set up.

What has Mike T used on his personal motors?
I know he's probably tried some aggressive rollers...


Seen them yes.. worked with them no.

The motor in the shop now already had the mods done to the TA rockers, so no R&D by me was required. But when we build the next one, I will be quite interested in working with them.

Not sure what Mike has on the wagon..

I am pretty sure Scotty used the standard stg 4 rockers on his STG 4 motor, and he prolly is the guy who has run the biggest rollers..

JW

[Bobtempest]

I drive my 455 on the street with .640 lift roller cam, plus a 50 passes at the track each year. How often should I change valve springs? Best brand of springs?

[Jeff Hart]

I pulled my roller out and put the solid back in for durability reasons as I was having too many engine problems, although really none were due to the roller. I took it out as I felt a problem was "just around the corner" Oil pressure was around 55psi from the back of the block at 7000 RPM's, with a basic stock oiling system. (This is a full GSE trim car) Best time ever with the roller 10.53@129.85 MPH, with consistant 10.60's. (I was using the TA 1.65 rockers with some grinding to get them to clear the springs) When the solid went in, I had to turn down the oil pressure regulator as it would go well over 100psi going through the traps at 7000 RPM's. The car went consistant 10.40's last year with a best of 10.25@128.95 MPH. I did make a gear change at the same time going from 4.10 to 3.89, but that was the only change.

Duration and lift numbers were real close to the same from the roller to the solid.

[killrbuick66455]

HI Guys, I just bought a roller cam set up for my 455,Now i see that some people are going back to solids for better insurance of not breaking the lifter bores ?? so did i just waist 700.00 ??? :ball:

[Jeff Hart]

Eric, I was only concerned about having a problem, I never really did. My roller wasn't real aggressive which helped my basically stock block. There still many running the roller's you just have to make sure your engine builder know's what there doing. There is a lifter bore girdle on the market also, which theoretically should help. There has been talk on problems running rocker arms with greater then a 1.65 ratio throwing off the valve train geometry. I am sure there will be more on this subject from those who know a lot more then I do, that can help you out.

I had over 100 passes on the motor running deep in the 10's in my GSE car without any problems at all.

[Staged70Lark]

Eric,

I pulled the roller out of my engine also for durability reasons. I put well over 100 1/4 mile passes a year on my car. The one year it was very close to 200.

As I explained to you when you bought the cam. It will make more power than a solid cam. Plus you dont put anywhere near the amount of wear on your car to worry about the draw backs.

If you have any additional questions just drop me an email.

Good Luck

[killrbuick66455]

Hello Guys, Thanks for the replys.. IM alot better about the hole roller cam thing now.. I have a great engine builder!! looks like a cam girdle is in the near future for me..........

:TU:

[tommieboy]

http://www.taperformance.com/lifter.htm

http://www.taperformance.com/_derived/lifter.htm_txt_lifter_bore_girdle_2.gif

[GSXMEN]

Bobtempest said:I drive my 455 on the street with .640 lift roller cam, plus a 50 passes at the track each year. How often should I change valve springs? Best brand of springs?

Most all of my experience is with flat tappet springs, but...best brand of springs I ever tested was Isky. They really seem to hold their pressure!! Same could be said for their roller lifters!!

Ever consider adding spring oilers inside the valve covers? I've seen some of the Fastest Street Car type engines that actually run on the street, with oilers to keep the springs cooler.

[Jim Weise]

12lives said:Jim - what kind of improvement can one expect out of going to a roller? Also, Is it worth while on a street car?

- Bill

Here is your answer.. at least in the motor we had on the dyno today.

494
TE heads
1250 dommie
13-1 compression

TA 308S -- (as measured) 270/275 duration at .050 -- 617/602 lift

Duration at .200 lift -- 214/220

Without out eeking every last HP out of it (we were tight on time, and were just looking for a comparision number) it easily put out 710 HP and 660 torque

Comp cams roller


260/267 degrees of duration at .050 .669/696 lift at valve

213/220 duration at .200 lifter rise.. nearly identical to the 308

changing nothing but the cam, lifters, and valvesprings, motor put out 732 HP, and 677 TQ.

Average increase of almost exactly 20 ft/bs and 20 HP, from the roller design. From 4600-6200. Roller cam peaked 200 rpm earlier.

Not as much as one might think.

Motor went on to make 745 HP, would have made an easy 750, but with all the work going on, it could not pull more than 9" of vacuum.. in the crankcase, due to the fact it kept sucking in the sealer at the corner of the intake end seals.


But even at only 9" the pump was worth and easy 15 HP. And the motor did not leak a drop of oil. Gotta love those vac pumps.

New system worked very well, considering all the work that was going on with that motor on the dyno.

JW

[12lives]

700+HP and 650+ FT-LBS!!!!

Can't wait to hear what the ET is!

:eek2:

- Bill

[stagetwo65]

With my big roller I've been using K-Motion springs with a 1.55 diameter for several years. I've never had to replace any of them. I did have one or two rockers break due to the amount of grinding that had to be done. I also did have one rocker shaft break, probably due to a combination of spring pressure and fatigue (it was 5 years old). I DID try to get Mike T/A to warranty the shaft but he asked me how many motors did I blow up with that shaft on them. I said "five or six, what's your point?" :laugh: He said "Go Scratch" . BTW Jim W, Scotty used Jesel individual pairs on his Stg-4 motor (the one that ran 7.68). Later, Doug.

[Buicks4Speed]

I know this is a little late but you have to watch out for the cam digging into the front of the block. Just like running a bronze distributor gear. I thought i did something wrong but other people have had the same problem. I caught mine earily and cleaned it up and did a "fix "for it but its something you'll never see untill its too late.
Rollers I would consider the last resort for that last bit of power. Very $$$$. i would also recommend playing with flat tappets until you find the perfect grind then swap to a roller if you still feel the need. But thats how I'd do it if I started over again. Unless, of coarse you have money just falling out of your pockets.

My expense putting a roller in my race car is almost $3000.00
:jd: I think you could spend that money somewhere else and make up the 20-40 HP. Not to mention the headache involve.

[buick535]

[

Now what would be really nice!!!!! Is if the new blocks (T/As or Bureks) would be made to use the BB Chrysler lifter diameter. The larger lifter diameter would allow us to grind some solid lifter cams that would compare to our present day rollers.

Take Care [/QUOTE]



John, Actually, that is an option on our block, larger diameter lifters, oh , the cam profiles that we could run. Jim Burek
p.a.e. enterprises

[miniv8]

mushroom style lifters, you guys should check that out .
used in early rover v8 engines in formula 5000

[Keith Diabo]

Know of an 800+ HP engine that had a solid roller cam break the roller rockers(new).Not too long ago.Grinding for clearnace could weaken them.
Also saw a non roller hyd cam engine running T/A 1125 Springs
over a period of time that had a push rod go right through the
rocker and break, the rest of the roller rocker openings that slide on the shaft were starting to go oval !!!the one failed from going oval and finally cracke and broke on the bottom This with no grinding and only an 1125 spring.This motor also had at least 10 years of use.Did replace the rockers on this motor and running OK again lucky nothing else broke !!! Springs checked out fine with correct heights & open and closed seat pressures and checked for no coil bind.Roller Rockers DO wear out and weaken over time and should be inspected and replaced as needed.

[miniv8]

http://www.sierranevada.edu/people/chris/5-48.html

The MUSHROOM lifter is a derivative design of the mechanical lifter. This is a design which takes advantage of the wider contact face to facilitate a broader and steeper cam lobe, thus allowing a higher rate of valve lift (velocity).