[ss3966]

I'm racing in Pinks All-Out at Denver August 8/9, and just broke a GM blue Performance Parts roller rocker tip off when I increased the boost from 7 to 9 lbs. I had planned to add alot more boost for what my guess is at what's necessary to get into the show. The combination is a 496/turbo 400/3.90 with a Vortech V-7 YSI in a '70 chevelle.

The GM roller rockers have 3 seasons of bracket racing on them, and I just lost confidence in the other 15 rockers. I went to an Edelbrock 60559 aluminum head over the winter, and understand that aluminum heads can allow a rocker stud to flex. So now I'm considering going to Crane gold rockers, with the Crane stud girdle. I see the combined price will approach a set of Jesel Sportsman shaft rockers, but the Jesel's require special tools to set up, and the push rod lengths must be perfect. There are also the more expensive T&D shaft set-ups, and I understand Crane has a new one also. I don't really know that Cranes roller rockers are any better than the GM Perf Parts, but they wouldn't have three seasons racing on them, and I suspect GM doesn't makes the rockers themselves.

The cam is a non-sexy flat hydraulic blower cam by Comp with 232/240, .547/.547, 114 LSA, with 6,500 shift points, but gets alot of use in the local bracket series and is street driven to the track; I would hate to make it into the final 16 at Pinks only to have another failed rocker/valve issue.

Any suggestions on how I can step up the valve-train's reliability to for my crack at the Rich Christensen arm-drop?

Separately, I've recovered the broken roll-tip shaft from beneath the valve cover, but not the roller itself. The shaft was at the back of the head, close to falling down the oil return hole. There is an intake manifold oil shield I hope the roller is laying on top of. I plan to remove the intake to inspect the lifter in question, and hope to Hades to find the roller too. It may have made it to the Moroso baffled oil pan. I tapped on the empty pan to get it to bounce, but heard nothing. This matter could also affect reliability in a big, big way.

I've still got some TNT's left before Pinks and seek suggestions on the trade-off between valve train reliability/maintenance/ and costs. I've avoided roller cams due to the street miles driven and required rebuilds. This combination probably doesn't rev high enough to justify shaft rockers, but since I have to drive it home from the track I don't like surprises and missed money rounds. I've also read you get good at taking the stud girdles on and off after awhile.

Any suggestions?

1970 Chevelle with:
8.5:1 JE 2618 flat tops
Eagle 4.25 Steel Crank, rods
ATI 7" balancer, single keyway
Edelbrock Victor Jr.
Edlelbrock 60559 Rectangular Aluminum
AR3934 Autolite - 1 step colder
Comp Cams 11-404-4
GM Perf. Parts Roller Rockers
Holley 700 DP
1 inch carb spacer
Vortech V-7 YSI, 2.95 pulley @ 9 lbs
Superior Airflow carb bonnet
Glasstek 4" cowl hood
Aeromotive 17242 fuel system (A-1000)
MSD 6AL BTM, 8361 Dist
Snow Performance Boost Cooler
TCI Ultimate Street Fighter 10" w/3500 stall
3.90 12 bolt
Strange C-clip elims
Gear Vendors (street use only)
12.50/28/16 ET Street
Shift Point 6-6,500 RPM
Race Weight: Portly 3960 lbs
ET: 11.4 @122 w/ 9 lbs boost
Density Altitude: 9,000-10,000 routinely
Footbraking at 2,000-looking at 2 step

 

[Harold Sutton]

Even if you use Crane Roller Rockers, get BLP stud girdles. They have the best design on the market.

 

[ss3966]

The BLP stud girdles look like a solid design that goes beyond the Crane girdle system. I'm currently looking at the Jesel Sportsman shaft rockers as they are supposed to be make valve adjustments a thing of the past. The special tools are also supposed to be low in cost, even for a one-time use. At $300 more than new Crane gold rockers and a girdle I think I'll place some calls to the tech/sales lines as the shaft rockers could provide relatively cheap insurance.

I would still appreciate additional feedback as well. This is the first time I've posted the entire combination and there may be other things I could also improve on.

I have no idea what ET class will be selected for Pinks All Out/Denver, but I'm pretty sure I still have to get into the 10's - not so easy at 9-10K density altitudes with a race weight near 4000 lbs. I had hoped to add 5 more pounds boost to take me from 11.4 to 10.9 ET's - before the valve train became a large question mark.

 

[rustbucket79]

What special tools? I've installed a few sets of the sportsman BBC rocker arms and other than a stand height snafu on a set of Edelbrock Victor heads with lash caps they've been a drop on installation. (OK that isn't fair, on those same victor heads I had a fair amount of clearancing on the head casting to give room for the link plates)

You can almost guarantee you'll be buying different length pushrods. You will jump for joy when the roller placement is perfect throughout the lift curve, and the lash never changes more than a thousanth. Adjusting valves is a 10 to 15 minute process, most valves won't need adjusting.

Your valve covers may not fit. (rocker is bulky on the intake side)

Your current rocker failure could be due to poor quality/defect, or it could be telling you about a problem developing.

Which rocker failed, int or ex? What are your spring pressures? what Peak RPM?

 

[trmnatr]

The Crane Pro Series is a nice shaft mount but for your application i would look at the Crane Sportsman series depending on open spring pressure @ cam lift/valve lift {max}

 

[stock48]

I would run the Crower enduro stainless rockers, or ISKY's with a good girdle and you should be fine. If you break either of those with a .550'' flat tappet HYD, and less than 15psi of boost there is something else wrong. You might have gone into valve float when you increased the boost. What is your spring psi?

 

[Bob West]

Crane Golds, no girdle

 

[godsend]

Jesel sportmans... Withe the extra stuff for girdles, longer bolts, rockers, girdles, tall valve covers and so on. I doubt it differs alot after that. And youll get a better rockers systerm.

 

[ss3966]

Maybe I am getting into valve float when I added boost, as suggested. The Edelbrock 60559 Performer Rect. heads come with 125 lbs at 1.975 height, and 310 lbs. at 1.475. The lift is .547 on both valves. The rocker that broke is was on #3 cylinder, intake side, and my shift point was 6,000 rpm.

Jesel lists a shaft rocker kit specifically for the Performer head, so I hope there wouldn't be clearancing for the link plates - grinding on installed heads doesn't sound so good. My valve covers are GM tall black powder coated ($379) and I did have to clearance them for the corners of the GM rockers. I would be like to be able to use these valve covers again. New push rods are sounding like an eventuality too. Could also go with 1.8 rocker ratios to pick up some lift over the .547 lift I now have.

Sounds like I may have bigger issues that adding a shaft rocker system may not solve. I've considered going to a solid flat blower cam by Comp (11-405-5) with 255/266, .612/.605, 114LSA. Would this reduce my valve float issue, if that sounds like the culprit here?

I would sure like to participate in Pinks All Out without valvetrain issues.

 

[Sandy]

I had a Comp pro magnum rocker break a year ago. Looked like a casting flaw.

Just replaced it with a new one and no problems since.

I don't know if it is offshore parts quality or just one of those things, but unless you have a lot of other people with the same problem I would not worry about it.

 

[BillsCamino]

Never had any issues with the comp Pro Magnums...big, street driven, solid roller.
Recently replaced them with a Jesel Comp Series shaft system...and a bigger street driven solid roller.

I believe the GM Perf rockers are actually mfg by Crane.

 

[rustbucket79]

Maybe I am getting into valve float when I added boost, as suggested. The Edelbrock 60559 Performer Rect. heads come with 125 lbs at 1.975 height, and 310 lbs. at 1.475. The lift is .547 on both valves. The rocker that broke is was on #3 cylinder, intake side.

Jesel lists a shaft rocker kit specifically for the Performer head, so I hope there wouldn't be clearancing for the link plates - grinding on installed heads doesn't sound so good. My valve covers are GM tall black powder coated ($379) and I did have to clearance them for the corners of the GM rockers. I would be like to be able to use these again. New push rods are sounding like an eventuality too. Could also go with 1.8 rocker ratios to pick up some lift over the .547 lift I now have.

Sounds like I may have bigger issues that adding a shaft rocker system may not solve. I've considered going to a solid flat blower cam by Comp (11-405-5) with 255/266, .612/.605, 114LSA. Would this reduce my valve float issue, if that sounds like the culprit here?

I would sure like to participate in Pinks All Out without valvetrain issues.

I worked with the Victor heads when they first came out, maybe 2000/2001. When the racer upgraded to different heads we took the rockers as a trade in, and they did drop on a set of the Edelbrock RPM heads.

If you planned to run a solid roller, the 1.8 rockers would be a good idea. For a hyd cam, you are actually lowering your valve float RPM with the higher ratios.

Not everyone believes this theory, but my feeling is when you add positive intake pressure, you steal away from your seat pressure at a ratio equal to the intake valve surface area. Without doing the math, I would be looking to add about 30 pounds seat pressure to counteract the boost you're running. That becomes a problem with lifter wear unfortunately.

I would strongly recommend stepping up to a solid roller cam while you're at it, then you can spring accordingly for the boost pressure.

You could go with that solid cam, but it won't cure the cam failure issues. EDM oiling lifters, special oils, nitrided cams will help.

 

[Dave427]

The GM Performance Parts Blue Roller rockers, I believe they are made by Crane. I think they are the same as the Crane Golds.

Dave

 

[godsend]

Youll need seat pressure around 130. With boost add 30. So 160 or something will be good.

Then hope your cam lives with extra pressure.

 

[stock48]

You need seat pressure around 130. With boost add 30. So 160 or something will be good.

Then hope your cam lives with extra pressure.

X2! You could try adding a little spring but as stated above the cam might not live. Definitely DON'T increase the rocker ratio. I would run an Isky HR 238/248, .578/.608'' on a 112~114* then run the Durathon solid roller lifters on the HYD roller cam lashed at .008''/.010''(hot). Run 180-200lbs seat psi, and 460~480 open psi. I have ran that setup several times and it has worked flawless on a 427 with a [email protected] PSI. It is on a boat and turns 6800RPM all the way across the lake. Also used that setup on a 110* in a 10 sec NA daily driven nova.

 

[ss3966]

I did a valvetrain inspection today, and found 3 roller rockers that had hard-turning trunion bearings. I also found that the hydraulic lifter in question had separated the top of the plunger and was also laying in the lifter valley. This is the second time this has happened at the track - any problem with a rocker and the 858-16 Comp lifter separates - maybe all hydraulics would.

I spoke with my machinist who tried to be as politically correct as he could, but let it be known that he doesn't care for the GM Perf. Parts roller rockers. His own preference are the Comp Cams stainless steel roller rockers, but that his take is its just a rocker failure of one that really wasn't intended for weekly bracket racing. He and I had never talked about what rockers I was using but did recommend I at least add a girdle.

Also spoke with a Jesel rep, who said no shimming is required to install the shaft rockers as the part number is specifically for the Edelbrock Performer RPM heads. but he also said they "might" need clearancing for the shaft links that tie each assembly together - leaving a little wiggle room. He also believed the the GM tall powdercoat valve covers will work.

So I'm leaning toward the Jesel sportsmans as they are a somewhat reasonable $300 more than new rockers and girdle - with less maintenance, even a little more power too. I'm also leaning toward the 11-405-5 flat, solid lifter blower cam as long as I'm in there.

Would think I could find a little ET with this, going from 232/237, .547/.547, 114LSA to 255/266, .612/.605, 114 LSA. This should prevent me from losing hydraulic lifter parts anytime there is a rocker issue, the shaft rockers should make adjusting solid lifters less frequent, and pulling the intake and relashing the engine between bracket rounds isn't realistic whenever a hydraulic lifter separates. It also might be less susceptible to valve float. I'll avoid the 1.8 shaft rockers as others have mentioned, although the cost is the same as 1.7 shaft rockers. I'll have to check with Comp Cams to see if this will still be streetable in a blowthru 496 - with that much duration. The description says "Good for street and mild strip with 6-71 or larger blower".

I'm just not sold on solid rollers for street use due to the required rebuilds, the cost, and that I've just seen losts of bad roller bearings. The cost of the shaft rockers and solid cam is just about the same as doing new stud rockers, a girdle, and a solid roller cam. I would also have to do new valve springs with a solid roller on an installed head.

Do you think ET will pick up - or what else I might be overlooking here?

 

[rustbucket79]

The Jesel SS's are one tough rocker arm. One set my customer has in service is running nearly 300 # seated, 800 # open for several seasons now w/o issue.

If you can successfully break in the solid cam you're looking at it should help improve the ET.

 

[ss3966]

Any more thoughts on my combination in general/cam change/twisted logic that I am suggesting? Just not comfortable changing valve springs for a solid roller on the head mid-season, or the eventual rebuilds required more often due to street driving.

What say ye?

 

[rustbucket79]

Just make sure your current springs have the rate and clearance to work with the new cam, that you have the valve to piston clearance for that cam to work, and that you run the EDM oiling lifters and you remove the inner springs for the cam break in. Use Joe Gibbs BR and EOS for the first couple of hours.

 

[ss3966]

Spoke to two Comp Cams Reps who suggested that going from 232/237, .547/.547, 114 LSA HYD, flat lifter to 255/266, .612/.605, 114 LSA solid, flat would cost me bottom end on a 3,960 race weight. The machinist said the blow-through would help offset that, but that I might want more spring pressure. I would also likely have a much rougher idle for street use.

The Performer RPM heads came with spring #5745 spring specs of:
125 @ 1.975, but installed height not stated
310 @ 1.475

The Comp 930 springs recommended with the solid cam are:
153 @ 1.900 - Installed Height
365 @ 1.300

The compressed height works out to being comprable, but the seat pressures likely differ, and there will be boost present. As Pinks is 4 weeks off, I don't know that I should be making spring changes. The tech did mention that going to their 84000 lifters would reduce the liklihood of hydraulic lifters separating when valve lash is lost due to a broken rocker, as they have a different internal clip.

Looks like I'll just do the Jesel shaft rockers and replace the bad lifter. But their tech just said they don't recommend the sportsman version on supercharged applications, and recommends the comp version which jumps the price from $925 to $1525. But I Believe the sportsmans still have to be a big step up from GM Perf. roller rockers that lasted 3 seasons. He also said the sportsmans have been used on supercharged applications - he just can't recommend it - which really throws my math into the trash.

Trying to get too smart just before the big show and making multiple changes probably isn't a good thing. Sure had wanted to go to a solid cam, but don't want to get into changing valve springs on the head as I haven't climbed that learning curve before, and its mid-season now.

Thanks for the reminder on valve/piston clearance. When I checked it during initial assembly, the valves didn't even touch the clay with .547 lift on the flat-tops. I would have felt safe adding .060 more lift, although going up 30 degrees of duration could change things more.