[Bill S]

Two rocker arms have come loose on my 455. I adjusted them but they appear to not open the valve as far as the other valves. Pulling the intake / valley pan this weekend to inspect further.

Thinking of going hydraulic roller. Current setup, 455 .040 over, 6X heads ported per Jim Hand’s book, 9.4:1 compression, 995-16 valve springs, Mellings 041 cam, Rhoads Vmax lifters, HS 1.65 roller rockers, modified stock intake, Cliff’s 800 cfm Qjet., headers.

Thinking about a hydraulic roller with 230 @.050 intake, 112 LSA, but I want to keep my HS rockers. The issue is lift.
Do I need to order a custom cam, or is there an off the shelf one that will work with high lift rockers ?
Depending on lift, will the 995-16 springs be okay ?
From Jim’s test, flow is good to 0.550” lift.

Just looking for street fun power. Power was good at 3000-5500 rpm on the current setup.
I

[Scott65]

Did you check piston to valve, retainer to seal, etc. clearances to know how much lift you can tolerate? Personally I would run all the lift you can, unless you know by flowing the heads that they go into turbulence at a certain point(and where that point is) If you know the lift you're looking for, using lobe lift x 1.65 will tell you if the off the shelf grinds will meet your needs in that area. I'm fuzzy on the 995, but I think they will be light for a hydraulic roller.

[mchell]

With the combo you’re running, I would be sticking with what you have......HR setups can cost A LOT of $$ with marginal gains , especially on a mild build. If you don’t care and simply want to try something different, go for it. Like anything in this hobby be prepared to open the proverbial “can of worms”

[RocktimusPryme]

If you end up actually needing to replace the cam I would go with the roller. I despise breaking in cams correctly. Ill happily pay the money for a roller to not have to remove the inner springs.

But the above is correct, the cost will be at a premium, and I dont know what the current availability of lifters is.

[Formulajones]

Butler sells the RA series of Pontiac cams in rollers, and they don't have a ton of lift (for a roller cam)

The RA IV roller is very similar on paper to the flat tappet version. 232/241 @ .050 and .507/.541 lift, ground on a 113 lsa.

Would probably perform and act much like your 041 clone with Rhoads lifters.

Just one of many options.

[RocktimusPryme]

With a mild cam you can probably look into one of those systems that have popped up using factory roller lifters and the lifter spiders or whatever you want to call them.

Save a little money.

[Steve C.]

"Depending on lift, will the 995-16 springs be okay ?"

If switching to a hydraulic roller I'd highly suggest you remove a few, if not all, of the 995 valve springs and have their pressure checked with a Rimac machine (or similar bench spring tester). And make sure they are tested at their actual verified installed height with their retainers in place.


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[Bill S]

I have had this car since 1980, and plan to keep it. So spreading the cost over the next hopefully 35 years ( need to be optimistic !), a few hundred bucks, vs avoiding a future wear mode in the cam/lifter may be a worth while trade off.

I do like the performance it used to have, but it developed a misfire this year. I don't drive it much over the years.

My concern is the HS rocker which I heard are actually 1.7 ratio, and valve springs. I don't want to deal with new rocker as the HS are expensive and paid for. So not sure what cam option are out there, and what lift to shoot for.

[Scott65]

Your gonna have to verify the piston to valve clearance, installed height, retainer to seal clearances, etc before you can make a good decision. IMO, a roller chosen for safety sake with low lift, just isn't worth it. Do the checks and you can make a good selection that will perform well. There are numerous lobe lifts available within the duration range you're interested in.

[Will]

What is your installed height? That will determine, mostly, what springs you can install. You can shim a little if you need to work with a shorter spring or bring seat pressures up a bit.

Your max lift will be limited by the available springs for your installed height and your retainer-seal clearances. I wouldn't worry about piston-valve clearance, I've never once run into a problem with that but I've never built a race engine. It's really only a problem for engines with LOTS of lift and long durations.

There are a couple advantages to rollers beyond just being able to run lots of lift - the valve opening and closing rates can be much faster than with a flat tappet is the main advantage. Not worrying about lobes going flat is another advantage, but the tradeoff there is worrying about lifter failure. A someone else mentioned, this is a perfect application for the LS lifters. Do a little searching in this forum for LS lifters and you'll find a couple good threads about that which specify the particular lifters you can use and the other parts to make them work. I would go that route if I was in your shoes.

I have a small solid roller that's an old Crane grind meant to duplicate the RAIV. It's 230/240 @ .050" on a 113LSA and I ran it at 109 ICL and the lobes are only something like .337". I ran the HS 1.65(1.7) rockers on this cam with some Crane springs on iron heads with RAIV length valves. I think my installed height ended up at or just under 1.8" It ran good and sounded good and was a decent street cam though my engine needed a tad more compression to work best with it. Made enough torque to push me into the mid 12s @ 108 on street tires with 3.23 gears with a 440" engine in a 4000 lb car, so a cam like that would work fine in your 455 provided you can find some springs to work with the lift and you have enough retainer-seal clearance.

There are a plethora of roller grinds out there from various manufacturers and it's not hard to order a custom from Comp if no one has something on the shelf you like, so you should have no problem finding a cam that will work for you.

[OCMDGTO]

Rollers are nice but nothing wrong w HFT