Thread: Rocker Not fitting right

Tweet

I have a 383 sbc and i just bought new rockers arms for it.They are the alum roller tips set up.I went to put them on and the bottom of the rocker hits the head were the stud goes.They are stock head.Does any think i need to do machine work on the head to make them clear or you think they are the wrong rockers?They are summit rockers (SUM-G6905)I know they say they should fit.But they don't.I will be calling them.But maybe some one can point me to the one's i should get or the best ones that fit.
Thanks ALL

could be as simple as getting the correct length pushrods, I had to do this. others will be along to help out.

That is some thing i will look into.but you would think when i bought them it would of said i need longer push rods.I did get pushrods 7.90in long due to the small base cicrle cam i had to use with stock rockers.

Not really there are a few things that come into play that it is impossible for the manufacturer to know what length you need. Also this may or may not be your problem ,but dont get frustrated a little reading and its pretty simple, you may have to buy a few tools to check though. If not take it by your local performance shop. There is a pushrod length checker you can buy on the cheap. It extends to what you need and then you measure (twice and a third time) and thats the length you need. Check on the comp cams web site they have a lot of useful info.

i just got done checking length of the push rods with the checker.I don't have a mic to get the right length yet but the push rods have to be just over 8.0in to kept the bottom of the rockers from hitting the head.Now with that done it looks like the tip of the rocker is sitting in the right spot.Its just not easy to do this with the engine in the truck.

Use BTD's advice and go to the website. Use all the websites you have patience for. Geometry will change with newer style rockers and by addressing only the pushrod length problem, you'll create a whole new problem elsewhere, such as tip to stem goemetry or valveguide load geomtry........ This needs to be addressed before you open "Pandora's box". You didn't state the head casting number or style or what they came off of, so it's hard to give you what you need in info. There are other alternatives to achieve your goal. Give us some extra info please and see if somebody here has the solution. Keep up the good work. P.S. are you stepping up to 1.6 or just trying to get better rocker arm symetry?

All the components in the valve train should be matched to each other in order to ensure the geometry is correct. What heads are you running? Stock studs or screw ins?

I'm going with 1.5 rockers.The stock gm heads are i think 882 some think like that.
everything i have done so far is

Brand: COMP Cams
Product Line: COMP Cams Magnum Hydraulic Cam and Lifter Kits
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 2,000-6,000 RPM
Intake Duration at 050 inch Lift: 230
Exhaust Duration at 050 inch Lift: 230
Duration at 050 inch Lift: 230 int./230 exh.
Advertised Intake Duration: 280
Advertised Exhaust Duration: 280
Advertised Duration: 280 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.480 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.480 in.
Valve Lift with Factory Rocker Arm Ratio: 0.480 int./0.480 exh. lift
Lobe Separation (degrees): 110
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in.
Grind Number: CS 280H-10
Computer Controlled Compatible: No
Lifters Included: Yes
Lifter Style: Hydraulic flat tappet
Valve Springs Included: Yes
Outside Diameter of Outer Spring (in): 1.254 in.
Retainers Included: Yes
Locks Included: Yes
Valve Stem Seals Included: Yes
Timing Chain and Gears Included: Yes
Timing Chain Style: Double non-roller

Brand: Eagle Specialty Products, Inc.
Product Line: Eagle Street and Strip Rotating Assemblies
Actual Engine CID: 383
Engine Stroke (in): 3.750 in.
Pistons Included: Yes
Piston Rings Included: Yes
Piston and Ring Oversize (in): 0.030 in.
Piston Material: Hypereutectic aluminum
Piston Style: Flat
Piston Head Volume (cc): +7.00cc
Valve Reliefs: Four
Wrist Pin Style: Press fit or floating
Piston Ring Facing Material: Plasmamoly
Crankshaft Included: Yes
Crankshaft Material: Cast steel
Rear Main Seal Style: 2-piece
Balanced: Yes
Engine Balance: External
Connecting Rods Included: Yes
Connecting Rod Material: Forged 5140 steel
Connecting Rod Beam Style: I-beam


Holley 650 carb vac. sec.
accel DIS hei vac

the heads have stock studs.and the rocker arm kit does not call for diff studs.
The engine runs great i'm just doing one upgrade at a time now.Next is the intake then the heads.And then the rest trans, axles

Money only grows so fast on my tree

At this point in time you're gonna need to do the machine work. If it were me, I would exchange or return these. There are others that will do a better clearance jobs with no hassles and no pushrod change overs, etc. My real concern is push-in stock studs. They will pull out of the head and under rpm load, the studs are not as sturdy (flex) and have a tendency to break. I would recommend machine work in almost all cases of trying to achieve your goal.

I don't plan on going over 5000rpm's..I won't be buying the head till next year.And later this year i will pick up the intake.and a new carb in a week or so.which will be a 750cfm.I'm working out all the bug's before i put this in my other truck when i get it done some time next year.

If you wanna go affordable, get the Elgin or comparable roller tipped rockers for now. There are many who supply this style. Elgin happens to be cheaper in price in most locations, or mail order. Just double check roller contact point on the valve stem. You'll afford the "fix" until the next swap time. And I like 750 cfm, but I think it's a bit much for your combo. Let's see if others agree or disagree. Good advice on this site.

Probably not a good reason to spend a lot of money on the existing heads if you are planning on relplacing them.... Just a suggestion, why not just leave the engine you have as is, then start accumlating parts as your budget allows and build a complete new engine. You can keep driving your car as it is, then when you have all the pieces for your new one you can put it together and install it in your car and everything is fresh at the same time.....It will save you a bunch of money in the long run...

it is a good idea but the engine is new.And what i have buildit for will not be done for a few more years and i want to work any and all bugs out of it now before i put it in the next truck.I don't plan on driving this truck all the time just now and then like the rest of the ppl that spend a million dollar on a car and look at it.This was my winter truck but things changed and the motor just got done 4 weeks ago.And now i want to drive it.IT all test and tune lets see what works the best with what i got and stick with it.