When I bought my set I spoke to one of the guys at YT
He said his kid had a 1200 he raced in junior speedway
This is why they designed the rollers for the A series... usually a company like that wouldn't care about an obscure little engine if there wasn't a reason

He told me that he used the 1.55 ones on his kids car and it regularly revved out to 9500.

I went with the 1.65 for some free lift and I knew I wouldn't be turning mine that hard anyway

I'm not saying its not the rockers causing an issue
You guys have used them and had issues so I'll believe you
And truth be known my engine seems to run out of puff around 7700 rpm which if you look at the specs it shouldn't... it should scream to over 9000
But.... I never planned on turning it hard anyway so for me its not yet an issue
Maybe with different rockers and valve springs I could spin some more revs out of it
But looking at my dyno sheet (98.7hp atw... whooo hoo) the beast stops making usable power at 7000 and starts to drop away anyway.... so after that its just noise.... I just change gear.

I wish you luck finding a solution

I wouldn't be trying to lighten the rockers without consulting YT first though. They may be able to tell you where you can and can't have a diet

Does anyone know how much the other brand of aftermarket rockers weighs? (I can't think of the brand name right now)

seems like the man from YT knows something!
they will make it and sell it , but they dont have to prove it's better,
i used TRW lifters once .

Quote:

I am really curious what is going on here.
I would also say to go back to standard and see what happens.If reliability increases, then you know that they are not that good for racing applications.Strange, these things are very expensive.They are suppose to give you good quality for your money.

Answers to these questions I am using a JTS prepared head, the man knows his stuff.

What springs - JTS DOUBLE VALVE SPRINGS
What installed height - 1.610"
What valves - 40MM INLET 33MM EXHAUST (DATSUN 1600) OK THESE ARE HEAVIER THAN STANDARD
Whats the valve length - CUT TO STANDARD 1200 LENGTH MINUS ROOM FOR LASH CAPS
Whats your seat pressures - 110LBS SEAT AND 290LBS @ .470 LIFT

I have pulled the engine down and there are no marks on pistons or block it is not a clearance issue. and the spring i am using are not little, I don

this is interesting info. do you guys reckon the rollas would be ok for a turbo application that isnt going to rev that hard?

Gary, do you still use the same lifter/followers that you were running with the roller rockers? Did you try the standard lifters/followers with the roller rockers? There could have been a metalurgy or design problem with the aftermarket lifters.

the extra lift of the yella terras and less flex if you use moly pushrods will both put more pressure on the cam lobes.

do you use a pushrod guide with the roller rockers? is there a possible binding problem being caused there?

I'm with rally1200, I've taken mine off and at this stage have no intention putting them back on.

Why! I know have a collection of 3 worn out camshafts sitting under the house. Be it a coincidence, but I have only started wearing out cams since the rockers went on, and to be honest I'm sick of pulling the motor out and changing the cam.

The valve springs in it are about 90lb and the tappet clearance is set to the cam grinders specs, I rang y/t and asked if I should use a different tappet clearance and said no use the recmmended.

I have done BULK research on why the camshaft might be wearing out and its come down to two items...quality of todays oil and the roller rockers.

I think the roller rockers would be great in a good street car but under full race situation like what I'm doing I don't they are good at all.

I'm not trying to put people off using them or #### caning them, in my situation they don't suit.

I'm with dattoman - still seems to only be anecdotal evidence even 8 months later. A more systematic approach would be a good idea. Stop "thinking" that clearance isn't a problem - measure it.

I'd check all the things dattoman listed as well as spring pressure at full lift and all clearances with the increased ratio roller rockers - valve to piston, retainer to guide/seal, and spring bind.

You'd knock that all over in a day and have a real picture of what's happening.

I'm still bemused
What springs
What installed height
What valves
Whats the valve length
Whats your seat pressures