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I was checking the lash today and came upon a very loose rocker arm. Upon closer observation I noticed that the lash cap had shattered. I removed the shaft rocker to confirm. The other cap is also showing signs of excessive wear. Is this common? The heads have very few miles on them and probably about 8 6500+ rpm dyno pulls.
I was checking the lash today and came upon a very loose rocker arm. Upon closer observation I noticed that the lash cap had shattered. I removed the shaft rocker to confirm. The other cap is also showing signs of excessive wear. Is this common? The heads have very few miles on them and probably about 8 6500+ rpm dyno pulls.
is there a groove in the stem also? it is center, but. would that be from being loose?
is there a groove in the stem also? it is center, but. would that be from being loose?
No grove in the stem, just a slight wear mark. The rocker roller and push rode all seem fine. The only thing I can think of regarding the wear is not enough oil is getting to the valve tip. I am switching from 10W30 to Amsoil 20w50 racing oil. Hopefully that may help. I guess I will need to replace all the lash caps. That worn grove will mess up the valve lash as well.
I've run lash caps with .900" lift and 360 pound seat pressure with over 1000 pounds on the nose and never had a lash cap have a groove wear in it.
Mike
I'm with Mike. I've seen lash caps beat to death on a motor that broke some springs and went into uncontrolled valve float. I would guess first at excessive lash. Second I would get a spring checker and see how the springs are. Third I would install a sequential rev limiter and turn it down a few hundred from what you have now. Shaft rockers should be very safe. You might have a spring harmonic problem.
I would suspect there is something wrong with those lash caps. Do a file test on them. If you can get a file to bite, then the material is soft. Lash caps are usually very hard and you will hardly be able to scratch them with a file.
Never seen one break either. Are you sure they are sitting all the way down on valve tip and not touching keeper? I can't tell in pic..but it looks like you have the right keepers with the recess for a cap....but that doesn't guarantee the tip height matches the cap depth.
Any particular reason you're running them? They just add weight to valve assy.
As mentioned....I'd ck lifters also. They don't like getting pounded like that....
Never seen one break either. Are you sure they are sitting all the way down on valve tip and not touching keeper? I can't tell in pic..but it looks like you have the right keepers with the recess for a cap....but that doesn't guarantee the tip height matches the cap depth.
Any particular reason you're running them? They just add weight to valve assy.
As mentioned....I'd ck lifters also. They don't like getting pounded like that....
JIM
Jim, I'm from the old school when solid rollers had .024 lash. I used to beat up even hardened tip valve stems. Them someone showed me lash caps and the theory of them spreading the load on the roller wheel and stem tip. lash caps Weight is tiny addition.
As to oil being a problem. Many race/ hot street engines restrict the oil to the top end with oil restrictors. aftermarket blocks are priority oil to the mains and restrict oil to the top end. Even certain pushrods have a smaller hole to limit top end oiling. Solid roller motors can have a lack of oiling at low rpm. Like sitting at a stop light at 800 rpm. You are better off having a 1000, 1050, 1100 rpm idle speed
Jim, I'm from the old school when solid rollers had .024 lash. I used to beat up even hardened tip valve stems. Them someone showed me lash caps and the theory of them spreading the load on the roller wheel and stem tip. lash caps Weight is tiny addition.
I've run them before....still have several sets in my toolbox along with keepers. I've used them to help correct geometry when needed. They do a nice job of protecting valve tips...helps on titanium stuff....but I can't remember ever having any tips really beat up either. Weight is always bad. Maybe not a big deal and certainly not on something only going 6500 or so.
Thanks for the replies. I check them with a file and it seamed quite easy to scratch them. I know what hardened steel should feel like and this one seemed hardened but not to a point where the file just glides along with only a scratch. I need to check all of them. It will be telling if any are OK. I really keep a close eye on my lash adjustments. The car has been run up to 6600 on the dyno. The engine builder says engine is good to 7000. I use my cam card lash values, correct to my 1.7 rocker ratio and check on hot engine.
-Are there any recommend suppliers for these caps?
-Once all the shaft rockers are removed, aside from installing at same location, is there a process for initial setup? It has been a long time since I have installed rockers and the last time they were hydraulic lifters so it was fairly easy.
-Does anyone know the T&D shaft torque spec? I think they are around 30 ft-lbs.
My plan is to replace all the caps and make sure they are all seated....not really sure how to verify with 100% certainty they are seated 100% but I will do my best. After I get the rockers installed and adjusted, I will make sure the valve lift travel is the same on that valve as it is for the other exhaust valves to make sure there is nothing funky going on with the lifter or cam lobe.
Measure depth of pocket in cap and then measure tip down to keeper. Make sure outer diameter of cap will sit down inside the groove in keeper. Or if stem is tall enough it can just sit on top.
You can also use a small blob of Plasticine to ensure you have a gap when the lash cap is seated. The plasticine will leave some remaining if there is a gap.
What is your lift with 1.7. Do you have any information on your springs
Unfortunately no. Tony Mamo set up the heads for me but I forgot to ask for the spec sheet. I just sent him an email to see if he still has any of the stuff. The only info I have is a verbal from him stating the following: 240 ish on the seat btw.....600 lbs open on the springs
Lift .731/.736
Unfortunately no. Tony Mamo set up the heads for me but I forgot to ask for the spec sheet. I just sent him an email to see if he still has any of the stuff. The only info I have is a verbal from him stating the following: 240 ish on the seat btw.....600 lbs open on the springs
Lift .731/.736
I am just going to replace them and see how it goes. Problem I am having now is I cannot seem to get the cap next to it off. Not enough meat to grab with pliers. My vice grips dug into the cap a bit more than one would expect for hardened steel. I figure I have 2 choices, try some gentle heat on the cap with a torch or put some air pressure on the cylinder and remove the spring for a better grab. I think I can remove the springs with the cap in place. Any thought on this?
AFR Head Broken Lash Cap
Shaft rockers should be very safe. You might have a spring harmonic problem.
