Rocker arms with Lunati camshaft

[Hipster]

bent puhrod indicates contact of some sort, whether valve spring coil bind, guide to retainer clearance, or a valve hit piston and created a bent valve. Valve lash settings and clearances are critical and when you get into aftermarket cams the service manual doesn't really apply. You have to go by what the lifter manufacture says, check clearances on everything etc., and most hydraulic lifters will call for .030-.060 preload. Most list lifter preload specs on their website. You can get very technical with this as I have in certain applications with a dial indicator and measure preload.

You didn't say but it's also critical to have the correct valve springs installed on the engine as well.

 

[MiGorda]

Yes, pull the intake manifold and pull the lifter(s) out to inspect/clean them. Keep them in the same position they came from!

I didn't even get to 9,000 miles before my lifters started wearing out and grinding the cam down (a Lunati too BTW). I found a collapsed lifter and one ground down.

Here's a couple - 1 worn down, notice the dish in the bottom. The other is collapsed.

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BTW I had the same lobe wear down - arrow on the right.

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Wow, why could this happenned?

This is my second Lunati, first lasted over 10 years and at least 40,000 miles, with the rest of the engine OEM.

In my case, I'm almost sure that overthiged the nuts and just drive like 50 miles with a bad valves calibration.

I'll remove the intake and check it out, hopefully the camshaft will be fine.

 

[MiGorda]

bent puhrod indicates contact of some sort, whether valve spring coil bind, guide to retainer clearance, or a valve hit piston and created a bent valve. Valve lash settings and clearances are critical and when you get into aftermarket cams the service manual doesn't really apply. You have to go by what the lifter manufacture says, check clearances on everything etc., and most hydraulic lifters will call for .030-.060 preload. Most list lifter preload specs on their website. You can get very technical with this as I have in certain applications with a dial indicator and measure preload.

You didn't say but it's also critical to have the correct valve springs installed on the engine as well.

Valve springs, rocker arms and push rods are OEM.

I'm sure I overtighed the nuts too much, everything was fine before, just a little thicking.

I thought it was easier, I have little experience on engines but I want to tried it and I screwed it

 

[Hipster]

Valve springs, rocker arms and push rods are OEM.

I'm sure I overtighed the nuts too much, everything was fine before, just a little thicking.

I thought it was easier, I have little experience on engines but I want to tried it and I screwed it

reinstalled stock springs at time of rebuild?................. umpteen thousands of miles and heat cycles later.? Valve springs have a cycle life especially with a hotter than stock cam. You answered your own question as to why this happened. Always go with the springs the cam manufacture recommends for the cam used. No exceptions. It's the best way to avoid issues.

 

[MiGorda]

reinstalled stock springs at time of rebuild?................. umpteen thousands of miles and heat cycles later.? Valve springs have a cycle life especially with a hotter than stock cam. You answered your own question as to why this happened. Always go with the springs the cam manufacture recommends for the cam used. No exceptions.

Sorry, I was wrong. I got the whole Lunati kit, includes springs, so they are matched to the cam.

Now I know I need to remove the intake but what do you think about it, could be only the lifter damaged? If the lifter is damaged, I need another one from Lunati or the OEM could do its job?

 

[Hipster]

Sorry, I was wrong. I got the whole Lunati kit, includes springs, so they are matched to the cam.

Now I know I need to remove the intake but what do you think about it, could be only the lifter damaged? If the lifter is damaged, I need another one from Lunati or the OEM could do its job?

If the wasn't already an issue you wouldn't have been adjusting the valves. This issue started before......the adjustment. I'm thinking.

 

[MiGorda]

If the wasn't already an issue you wouldn't have been adjusting the valves. This issue started before......the adjustment. I'm thinking.

Yes indeed I shouldn´t touch them but I tought they were too loose because I could move the rocker arm with my hand, a little bit only, so I tighten them. Then the engine worked bad, like without one piston, so I tried the process of loosing the nut until the tick began, then tighten it until the tick went off and then turned it 3/4, after that everything sounded good at idle. Next day went out for a few miles and hear the bang coming from the TBI and opened this thread.

Now my conclusion is that overtighed them the first time.

At least I'm learning, lol.