Need some help figuring this out

[67cuda360]

I am having some strange results trying to set the valves.
First the specs.


- Engine is 360, bored .30 over (I think it has a ’76 year stamp)
- flat top pistons
- 273’s adjustable rockers (ball and cup pushrod type)
- Ported J-Heads with stock size valves
- I think the camshaft is some kind of RV cam
(previous owner listed a Direct Connection Comp RV, can’t seem to find any info on it on the web. Previous owner said it used hydraulic lifters.)

So here is the problem, when I bought the car (about 3 months ago) the engine ran a little rough and the valves were noisy. The previous owner said the valves needed to be adjusted. So last weekend I set the valves following the method below:


I worked one cylinder at a time, adjusting the intake when the exhaust valve starts to move down (opening), and adjusting the exhaust valve on the same cylinder when the intake has past its max lift (fully open) and is 2/3 of the way up, so almost closed.

When I was sure the cam was on the base circle I tightened the adjustable rocker to zero-lash, I used a 0.0015 feeler gauge to make sure I wasn’t over tightening it (sometimes it is a bit difficult to find zero-lash wiggling the pushrod between your fingers). After having zero-lash I gave the adjustable rocker another ¼ turn to get to the minimum pre-load on a hydraulic lifter.

After doing this to all the cylinders I put the valve covers back on and tried to start the engine. All it did was spin, there didn’t seem to be any compression so the valves must have been partly stuck open.

I took the valve covers back off and backed the adjustable rockers off a ¼ turn on all valves, so pretty much back to zero lash. I turned the engine over and she started right up and it runs good.

What’s going on, it almost seems like it has solid lifters that need a “Lash” instead of a “preload”

I have been searching the internet but I can’t seem to find any RV cams that would use solid lifters. One thing I did find was some info on "Anti-Pump Up" hydraulic lifters, they seem to act like solid lifters.

Does anyone know how to check if I have normal hydraulic lifters, “Anti-Pump Up” Hydraulic lifters or Solid lifters without me having to take the intake off engine?

I would really like to set the valves to the proper setting so I don’t damage anything.

Thanks, Wilco.

 

[bamacuda]

Hmmmm! Solid? Anti-pump up? Not sure how to tell with your scenario without pulling them. Anyway, you get a bump so that maybe someone smarter than me (like everyone) can help!

 

[ramcharger]

You most likely are tightening the hydraulic lifters past their point of pre-load until they are locked solid and then going another 1/4 turn. The hydraulic lifter internal springs are very light and it takes a certain amount of "feel" to do this correctly.

If the lifters have been run solid tight for any real amount of time, they may well collapsed and in need of replacement.

 

[67cuda360]

You most likely are tightening the hydraulic lifters past their point of pre-load until they are locked solid and then going another 1/4 turn. The hydraulic lifter internal springs are very light and it takes a certain amount of "feel" to do this correctly.

If the lifters have been run solid tight for any real amount of time, they may well collapsed and in need of replacement.

If that is the case then the lifters must have already been collapsed before i started the adjustment, i used the feeler gauge to make sure i would detect zero-lash so i wouldn't over tighten it, strange thing is that it runs good when i backed the adjustment nut off a 1/4 turn. And the engine sounds healthy.

Wouldn't you hear some sort of bad engine noise if it would be running on all collapsed lifters?

 

[ramcharger]

If that is the case then the lifters must have already been collapsed before i started the adjustment, i used the feeler gauge to make sure i would detect zero-lash so i wouldn't over tighten it, strange thing is that it runs good when i backed the adjustment nut off a 1/4 turn. And the engine sounds healthy.

Wouldn't you hear some sort of bad engine noise if it would be running on all collapsed lifters?

A feeler gauge can easily override the internal lifter spring. It's almost impossible to explain in writing a sense of feel.

If they were collasped it would tick at hot/idle when oil pressure is low.

 

[moper]

I tend to agree with Ram... It sounds like the lifters are/were collapsed and you held the valves open by tightening the adjustment. For the price of an intake gasket you can pull it and look for yourself. I hate trying to set preload by feel. I can't do it well either. If I can see it that's another matter.

 

[67cuda360]

Thanks for the replies.

I just came home and started the barracuda and let it warm up, there is a slight tick on maybe one cylinder (i'll try to adjust this maybe tomorrow), but otherwise it sounds good. I hooked a vacuum gauge up to one of the intake ports and it is pulling a healthy 19 inches of vacuum at idle.

When i went to look at the car before i bought it i was certain the previous owner told me it had a cam with solid lifters, my friend who came with me remembers him saying the same thing. But when i came to pick the car up and i asked him about what exact cam was in it so that i could look up the manufaturers "lash" settings he told me it was hydraulic.

So to make things complicated :-D it is possible the car has solid lifters.
If i do pull the intake, i might aswell upgrade to an edelbrock airgap RPM while i'm at it. It currently has an edelbrock torker 340.