Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

Odd experience with rockers

Thread Tools
 
Search this Thread
 
Old May 22, 2007 | 01:32 PM
  #1  
J Wikoff's Avatar
Thread Starter
Senior Member
Certified Car Nut
 
Joined: Mar 2003
Posts: 12,433
Likes: 2
J Wikoff is on a distinguished road
Default Odd experience with rockers

Upon installing a YT roller rocker, it compressed the valve spring ~1/8". I installed as directed:

"Tighten to the starting point of zero-play (push rod cannot easily be turned by hand), then torque to 25 ft-lb."

At that point, most of the any play in the pushrod is gone, but the valve is slightly open. If I give it a couple minutes and turn the engine over by hand a few times, it seems to settle in and let the valve close. I reinstalled the stock rocker and it acted the same way. Is this normal?
Reply
Old May 22, 2007 | 01:55 PM
  #2  
agrazela's Avatar
Senior Member
Posts like a Corvette
 
Joined: Jan 2007
Posts: 1,451
Likes: 0
From: San Diego, CA
agrazela is on a distinguished road
Default

Sounds like the hydraulic lifter got pumped up when the rocker was removed, but went "back to normal" after a few revolutions with rockers replaced.

But, how the heck does a lifter pump up if it'* just sitting there? I suppose there'* a piston and spring inside the lifter that "sucked" oil in after the tension from the rocker/pushrod was removed?
Reply
Old May 22, 2007 | 01:57 PM
  #3  
J Wikoff's Avatar
Thread Starter
Senior Member
Certified Car Nut
 
Joined: Mar 2003
Posts: 12,433
Likes: 2
J Wikoff is on a distinguished road
Default

This engine is on a stand with no oil pan and likely very little oil in the passages.

I should say, this is a fresh reman motor.
Reply
Old May 22, 2007 | 03:01 PM
  #4  
95naSTA's Avatar
Senior Member
True Car Nut
 
Joined: Feb 2003
Posts: 4,508
Likes: 2
From: Philly
95naSTA is on a distinguished road
Default

Sounds like the lifter wasn't on the base circle portion of the cam lobe at first?
Reply
Old May 22, 2007 | 03:16 PM
  #5  
J Wikoff's Avatar
Thread Starter
Senior Member
Certified Car Nut
 
Joined: Mar 2003
Posts: 12,433
Likes: 2
J Wikoff is on a distinguished road
Default

I verified that is was before I torqued it down. I tried it on other cylinders as well and had the same result.
Reply
Old May 22, 2007 | 04:19 PM
  #6  
willwren's Avatar
Junior Member
Posts like a Ricer Type-R
 
Joined: Aug 2002
Posts: 11
Likes: 13
willwren is on a distinguished road
Default

I talked with John on the phone about this last night. Keep in mind these are YT 1.7 ratio rockers. The pedestal is integral to a valve cover spacer. All once piece. The only reason I can figure why they would raise the cover is because the snout of the rocker arm is thicker (higher profile, not tapered off) than my 1.8'*.

The suggestion I made was to rotate the engine through with them torqued, and use an air chuck adapter in the spark plug hole and a compressor to see if they're actually fully closed or not.

John, are you going to try this tonight? Your pushrods should be able to spin with the valves fully closed as well, with just finger-force, especially since the lifters have never been pumped up before.
Reply
Old May 22, 2007 | 04:24 PM
  #7  
J Wikoff's Avatar
Thread Starter
Senior Member
Certified Car Nut
 
Joined: Mar 2003
Posts: 12,433
Likes: 2
J Wikoff is on a distinguished road
Default

I'll get the adapter on the way home today. I can spin the pushrods still with my fingers, but it'* not what I would call free, it'* pretty stiff.
Reply
Old May 22, 2007 | 07:15 PM
  #8  
J Wikoff's Avatar
Thread Starter
Senior Member
Certified Car Nut
 
Joined: Mar 2003
Posts: 12,433
Likes: 2
J Wikoff is on a distinguished road
Default

No dice on the fitting. Went to Napa, Lowes, a large local hardware store, then Advance. Noone even gave me a knowing look as to what I was talking about.
Reply
Old May 22, 2007 | 08:03 PM
  #9  
willwren's Avatar
Junior Member
Posts like a Ricer Type-R
 
Joined: Aug 2002
Posts: 11
Likes: 13
willwren is on a distinguished road
Default

Most of them don't know what it is. But I can tell you it'* a normally stocked item at my local Autozone, NAPA, and CarQuest.
Reply
Old May 23, 2007 | 12:49 PM
  #10  
BillBoost37's Avatar
DINOSAURUS BOOSTUS

Expert Gearhead
 
Joined: Mar 2005
Posts: 41,391
Likes: 30
From: Enfield, CT
BillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of light
Default

The same fitting can be found in any compression testing kit.
Reply



All times are GMT -4. The time now is 07:52 PM.