CLASS RACER FORUM - View Single Post - Powerglide damage from 'clicking' engine off in lights

Kevin Panzino · 08-16-2013, 07:10 PM

Well, guys, I got to the bottom of this. You wont believe what I found... Amazing...

The shutting down in the traps was not the issue. Bearings, bushings etc were all fine. The issue I was having was burnt up high gear clutches and fairly excessive band wear and occasional burning of same.

I was convinced I was doing everything perfectly regarding setup, clearances, etc...

Both ATI, and TSR racing kept suggesting it was shifter adjustment, and/or a shifter problem. I had previously checked this several times, but checked again in the most thorough fashion. It was perfect.

So then I decided to tear into the valve body (ATI #203300) and take a close look at everything there, suspecting an internal problem. Everything looked ok in there with one exception.. The manual spool valve seemed to not line up properly with all the lands in the body as I moved it into each gear position. I had bought a new manual valve from ATI a week earlier figuring I would change it out as well, if perhaps mine was worn in diameter and causing leakage....

Well what I found is that my manual spool valve had two of the spools in a roughly 1/8" different position than the new spool valve, as well as one spool which was narrower. See the attached pic below of the comparison. When I put the new spool valve in the body, each spool lined up perfectly with each land in the body.

Further analysis of each position, and each port showed that in Low gear, only 1/16" of the low apply port was being connected to line pressure. Likewise in high gear the same problem was present. depending on ever so slight slop, it could have even been worse, as well as causing leakage from each port into another, or to exhaust...

I never would have thought of this. I assumed all powerglide manual spool valves were identical. Most folks I talked to did as well. I don't know where that spool valve came from, and what the heck could be the history of it, but I know realize I have had all these problems since installing that valve body, and this was the cause.

So moral to the story, if you build glides, have several manual valves on hand, compare them and make sure they are all the same, and that they line up well with each land in the valve body.

The car picked up .2 and 3 MPH, shifted like a raped ape, and ran four passes within .01 of each other. And the fluid is as perfect as when I poured it out of the bottle.

Sorry for the long post, but I don't want ANYONE to have to go through what I have gone through the past month, and its certainly a 'weird' one, so keep this in mind.

See pics below. 1st pic: both spools. 2nd pic, the old spool in 1st gear position. 3rd pic the new, correct spool in 1st gear position.

Than you everyone for the replies and the help.

Kevin

08-16-2013, 07:10 PM	#24
Kevin Panzino Senior Member Join Date: Oct 2002 Location: Pittsburgh Posts: 575 Likes: 298 Liked 747 Times in 136 Posts	Re: Powerglide damage from 'clicking' engine off in lights Well, guys, I got to the bottom of this. You wont believe what I found... Amazing... The shutting down in the traps was not the issue. Bearings, bushings etc were all fine. The issue I was having was burnt up high gear clutches and fairly excessive band wear and occasional burning of same. I was convinced I was doing everything perfectly regarding setup, clearances, etc... Both ATI, and TSR racing kept suggesting it was shifter adjustment, and/or a shifter problem. I had previously checked this several times, but checked again in the most thorough fashion. It was perfect. So then I decided to tear into the valve body (ATI #203300) and take a close look at everything there, suspecting an internal problem. Everything looked ok in there with one exception.. The manual spool valve seemed to not line up properly with all the lands in the body as I moved it into each gear position. I had bought a new manual valve from ATI a week earlier figuring I would change it out as well, if perhaps mine was worn in diameter and causing leakage.... Well what I found is that my manual spool valve had two of the spools in a roughly 1/8" different position than the new spool valve, as well as one spool which was narrower. See the attached pic below of the comparison. When I put the new spool valve in the body, each spool lined up perfectly with each land in the body. Further analysis of each position, and each port showed that in Low gear, only 1/16" of the low apply port was being connected to line pressure. Likewise in high gear the same problem was present. depending on ever so slight slop, it could have even been worse, as well as causing leakage from each port into another, or to exhaust... I never would have thought of this. I assumed all powerglide manual spool valves were identical. Most folks I talked to did as well. I don't know where that spool valve came from, and what the heck could be the history of it, but I know realize I have had all these problems since installing that valve body, and this was the cause. So moral to the story, if you build glides, have several manual valves on hand, compare them and make sure they are all the same, and that they line up well with each land in the valve body. The car picked up .2 and 3 MPH, shifted like a raped ape, and ran four passes within .01 of each other. And the fluid is as perfect as when I poured it out of the bottle. Sorry for the long post, but I don't want ANYONE to have to go through what I have gone through the past month, and its certainly a 'weird' one, so keep this in mind. See pics below. 1st pic: both spools. 2nd pic, the old spool in 1st gear position. 3rd pic the new, correct spool in 1st gear position. Than you everyone for the replies and the help. Kevin Attached Thumbnails