Valve Oil Seal Help

[msholl52]

Hello All-

Have a 2001 Ch613 with an E7 330...bought used from Ryder (if ever given the chance...dont) Has 223k original miles on it...I have put 10k on it. Last week I fired it and heard the dreaded valve / broken spring noise. Couldnt get a Mack tech to my shop to look at it, so I pulled the valve covers myself and with the help of a local mechanic began diagnosing the issue. To cut this story down to under 20 pages...we finally realized that at some point someone had gone into the valves, replaced the springs but didnt put the bottom rotators back in, instead put them on top of the spring. The rotocoil (the part the washer spins in) had broke on almost every valve which meant to us that we needed to reinstall all of it, springs, rotators, washers, keepers, and seals. It took me a week, but I got the correct parts and began pulling 2 and 5, and when we went to re-install the E7 rebuild book says you MUST have the "Mack" tool to install the seals.

To be more brief...its going to take at least 2 weeks to get the tool and as Im sure most of you know (and now I do)...no body works on Mack heads anymore...they just install remans. So no one within a 500 miles radius of me has the damn tool. Does anyone have the tool and want to get rid of it, or know a way around this or should I just punt and give back the parts and buy reman heads? Help.

[rhasler]

Hello All-

Have a 2001 Ch613 with an E7 330...bought used from Ryder (if ever given the chance...dont) Has 223k original miles on it...I have put 10k on it. Last week I fired it and heard the dreaded valve / broken spring noise. Couldnt get a Mack tech to my shop to look at it, so I pulled the valve covers myself and with the help of a local mechanic began diagnosing the issue. To cut this story down to under 20 pages...we finally realized that at some point someone had gone into the valves, replaced the springs but didnt put the bottom rotators back in, instead put them on top of the spring. The rotocoil (the part the washer spins in) had broke on almost every valve which meant to us that we needed to reinstall all of it, springs, rotators, washers, keepers, and seals. It took me a week, but I got the correct parts and began pulling 2 and 5, and when we went to re-install the E7 rebuild book says you MUST have the "Mack" tool to install the seals.

To be more brief...its going to take at least 2 weeks to get the tool and as Im sure most of you know (and now I do)...no body works on Mack heads anymore...they just install remans. So no one within a 500 miles radius of me has the damn tool. Does anyone have the tool and want to get rid of it, or know a way around this or should I just punt and give back the parts and buy reman heads? Help.

Those heads weren't incorrectly assembled. The E-Techs of that era had upper rotators, but they can be retrofitted to the lower rotators as you have done (which is a much better arrangement and is less prone to problems). If you had broken rotocoil springs I would check the dimensions of the exhaust valve yoke adjusting screws, they generally wear down and will cause the yoke to become "unbalanced" resulting in side loading of the guide pin in the head, which can eventually break. The broken rotocoil springs are an early indication of this. I have the tool for the valve seals at work, I'll see if I can get the dimensions of it for you Monday.

[msholl52]

Id really appreciate it. Were between a rock and a hard place here. The reason that I think someone else had played with this thing is that it looks like someone has worked on it before, and the build report I got for this truck said that it was installed with the heavier springs and the rotators on the bottom. I dont know if build reports are totally accurate or not however.

If no one has worked on this before, besides putting new solenoids in the jake, what would cause the unbalancing? Is it driver error or just a normal wear feature?

[rhasler]

It could be that it had the original heads replaced prior to you buying it.

The screws just wear out. If you look at the bottom of the Jacobs valve yoke adjusting screw you will see that it is a conical type of wedge. Over time this will beat it's way up into the body of the screw. The new screws last longer, but will still go out. The solenoids will not actually cause the problem, it is most likely caused by a combination of parts inside the Jake assembly and the valve yoke adjusting screws. Theoretically it could be caused by recessed valve seats, which would cause increased valve stem height and consequent unbalancing of the yoke, but that is something that isn't too common, at least in my experience.

[rhasler]

Here's a link to the Jacobs Vehicle System website: http://www.jakebrake.com/support/parts-and-service-literature.php?engine_mfr=7&engine_model=42&jacobs_product=41. There is some useful information there.

Here is a Mack bulletin from that website regarding various scenarios with the 690 series brake.

SB-266-017.pdf

[rhasler]

Here are a couple of pictures of tool J-45423, one from the side and one from the bottom side (where the seal fits into the tool)

dimensions are as follows:

Overall length-3.000"

Large OD length-1.425"

Small OD length-1.575"

Large OD-1.750"

Small OD-1.250"

ID #1 (opening)-.818"

ID #2 (middle opening)-.650"

ID #3 (lowest opening, valve stem pilots into this bore)- approx. .375"

Valve stem pilot hole depth (from end of tool opening to bottom of bore)- 2.512"

ID #1 length (length between ID #1 and ID #2) -.486"

ID #2 length (length between ID #1 and ID #3) -.786