Rocker Arm/Trunnion Wear - Competition Diesel.Com

XLR8R · 10-26-2008, 04:39 PM

Saw pix of this before somewhere - searched to no avail.

These are from what I'm currently wrenching on:

RockerWear (Large).jpg
Rocker arms have some galling on the pressure side.

TrunnionWear.jpg
Trunnions exhibit similiar features, wear on pressure side is right at .001"

What's acceptable wear on these?
Won't polishing the rocker bores and trunnion ODs to remove the galling be fine, especially in addition to HPC-coating the trunnions?

All rockers & trunnions show more wear on their rearward side than the front - any ideas as to the cause of this phenomenom?

cbtoyz · 10-26-2008, 04:51 PM

Mine look the same way, I have about 26k miles on them. Seems kind of strange to me.

joefarmer · 10-26-2008, 05:08 PM

I was in a 01 yesterday with the same problem. Some have mentioned the lack of ZDDP causes this condition. The truck in question has used Rotella consistently. I have recommended polishing and coating to see if the wear couldn't be reduced or avoided.

triton · 10-26-2008, 05:15 PM

Rocker Lever Bore

Maximum - 22.027mm /0.867in.

Rocker Lever Shaft

Minimum - 21.965mm / 0.865in.

JOHNBOY · 10-26-2008, 05:34 PM

Quote:

Originally Posted by joefarmer

I was in a 01 yesterday with the same problem. Some have mentioned the lack of ZDDP causes this condition. The truck in question has used Rotella consistently. I have recommended polishing and coating to see if the wear couldn't be reduced or avoided.

I have seen it in an 02 that ran Rotella. Which supposedly has more ZDDP than most oils.

Billyram · 10-26-2008, 05:40 PM

That's one of the reasons I don't put CJ oil in my truck

XLR8R · 10-26-2008, 07:59 PM

Well, this truck had a pretty bad oiling history.

The wear limits barely mic'd out OK (thanks Ty), so I reckon there's enough room for the coating.

... now I just need to convince our lube engineer to recommend a sacrificial coating!

GMac · 10-26-2008, 08:13 PM

I had the same problem. I now machine them and use needle bearings.

luvinacummins · 10-26-2008, 08:32 PM

hmmmm i am goona check mine really good next week when i pull the injectors and tighten the studs again...

WUnderwood · 10-26-2008, 08:37 PM

Quote:

Originally Posted by GMac

I had the same problem. I now machine them and use needle bearings.

any pics?

triton · 10-26-2008, 08:39 PM

X2 ^^^^

something like this...

since most of the wear is on the bottom, I wonder how well bearing would hold up.

XLR8R · 10-26-2008, 08:58 PM

Me too - the psi loading has to be an order or two of magnitude higher...

GMac · 10-28-2008, 03:21 PM

I don't have any pics but it looks something like that bearing. The bearing I have has alot more needles in it for support

XLR8R · 10-29-2008, 11:48 AM

You probably use a needle bearing without intervening dead space between the rollers - like in a U-joint cup... that'd be much stronger.

On this mill, we are going with a proprietary coating that has shown great results on piston skirts.

We also have a nifty machining solution that would address the (lack of) hydrodynamic wedge support across the bearing surface, but it does nothing for the dry-start issue... which IMO is responsible for the majority of wear.

GOT-Torque · 10-29-2008, 03:39 PM

XLR8R,

Since the shaft constantly rotates back and forth a small amount (and not continuously in one direction), developing a hydrodynamic wedge support across the bearing surface does not seem feasible... What did you do to address it?

In any attempt to correct the situation, I would think making the bearing the only item that wears would be a benefit (press fit into rocker and onto the shaft). That would make it possible to swap the bearings out every so often (50,000 miles or what ever is necessary) instead of needing to buy new shafts or rockers once they are worn out. If you used the bearing type shown above, it would still wear the shaft out and it would then require replacement...

zstroken · 10-29-2008, 04:09 PM

you could put in a sacrificial wear item. Something that requires lots of attention. What about a brass bushing?

GOT-Torque · 10-29-2008, 04:34 PM

A few months back I contacted Harland Sharp about their rockers (the ones that Zach will be selling soon I think?) and it sounded as though they weren't recommended for the street or many miles due to the wearing involved. Not sure if they used a brass bushing or what?

XLR8R · 10-29-2008, 10:51 PM

Quote:

Originally Posted by GOT-Torque

XLR8R,

Since the shaft constantly rotates back and forth a small amount (and not continuously in one direction), developing a hydrodynamic wedge support across the bearing surface does not seem feasible... What did you do to address it?

Exactly - I could have chosen the wording of my earlier post a bit clearer...

the oil film's thickness is inversely related to the highest-wearing portion of the rocker lever/shaft; machining to increase the oil film's width & thickness could only reduce or eliminate undesirable wear (especially galling).

As posted earlier, I chose to beta-test a proprietary coating for the problem areas in this engine's valvetrain.

Any kind of a brass/bronze (even if oil-impregnated) bushing in this application isn't going to have an adequate TBO on a high-mileage street vehicle.... just too soft.

Full-roller rockers, with needle bearing trunnions, offer low friction and long life.

SPEEDSHIFT · 11-01-2008, 01:46 AM

Mine look the same way as well, and I have ran nothing but Amsoil since 10k. Weird.

*Soup Nazi* · 01-05-2009, 04:32 PM

I got the coating on the trunnions done now. Seems like a winner. Maybe in a few months we can get some data for wear and report back.

The first photo is pre coating and 2nd is after the coating was applied.

10-26-2008, 04:39 PM	#1
XLR8R Name: XLR8R Title: Crew Chief Status: Not Here Join Date: Sep 2007 Location: Denison, TX Member`s Gallery Posts: 1,481	Rocker Arm/Trunnion Wear Saw pix of this before somewhere - searched to no avail. These are from what I'm currently wrenching on: RockerWear (Large).jpg Rocker arms have some galling on the pressure side. TrunnionWear.jpg Trunnions exhibit similiar features, wear on pressure side is right at .001" What's acceptable wear on these? Won't polishing the rocker bores and trunnion ODs to remove the galling be fine, especially in addition to HPC-coating the trunnions? All rockers & trunnions show more wear on their rearward side than the front - any ideas as to the cause of this phenomenom? __________________ 3 Nails Garage Sleeps 3 Rams, 1 G8 & a Goat GUN-HAPPY

10-26-2008, 04:51 PM	#2
cbtoyz Name: cbtoyz Title: Vaginatarian Status: Not Here Join Date: Apr 2008 Location: Fortuna, Ca Member`s Gallery Posts: 577	Mine look the same way, I have about 26k miles on them. Seems kind of strange to me. __________________ Colin. '06 QC, SB, 4x4- 853hp/1467tq. 11.30 @ 122mph "Now a retired tow truck" New project, '96 2wd 12valve= 11.64 @ 120mph. Ponci's Diesel Center (707) 725-3307 Goerend Transmissions Inc. (536)778-2719 ...

10-26-2008, 05:08 PM	#3
joefarmer Name: joefarmer Title: Whiteboards're REMARKABLE Status: Not Here Join Date: Jul 2006 Location: ohio Member`s Gallery Posts: 2,318	I was in a 01 yesterday with the same problem. Some have mentioned the lack of ZDDP causes this condition. The truck in question has used Rotella consistently. I have recommended polishing and coating to see if the wear couldn't be reduced or avoided. __________________ brandon. NHRDA 2009 East Coast Prostock Champion NADM 2009 "Broke for Every Race" Champion firepunk.com buy team shirts

10-26-2008, 05:15 PM	#4
triton Name: triton Title: INTERCEPTOR NIGHTMARE II Status: Not Here Join Date: May 2007 Location: NC mountains Member`s Gallery Posts: 4,551	Rocker Lever Bore Maximum - 22.027mm /0.867in. Rocker Lever Shaft Minimum - 21.965mm / 0.865in. __________________ Garmon's Diesel / Diesel Performance Converters / T&C Diesel Airwerks / High Tech Turbo / AirDog / Glacier Diesel / NADM

10-26-2008, 05:40 PM	#6
Billyram Name: Billyram Title: Diesel Pro Status: Not Here Join Date: Jan 2007 Location: N.Augusta,SC Member`s Gallery Posts: 579	That's one of the reasons I don't put CJ oil in my truck __________________ Billy 04.5 Blue Ram Garmon built tranny SunCoast ProLoc II Dragonflows Wicked's Dragonslayer Smarty

10-26-2008, 07:59 PM	#7
XLR8R Name: XLR8R Title: Crew Chief Status: Not Here Join Date: Sep 2007 Location: Denison, TX Member`s Gallery Posts: 1,481	Well, this truck had a pretty bad oiling history. The wear limits barely mic'd out OK (thanks Ty), so I reckon there's enough room for the coating. ... now I just need to convince our lube engineer to recommend a sacrificial coating!

10-26-2008, 08:13 PM	#8
GMac Name: GMac Title: Stallion High Performance Status: Not Here Join Date: Feb 2007 Location: ohio Member`s Gallery Posts: 68	I had the same problem. I now machine them and use needle bearings. __________________ 2000 Dodge 3500 ext. cab longbed sport, converted to single rear wheel, soon to be 6.7 vgt engine, allison 1000 stage 4 tranny, 315 tires, 4:10 gears, PSC steering box, and way more.... Built By Stallion High Performance 419-545-4217

10-26-2008, 08:32 PM	#9
luvinacummins Name: luvinacummins Title: Diesel Pro Status: Not Here Join Date: Sep 2007 Member`s Gallery Posts: 1,015	hmmmm i am goona check mine really good next week when i pull the injectors and tighten the studs again... __________________ 95 12 Valve with some work...

10-26-2008, 08:39 PM	#11
triton Name: triton Title: INTERCEPTOR NIGHTMARE II Status: Not Here Join Date: May 2007 Location: NC mountains Member`s Gallery Posts: 4,551	X2 ^^^^ something like this... since most of the wear is on the bottom, I wonder how well bearing would hold up.

10-26-2008, 08:58 PM	#12
XLR8R Name: XLR8R Title: Crew Chief Status: Not Here Join Date: Sep 2007 Location: Denison, TX Member`s Gallery Posts: 1,481	Me too - the psi loading has to be an order or two of magnitude higher...

10-28-2008, 03:21 PM	#13
GMac Name: GMac Title: Stallion High Performance Status: Not Here Join Date: Feb 2007 Location: ohio Member`s Gallery Posts: 68	I don't have any pics but it looks something like that bearing. The bearing I have has alot more needles in it for support

10-29-2008, 11:48 AM	#14
XLR8R Name: XLR8R Title: Crew Chief Status: Not Here Join Date: Sep 2007 Location: Denison, TX Member`s Gallery Posts: 1,481	You probably use a needle bearing without intervening dead space between the rollers - like in a U-joint cup... that'd be much stronger. On this mill, we are going with a proprietary coating that has shown great results on piston skirts. We also have a nifty machining solution that would address the (lack of) hydrodynamic wedge support across the bearing surface, but it does nothing for the dry-start issue... which IMO is responsible for the majority of wear.

10-29-2008, 03:39 PM	#15
GOT-Torque Name: GOT-Torque Title: new setup for 2010 Status: Here Join Date: Jul 2007 Location: in the garage Member`s Gallery Posts: 2,647	XLR8R, Since the shaft constantly rotates back and forth a small amount (and not continuously in one direction), developing a hydrodynamic wedge support across the bearing surface does not seem feasible... What did you do to address it? In any attempt to correct the situation, I would think making the bearing the only item that wears would be a benefit (press fit into rocker and onto the shaft). That would make it possible to swap the bearings out every so often (50,000 miles or what ever is necessary) instead of needing to buy new shafts or rockers once they are worn out. If you used the bearing type shown above, it would still wear the shaft out and it would then require replacement... __________________ 2003 6.7 dually - still in progress 2001 PPUMP - Alive once again 2001 bone stock 2000 5.9 305/555 Excursion (wife's rig) www.EATSOOT.com

10-29-2008, 04:09 PM	#16
zstroken Name: zstroken Title: For $$$ your name here Status: Not Here Join Date: Sep 2006 Location: Southwest MO Member`s Gallery Posts: 10,833	you could put in a sacrificial wear item. Something that requires lots of attention. What about a brass bushing? __________________ 01 HO featuring F1, HTT, SouthBend, Haisley 97 Dodge under construction... 24V P-Pump Mafia member #2 Thanks to Mumau Diesel, Goerend Transmission, Hamilton, Disturbed Motorsports, Northeast Diesel Service!

10-29-2008, 04:34 PM	#17
GOT-Torque Name: GOT-Torque Title: new setup for 2010 Status: Here Join Date: Jul 2007 Location: in the garage Member`s Gallery Posts: 2,647	A few months back I contacted Harland Sharp about their rockers (the ones that Zach will be selling soon I think?) and it sounded as though they weren't recommended for the street or many miles due to the wearing involved. Not sure if they used a brass bushing or what?

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