Engine/Transmission (1994 - 1998) How much valve lash variance do you have?

[SRath]

How much variance do you guys usually find when you check your lash?



How often do they usually need adjusting?



I was just out checking the valve lash on my '96. It is the first time it has been done in at least 8 years and nearly 100k miles (oops... ).



After finding TDC for #1 and checking all 6 valves for that position, the worst I could find was ONE exhaust valve that was at . 021 instead of . 020 . "Oh c'mon! That can't be right. "



So I double checked them: The intakes would just take a . 010 with some drag, but would not take a . 011 feeler gauge. The exhausts were the same using . 020 and . 021 .



I find this a little strange. Is this normal? If it weren't for the leaky valve cover gaskets that I needed to replace, this would have been a wasted effort so far. It is really tempting not to even bother to rotate 360* to check the other six valves, though I know I will...

 

[PToombs]

The first time I did mine, it had 190k on it. I found 3 or 4 that were out 1 or 2 thousandths. I know the valves hadn't been done since the truck was young, 30k or less. I was pleasently surprised.

I must have 1 of the trucks the assembly line guys liked. I did the KDP and cover bolts today. Pin hadn't moved, and the bolts were all tight!

I love my truck!

 

[SRath]

That is good news, Pete. It's kind of strange to think there might be something I'm doing wrong when I find no wear. The only reasons I can think of for the lash to change would be cam lobe/lifter wear, valve seat wear, or rocker arm/valve stem tip wear. A lifetime of good synthetic oil and good pre-ULSD fuel (with lubricant) may be paying off. It will be more of a challenge and expense now that USLD has taken over...



I was going to start my KDP tab fix today, but discovered my biggest wrench was only 34 or 35mm, and I need a 36mm for the fan. I'll have to bribe one of the shop mechanics into loaning me one tonight when I go to work.



It is especially encouraging to hear your dowel pin hadn't moved. I'm hoping all the oil grunge I washed off my timing cover is just from the seal. The sides of the block were far worse from the leaky valve cover gaskets. I would think a cracked timing gear case from the KDP would leak a lot more oil than I found, so I'm hoping I find my KDP still where it belongs, too.



I don't blame you for loving that truck! That is tremendous durability.



My son is gung-ho to build his first truck. He's almost 14 and still "has nothing to drive" after all... (two motocross racebikes and a jonboat don't count?)



I think a nice 1st generation Cummins Dodge like your's would be a good truck to build. I'll have to do a lot more power improvements to my stock '96 to convince him the Cummins is at least "as cool" as the built 454 in my K30, though. (not to mention far more affordable to drive... ).

 

[hsmith]

I've done several, and have not found any more than a couple of thousandts out of specs. Always go back with new gaskets too.

 

[Dieseldemon]

I have seen them from a couple of thousands out to 30 to 40 thousands out the intakes tend to tighten up and the ex loosen up.

 

[SRath]

I wondered if they could tighten as well as loosen. On our 4-stroke motocross bikes, tightening is what you have to mainly check for. They are more of a pain to adjust, and require shims instead of having adjustment screws. Good to know, thanks.

 

[tgordon]

Hmmmm, maybe at 180K I should actually buy myself a set of feeler gauges and check mine:-laf Before it quites purring .

 

[PToombs]

SRath, I didn't pull the fan from the hub. I removed the 6 10mm bolts that hold the pulley on the hub, slid the pulley foward, then had enough room to pull the fan tower bolts. It was interesting putting the fan, tower and shroud all in at once, but it wasn't too bad.

I work on these in a Case dealership, and can't remember ever seeing any valves tight when I did an adjustment. Usually either good, or loose.

The oil on the side of your block could also be from the tappet cover. The bolt behind the IP is a tough one to get to.

 

[GAmes]

I'd say it is normal. I seldom have to do any adjustments, and then, as you, only 1 or 2 thousandths. I keep extending my mileage intervals, but I'm afraid to ignore checking it entirely. I replaced my original cam and lifters at about 450k with a PDR cam, not because of wear, but because the front gear case was off to replace the gasket anyway, and I knew the increase in fuel mileage would be paid back in a few months.

 

[SRath]

"The oil on the side of your block could also be from the tappet cover. The bolt behind the IP is a tough one to get to. "



PToombs, Can you elaborate on this for me? Is there a cover on the side of the block hidden behind the fuel pump? Just on the drivers side of the engine?



I will check that, if so and if I can, and appreciate your bringing it up.



I know for a fact the valve cover gaskets leak down the passenger side. I could see oil dribbling down even right after washing it. It fills up the little cups that look like mini freeze plugs and then runs down around the injector bases.



Thanks!

 

[SRath]

As a member of the 550K+ club, GAmes, you certainly are doing something right! That's impressive. How many miles are you shooting for?



Its good to be reassured by you guys that this is normal. Did the PDR cam deliver noticeably better mileage?

Thanks!

 

[GAmes]

How many miles are you shooting for?



Did the PDR cam deliver noticeably better mileage?

A million of course



The cam gave me about 1. 5 mpg average. I did the math once, I think payback started around 58k.



As for the leak behind the IP, that is why I had the gear case off. It was leaking from the gear case to block gasket. The oil streamed down from just below the head (about a quart every 1000 miles). When it was just a trickle I had limited success with spraying brake cleaner behind the IP and then coating the area with black RTV using a long handled artist paint brush. That worked for 150k or so. Recently I had my vacuum/power steering pumps off and saw that I had a lot better access to that area. The leak is fixed, but if it starts again I'll remove the pumps and try the external RTV again. Way cheaper than removing the front of the engine for a $20 gasket if it works.



Of note here is when Michael from Hot Rod DieselHotRodDiesels, Your Houston/Galveston Diesel Performance Headquarters

removed the IP he noted that the rear mounting bolt was gone. My theory is that since there was no support on the rear of the pump that the weight hanging off the front mounting bolts caused enough distortion in the gear case to cause the gasket to leak. If you want to look for it, I'll try to explain where it is located. There is a bracket bolted to the side of the block. At the bottom of the bracket is an L shaped bracket for the power steering pump. At the top of that bracket is a bolt that goes into the IP. It is hard to see in a 2WD, I'm not sure if you can see it at all with a 4WD. I can feel your pain chasing leaks. I've replaced every gasket and seal on the engine at least once.



On edit. The tappet cover is shown in this picture. It is the rectangular plate behind the arrow pointing to the fuel/water separator and drain valve.