Engine/Transmission (1998.5 - 2002) Valve Adjustment... Wow what a difference!

[rashwor]

As many of you know, two weeks ago, I had a new VP44 put on the truck which solved my hard start problems that had been in existance since 84,000 miles, but getting worse fast since March of 2003. While the diesel shop was doing this, I also had them do the valve adjustment at 137677 miles. It is unbelieveable how much quieter the engine is now. Sounds like a 3rd Gen truck... almost (gotta love that straigt pipe! ). I was driving to work this morning and had to turn the radio way down just to make sure the motor was running... the tach and speedometer said it was. It was not this quiet when I bought it new in 1999.



You might never hear a 3rd Gen blow by if the valves were set right. :{

 

[krs]

"It was not this quiet when I bought it new in 1999".







They're probably too tight.

 

[Pit Bull]

Originally posted by KRS

"It was not this quiet when I bought it new in 1999".







They're probably too tight.

Don't say that your going to make him paranoid.

 

[John]

rashwor, do you know what the valve lash was set to (intake lash/exhaust lash)?



Just wondering

 

[rashwor]

I don't know what it was before or after the adjustment. The truck runs great, just like before. Just quieter.



Don't make me paranoid! I want to believe that there is a good diesel shop in the 'hood.

 

[krs]

I was just teasing you, but you might want to find a subtle way to ask them if they know that you've got solid lifters in there, and not hydraulic ones like some newer trucks have.

 

[Huff N Puff]

The valve lash is .010 on the intake and .020 on the exhaust

Thats quite a bit of lash. KRS is right they are probably too tight. Merv

 

[LSMITH]

I have been running 7 and 16 for 50K miles+. Some members have gone quite a bit tighter than that even. A quick search should turn up enough evidence to ease the fears.

 

[rashwor]

Fears eased...

There was not much to begin with. Considering the miles I get out of these trucks without rebuilds, I tend to think they are well engineered and built. Pretty much bullet proof as long as you don't get carried away.

 

[Huff N Puff]

The Tighter you run a valve

The hotter it runs,a valve cools down, when it seats. So the tighter you run it the hotter it gets. Guys who haul heavy loads with lots of boost are likely to burn a valve. What you gained on the top end,you probably lost on the bottom end,by running the valves tight. Do it right,and you wont have to worry about unintended consequences. Merv

 

[LSMITH]

You will melt pistons LONG before you burn a valve in the Cummins B series turbocharged engines when set to anything that actually lets them close for duration the combustion event. 3 and 11 would probably be safe even.



You are talking gasser Merv, they will burn a valve quickly in the manner you describe. I would also like to mention some of us make our 300HP++ and don't have EGT even approaching dangerous levels no matter what we do, and my low end power is FAR better than anything else I have driven within 100 HP of me. It is also WAY stronger on the bottom than stock. Tight valves did not take bottom end power away, not above 1200 RPM anyway.

 

[TomGolden]

Wow, you guys had me worried a little too, for a bit. I am thinking of having my valves adjusted, truck has 65K miles, and thought it might be worth having done. I posted another thread on this, and those who posted specs, said either 8 & 16 or 9 & 18. Guess they're right in the ballpark then



Tom

 

[Pit Bull]

On both of the 1,000,000 mile trucks I have read about in the TDR they have never mentioned adjusting their valves. They talked about other maintenance being performed. I am not suggesting that you should not adjust your valves at the recommended interval but I wonder how long any members have gone without ever adjusting the valves in their truck?

 

[Huff N Puff]

One more thing to think about when running your valves tooo tight

The engine we all run,and bomb to the hilt has a very tight piston to valve clearance. So tight that if you shave the head . 030 you will probably have to trash the head or run a thicker head gasket. With this really tight clearance between the valve and the piston,it is concievable at high boost, high RPMs the combination of the two could float the valves tapping them on the pistons,and this is more likely to happen the tighter the valve is. Remember the valve spring is only a 70lb spring 50 to 60 lbs of boost is close to blowing it open. That is 70lbs new I,m sure it will weaken as it ages. Not knocking you guys that are running them tight,just trying to make you think and consider the other issues also. Merv

 

[Roger rodbolt]

Huff N Puff,

You are exactly right. The valve springs weaken quickly and the valve guides on the ISB are wearing out before warranty is up. I put in a bit too much fuel with my new P7100 pump, pegged a 60lb boost gage and drilled the imprint of 12 intake valve neatly in my pistons... ... ... ... ... ... ... ... ... ..... Too much boost with too little spring pressure. On lower horsepower setups I've run tighter valve lash with good luck, the stock spec's have a lot of tolerence but if you are running big boost or rpm watch out :--). Larry

 

[dshawhan]

Roger rodbolt

How much power/fuel did you have hitting that thing with the

P-7100 pump in order to do that? Just curious about it.

Thanks Dan

 

[Roger rodbolt]

Dan,

I had an excess of fuel but lower power when the valves hit. The didn't just kiss, but made clearance grooves in the pistons!!Blew the head gasket on all six cylinders at the same time. The 60lb boost gauge pegged the first time I opened it up in 6th gear on a steep hill, made it to 2600rpm and pow... ..... This was with a Piers Stupid pump, first tried a '913 pump with all the mod's I could do but couldn't get the power that I had with a VP44. Now I have plenty of fuel but still down on power. I've won most of the dyno days and single turbo sled pull classes with my other VP44 setup. I didn't dyno at Muncie this year but guess that I'm still down a hundred peak horsepower or there about and lost tons of low end torque. At Muncie I had other issues too, split intercooler losing boost and external wastegate problems. This week I swapped out the intercooler and resolved the wastegate problem, cut the fuel back a bit, the truck runs better and I will get a couple of sled pulls Sat. night against some ShowMe Smoker trucks.



Just so you know, I ran the stock headgasket and head and had no engine troubles, until I put on the P7100. There is a glimmer of hope that I can get the problems resolved but right now I'd say I took a good running (well past 500hp), very streetable CTD and turned in it to a piece of . Still working on it. Larry



Edit,

BTW, I ran same LSmith's valve clearance when I had a stock cam without any issues.

 

[Josparkz]

right now I'd say I took a good running (well past 500hp), very streetable CTD and turned in it to a piece of . Still working on it. Larry



Edit,

BTW, I ran same LSmith's valve clearance when I had a stock cam without any issues. [/B][/QUOTE]



I guess I missed the story on why you switched pumps and don't switch the old one back

 

[JJW_ND]

Tighter clearance OK for 12Vs ?

I see most of you are 24V's. Anyone running tighter clearance with a 12V?



What exactly do you gain? what do you loose?



jjw

ND

 

[LSMITH]

12V can run a tad tighter too. You gain airflow, and slightly advance cam timing. EGT will drop a tad, power will move up slightly in the RPM band and throttle reponse/spool seems to be a tad better. Noise drops quite a bit too.



The best way to explain what it does is for you to spend an hour under the hood. Set them loose on saturday morning, say 14 and 25, then sunday morning set them at 7 and 16. You get to drive around a little with them set at spec on friday if you have been keeping up with them, loose on saturday and tight on sunday. It will be dead obvious to you at that point what suits your personal driving style and use of your truck, then you can fine tune a couple thou each way of the one you liked to get the best for you in your truck.