turbo noise after adjusting engine valves

[jakecorn]

I have a 1990 Dodge diesel that a local mechanic adjusted the engine valves. Now the truck sounds like a non-turbo diesel with the air cleaner off--you hear a intermient sound in the air intake. We double checked the valves and one was very loose and one was a little tight, even though they just adjusted them about 10 miles before. We set them again, and the noise was a little less, but still very noticeable. I wish I could describe the noise better, but you can hear it very noticeable by listing on the air cleaner housing and the duct that attaches to the turbo. The turbo seems to be spinning.



It seems to have great power, but might be running higher exhaust temps than before.



Any ideas what could be wrong?



Jakecorn

 

[MFalkinham]

Was the engine cold the first time the valves were adjusted? I believe the valve specs are for a cold engine.



- Mike

 

[jakecorn]

I am not sure about the first time, but the second time it was warm. Do you think having the valves adjusted incorrectly could cause the noise?

 

[1stgen4evr]

valve adjustment

If you have any doubt as to whether the valve adjustment is correct look at this:



http://dodgeram.org/tech/dsl/valve_adj/12_valve.html



James

 

[boatpuller]

I would readjust all the valves when the engine is cold, if you have valves that are too tight(which on other engines happens if you adjust them warm when they require cold adjustment and is probably the same on a Cummins) you can burn a valve easily as they won't spend enough time against the seat to tranfer the heat to the head so the valve will get to hot. If you had some to loose and some to tight I would be going back to whomever adjusted them for you and have them go through them again or get your money back because they didn't perform the work you paid them for.



But no matter how you handle it the valves need readjusted when the engine is cold.





Caleb

 

[Greenleaf]

This brings up and interesting question... ... does installing the high performance cam cause burned valves?? I don't believe so. However, what does it change... ... ... ... lift, duration or both? If it changes duration, then the valves are burnes right??? I don't believe a high performance cam will burn valves nor adjusting them a little tight.



Replies... . ?



GL

 

[cerberusiam]

If the sound is intemittent it could be a valve hanging open. What is causing it to hang would be the question. Could be out of adjustment, bent, or a bad valve/valve seat. You should probably do a compression/leak down test to see if you have some valve problems.



Vavles can get burned for a variety of reasons but given they are adjusted correctly, valves and seats good, a performance cam will not contribute to burning valves. The performance cam allows more air into the combustion chamber by changing lift and/or duration. Change either one too much and/or valve springs not heavy enough and the chance of kissing a piston goes up dramtically but since the valves still spend roughly 3/4 of their time closed that in itslef won't cause issues.

 

[boatpuller]

I learned the hard way years ago that valves to tight on an aircooled Volkswagon will burn up, most performance cams increase both duration and lift but the valve still sets on the seat for a good amount of time. I belive that having your valves adjusted slightly tight probably won't hurt anything, but if some valves are tight and some are loose because they did a poor job of adjusting then there may be a valve that is more than slightly tight and I still believe it could cause it to burn.



Just my opinion,

Caleb

 

[JLEONARD]

I agree with what Caleb just posted.

The variation of adjustment indicates very poor practice and who knows what they really got set to. Sounds like that mechanic needs a few more CTDs to practice on before I'd trust him.

FWIW... I vaguely remember a post by the pastor saying there was a temp... maybe 100/120 deg F ... when the valves were supposed to be adjusted. I searched yesterday but couldn't find the post.

Anybody else remember that?

Jay

 

[boatpuller]

My Chrysler Factory service manual says:

"Adjust the valves when the engine is cold, below 60degreesC (140degreesF). "

That isn't very cold, when cold usually means close to room temperature to me.



I would think that if you adjusted them at 140 and then again at 50 there may be a difference, but it's probably not much.



Just my $. 02



Caleb