Engine/Transmission (1994 - 1998) Who here has Floated/bent a valve?

[JoshPeters]

What am I in for when I get the head off?



How do I know... ... I pulled the intake air horn off... . and fired it up... . it sounds like a helicopter comming back OUT the intake.



What happened? 3200rpm before a shift according to the perfectly accurate, never wrong Dodge tach. I'm guessing it was higher than that, I just don't know it for sure.



I'll take pictures and let you guys know what I find when I get the head off..... :{



Obviously a valve..... possibly some seat work..... ? What do you think guys?



Josh

 

[bmoeller]

Valve(s) may be fine. Check the the pushrods first. Could be one that is bent. Maybe a problem with a rocker arm as well.

 

[Vaughn MacKenzie]

How do I know... ... I pulled the intake air horn off... . and fired it up... . it sounds like a helicopter comming back OUT the intake.

Hmmmmm . . . a loud choppy sound out the intake is normal when running without the air horn installed. Are you sure it's broke?

 

[JoshPeters]

What I have done..... Removed and checked all the pushrods... . Good. Set the valve lash, good. Cracked the injection lines one at a time to find a miss... . all cylinders seem to drop off approx the same. The sound is like a one bladed helicopter comming out the intake. The engine Misses on one cylinder VERY heavy, but it still fires slightly. The noise out the intake is in time with the miss. When I turn the engine over without starting it, there is one cylinder that turns over WAY to easily.



The sound is like nothing I have heard out of a diesel engine before. I wish I could record it for you and play it here. Mark at Piers, Turbo Tweaker, HoleshotHoleset and SpicyJam have heard the noise, and we all agree that it seems to be a bent valve.



Josh

 

[NIsaacs]

Josh, it sounds like you are not sure which cylinder is bad. You need to find it and check the valve operation while it is running. Usually when you get noise out of the intake, it means the exhaust valve is not opening, maybe a flat cam?





"NICK"

 

[JoshPeters]

Well I have run the truck with the valve covers off, and watched the valvetrain. Everything appears to move normally and equally on all cylinders.



I do have a pretty good idea what cylinder (#1) is the issue. When I first fire it up and run it for a couple of min number 1 is much much cooler than the other 5 cylinders at the exhaust manifold.



I'm open to ideas guys... believe me I'm not looking forward to pulling the head again... . but ya gotta do what ya gotta do.



Josh

 

[NIsaacs]

Josh, I would pull number 1 injector and do a compression check. If it is good, maybe your injector is bad, if the compression is low, then you must have a bad valve or piston. But if it was a piston, you shouldn't have the helicopter noise.





"NICK"

 

[Vaughn MacKenzie]

Josh a couple ideas. . . if you can get a hold of an infrared thermometer you can check the temp of the exhaust at each cylinder after it's warmed up. The bad hole should be cooler.



A compression check would tell the story too like Nick said, if you can get a hold of a tester.



I have quite a miss on my '96 as well, but I'm sure my motor is tight and the pump is the problem.



Good luck, Vaughn

 

[JoshPeters]

I don't have access to a compression checker or that would be done already. I'll have to get my infared thermometer from work on monday.



I'm sure it's not a piston... . I'm quite sure it's a valve at this point.



So back to the origional question... .



What am I in for here?



Josh

 

[Vaughn MacKenzie]

Josh when you did the valve lash was any of them off much? If a valve is stuck and not closing all the way then the lash would be quite loose on that valve. Any way you can measure stem height?



If you were to disconnect the plug controlling the shutdown solenoid and crank the motor over does it sound uneven? Have someone crank the motor while you listen at the intake with the horn off too.



It sounds like an intake valve if you hear a helicopter sound. So if someone cranks it you should hear it hissing back into the intake.



If it cranks over with a lope and you hear air hissing back into the intake I think you'll be looking at pulling the head. I know how you feel, I'd hate pulling the head again on my truck. . . there's a point where wrenching on a truck gets pretty old (I'm there myself).



I don't see how 3200 RPM would cause a problem, unless you got a real weak valve spring (definitely have them tested when you remove the head). Have you ever replaced them? You got a lot of miles on your truck? How did your head look when it was off before (why did you have it off)?



Good luck, Vaughn

 

[JoshPeters]

Josh when you did the valve lash was any of them off much? If a valve is stuck and not closing all the way then the lash would be quite loose on that valve. Any way you can measure stem height?



If you were to disconnect the plug controlling the shutdown solenoid and crank the motor over does it sound uneven? Have someone crank the motor while you listen at the intake with the horn off too.



It sounds like an intake valve if you hear a helicopter sound. So if someone cranks it you should hear it hissing back into the intake.



If it cranks over with a lope and you hear air hissing back into the intake I think you'll be looking at pulling the head. I know how you feel, I'd hate pulling the head again on my truck. . . there's a point where wrenching on a truck gets pretty old (I'm there myself).



I don't see how 3200 RPM would cause a problem, unless you got a real weak valve spring (definitely have them tested when you remove the head). Have you ever replaced them? You got a lot of miles on your truck? How did your head look when it was off before (why did you have it off)?



Good luck, Vaughn

OK, sorry about the delay getting back to this thread.....

The valve lash was all out of whack due to the last time I did a headgasket, after my last retorque I didn't get a chance to reset the lash. No real indicator there... . But very good idea!



Before I tore it appart (yes it's appart again) I would turn the engine over and Your "Lope" as you said, is a very nice way to describe it. Definatly back out the intake, in the 1mile from my house to the shop I work at, the intake air preheater turned black!



I'll get pictures, but the headgasket blew... . again. This is number 5. This time I deserved it. It's blown between cylinders 4 and 5. The blown our portion is over 1/4'' wide between the cylinders!



I tried to go cheep and just use a Fel-Pro headgasket and studs. I knew I was going to be pulling the head again, but I didn't think it would be this soon. The truck has 260,000 miles on it and will be getting 4,000rpm valve springs as well as Fire Rings before it goes back together.



Just a little history for ya on this whole ordeal for me... .

About a year ago, I blew my first, stock headgasket. I replaced it, but got the wrong torque specs. Blew it, replaced it. Blew it for no known reason. Looking at the gasket possibly not enough clamping force. Studed it with another stock gasket. Blew it. (each time the headgasket blows it's about 300 miles) but the entire time I had been checking the head with a 12'' straight edge... . After a Fellow TDR member SpicyJam brought over a 36'' straight edge it was found the head was warped. Machined the head, and put it together. This time I put in a FelPro Gasket ($40 vs $100 for Cummins) Well I just blew that one... this time I honestly think it's because of Cylinder pressures, not a head issue.



Sorry for the long post... but it's the update. Pictures to come!

Josh

 

[HoleshotHolset]

Did you fix your delivery valves yet?

Now you can fix it like I told you to fix it a year ago! :-laf



Matt

 

[Vaughn MacKenzie]

Josh now with a decked head, studs, and the right head gasket, the next one should be your last.



Even though you just decked your head, might not hurt to straightedge it again before putting it back on.



Vaughn

 

[JoshPeters]

Yes Matt I did switch the DV's. I did that and fired it up... . Man was there soot! :-laf



I'll definatly be running a straight edge over it again. I don't want to spend the "big money" on a Fire ring gasket and have a warped head.



Hey Matt..... If I only had the money! And a Year ago I didn't know the head was warped!



I'm honestly thinking about changing my SN here to BrokeItAll or HeadgasketMan..... What do you guys think?



Josh

 

[CumminsAholic]

I think that what goes wrong with your truck goes wrong with mine. You didn't bend a valve then? I think I may have. I'm going ot see if I can find a comp gauge to test it, but i makes a weird almost surge shh shh shh (really quick) after 25lbs of boost if I'm not at wot. At wot I have a miss. Will post in the 24v forum about that. Maybe the surge is the turbo, it didn't do it with the stocker. Other than that I'm really happy with the mods, this thing rips.

Corey

 

[JoshPeters]

Corey, I believe that is the compressor surge that they have been talking about with those Phat Shaft turbos. I would like to hear if to know for sure, but that's what your description sounds like.



The Miss sounds interesting.



Josh

 

[CumminsAholic]

I'm really hoping that's what it is. If that's the surge, no big deal I can easily live with it. I still have to find the miss though. I'm calling Brett tomorrow to see if that's the surge or not and to see If I should turn the wastegate shaft or boost elbow to turn up the boost. Overall though all I can say is WOW, I can't believe that a turbo can make that big of a difference. I can't wait to see what Jim says when he gets his on. If you want a hand putting the head back on give me a call, I'd gladly give ya a hand if I can swing it. Also... get that thing fireringed and put some studs in it already, or be a little nicer to it. You drive like me and if you just throw another gasket in it it'll throw it back at you. At least if you were nice to it until you got the other head "done up" you could drive it.

Corey

 

[Johnstra]

btt...



I'm real interested in this thread. I posted a while back that my engine makes a whump whump whump kind of sound when it's climbing a steep hill. It's most noticeable in 5th gear with RPM around 1800-2000. I adjusted valve lash and found #5 exhaust to be pretty far out (loose). After adjusting the sound is much improved but it's still there. Power is good, EGTs are where they should be, boost is good.



Any ideas what the sound is? I read on some old threads in the 24-valve section about thumping noises while loaded heavily being caused by cavitation at the thermostat.



Any other ideas?



Thanks,

-john

 

[Bandit1]

i am wondering if you have a bad injector, like one not popping off with a high enough pressure or more of a stream of fuel putting the fire in the cylinder out.

 

[Johnstra]

I hadn't thought of that, Bandit. Thanks. The shop that tuned my pump can test and rework injectors too. I think I'll give them a call.

-john