Shop project...

[squonk 41,051]

16 hours ago, WHX24 said:

He's right & youda had one for FREE if Ida known ... I kinda hoard them... 

Can't believe a High Roller like Jim has a couple of old ratty Robinairs around and not a high faluting Appion vacuum pump. Yes Kevin you need to evacuate your ac system. Run the pump OVERNITE. Who cares if you burn up one of Jim's pumps anyway. You had that ac system open for a long time. A common mistake shops make is to run a pump for 20 minutes and call it good cause they are in a hurry. I fixed countless body shop ac problems because there was still moisture in the system.

[Pullstart 62,831]

Cool @squonk, I had that feeling but even needed a little confirmation.  Yes, the sound is from the intake pipe.  Lift the filter hat and it’s like sticking your head inside a kick drum.  I feel like the exhaust valve is more of a possibility than the injector, because an injector misfire would likely make smoke in the tailpipe if it COULD escape.  

[squonk 41,051]

1 minute ago, pullstart said:

Cool @squonk, I had that feeling but even needed a little confirmation.  Yes, the sound is from the intake pipe.  Lift the filter hat and it’s like sticking your head inside a kick drum.  I feel like the exhaust valve is more of a possibility than the injector, because an injector misfire would likely make smoke in the tailpipe if it COULD escape.  

In 1980 we had a brand new V-6 Malibu come into the shop thumping. As I was taking off the air cleaner with it running , the lid was hopping up and down. Bad exhaust cam lobe.

[ZXT 2,401]

1 hour ago, pullstart said:

@953 nut @WVHillbilly520H @PeacemakerJack @ZXT @Achto @Greentored @Redneckdavis @ebinmaine @oliver2-44 @HandyProfessor @stevebo @richmondred01 @pfrederi @squonk @WHX24 all you guys and more I think of as hot rodders, engine mechanics, gear heads or might just have a wild hair thought here.  Some of ya might not know diesel stuff, but let’s just think.

 

I know that funnies can get me through this, but please let’s try to focus on the fix for a minute and throw sticks when it’s figured out? Tall order Uncle Jim I know.

 

If you go to the end of the video above, you’ll hear the rhythmic thump backfire.  Diesels don’t have spark, so no ignition timing.  Would valve timing be the only possible answer?  There is no smoke out the tailpipe, leads me to one exhaust valve maybe stuck closed?  Pushrod bent or broken?  I also wonder if the pushrod did something which deadheaded the boost which blew the boot... instead of the boot blowing, damaging something else when the boost all went away?

Somehow I always miss threads.. Didn't see this one!

Sounds to me like it's missing on more than one hole. I'd go for bent push rods first. Sounds like it is hitting at times but not fully - like maybe a valve is opening partially. What were you turning when the hose let go? If you overrevved it and "floated" the valves, you could've smacked a piston with one. Hopefully it's only push rod related.. It definitely sounds like it does have compression on those holes so you're probably ok. 

[Pullstart 62,831]

8 minutes ago, ZXT said:

Somehow I always miss threads.. Didn't see this one!

Sounds to me like it's missing on more than one hole. I'd go for bent push rods first. Sounds like it is hitting at times but not fully - like maybe a valve is opening partially. What were you turning when the hose let go? If you overrevved it and "floated" the valves, you could've smacked a piston with one. Hopefully it's only push rod related.. It definitely sounds like it does have compression on those holes so you're probably ok. 

 

23 minutes ago, squonk said:

In 1980 we had a brand new V-6 Malibu come into the shop thumping. As I was taking off the air cleaner with it running , the lid was hopping up and down. Bad exhaust cam lobe.

 

It was pushing under the red line, but I was surely under a good pull Jonah.

 

I am going to borrow my FIL’s engine stethoscope tool to see if I can pinpoint which side is hurt.  

[Pullstart 62,831]

One of my tool and die tools is a magnetic base and dial indicator.  If there is no visual damage, I’ll roll it over and check the lift and close of each rocker.  
 

Plan of attack is complete!  I think!

[Pullstart 62,831]

The passenger side sounds louder, apart it comes!  Or goes!

 

 

[Pullstart 62,831]

Broken exhaust pushrod!  Intake half sucked air in, combustion happened, blew back out the intake, made noise.

 

 

 

 

[squonk 41,051]

1 hour ago, pullstart said:

Broken exhaust pushrod!  Intake half sucked air in, combustion happened, blew back out the intake, made noise.

 

 

 

 

I guess my hearing isn't as bad as my eyesight. 

[Pullstart 62,831]

So far I have found one bent and two broken rods.  I’ll see about some high performance pushrods to put this back together with.

[Tractorhead 9,064]

Ooooh man, so short before final, that ain‘t fair.

 

Thought the same about eyesight, 

can you make a short vid pointed to the Rocker arm while cranking to see what‘s happen,

or does it hurts anything?

 

never heared before that „pumping“ noise, but in the pict i also didn‘t see any troubles on first view.

was the Pushrod completely cracked or does it just hung by a  stuck valve or similar?

 

 

but however it sounds it can be fixed relativeley simply.

 

I‘m crossing my finger‘s that it be a simple Fix after all the Work you have done.

 

Edited October 1, 2020 by Tractorhead

[SylvanLakeWH 25,525]

7 minutes ago, pullstart said:

So far I have found one bent and two broken rods.  I’ll see about some high performance pushrods to put this back together with.

 

Any guess on cause?

[ebinmaine 67,397]

43 minutes ago, SylvanLakeWH said:

 

Any guess on cause?

That's what I was wondering too.....

[squonk 41,051]

55 minutes ago, SylvanLakeWH said:

 

Any guess on cause?

Yup. You better find out why before you do more damage. Valve spring binding? Collapsed lifters? Pushrods don’t just give up for the heck of it. 

[Pullstart 62,831]

Well, I read now that with increased cylinder pressure (More boost Like the billet compressor wheel) that Duramax engines like to deflect the pushrods.  A turbo boot blew off, but I will likely never know if the boot happened then valve stuff, or valve stuff then the boot blew.

[Tractorhead 9,064]

Yap, i’m with Mike,

the cause was not the bend or broken Pushrod, 

the reason why this happens is more important to find out before try another Start.

 

May be a jumped timing belt?

Dejusted timing...

 

[Tractorhead 9,064]

8 minutes ago, pullstart said:

Well, I read now that with increased cylinder pressure (More boost Like the billet compressor wheel) that Duramax engines like to deflect the pushrods.  A turbo boot blew off, but I will likely never know if the boot happened then valve stuff, or valve stuff then the boot blew.

You mean that the increased boost happened on that issue?

did you know how much the boost is increased?

 

no Wastegate?

did you remember when this issue was happen ?

 

does it comes slightly or immediately?

Edited October 1, 2020 by Tractorhead

[Pullstart 62,831]

I spoke with a Duramax specialist from a nearby performance shop.  He happens to live just more than 10 minutes away.  We came up with a game plan.  I am going to use a straight edge and depth gauge to measure all the valve stem heights.  A bent valve would surely not close all the way.

 

Josh and I were on the road for less than an eight mile.  It all happened so quick, we don’t know what happened first but the noise was immediately following the burst boot. 

[Tractorhead 9,064]

Dang - that‘s the things nobody needs.

 

Are there reinforced pushrods available?

If that’s the reason, that sounds to an relatively easy fix.

Is the duramax valvesteering be belt or gear driven?

 

Keep my fingers crossing that this is all what‘s happen and it can be fixed without much cost.

 

regards to josh

 

 

[squonk 41,051]

If your over boosting not only are going to rattle some pushrods, your going to be popping head gaskets ect. You should watch Gale Banks video's on killing a Duramax. It's for the new L5P engine but there is a lot of diesel info he rattles off that explains what starts going on when you start pushing things. 

[Pullstart 62,831]

1 hour ago, squonk said:

If your over boosting not only are going to rattle some pushrods, your going to be popping head gaskets ect. You should watch Gale Banks video's on killing a Duramax. It's for the new L5P engine but there is a lot of diesel info he rattles off that explains what starts going on when you start pushing things. 

 

1 hour ago, Tractorhead said:

Dang - that‘s the things nobody needs.

 

Are there reinforced pushrods available?

If that’s the reason, that sounds to an relatively easy fix.

Is the duramax valvesteering be belt or gear driven?

 

Keep my fingers crossing that this is all what‘s happen and it can be fixed without much cost.

 

regards to josh

 

 

I am on my way to the salesman’s house to pick up new heavy duty pushrods.  As for over boosting, I don’t believe I’m anywhere near excessive boost, but come to find out stock pushrods are not that strong when a little boost comes into play.  The deck of the upper valve cover is clean of all RTV now and I’ll do some measuring before assembly for sure.

[ebinmaine 67,397]

Interesting and somewhat disconcerting that a manufacturer would spec and build something so close to the theoretical failure point

[Pullstart 62,831]

You know, those cylinder pressures are around 300+ psi compression stock.  Adding even 7-8 pounds of boost is around half an atmospheric bar.  That half bar could effectively equate to another 150 psi if I can be cooled enough when you calculate all the compression ratios... so it’s easy to see how a measly few lbs of boost could have hurt the rods.  

[ZXT 2,401]

Good to see that it doesn't appear to be anything too serious! Were you able to get all of the pieces of the broken push rod out? 

[squonk 41,051]

I would check cam timing at least. All this happened at once. Cam gear pin may have sheared. I don't buy the fact that stock pushrods are barely adequate. I read that bent pushed are common, but there's an underlying issue.