1991 MH 600 cabover white smoke

[South of Heaven]

Hi boys. So I have a 91 MH 600 cab over with the E6 engine that I added to my fleet last year. It's been pretty solid so far but we've put some decent money into it as of recently....new turbo, straight pipe exhaust, replaced 4,5 and 6th injector lines, etc....

Well as of last week it's been blowing white smoke a lot. At idle, at low revs and at full revs under load. Also noticed some smoke coming from the oil dipstick tube. I don't know what's going on but I'm not happy. This is a daily driver and does 400 plus miles a day to Mass and NYC/PA most weeks. Need to get a handle on this.

PM was done 10k miles ago but we'll do another one this week...I usually go about 20k miles in between oil and filter changes but now I wanna do it soon and see if that helps.

It has had a bit of blow by ever since I bought it. My mechanic is thinking a valve adjustment would be good to do too.

 

Any other ways to point me about this white smoke?!!!!

Edited Thursday at 02:11 AM by South of Heaven

[Joey Mack]

Are you using coolant ?

[South of Heaven]

7 hours ago, Joey Mack said:

Are you using coolant ?

Not really...it's got a small coolant leak on the left side of the motor by the freeze plug but that's it

[Joey Mack]

Ok. So you suspect raw fuel as the source of the white smoke? You say its a '91 E-6... Shouldnt it be an E-7? And has the injection pump timing been changed or checked recently? When was valve lash checked last?

[Joseph Cummings]

Sudden onset of white smoke and blowby makes me suspect it needs at least one liner kit replaced, if not all 6

[Joey Mack]

You reckon he can use a temperature gun on the exh manifold to find the bad cylinder? 

[Joseph Cummings]

35 minutes ago, Joey Mack said:

You reckon he can use a temperature gun on the exh manifold to find the bad cylinder? 

Can't hurt to try. Lots of times times it'll look wet around that cylinder's exhaust port. Taking the exhaust manifold off is usually a dead giveaway. Usually number 4 or 5 lets go first.

Cracking injection lines one at a time and listening/looking for a change in smoke and blowby can be helpful too

[Mark T]

2 hours ago, Joey Mack said:

Ok. So you suspect raw fuel as the source of the white smoke? You say its a '91 E-6... Shouldnt it be an E-7? And has the injection pump timing been changed or checked recently? When was valve lash checked last?

[Mark T]

I see cylinder kits in someone's future.  

[South of Heaven]

15 hours ago, Joey Mack said:

Are you using coolant ?

Not really...it's got a small coolant leak on the left side of the motor by the freeze plug but that's it

[South of Heaven]

I really don't know any history of this truck and what's been done to it. The only thing I noticed was the fuse panel was replaced because it said 2004 on it.

Radiator looks fairly new too.

I bought this truck pretty much on a whim..... Had it since August of last year. She runs hard. And little by little I'm working through all the problems. We run her all week and then set her in the shop all weekend and dig into her

[fjh]

12 hours ago, South of Heaven said:

I really don't know any history of this truck and what's been done to it. The only thing I noticed was the fuse panel was replaced because it said 2004 on it.

Radiator looks fairly new too.

I bought this truck pretty much on a whim..... Had it since August of last year. She runs hard. And little by little I'm working through all the problems. We run her all week and then set her in the shop all weekend and dig into her

could you post a picture of the injection pump side of the engine!

[Vladislav]

Yup, 1991 is more for a E7. 

E6 has oval side covers on the block at the right side. Those were eliminated on E7. Probably for higher block steadyness for getting more HP and torque possible. E6 has dry liners so seems not much of a chance the coolant gets into the cylinders. E7 has wet liners so possibly indeed. 

[fjh]

4 hours ago, Vladislav said:

Yup, 1991 is more for a E7. 

E6 has oval side covers on the block at the right side. Those were eliminated on E7. Probably for higher block steadyness for getting more HP and torque possible. E6 has dry liners so seems not much of a chance the coolant gets into the cylinders. E7 has wet liners so possibly indeed. 

Pictures please! I hate guessing at shit! Facts!

could be vmac for all we know! Don’t want to send guys chasing rainbows!

[BOBWhite]

Joey you would probably know this; What years and models had the "Econovance" electronic Bocsh pump? I don't know if the Mh ever had that system or if they ever go bad, but that goes along with the subject of timing.

Did you say you had some injectors replaced or was it just the injector lines? Either way finding good parts now is tough especially for fuel injectors. The cracking pressure of the injectors and the spill port timing of the pump is crucial for a smoke free smooth running engine, and most shops don't even offer to check that kind of thing anymore. Now maybe it is just a worn out engine but in that case you can limp it along for a long time if you know what you're doing and diligent about maintenance. I've heard good things about running diesel purge through the system to clear up smoke and smooth out the engine but it's not a permanent fix. 

Now only after you've checked valve lash, injection timing, and the works would I recommend a rebuild. If you are doing 400+ miles per day it's well worth it to schedule a rebuild even just for peace of mind, plan ahead and doing your research will make rebuilds not that big of deal. Hope this helps some