Old is new

[gmctd]

Have been helping the neighbor with his '83 6.2 Burb - it's still a 23mpg 2500hd tow monster, but needed gp's and injectors and timing chainset at 289kmi - disassembly sorta seems like it may have been a '93 Mr Goodwrench crate engine, with the '93 DB2

The CDR system from '83 is clunky and Goldbergian, CDR input directly from the oil-fill tube neck, CDR mounted on the alternator, two tubes run to the divided-plenum intake manifold, so I upgraded it to the simpler '89-up system.

Which brings me to the subject of this post: the beauty of that '83 system is that the new AMG 6.5TD engine uses that identical CDR system: CDR input directly from the oil-fill tube, thru the CDR cannister, thence to the compressor inlet plenum

Now, why would the engineers revert to that earlier, superseded, obsolete design for the newest upgraded version of the 6.5TD?

Well might you ask, gentle readers, so gather 'round for a tale of intrigue and far-reaching consequence.

To wit, the new 6.5TD engines are designed to be used with a charge-air cooler, but the most recent CDR system results in much oily vapors in the intake system, being drawn out of the passenger-side valve cover, with all that valve-train action thrashing the oil into excessively rich vapor(s) - even takes a bunch of 3M Brillo pads in the valve-cover to attempt some coalescing of the heavier component, but still not good enuff for a t\c c\a cooled system.

Thus, the move back to the oil-filler tube crankcase depression regulation system, with an internal splash-shield over the timing chain-set, reducing the oily mist in the crankcase effluent

Guess whose '89 GMC 6.5TD charge-air cooled engine was the recipient of that old\new CDR system, eh........................:coolgleamA:

 

[Z79outlaw]

I was under the impression that the design that exits at the turbo compressor had to do with emissions also? This new engine design would not be under as strict emissions rules either. Am I off base here?

 

[gmctd]

Correct - all the CDR systems are to help the light-duty 6.X GM Diesel engine (and others) meet passenger-vehicle emissions requirements - that was the pennance for installing the Diesel in the 1500 series trucks - but it is a problem with a turbo-charged system, which will draw way more vacuum than a n\a engine of the same displacement

And current emissions standards are becoming tuffer, not easier, with more and more states testing the Diesel to meet specs

 

[Canadian Rigger]

this is the reason why i'm contemplating dual covers going to one CDR.

 

[Z79outlaw]

And current emissions standards are becoming tuffer, not easier, with more and more states testing the Diesel to meet specs

Correct, but I was was thinking that this new motor would be under less strict emissions due to the fact, that it isnt going into any production vehicles? or is because it is intended to be used for re-powering and updating older fleets, for the military and on a lesser note public vehicles, it is still subject to current emissions laws? and if that is the case wouldnt, this motor require a DPF or some other type of after combustion emissions device? That is one of the reasons I originally assumed it wasnt subject to the same emissions laws of the L65 and L56 motors.

 

[gmctd]

Dunno - if it has an EGR, it will be to meet civilian EPA reg - but, since it was only for military, and popular demand has made it available to civvies, who knows how states will handle installation into older production vehicles - grandfather clause, maybe

Point of my post was for the charge-air cooled crowd needing to meet federally-mandated state inspection criteria, the old-style setup would create less mess in the intake while meeting equipment requirements, with functioning CDR system

If you do run across any further info on the emissions scenario, post it up - won't be long B4 everyone will be asking about it

 

[Slim Shady]

====

GMCTD, How much less, oil mess do you get in the intake/ intercooler? I uh kind of uh didn't hook mine up to the intake. I couldn't bring myself to get my new intake or intercooler dirty. I kind of regressed back to the old draft tube days, only it drafts into my frame. Makes good rust proofing though:errr:

 

[Brooklyn Tow]

So with all this being said............Would members of the Massive Blowby Club benefit from this older system?
Any tips on keeping my intake and turbo a little cleaner...........it's an oily mess!

Thanks,
Louis

 

[gmctd]

There is no easy cure for massive blowby - worst case = long difficult starting, like my Kubota, soon to be rectified - guess you could plumb that into the exhaust pipe, back B4 the muffler, so it wouldn't be so obvious

I just installed the '83 oil-filler tube yesterday, but didn't get any further than that, as the CRD Jeep in my driveway is way more interesting - however, if oem is using the system again, they must have tested it for less raw vapors into the CDR, or they'da just left it the way it has been since '88, imo

 

[ghitch75]

as far as blowby goes...was playin' with the 93 a few weeks ago and it has a little blowby...so i removed the air filter(elbow with a 25 buc cone filter) from the elbow and i covered a 1/4 of the elbow with my hand and all signs of blowby where gone(this was at idle)..uncovered and the blowby came back.......my point is do this high flow air filter make blowby worse?..there has to be a fine line between enough cfm for little smoke and full power?...so could it be that a lot of blowby pep's are seein' from a to open air filter for the CDR to wok as designed?.....never payed an attention when it had the factory air box on it....

 

[Slim Shady]

as far as blowby goes...was playin' with the 93 a few weeks ago and it has a little blowby...so i removed the air filter(elbow with a 25 buc cone filter) from the elbow and i covered a 1/4 of the elbow with my hand and all signs of blowby where gone(this was at idle)..uncovered and the blowby came back.......my point is do this high flow air filter make blowby worse?..there has to be a fine line between enough cfm for little smoke and full power?...so could it be that a lot of blowby pep's are seein' from a to open air filter for the CDR to wok as designed?.....never payed an attention when it had the factory air box on it....

What you did was restrict the air intake so it sucked more air from the crank case.

Like having a draft tube seeing smoke coming from it then adding vacuum to the tube. When you restricted the intake by covering the elbow you created a pressure differential that drew more of the crank case vapors from the engine.

In the original 5.7 liter diesel days we used to put a piece of paper over the oil fill tube and if the paper stayed sucked to the oil fill tube the engine was deemed ok as far as blow by, If the paper wouldn't stay after a thorough check of the engine then the motor had to much blow by and may need a re ring. The heavy guys did more re-ring jobs than I can remember. One guy could do one a day, but he worked for his money.