Engine/Transmission (1994 - 1998) blowby

[RBratby]

just wondering how do you know if you have blowby? i dont think i do but my engine sounds like it has a little metal to metal sound when crusing. does anybody know what this sound could be? thanks.

 

[bmoeller]

When you have blow-by, if you look under the truck, you can see light smoke coming out of the blow-by tube. If it is light enough though, you may not be able to see it because of the fan blowing it away.

 

[RBratby]

on startup of the truck should you see some smoke come out of the blowby tube?

 

[bmoeller]

To be honest, I've never paid attention at start up. Haven't noticed any with my truck yet. With farm tractors, that is a different story. I think generally, an engine either will or won't when running. I suppose it is possible to have it only at start up. That is the time the engine will get the most fuel, even compared to a hard pull. Could be different on a heavily modified engine though. Not sure, haven't been around one that was (at least up close to look at it).

 

[CATCRACKER]

i have a d3 cat dozer that pours out white smoke at start up when it is cold and clears some when warmed fully.

 

[Forrest Nearing]

my truck coats the underside and the back of the truck with oil mist on long trips... oil consumption is still well within Cummins spec, so I just look at it as corrosion protection and hose it off at the coin-op



Forrest

 

[JGheen]

Yeah, I don't get much consumption, but every once in a while my blow-by tube drips one or two drops of oil onto the driveway. Noticed some drops this weekend while changing the oil.



BTW, since I mentioned oil change... . does anyone know what the oil drain plug is torqued to?? I always tighten mine too tight and this weekend I torqued it to 45 ft. -lbs. Is that too much?? It didn't feel like much.

 

[bmoeller]

The drain plug doesn't even have to be that tight. I just grab the ratchet at the head, and turn til snug. Still have to use my long handled 3/8" drive ratchet to break it loose on mine.

 

[Softe]

'99 manual specs the oil pan drain plug at 44 ft. /lbs.

 

[JGheen]

Thanks, guys. Glad I didn't tighten it too tight this time.

 

[Andy Redmond]

Blow by can be checked precisely by a manometer and a restriction orifice in the blowby tube. A wide parameter can be in spec. and explain why Forrests' truck will give free undercoating and others only drip a couple of drops. Further Forrests' truck may have done this since new (to a lesser extent)... In a rebuild situation tighter clearances are usually preferable to prevent as much blow by as possible, as the engine wears over its lifespan.



My own ride is in the middle of the spec. and seems to need the "catch bottle" dumped every three to five thousand. It has not changed appreciably since I purchased the truck and to date.



I've noticed different oils seem to be more easily consumed than others. Currently, I'm running some syn-blend by Shaeffer Mfg. (St. Louis). On this cycle, I've not needed my add'l pint at 3000 miles as has been the standard with Delo, Rotella and some others that I've run in the past.



Good luck

Andy

 

[Forrest]

Got some broken plug pics on the readers rigs.

 

[Vaughn MacKenzie]

Forrest can you tell us how to go about testing blowby volume? What size orifice? I would like to do a "baseline" reading on my 2003 now that I have 27,000 miles and should be nicely broken in, and then I could see how it does at say 100,000 miles for comparision and thereafter.



Vaughn

 

[Andy Redmond]

Vaughn:



I don't have the service tool book on the ISBe/HPCR?



The 6BTA5. 9 (12 valve) uses a 3822476 # the orifice is . 221, the manometer that connects to it is 3824637 or the ST 1111-3 and the ST 434 vacuum gauge.



Its much cheaper to find and independent or a Cummins Service center to perform the test than to buy the tools. Many Cummins places only charge an hour of time for this. .