Author Topic: reply to the detroit question  (Read 2631 times)

32 coupe

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reply to the detroit question
« on: March 02, 2014, 06:14:17 PM »
I am around them every day.
Great design.. they all have superchargers....some have turbos..
Run forever...bad on fuel....EXPENSIVE to repair.....'nuf said.
Doc
Metro 6/1 turning a ST 7.5 KW gen head
Changfa 1115 turning a ST 15 KW gen head
Ashwamegh 2/25
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New Holland TC 30

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mobile_bob

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Re: reply to the detroit question
« Reply #1 on: March 05, 2014, 01:05:30 AM »
back when they were used in trucks, pre '85 or so, detroit would not warranty for oil consumption until it exceeded 1 gallon per 800 miles

1 gallon in 4000 is very good in my opinion, most never came close to that good even when new.

as for how long will it live? no way to tell other than it should have another couple hundred thousand in it given the oil consumption criteria and if it is well maintained and not abused.

problem is there are any things that can take it out long before then, it could be 200k more miles or it could be 10k more miles... all it takes is a liner o-ring failure and antifreeze contaminating the oil, lack of attention and you loose bearing material pretty quickly... or  a bad water pump, blown coolant hose and a severe overheat and the engine is then due for an overhaul.

in my opinion, if you have no records of the last overhaul, or if the thing is 20-30 years old , or some combination, then you really can't say how long it might last.

bare minimum, if i knew nothing of the records of the engine, i would at the very least
drop the oil pan and have a look at the brgs, pressure test the coolant system and check for weeping around the bottom of the liners (*more on this below)  and if all looked good button it up... then replace the water pump even if it shows no signs of leaking, and replace all the upper end coolant hoses at the very least (they are the ones that run the hottest and under the most pressure and likely first to fail)

lastly (because i forgot to mention)  if the brgs look like they have a bit of wear, i would replace them while your in there... brgs, hoses and waterpump, along with new tstats are cheap insurance.  minimum oil pressure hot at idle is around 5psi, so don't freak out if it isn't much above that.

also... take a look at the air box drains!  the tubes below the air ports along the side of the engine right below the inspection covers... make sure these tubes are open to the ground and not connected back to the pan via some sort of check valve thing. there is a tube at the rear of the block on both sides and these must be open to drip on the ground...

reason being the 92 series has water above the ports on the liner, if the liner orings start to leak the tubes must allow this coolant to drip on the ground, else it will end up in the crankcase and brg failure is the end result. 

there were a few years of production where detroit used the check valves and ported the tubes into the crankcase!!  this proved to be a very costly mistake for detroit and they put out a service bulletin calling for the removal of the checkvalves and porting the tubes so that they could leak on the ground.

not all of those engines got the alteration/recall done on them, it might be this engine has them and that would be the first thing i would remove.... if the engine has them and you remove them, then yes you will get some oil on the ground where you park, that is just part of the fun of living with a detroit... far better to deal with some dribbling than to have crankcase contamination and bearing failure in my opinion (and also in the opinion of detroit)

*getting back to checking for seepage at the liner packing... the only way to really check this is to pressure test the cooling system, and leave it pressured up for a couple hours, both hot and cold test, and look for drops on the ground under those pee tubes (airbox drains)  if you have any signs of antifreeze on the ground, you must then remove the airbox covers from the side of the engine and check around the liners above the ports for seepage of coolant... this can be quite a challenge because access is tough in most cases, so maybe one of the new fangled video probs could be pressed into service to aid in checking thing over...

if you see no antifreeze seeping around a liner, but coming down under the ports along the bottom of the airbox, and if the engine is turbocharged it will have an intercooler, which might have an o-ring failing or a crack in the cooler core itself. 

in any case, there should be no signs of antifreeze coming out of those pee tubes.

having said all that, you might see some water droplets under some conditions, such as cold running and very humid days, the water in the air can condense (will condense) and show up with the oil droplets on the floor... don't worry about that source of water, it is normal
 
you do a taste test to determine if it is water or antifreeze (yes i know folks are gonna gag on this one)  just dip the end of a finger into the water and touch it to the end of your tounge, if it isn't sweet, but just tastes like oily water your ok!  if it tastes sweet it likely has antifreeze leaking somewhere.

in closing these engines are quite durable and can provide a long service life, given decent maintenance and driven properly.. don't overheat them, and don't allow them to run unloaded any longer than is absolutely necessary... use straight weight oil only, minimum 30weight, preferably 40weight series 3 diesel oil only... do not use multiweight oil unless you want to see the oil consumption to escalate.

and never ever ever let any mechanic do any sort of adjustments, valve/injector setting, rack setting or even lift a valve cover and definitely never the governor unless he is an experienced and certified detroit 2 stroke mechanic! 

water pumps, hoses, tstats and even bottom end brg replacement a qualified diesel mechanic should be ok there, but don't let anyone mess with the top end.

doing otherwise and 999 times out of 1000 the engine will not run right till you get it to the guy that should have been working on it in the first place.

good luck
bob g

 
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

honda lee

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Re: reply to the detroit question
« Reply #2 on: March 25, 2014, 02:18:58 PM »
Thanks for all the great info! If I do have a major problem in the future is it an option to replace it with something else? I know anything is posable with enough money but I'm thinking more like a good used commings  out of the recking yard. What's your thoughts?