74 Ford L9000 With Dripotroit

[xcavate]

I recently purchased a 74 Ford L9000 Tri-axle Dump Truck. So Far the truck was $3500 and the tow was $700 so I have $4200 as the truck sits.

The problem is the detroit 8v71 motor is dripping out the oil breather tube at about a half quart per hour. The was just at an idle as the truck smokes to much to drive onthe street with a load. Anyone know what I should look for onthe motor? I guess I am going to take the valve covers off and see if some return ports are all gummed up. I know these detroits like a lil but this on seems excessive. The truck had been sitting for a year and before it was parked the owner told me he had a exhaust manifold bolt snap off and the smoke started after the guy repair that. He drilled and tapped the head.

I am just looking to do some local hauling around town with this so i am not trying to spend alot of money and thoughts would be appreciated.

 

[xcavate]

Here are some pics

 

[BIGDAN315]

Is the smoke white ? Does it have a sweet smell ? Things that it would indicate cooling leaking by in the head. Is there any blowby I am not a deisel mechanic but just going by past experiance with them.

 

[xcavate]

I think its burning antifreeze very little smoke at idle looks like just a cold motor then when you step on it the smoke just bellows out and doesnt really look like normal white smoke. The anti freeze was also dripping out the radiator overflow for some reason too.

The previous owner said he had a exhaust manifold bolt drilled out and the guy went to far maybe into the water jacket? Anyone know a way i can test this.

 

[dumptrucker]

does the smoke go away after it is up to temp? As far as the oil is concerned , Just keep adding to it. Never new a detroit not to leak.

 

[Freightrain]

Ya dripping is common issue with Jimmy's. I think it gets worse when it's idled for extented periods(as you see).

 

[xcavate]

Is a half a quart over an hour of idling bad? And it leaked out the same amount of antifreeze from the overflow tank.The truck hasnt been driven on the road in over a year. The previous owner had a problem with the exhaust manifold stud and parked it. The truck has been started twice in the last year and only let to idle. I have to go get a set of batteries and get her running and all warmed up.

 

[rino]

Engine Test

Put a radiator pressure tester on the cap of the radiator, and start the engine. Check the pressure. It should not be over 13 to 15 LBS. If it is, there are remedys that involve head removal. There is a gasket called a figure 8 gasker that seals the water jacket and oil galley from the block deck to the head. These are prone to failure, and since the engine sat for a year, they may be the problem, and oil and water are ran next to each other through these gaskets. Also you might want to have the head magnafluxed at a rebuild center to check the condition of the head! Either way the head has got to come off, and if you don't know haow to set the rack, take it in and let the pro's do it!

Also Check the air box vent to see if there is oil/coolant leaking into the air box! Don't forget that 8v71 is a 2 stroke, and is naturally asperated with the blower! Having a 2 stroke Detroit will make your local Detroit Diesel store very happy! You'll be seeing them once a year with a major problem! Sorry I don't have good news other that be glad that you don't have the 3208 Cat yellow boat anchor!

 

[xcavate]

I believe the air box is where it is all coming from. Its coming from two flexible tubes on either side of the motor on the back side. On one side some white smoke that looks like coolant which isnt that bad and the other side is dripping oil like crazy. Which i am guessing the leaking air box is causing the exhaust to smoke to. I am guessing that i am burning this fluid as it mixes with the air. Which would explain the smoke i am having.


So the question what causes a leaking airbox

 

[JDOFMEMI]

Sounds like most of the oil MAY be coming into the blower through the seals at the ends of the blower housing. That is a common problem, and an easy fix.

Check out the water more though

 

[xcavate]

The water I think may be because the exhaust manifold stud was drilled out to far but I would think that would just drip into the exhaust not into the air box.

How would I test to see if it is the blower seals that are leaking?

 

[Underdog]

I don't think a lot of new mechanics know or want to work on old two cycle Detroit's now a days. I'd get on ebay and get yourself a 8v71 service manual. You'll need it if your going to keep that Detroit.

 

[JDOFMEMI]

Pull the air intake from the blwer and look inside. If there is oil inside, chances are thats where it came from

 

[Ray Welsh]

Pull the air intake from the blwer and look inside. If there is oil inside, chances are thats where it came from

Don't be too unkind in remarks about 8V-71 jimmys. They were a fine motor in their day. Could be blower seals but excessive idling can also shine the bores. They are easy to work on and used to be fairly cheap to repair. (In Australia anyway!!)
First step would be check blower seals, then pull the heads, look for gasket leakage then test heads and inspect bores. If bores are shot, drop the sump and start a rebuild from bottom-up. Good luck.......C ya........Ray

 

[woberlin]

Those two tubes hanging down are the air box drains, and are there to drip oil. I believe at idle the engine does'nt develop enough vacuum and will leak oil into the airbox, or so that is how it was explained to me. Detroit Deisel makes a kit that catches the oil, and then you can drain it out. Basically a cylinder that the tubes drain into, and a petcock to drain the oil. It is very pricy for what it is. If you go to Yahoo, there is a group for detroit deisel enthusiasts that can tell you anything you can need to know about them.

 

[JDOFMEMI]

Ray
No dissing the DD's here, I have had about 40 or 50 of them. They were fine in their day, but most are too long in the tooth to be very reliable anymore in hard daily use. Even with quality rebuilds, metal fatigue strains them.
Still a good engine, but its days are numbered now with the emmissions regs, especially here in CA.
I just took a 6-71 out of my 6X6 water truck for a M-11 Cummins for that reason.

 

[xcavate]

How Hard would it be to swap in a Big Cam Cummins?I think I may be able to get one rebuilt for $1,000. Does the Tranny Match Up? I know I would a new exhaust system but that shouldnt be to hard.

 

[xcavate]

The motor is a 400 Big Cam Cummins it is a 1986 block that has a fresh rebuild and the guy has all the receipts. I am thinking its way easier to just swap in a new motor for 1,000 then to try and fix the detroit. I just dont want to spin my wheels. Where would i get motor mounts? The tranny hopefully will bolt up cause I have a new tranny and clutch. Then other then that its just fuel line, air line and wire up starter.

 

[rino]

Engine Swap

Look for a junker somewhere that has the big cam 400! I'm sure there are salvage yards around that will have all the parts you'll need! Trans should be universal unlike the automotive industry. Frame mounts might be the same also. The thing is going to be the radator plumbing. The in and out for the rad in the right place so you don't have a plumbers nightmare just getting the hoses to mate!

Am I glad their 1997 LTL9000 was ordered with a 3406E Cat @ 475 HP! Last of the classy looking LTL long hood!

 

[rino]

Try to make a bid on all the parts you need for the change! Say you need mounts, and rad. Price them new and offer them 30% of their retail value. Have them throw in the exhaust, and also check the passenger side steering cylinder! The end caps are prone to blow off when in a tight turn! Add parts that you know you won't need, and just leave them there! I'm talking a $50.00 value!