Hi,

New to the forum but long time IDI owner.

I have a high mile 6.9 that has a couple of issues.
1) It is pushing water into the overflow when I work it. No water in oil or oil in water. Head Gasket I suspect?
2) It uses tons of oil, 5 quarts in 1000 miles.

I am considering
new std pistons and rings
new bearings
oil pump
cam and lifters if it looks worn
Freshen up the heads with a valve grind (recondition guides if needed)

I have done this to many gas engines with great results (except i do not put in new pistons)

I do not plan on putting many miles on the truck, I just want it to run clean and strong when I use it.

Has anyone done this type of repair on 6.9's or 7.3's and if so how were your results?

Thanks for your input

Jim B

 

Welcome to FTE.

I would guess the valve guides and seals are your oil problems.
It could also be a bad CDR that has never been cleaned.
Also you do not say what high mileage actually is or what year the truck is.

 

Hi,


Sorry about that.
My truck is a 1985 6.9 4X4 4spd W 3.54 gears. It has 289K miles and an early banks turbo system.

It has been worked hard all of it's life with very few unloaded miles.

Being a banks turbo it has the marginal K&N type air filter. I have cleand the breather valve although not real often.

My information is in my signiture but I see that my sig is not showing up on the post.

Thanks.

Jim B

 

Hello windyr1. Welcome to Ford Truck Enthusiasts.

Your signatue, when enabled, will not show up in your post, but rather will be visible in the "signature" block below you post count. Hold your mouse pointer over the word signature under Dave Sponaugle's post count and you will see what I mean.

If you have already created a sig you need to mae sure the
enable signature" box is checked the next time you reply to a post.

 

OK, you have the same truck I have, only one year older and about 20,000 miles less on it.

Your oil consumption is still rather low. High oil consumption is about 5 gallons per thousand miles.

I was in the same place you are now a couple of years ago.
After checking around I was getting numbers like 5 thousand and 6 weeks down time to rebuild the engine depending on how bad it was inside. It had never been opened up in 300 thousand.

I started to do online research and found a 7.3 turbo upgrade motor for 7000 exchange. Had a two year unlimited mileage warranty. I went that route. The swap took 14 hours which included changing the glow plug system to the late style system.
2800 miles the block cracked on the first engine. Warranty sent me an engine and covered labor, but the truck was down for 2 weeks.
During diagnosing the engine we found it built 30 PSI pressure in the radiator in 15 seconds running. After the replacement engine was installed in the truck I also found out I needed to replace the radiator and heater core due to the extreme pressure in the radiator, not covered under warranty.
9700 miles later the crank broke on engine #2. Warranty sent me a third engine and covered labor, but the truck was down for 2 weeks again.
The third engine made it to 18,000 miles before the block cracked. Since the fuel system and turbo were out of the one year warranty they sent me a long block engine.
I opened the engine up and found the sleeves had slipped down, 2 cylinders were not sleeved but were bored .020 over and the sleeves were out of round. It took three months to get a buy out on the engine and I lost 2000 dollars but did wind up with an ATS turbo and the fuel system off a 7.3.

I was so disgusted I bought an 87 model 6.9 salvage yard engine with 125,000 miles on it and installed that in my truck. Installed the ATS turbo and 7.3 fuel system on it and am still driving it. Oil consumption is about 2 quarts in 1000 miles and the power is great.

If I were in your shoes.
I would get the heads rebuilt.
I would also bore the block a minimumal amount to get the cylinders true again.
I would also replace what ever was required as far as other internals go.

Most of the problems I had were due to the sleeves installed to get the block back to stock bore. I really have no idea why they then bored the block and sleeves to 20 over on a 7.3.

I would also consider head studs to help with the head gasket problems the 6.9 had.

Where are you located?

 

Dave,

Thanks for the advice, your story on the "profesionally" rebuilt engines
are exactally my motivation for wanting to keep my old block and heads.
Like I stated in my first post I have had better luck than I deserve freshening up running engines by replacing the wear components.

I have heard many horror stories similar to yours from people who have purchased unknown history rebuilds.

You mentioned that my oil consumption is not very high for one of these engines. My father had a 1984 6.9 (bought it new) that went about 4-5K miles before it used a quart. Is it unreasonable to expect that from a fresh 6.9? Do the heads tend to be the biggest contributer to oil consumption problems?
I did have a 77 Ford 351M that all of the valve stems wore out (45K miles) and it used a quart of oil about every 100 miles. A set of junkyard heads (because a set of valves were real expensive) and a re-ring put it into the 3-4K per quart zone.

I have always heard that cylinder taper could be a big issue on a rebuilt engine but I have just reringed some really worn engines and had years of good performance with very low oil consumption after doing so.

My truck does not have a bad history with head gaskets. I have never had a head off to this point. Assuming that a head gasket is the cause of the cooling system pressurization this will be the first. I suspect that it is possible that I have a cracked head. I plan on doing the cylinder pressure test through the glow plug holes to pinpoint the leak location prior to any tear down.

The head bolt replacement with studs will allow for higher torque setting?

BTW I live near Portland Oregon.

Regards,

Jim B

 

the only time i had an oil consuption problem with my old F250 6.9 was when the O rings on the oil cooler expired. i used something like 15qts of oil in like 75 miles. once repaired i went from 2 qts of oil every 1k miles, to 1 qt every 1500 miles(and that was with a engine that had over 200k miles). even with a diesel 5 qts every 1k miles is too much. check the valve cover gaskets, oil pan gasket, rear main seal, front cover seal, and the oil cooler for signs of oil leakage.i would bet the valve cover gaskets are leaking.

 

This info by a Navistar/Ford expert may help with oil consumption.......

DieselDon

Oil consumption, and the proper checking of the oil levels in Ford diesels comes up periodically. Ford dipsticks are calibrated for hot oil. The 10 quarts in the IDI engines expand about 1/2 to 3/4 of a quart as the oil heats up, and contracts the same amout after cooling. If you check the oil first thing in the morning ( which I grew up doing ) the engines will all indicate oils level below full, but when checked hot, will ( after a 10 minute drain time ) the oil level is usually at full. If you are checking the oil cold, and keeping the level at full, you are actually over filling the engine which will burn of the extra rapidly.

Suggestion: Check oil hot after 10 minute drain time.
Don't add until level reaches add line ( 2 quarts ).

In my days at Ford this often cured, or at least improved, the apparent oil consumption complaints.

 

I wish the issue that you listed with checking warm vs checking cold was my problem. No If I forget to check it/refill it at a fuel fill up it will be off of the stick by the next fill up. If only running it 2 quarts low would slow down the consumption I would not worry about it. I have minimal leaks and seeps. No splatters on the rear bumper, no puddle on the garage floor. (maybe a drip or 2)
On a fresh change consumption is better for the first 1500 miles or so. Once the oil gets slightly dirty it's off to the races.

It sounds like this oil consumption problem on these engines is not well understood and somewhat of a mystery. I guess it is because they can start and run perfectly even when they are using massive amounts of oil. (more fuel egor!) However even with diesel at $3.00 a gallon, the oil I use is more expensive. Also I am worried about running it so low that I wipe out the cam or my turbo.

One other symptom that my truck has is a really rotten smell from the tail pipe. I suspect it is due to reburned blow by.

Regards,

Jim B

 

windyr1, Some of the early 6.9 engines had valve guide and seal issues that led to high oil comsumption. I would suspect this is your main oil loss area.
Also it seems that all these engines do have a large amount of blow by even after a rebuild. I have talked to one other person on here that was having trouble with excessive oil consumption after installing a turbo. Where does Banks route the CDR vapors to be burnt? ATS routes the CDR return into the section of pipe between the turbo and the air filter. During high boost times if the air filter is restricted in any way, between the boost pressure in the cylinders and the suction of the turbo against the filter I could see a good bit of oil getting sucked into the turbo intake.

Rings are getting worn at 289 thousand I am sure.

I can also tell you that my rings on the reman engines were not seated at 10 thousand miles. In fact the cross hatch in the cylinders was still plain as day after 18 thousand miles.

Also I forgot to mention the four reman engines I had all had rather large cracks in the heads between the intake and exhaust valves.

I have talked to several different rebuilders since I had all the problems with the reman 7.3's. I think the general consensus is it is better to rebuild a 6.9 than it is a 7.3.
There is more meat in the cylinder walls to work with on the 6.9.

I talked with Deisel Auto Services in Vancouver about a reman engine, they talked like they knew what had to be done and how to do it.
I also had a long talk with DPS performance about an engine, they do not even rebuild 7.3's.
If I would have had time I probably would have gone with either one of their engines.
But it was getting late in the year and I have several snow plow customers that would have been lost if my truck was not running and it snowed. So I opted to do the quick fix route and get my truck running. As luck would have it though, it has not snowed enough to plow this winter yet.

 

heres my take--get a rering kit--stock--pull heads--raise the engine-and jam 2x's between the mounts-pull pan--its doable--pull pistons--clean up--run a rabbit hone lightly thru cyl-put pistons back in--with the new rings!!--if rod bearings are wore--replace--same with crank bearings--have the guides on heads checked-if not too bad--leave alone--but replace stem seals--and put back together--done a few this way--and they just keep on ticking--the 6.9--and 7.3 blocks are HARD--and so are the pistons--their forged--and they get plenty of lube from the cooler jets--so they really wear almost none--the truck aint worth high bucks--this will cost very little--and should last a long time--and no--the cam bearings are very seldom wore---

 

94 Turbo,

I like that approach, Kind of what I had in mind. I think if I can pinpoint my cylinder to cooling system leak with the 1 cylinder at a time pressure test I will pull it apart for an inspection and replace what is really in need. You are so correct about the marginal value of one of these old trucks. In great condition they have some value but people won't give peanuts for one with a sick engine. Mine just seems to solid to just part out.

And Dave thanks for all of your great insight. Nothing like having been there done that!

I suspect that the rebuilders end up with some core engines that have some pretty expensive problems in them. I think if I was probably easy to get upside down in one.

Regards,

Jim B

 

Just another comparison on the oil usage, my 6.9 was rebuilt 5000 miles before I got the truck, and it uses about 1 quart per 800 miles consistently. My father's 84 6.9 uses it about twice as fast, but we don't know how many times the odometer has rolled over... I have found that using quality oil does reduce usage, I started out using the Mystic brand from the local farm store, and switched to Rotella, and use less oil now than I did at first.

 

windyr1, when you check for the leak pull the rockers off the valves and let the motor roll over till the piston is at BDC when you apply air. That way you get to check the entire cylinder area for leaks. If you have water in the radiator it will be easy to see when you get to the one with the leak.

Also if I were doing a head removal I would pull the engine.
It is not that hard and it will be so much easier to work on.
With two mechanics helping me we can swap a motor in 8 hours. But we have had a lot of practice on my truck.

As far as not worth the money to rebuild the engine, I bought a reman engine (7000), a new radiator (400) and a completely rebuilt Dana 60 limited slip front axle (3000) for mine in one year. I could have bought a newer Power Stroke for the same money. I just happen to like the one I have though.