6.9 liter diesel , what are the pros and cons of this engine - Diesel Forum - TheDieselStop.com
Ford Diesel Forum / Powerstroke Forum
Ford Diesel Forum / Powerstroke Forum
Go Back   Diesel Forum - TheDieselStop.com > Ford Diesels > 6.9L Diesels

6.9L Diesels Technical discussion of topics related to vehicles powered by the 6.9 Liter In-Direct Injection Navistar engines.

TheDieselstop.com is the premier Diesel Truck Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 08-13-2005, 09:40 AM   #1 (permalink)
Junior Member
 
Join Date: Jun 2005
Posts: 6
My Photos: (0)
Feedback Score: 0 reviews
6.9 liter diesel , what are the pros and cons of this engine

Hello everyone. I have a 1986 (built in August of 86) F350 crew cab dually. The truck was given to me by my brother. A tree had fallen on the cab and he doesn't like diesels. The truck looks like the hind wheels of bad luck, but I am happy with it. I like diesels. To date I have had to put a about $2k into to get it running, front end rebuild and rear fuel tank. The engine is naturally aspirated. The odometer shows about 79,000 miles. The real mileage is unknown. The previous owner used it to pull horse trailers. Last night my brother left me a message that a diesel mechanic he knows says the 6.9 L diesel are no good and that I shouldn't bother putting any money into this truck. So what are the pro and cons of this engine? It is a project truck so I won't pour a bunch of money into right away, but over time I could put alot of time and money into it. What do you all think? -Pfowl
pfowl is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 08-13-2005, 10:02 AM   #2 (permalink)
Senior Member
 
Join Date: May 2004
Location: Adams/Clarksville, TN
Posts: 302
My Photos: (5)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

That diesel mechanic must not know his stuff.

The 6.9 is a good engine, very good engine especially for pickup type use.

Pros, compareable power to the 7.3IDI actually about the same, NO cavitation worries, although it's still a good idea to keep the coolant serviced. They last forever. With a turbo they keep up with 1st gen PSD's

Cons, head gaskets can blow. But that can be fixed with head studs and IH updated headgaskets, glowplugs system somepeople have problems some don't but it's easy to fix or convert to a push button type set up. If the fuel system is not kept serviced the IP can take a crap at around 100 miles, but it's only 300 or so bucks, cheaper than a PSD injector i think.

It's a good engine.

I have the Banks brochure, and it actually says the IDI with a sidwinder is quicker accelerating with a load than a PSD with the same kit. Solo acceleration was a couple tenths better with the IDI from 0-60 also

Don't know how true that is. I kind of find it hard to believe.

So tell your brother to stop trying to stop you from having some fun

Hope you have some fun with the truck

DT
__________________
2005 F250 KR 6.0/Torqueshift. every option availible. fx4 high idle mod. 144k miles 5%tint all the way around. On the way: mbrp new ID tunes, edge cts, swamps egr delete/ oil cooler change.

1992 F150 4x4 reg cab long bed 4x4. frame offed in 2009. sat radio, leather, 393 windsor monster AOD 4.10's stock front suspension rear dropped 2" 31's

1984F350srw 4x4 6.9 turbo 4spd. pw/pdl a/c 6" lift waiting for paint
dt466man22 is offline   Reply With Quote Quick reply to this message
Old 08-13-2005, 12:25 PM   #3 (permalink)
Senior Member
 
Join Date: Jan 2003
Location: Gainesville, FL, USA
Posts: 4,103
My Photos: (7)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

DT pretty much summed it up. Head gaskets and glow plugs were a weak point, and they also tend to use a lot of oil even when they are not really worn out, but they last a long time unless something horrible happens to the engine. Most here are getting 250-300K miles out of teh truck before any real engine work with teh exception of head gaskets is needed. If it were mine I'd ditch that glo0w plug system now while you still can and hook up a manual button for the time being and maybe switch to a solid state controller soon. The push button system will cause you no problems as long as you don't leave the plugs on longer than 8-10 seconds. Read Ziggster 40s page for a reference on GP removal and setting up a manual system. Injectors and injector pump aren't what I'd call bullet proof, but they should last 100-200K miles if you keep good clean fuel and throw in some kind of lubricity additive. Good luck with it, and welcome
J.D.
__________________
J.D.'s Fords: 1986 F-250 6.9 diesel Solid State Glow Plug System 3.55 gears C-6 2WD 178,960 miles.... it still runs pretty good!
Wishlist H-max turbo, T19 tranny,
1989 Ford Ranger ga$$er, non runner, soon to be donated or scrapped!
jdkline is offline   Reply With Quote Quick reply to this message
Old 08-13-2005, 06:04 PM   #4 (permalink)
Senior Member
 
Join Date: Aug 2005
Location: Bel Air, MD
Posts: 119
My Photos: (0)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

That "mechanic's) opinion is worth exactly what you paid for it.....absolutely nothing. It might be interesting to hear his rationale, maybe he herard of someone who had a problem, maybe he priced paerts and saw they cosy more than a small block chevy. Who knows how he arrived at that opinion.
The factory HP ratings on these engines are lower than some people expect today, but they are nearly bullet-proof. I did a rebuild a couple of years ago at about 320,000 miles. When I pulled the pistons, I could still see cross hatch in the lower half of the cylinders, and the taper was not measureable. These are heavy duty, well-built engines. Replacement parts cost a bit more, but Mercedes parts cost more than Geo parts.
The power issue can be dealt with by adding a turbo. I am looking to install one, myself. The many people who have installed turbos are almost universal in their, " Why did I wait so long to do this?" response.
Problem areas are discussed above. Also remember, as you read thru the posts here, it may seem that a lot of people have problems with their trucks. Well, duh! Thats why people post here-to get information.
Change the oil often, keep the filters clean, use a fuel additive, and monitot the SCA level in the coolant, and they'll last for a long time. And don't forget, you've already found the best resource for maintaining, and if necessary, repairing your new 6.9 diesel-the dieselstop.com.
MSFII is offline   Reply With Quote Quick reply to this message
Old 08-13-2005, 09:38 PM   #5 (permalink)
ZOP
Senior Member
 
Join Date: Oct 2004
Location: Clinton, MT, US
Posts: 302
My Photos: (0)
Feedback Score: 0 reviews
Send a message via ICQ to ZOP Send a message via AIM to ZOP Send a message via Yahoo to ZOP
Re: 6.9 liter diesel , what are the pros and cons of this engine

as has been noted elsewhere in this thread that mechanics opinion is just that, his opinion. the weak points are the GPs, and head gaskets. Also the 4x4 t-case can be...most of these old rigs have a chain drive unit. the clutch throwout bushing and the master/slave cylinder clutch setup *can* be a problem too, keep it lubed and serviced and you'll see plenty of life out of it.

the one thing we all pretty much replace is the stock water seperator. some mod it witha 7.3 filter head and filter, some (many? most?) of us use a racor screw on replacement the PF811 iirc. others will know exactly. the stock unit sucks universally.

as far as durability...bullet proof. you'll trash the u-joints, rear end, driveshaft, and the transmission before you have serious problems with the motor if you're beating on the truck. they were built to go to work, and work hard. my truck is used mostly for off road and hauling. 6.9NA isn't going to get you there fast, but it will get you there. i can't count the number of brand new dodge cummins i've seen on the side of the road...granted, i keep my mechanicals in decent shape. the body is another story [img]/ubbthreads/images/graemlins/smile.gif[/img] i'm not exactly 'gentle' with the thing offroad. but it takes all the abuse i dish out. worst i've had was snapped u-joints (cheap low quality parts that it came with).

the only problem...is recently gas and diesel prices are up pretty high. With 3.54 rear end, 4spd tranny and more or less stock size tires i get from 12mpg to 18mpg on the freeway@75mph.
__________________
1984 F250 4x4 6.9 IDI w/ 208k (2011/09/03) and counting! (Yup, hit zero again) 4spd Handshaker 3.54 Rear 3" Exhaust - The smoke blowing n/a mechanically injected RELIABLE old dinosaur!
2011.5 Dodge/Cummins 6.7L HO 3500 4x4 ST Crew Long 3.73 SRW L/S Rear 170" WB 6spd 68RFE Auto
2012 Fuzion 35' Toy Hauler (no, the Ford does not pull this...)

Clinton, MT
Lunatic In Charge(tm) of The Diesel Files
ZOP is offline   Reply With Quote Quick reply to this message
Old 08-14-2005, 06:26 PM   #6 (permalink)
Junior Member
 
Join Date: Jun 2005
Posts: 6
My Photos: (0)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

Thanks for the informtion. It sounds like I should keep an eye on the head gasket, and change the bolts if I have to do the head gasket. I have read the archives here and may get a turbo and a transmission modification such as gear vendors in the future. I have the c6 transmission. I am goiing to drive it for a while before I make naty major changes just to get a fell for what I have. Thanks again.
pfowl is offline   Reply With Quote Quick reply to this message
Old 08-14-2005, 06:29 PM   #7 (permalink)
Junior Member
 
Join Date: Jun 2005
Posts: 6
My Photos: (0)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

Thanks for the reply. I am interested in the solid state set up but don't have a clue. I use a haynes and chilton manual do do my work on the truck. Where should I start?
pfowl is offline   Reply With Quote Quick reply to this message
Old 08-14-2005, 06:34 PM   #8 (permalink)
Junior Member
 
Join Date: Jun 2005
Posts: 6
My Photos: (0)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

Thanks for the reply. I do a pretty good job of keeping up the maintenence on my vehicles. I hope this truck last a long time. At the very least I will learn about diesels. I am considering a turbo.
pfowl is offline   Reply With Quote Quick reply to this message
Old 08-14-2005, 06:37 PM   #9 (permalink)
Junior Member
 
Join Date: Jun 2005
Posts: 6
My Photos: (0)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

Thanks for the information. I am going to move ahead on this truck. The fuel seperator appears to be working at present. But I gotta admitt I donn't know what you mean by "of us use a racor screw on replacement the PF811 iirc." Any detailed information how to switch the fuel seperator over to a different setup? Again, Thanks
pfowl is offline   Reply With Quote Quick reply to this message
Old 08-14-2005, 06:39 PM   #10 (permalink)
Senior Member
 
Join Date: Mar 2005
Posts: 121
My Photos: (0)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

hey that mechanic is defititly not an ih guy. i did the most punishing test to my 6.9 possible. started in albany, ny and drove straight to daytona beach fl. non stop other than fuel and food, 24 hours staight @ 3300 rpms somewhere near 80mph, same thing on the way back, truck had about 175k at the time and used 11 quarts of oil, this motor has never had the valve covers off. it is still runing and smoking like a stove to this day now around 199k. so now tell your mechanic he is a moron.i would take one of my idi's over my ps any day .john
__________________
2003 crew cab dually xlt 4x4 7.3 6 spd std tranfercase black w/ grey interior
6637 filter, 5 " mbrp straight pipe,wicked wheel,ebpv delete pedistal, high flow outlet housing, dp tuner(no start ,stock,1100 high idle,20 40 60 80 tow, 80 econo, 100 perf.) ih bellowed up pipes, coolant filter, isspro ev2 pyro and boost gauge, aih delete and a snap on screwdriver handle for my shifter handle
2003 excursion limited ultimate 7.3 black w/ tan
every available option bone stock
ihdieselnut is offline   Reply With Quote Quick reply to this message
Old 08-14-2005, 07:41 PM   #11 (permalink)
ZOP
Senior Member
 
Join Date: Oct 2004
Location: Clinton, MT, US
Posts: 302
My Photos: (0)
Feedback Score: 0 reviews
Send a message via ICQ to ZOP Send a message via AIM to ZOP Send a message via Yahoo to ZOP
Re: 6.9 liter diesel , what are the pros and cons of this engine

[ QUOTE ]
Thanks for the information. I am going to move ahead on this truck. The fuel seperator appears to be working at present. But I gotta admitt I donn't know what you mean by "of us use a racor screw on replacement the PF811 iirc." Any detailed information how to switch the fuel seperator over to a different setup? Again, Thanks

[/ QUOTE ]

the PF811/BF811 (thats the Racor part number) is a direct screw on replacement for the fuel filter on these 6.9L engines, IE it fits the fuel filter head, but the advantage is it's an integrated fuel filter+water seperator. the BF811 is the filter, plus the metal bowl (only need this once) the PF811 is just the filter. The factory/stock water seperator is on the drivers side near the brake master cylinder, and it's a piece of crap. it's often the source of air infiltration, and it does not do a very good job of removing the water anyway.
__________________
1984 F250 4x4 6.9 IDI w/ 208k (2011/09/03) and counting! (Yup, hit zero again) 4spd Handshaker 3.54 Rear 3" Exhaust - The smoke blowing n/a mechanically injected RELIABLE old dinosaur!
2011.5 Dodge/Cummins 6.7L HO 3500 4x4 ST Crew Long 3.73 SRW L/S Rear 170" WB 6spd 68RFE Auto
2012 Fuzion 35' Toy Hauler (no, the Ford does not pull this...)

Clinton, MT
Lunatic In Charge(tm) of The Diesel Files
ZOP is offline   Reply With Quote Quick reply to this message
Old 08-14-2005, 07:46 PM   #12 (permalink)
ZOP
Senior Member
 
Join Date: Oct 2004
Location: Clinton, MT, US
Posts: 302
My Photos: (0)
Feedback Score: 0 reviews
Send a message via ICQ to ZOP Send a message via AIM to ZOP Send a message via Yahoo to ZOP
Re: 6.9 liter diesel , what are the pros and cons of this engine

[ QUOTE ]
...non stop other than fuel and food, 24 hours staight @ 3300 rpms somewhere near 80mph, same thing on the way back, truck had about 175k at the time and used 11 quarts of oil, this motor has never had the valve covers off. it is still runing and smoking like a stove to this day now around 199k. ...

[/ QUOTE ]

yup like i've said many times before, these trucks work hard. ih built these 'cornbinders' to run at full power all day long. ford didn't mess too much with the 6.9Ls genetics. the 7.3L they took too much off the cyl walls, made it prone to cavitate without much extra power. the PSD is more of the same. i don't know what lineage the new 6L shares with anything though they're ahving some serious teething problems.

i'm very happy with my 6.9, and i'll keep it till it goes, which will probably be quite a long time from now, despite the 190k miles [img]/ubbthreads/images/graemlins/smile.gif[/img]
__________________
1984 F250 4x4 6.9 IDI w/ 208k (2011/09/03) and counting! (Yup, hit zero again) 4spd Handshaker 3.54 Rear 3" Exhaust - The smoke blowing n/a mechanically injected RELIABLE old dinosaur!
2011.5 Dodge/Cummins 6.7L HO 3500 4x4 ST Crew Long 3.73 SRW L/S Rear 170" WB 6spd 68RFE Auto
2012 Fuzion 35' Toy Hauler (no, the Ford does not pull this...)

Clinton, MT
Lunatic In Charge(tm) of The Diesel Files
ZOP is offline   Reply With Quote Quick reply to this message
Old 08-15-2005, 10:20 PM   #13 (permalink)
Junior Member
 
Join Date: Jun 2005
Posts: 6
My Photos: (0)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

So if I put the racor on, what do I do with the stock water seperator. Leave it attached, bypass, deadhead? -pfowl
pfowl is offline   Reply With Quote Quick reply to this message
Old 08-16-2005, 12:40 AM   #14 (permalink)
ZOP
Senior Member
 
Join Date: Oct 2004
Location: Clinton, MT, US
Posts: 302
My Photos: (0)
Feedback Score: 0 reviews
Send a message via ICQ to ZOP Send a message via AIM to ZOP Send a message via Yahoo to ZOP
Re: 6.9 liter diesel , what are the pros and cons of this engine

bypass it completely. after you do that -- what you do with it is up to you, i might suggest driving over the top of it a few times [img]/ubbthreads/images/graemlins/wink.gif[/img]

but yeah get some fuel line or hose, or if you've enough there to work with just some fittings, and bypass it completely. mine is still attached to the firewall (the way i bought it actually)
__________________
1984 F250 4x4 6.9 IDI w/ 208k (2011/09/03) and counting! (Yup, hit zero again) 4spd Handshaker 3.54 Rear 3" Exhaust - The smoke blowing n/a mechanically injected RELIABLE old dinosaur!
2011.5 Dodge/Cummins 6.7L HO 3500 4x4 ST Crew Long 3.73 SRW L/S Rear 170" WB 6spd 68RFE Auto
2012 Fuzion 35' Toy Hauler (no, the Ford does not pull this...)

Clinton, MT
Lunatic In Charge(tm) of The Diesel Files
ZOP is offline   Reply With Quote Quick reply to this message
Old 08-16-2005, 09:43 AM   #15 (permalink)
Senior Member
 
Join Date: Jun 1999
Location: Delta, PA. USA.
Posts: 15,209
My Photos: (23)
Feedback Score: 0 reviews
Re: 6.9 liter diesel , what are the pros and cons of this engine

Bah! The 6.9 is a terrible engine. That's why I have two of them and a 7.3 IDI also. [img]/ubbthreads/images/graemlins/crazy.gif[/img]

[img]/ubbthreads/images/graemlins/biggrin.gif[/img]
agnem is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

  Diesel Forum - TheDieselStop.com > Ford Diesels > 6.9L Diesels

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Diesel Forum - TheDieselStop.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



Wheel & Tire Center

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 11:54 AM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.