6.9 diesel swap question. [Archive] - FSB Forums

: 6.9 diesel swap question.


tog-e
02-24-2010, 01:08 AM
Hi, My Dad has a 1979 Bronco, and he just bought a 6.9 diesel from an 86 F250. It has a c6 auto transmission with it but... My question is this, we have a 4 speed manual transmission already in the bronco that came with the 400m, and we are wondering if it will work with the 6.9? It looks like it should all bolt up, and if it will work, will the clutch work also? The clutch is 11inch on a manual diesel f250, which is the same diamiter as my Dads bronco, but will the pressure plate be different? Will it need more clamping force or no? Thanks for any feed back.

IDIeselman
02-24-2010, 07:09 AM
http://www.oilburners.net/forums/showthread.php?t=37745 The answers to your questions within.

vreference
02-24-2010, 01:13 PM
The short answer is no - the Navistar diesel does not share a bellhousing with the ford motors. You'll need a bellhousing for the diesel.

tog-e
02-24-2010, 09:08 PM
Sorry but that link isnt working for me.

Vreference, the motor has a c6 bolted to it now, and there is an adapter plate between the international and the c6. The transmission will bolt up. I just need to get the right flywheel, and the right clutch set. Thanks for the help

IDIeselman
02-24-2010, 09:54 PM
No it won't, This will make it work but, There is alot more involved.http://www.supermotors.net/getfile/782483/fullsize/zf20bell.jpg blue. diesel bolt holes
pink. diesel dowels
green .460 bolt holes
brown 460 dowels

red 460 starter

top two are the same gas or diesel.

I logged off and you are correct, I can not view it either. Do yourself a favor and become a member.

strokin'_tatsch
02-24-2010, 11:15 PM
I'm unsure why y'all are wanting to drop a 6.9L in it??? every 6.9 i have ever seen runs worse than my 302 did when it was stock and MUCH MUCH MUCH worse than my powerstroke does. IMHO the 6.9 is wasted efforts, but some people like them i guess. i just haven't seen any that really amounted to much when compared to other engines out there. just my .02

vreference
02-25-2010, 02:34 AM
I'll agree that the 170HP IDI 6.9L is not exactly a power house but neither is the 132HP 5.8L. The extra 24CI is only worth 15HP (I'd bet the majority of that is from the slight compression ratio increase) for the naturally aspirated 7.3L; If we were talking about an IDI 7.3L would it sound better?

I wouldn't take the weight penalty on my stock axle'd 90% offroad truck but I'd bet money the 6.9L is better than the 351M at just about everything.

strokin'_tatsch
02-25-2010, 10:43 AM
I'll agree that the 170HP IDI 6.9L is not exactly a power house but neither is the 132HP 5.8L. The extra 24CI is only worth 15HP (I'd bet the majority of that is from the slight compression ratio increase) for the naturally aspirated 7.3L; If we were talking about an IDI 7.3L would it sound better?

I wouldn't take the weight penalty on my stock axle'd 90% offroad truck but I'd bet money the 6.9L is better than the 351M at just about everything.

i would have to disagree. with slight mods the 351 can make the same or better power than the 6.9 can with a turned up pump, 7.3 rockers, and ATS turbo kit and both the 6.9 and 7.3 IDI came with 21.5:1 compression IIRC and can't hold more than 10psi of boost if u decide to turbo without major mods.. I mean if your looking to swap an engine in there you can do better by finding a 460 somewhere. the 6.9 is just too slow reving w/ no real power and is just added weight IMO. if i were to swap something to a diesel(i love diesels, BTW) i would swap to either a 7.3L powerstroke or sad to say a 12v cummins. both those 2 engine came stock with over 200hp and both can easily be upgraded to make good power like my '95 PSD sitting at 350+hp with the stock turbo, heads/head bolts, etc.

i think the diesel swap would make it wheel worse if y'all do any wheeling also.

vreference
02-25-2010, 01:38 PM
both the 6.9 and 7.3 IDI came with 21.5:1 compression IIRC

'83 was 20.7:1 - 84-87 were the same as 7.3

I've only had PowerStrokes and I've never driven a N.A. Navistar. I don't think anyone was lying about the 170HP; guess it's up to you whether or not that's a good thing. Doesn't sound like much but neither does 215 (Which I always felt was more than sufficent for up 10KLbs trailer.)

IDIeselman
02-25-2010, 01:56 PM
You are better off with the 6.9, The 7.3 is basicly an overboared 6.9 and will usually suffer cavitation if not maintained because of the thin cylinder walls.

Everyone seems to think the IDI's are gutless but, Fail to realize by the time thay have a chance to drive one they are usually in the 250-300,000 mile range with no maintainance to the pump or injectors. With a little tweaking in the right areas I have seen them outpull Strokes and a few Cummins. Here's my N/A 6.9 pulling 12,000LBS 250 FT For the quickest time. If you are into Moddding or racing then I agree a Stroke or Cummins is better suited......For most people.

http://s174.photobucket.com/albums/w103/Dsl_Dog_Catcher/?action=view&current=IDIeselman.flv

tog-e
02-25-2010, 10:40 PM
The reason we wont pump up the 351 is becasue we live in California and with all the smog laws, so our best option is to switch to desiel wich is smog exempt. My dad has an 86 f250 2wheel drive 6.9 with a banks turbo kit on it and it runs really well.

We know the truck has a C6 transmission bolted to the navistar, so we thought the transmission on the bronco right now which is a np435 would have the same bolt pattern as the C6. But maybe not.

So would it be bettter off to add a transfercase tail housing on the back of the C6? We just wana do some research before we tear into it.

Oh and I did become a member for that other forum and everytime I hit that link it says I do not have permission to view.

IDIeselman
02-26-2010, 08:21 AM
460 clutch vs 6.9/7.3 clutch ( 1 2 3 4)
BigRigTech

It's on page 4 in the 6.9-7.3 IDI tech.