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225 vs. truck usage
https://slantsix.org/forum/viewtopic.php?t=6773		 Page 1 of 1
Author:  jwwebb [ Mon Sep 01, 2003 11:23 pm ]
Post subject:  225 vs. truck usage
There anyone out there that can give me information on how well/poor the slant six works in the full size truck? Any recomendations or pain cutting 'edge' on the 'how to's' and all?
Author:  v8440 [ Tue Sep 02, 2003 5:03 am ]
Post subject: 
Well, my '78 D100 came with a 225. It runs fine, though it's down on power at every point in the rpm band compared to what I think a truck ought to have. I can't claim wear and tear, as it has 32,000 actual miles. It's just slow. The super six setup helps some, but slant sixes just weren't intended for vehicles that large. I wouldn't turn one down, but if you plan on doing any real hauling, a 318 (even a 2 bbl) will start to seem pretty appealing. Another thing I noticed is that mine has the tightest converter I've ever seen in any vehicle. Getting a slightly looser one would considerably help off-idle acceleration, and would alleviate the feeling of having a brick strapped to an ant.
Author:  mnecaise [ Tue Sep 02, 2003 6:09 am ]
Post subject: 
Ya know, it's cubic inch limited; so, a stock 225 isn't as strong as a v-8. They are torquey though. My '84 has a 225 and a 4spd-od (a833) tranny. It's not as fast as I'd like it to be (but that's another story) The previous owner regularly used my truck to tow cars on a dolly. He also used it to tow around his 440 powered project truck. It has some guts...

If you're looking to use it for work, there are a few simple, low cost power adders (like a super six 2bbl carb setup) that will help.

If you're looking for performance, anything the car guys are doing will work on the truck engines (they're the same). Just remember it's a heavy vehicle: You don't want to put in a BIG cam because it hurts low rpm performance (torque). There's a guy named Jerry Engle who's got a "pro street" D-100 he claims will turn 12.90 in a quarter mile. His truck is mentioned on the allpar.com site.
Author:  v8440 [ Tue Sep 02, 2003 7:19 am ]
Post subject: 
Mine's not even torquey. Hmm, maybe something is a little off with mine despite the low mileage. Come to think of it, the one in my '70 valiant with a 1 bbl seems torquey by comparison. I always assumed it's because the car is lighter. But, the car has 2.76's and the truck has 3.55's, so you would think that alone would make up for the weight difference. Maybe I need to do some checking around on the truck motor.
Author:  Uptown Joe [ Tue Sep 02, 2003 7:43 am ]
Post subject: 
I don't have much slant experience, but I have had a few cars and trucks that were old with low milage. I found that they ran well but I had nagging problems with the seals and perfomance. They must have spent time sitting, and the seals dried out.

Joe.
Author:  mnecaise [ Tue Sep 02, 2003 9:21 am ]
Post subject: 
My D-100 has the same 3.55 gearing. I called it torquey; but, it's a perspective thing. It's no monster torque, stump-pulling big block V-8. It does pull itself fairly well and has been used (as I've said) to tow other cars. I've seen similar aged six cylinder Chevy trucks not do as well (Chevy's 250 cu.in intake manifold and head design doesn't work as well as a /6 for generating low rpm torque).

If you're having problems, I'd start looking at the engine. It's possible you have a vacuum leak (or three) causing the mixture to be a little lean. It's not uncommon for an engine of this age to have bad (brittle, cracking or poorly fitted) hoses -- I just replaced all of the hoses in my truck. Your timing may also be retarded. Mine is set to 12btdc at idle.

There's about a 1000 lb difference between a Valiant and a D-100. you are correct in assuming that the different gearing (2.76 in the Valiant and 3.55 in the D-100) should make up some of the difference. It also depends on what transmission is in them. If you've got an automatic in the truck, the tranny or the converter could be slipping.
Author:  v8440 [ Tue Sep 02, 2003 10:43 am ]
Post subject: 
My truck weighs 3670 pounds without the tailgate or a driver. It's not heavy at all for a fullsize truck. I expect the 4 door valiant to weigh about 3100 without me. The converter is not slipping excessively; if anything, it's too tight. It's incredibly tight-I don't think it would exceed 1300 rpm at WOT against the brakes. This may be contributing to the low-torque feel.
Author:  Doc [ Tue Sep 02, 2003 11:28 am ]
Post subject: 
You may want to chack the cam phasing, the later engines were known to run the cam retarded, add a little timing chain strech on top of that and you will loose low RPM torque.
Some careful measurements at TDCE - overlap will tell you a lot.
DD
Author:  Loghead [ Tue Sep 02, 2003 12:23 pm ]
Post subject:  it all depends on what you REALLY need...
I've had several /6 powered work vehicles:
'78 1/2 ton pickup w/3 on the tree
'77 1/2 ton van w/ 833 O.D.
'83 1/2 ton Power Ram w/NP435 4 speed

The 78 had lots of problems, rusted to the bone, electronics were corroded from salty air at the seashore. It was a horrible truck to begin with.
The 77 van was able to haul five of us, and you could load quite alot of lumber etc. when needed. It was able to get around 22mpg on the highway with the OD. My Plymouth Voyager with a 3.3 only gets 23!
The 83 truck is what I use to plow my driveway, I've hauled a car trailer with it and even 4 tons of firewood :shock:
It isn't the prettiest or fastest thing on the road, and if I were to be constantly pulling heavy loads, I would want to go to a 318 or maybe a 360, but the /6 is cheap to run. Why feed a monster every day when I don't need to?
Author:  v8440 [ Tue Sep 02, 2003 12:38 pm ]
Post subject: 
Loghead, I can see your experience with slant 6 trucks differs from mine. If you drove mine, you would probably be surprised at how slow it is. I'm beginning to think that there's something wrong with mine, probably the cam timing. Doc, please elaborate on exactly what you are telling me to measure at TDCE. (I assume that stands for Top Dead Center Exhaust?)
Author:  Doc [ Tue Sep 02, 2003 2:11 pm ]
Post subject: 
Quote:
I'm beginning to think that there's something wrong with mine, probably the cam timing. Doc, please elaborate on exactly what you are telling me to measure at TDCE. (I assume that stands for Top Dead Center Exhaust?)
Yes "TDCE" is Top Dead Center, Exhaust stroke, that is where the valve overlap event happens.
What you want to check is if the overlap event is centered over TDC, better yet, slightly advanced where the Intake valve is open a little longer (more) before TDC then the exhaust valve is open after TDC

You will need to find true TDC and it is best to have a degree wheel and a dial indicator to do the check. (there is a way to do it with thickness (feeler) gauges but that is less accurate)

You need to find (in degrees) where the intake valve starts to open and where the exhaust valve closes in relationship to TDC.
As an example, if the intake opens at 22 degrees BTDC and the exhaust closes at 22 degrees ATDC and the cam is advertised as having 44 degrees "overlap", then the cam is installed "straight-up" or said another way, the overlap event is evenly "split" over TDC.

In the case of a retarded cam you will find that the Intake will open closer to TDC and the Exhaust will close farther away from TDC.
DD
http://www.dutra.org/pictures/engine/cam-cards.jpg
Author:  Slanted73 [ Wed Sep 03, 2003 5:21 am ]
Post subject:  Another slant truck
I had an 86 with a short bed, 4 speed and low gears. I never had a problem with power or speed, but I never drove it higher than 85 either. Sure you didn't have to use 1st to take off. Mileage was low, but for a work truck/junk hauler, I don't think it can be beat for dependability. All I ever did to the engine was plugs, cap, rotor, plug wires, and coil.
Author:  v8440 [ Wed Sep 03, 2003 1:08 pm ]
Post subject: 
My truck might barely make 85, but that would be about it. It's not a matter of good performance at that speed, it's a matter of whether it can even make it. I don't drive it that way of course, I limit myself to about 65 on the interstate. This is one of those cases where I think a 318 might actually get better mileage than a slant six, as the slant six has to work so much harder. If that seems impossible, ask people who have had 318 c bodies and have also had 360 or 400 c bodies what kind of mileage the 318 got. At least some of them will probably cite the 318 as being a gas hog, for the same reason. There's something to be said for not having to hold the throttle 1/2 open to do much more than cruise.
Author:  Guest [ Wed Sep 03, 2003 4:33 pm ]
Post subject: 
I have a 71 D100 with a 82 225 with a Proline dual weber,Clifford shorty headers,MSD 6AL,AND AN O/D 4-SPD with 3.91 gears and it runs great (its my daily driver) and even turned 19.57 at the Bristol Mopar show(1/4mile),thats not too bad for a 4000 lb truck(truck-3600,my fat ass-300lbs,tool box full of junk-100lbs).It still has a stock bottom end.It will cruise at 75 but runs out of steam about 95.and I contribute that to lack of cam and aerodynamics of a brick and the afformentioned weight.It has much better torque than stock and actually feels more like a a 318.
When it was stock(1 BBL,single exaust,3 spd trans)it was a pure dog just barely able to 65 on the freeway.
Slanted Attitude
Author:  Bruce Johnson [ Wed Sep 03, 2003 6:06 pm ]
Post subject: 
After 20 years of driving it I realized I didn't use my short/fleetside d150 for hauling much of anything so I choped 14.5 inches off the bed and I'm in the the prosses of getting rid of heavy stuff, I kept the slant mainly to keep the front end light. its a blast to drive in the twistys and will pull hard to 120 but can get too hot sustaining high speed in the summer. Also for hauling a travel trailer I'ts crap. but the thing is ,its the way I want it. Some guys would put a 440 in it , Some guys would add a bunch of stuff to make it loud , dance around, fart and falldown. To each their own I guess. Bruce J.
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