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The V6 rods are a small bit narrower at the big end so they can ride over the split crank.

IIRC, they're .020 thinner; taking .010 off each side will take care of it. !IF! I'm remember correctly, that is. DO check.

RwP
 

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Discussion Starter #42
With a little machine work and $300. You can have a set of light weight Eagle rods new in the box with two spares. A set of ARP bolts, press off and on and recondition labor would cover it or near the cost, and I suspect the balance will be close. New rods have to beat 100,000 plus mile rods. Steve
 

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Yah.

I'm rebuilding a 5.0HO for my wife's 1991 Cougar; I can buy a balanced 331ci/5.4l kit (ENTIRE rotating assembly; crank, rods, pistons, rings, harmonic balancer, flex plate, all bearings) for less than I can get my current crank turned and a set of .010 pistons on my current rods(!!!)

It's ridiculous to me.

So I'll be actually building a 5.4HO for my 1991 Cougar 😆

RwP
 

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Discussion Starter #44
OK it looks like the late engines 3.9 and 5.9 went to press fit rods. And all the aftermarket rods are floated. Not a problem as there are 318 flat top pistons with clips. These rods are 100 grams lighter than stock. Claim safe for 500 HP at 6000 RPM. Now that would be a nice 3.9. The plan is to pick up a core engine strip it and have the bores tested and crank checked and turned or polished. Once that info is in hand I'll order pistons, rings, bearings and the rods mentioned. I'll also need the ring gear and clutch. This is what I'll need to do the balance work. Stripping the cyl heads, crack, surface and guide checking will determine if I order new castings. The cam kit comes with new springs, caps and keepers so valves and all new. Steve
 

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Discussion Starter #45
I have been crunching numbers and studying for several days now. I have done a lot of reading here and on other forums. As has been pointed out over and over there isn't a lot support for the 3.9 V6. Being a close cousin to the 318 and 360 some info from improving them may be helpful. Read a very well done paper on porting magnum heads. Dyno sheets show 60 HP increase. Percentage wise that would be a nice pickup for a small engine. I have located a camshaft and as you would suspect their offer dyno sheets showing 25 HP 35 lb ft increase. Then there are the SS headers, intake mods, exhaust system mods and throttle body upgrades. It takes a little time but I have come up with some numbers. It looks like parts to include the neat trick stuff $3,000 to $3500. Machine work not to include head porting works out around $1000 to $1250. Doing restoration work I always have to figure the cost as close as possible up front. How much would you have to love you truck to pop for one of these? Any thoughts on what kind of power output? I started looking for 20 hp if you believe any of the claims and add the numbers 50 to 100 may be there. Bulid it and put it on the dyno. Steve
 

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we rebuilt the 3.9 in my 96, bored it 30over, ported heads, bigger cam, headers with 3" high flow cat and 3' exhaust, V8 throttle body. But with out a tune Im not getting everything out of it that I should. Have yet to find anyone in our area that will tune it... Runs ok, but I know there has to be more in it
 

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Discussion Starter #47
Having been making little engines build more power all my life I understand the basics. I have been reading the claims and talking to people on the phone. Funny how some sales people seem to be reading directly from their web page. I realize this computer driven system is smarter than all the dizzys I have recurved and Weber carbs I have jetted. I'm trying to avoid spending money the system won't support.
Did a hundred mile delivery this morning pulling a little under 2000 lbs. Got that feeling again the 20 HP more would get it done and 50 would be a dream. Thanks for your input. Steve
 

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Chiming in again :sneaky:

Did a hundred mile delivery this morning pulling a little under 2000 lbs. Got that feeling again the 20 HP more would get it done and 50 would be a dream.
A few thoughts. The most powerful version of the 3.9 puts out 180 HP. A 20 HP gain gets you to 200 HP, a 50 HP gain would get you to 230 HP. A stock 318 (5.2) Magnum puts out 230 HP. For a lot less hassle and time, you could sell your V6 Dakota and use the money towards buying a Dakota that already has a 318 in it, or if you're really lucky, you might find a Dakota with a 360 (5.9 Magnum) which gets you 245 HP. Even the standard 4.7 V8 came with 235 HP.

So having crunched the numbers, how much will it cost you to make an additional 20HP?

Ed
 

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Discussion Starter #49
The issue is as much the cost of the std rebuild. Power adders are in the $1700 range not to include port work. About to turn 71 and have never needed a V8 yet. To be fair my racing team owned a 460 Ford bus to pull our 28 ft trailer. Before picking up two national sponsors we used a 300 six Ford van and open trailer. Steve
 

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We've come a long way since the 460. We recently purchased a 2016 Ram 1500 with the Ecodiesel. As far as engines go, the Ecodiesel is a high tech 3.0L V6 turbo diesel. It's a 60* degree V6 block w/ dual overhead cams, and undersquare bore and stroke ratio. It puts out 240 HP / 420 lb-ft @ 1600 rpm. The 460 had numerous hp and tq ratings over the years. The high water mark for the 460 were engines built before 72. Those made 365 hp / 485 lb-ft. After 72, power and torque dropped to pitiful levels during the smog years, then went back up when carburators were replaced by EFI, to, 245 hp / 400 lb-ft.
The Ecodiesel has about the same power as the EFI 460s with over double the fuel economy...So it's true, these days you no longer need a V8. Chrysler has two other really good V6s that make the old 318, 360 and 4.7 obsolete, that being the 3.7L Powertech and 3.6L Pentastar. The most powerful version of the 3.6L makes over 300hp!

Now, If I were so inclined and really wanted a 6 cylinder in a Dakota, I would actually consider an old school Slant Six. They are still easily found, last almost forever and have huge aftermarket support. And in case you're wondering, it will fit in a Dakota that had a V8 ('90 and newer)...then again, I do have a six in my Dakota...It's a 5.9 Cummins turbo diesel

Ed
 

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Discussion Starter #51
Thanks Ed, Just so you know I didn't jerk a 460 out of the junk yard to stick in the bus. It received the full Speed Pro treatment. with EFI aftermarket. If I recall we were 57 feet long and 17000 lbs. No the fuel mileage wasn't anything to write home about. If I were to locate a V8 powered Dakota it would get the same level of attention I plan for this 3.9. I'd expect it would cost as much and likely more. Additional pistons, rings, bearings, lifters, valves and a slight addition labor for machine work. My father bought mom in 73 a Valiant convertible with a 225 Slant 6. No thanks I'm good with what I have. Considering the cost I'm buying up parts as I can afford. Last week it was $400. for all cooling parts. This week parts have already started showing up. My friends at the local salvage yard are looking for the correct core unit for me. If I find someone willing to post pictures for me I can text them as I go along. I restored a 1970 National Championship winning race car after it flipped onto roof and was hit by two other cars before coming to rest. I took over 5000 pictures of the process. Proud to say it won every vintage entered in during my time supporting it. Steve
 

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Discussion Starter #52
Sorry my old brain can't tell the difference between 73 and 63 when mom got the convertible. By mid 70 my uncle had a Ford dealership and mom was riding LTDs from then on. Steve
 

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Hi Steve,
I've been following this thread with great interest. Like you my Dakota has the 3.9. Also like you I have been thinking of building the 3.9 for more power and torque. Personally I like the idea of a hot rod 3.9 judt to br different. I also think the v6 makes for a better balanced chassis, although I must admit I don't know what thw weight savings is vs the v8.
At some point could you post what you found (and where you found) the camshaft. Any other part finds as well?
Thanks,
Dynamo
 

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Discussion Starter #54
Hey Dynamo, it's good to know I'm not the only one who thinks the 3.9 can get the job done. I restore other people's classic cars. Quite often it takes a year or more as a one man shop. We have all heard the sayings " Speed costs money how fast can you afford to go?" As King Richard has often said " How do you make a small fortune racing? Start with a big fortune." The reason I bring this up is I have to have a very good idea how much a project will cost and if there is any chance a profit can be made. First I wanted to better understand the engine design and balance. I have heard that awful sound they make when pulling 2000 lbs in over drive up hill and pulling out to pass. Having balanced every engine I have built since 1968 I plan the same for this engine build. All that said needed or not, Hughes Engines is the only source I have found for a camshaft. They offer two as I understand it one works with current engine management and the second requires a chip and tune. Both require springs, retainers and keepers which reminds me of Comp Cams products which require you buy their kit. They also offer a intake manifold plate. I'll need to look again for the shop I liked for a up rated throttle body. I know a V8 TB is considered a easy swap but I'm after a V6 one with with larger plates and ported to match. I have looked at connecting rods due to aftermarket rods being stronger lighter and cheap all things considered. Part of the reason is quality rod bolts and recon labor nearly match the cost. The other reason is the weight which will help with the balance. The only issue is they are all floated and a little wider on the big end and the 3.9 is press fit. The 318 being same bore and stroke it's floated pistons with snap ring grooves will work. There is a lot said about the blocks being thin in the cyl wall area. The block after cleaning or before should be sonic tested before selecting an O/S piston. There are several sources for headers, I'm still trying to figure if they will be money well spent. A talk with my exhaust system guy explained why they are so short. It's against the law to move the cat further back. Little or no effort is made for equal length tubes. All kinds of claims are made about what they provide in the way of HP. There is power to be had in the cyl heads which is all hand work. There are things to be done in the intake also hand work. In rough numbers with complete cooling system, clutch motor mounts we are around $4,500. That does not include my hand labor on heads and intake or general labor. Waiting for the weather to break before digging though the junk yards for a core engine. Steve
 

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Hey Steve,
Wouldn't a solution to the thin wall casting be a sleeve? Don't know if that would be a possibility.
 

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Discussion Starter #57
If boring a cyl and a crack appears a single sleeve is a solution perhaps one per side. The deck is held to the balance of the block by the cylinders and water jacket. Installing all sleeves would weaken the block to much. A larger bore will increase displacement but not enough to make a big difference. I'd need to do the math but .020 vs .040 a inch or two. The long time Dodge guys mention cyl weakness, I'd call them old timers but they may not be as old as I am. If you could believe everything you read there could be 100 HP to be had. I'm thinking a chip and tune would be required to get there. Before ours began throwing codes and having running issues I delivered a car to Charleston SC picked up one there and returned ti Tidewater Va. I was completely satisfied with how it performed. If I have to fix it I'm going to fix it better. Do you post pictures? I take pictures as I work. 1000 on a 1 year project, 5000 on a multi year. People on the web love to see pictures. Steve
 

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Yeah, I haven't tried posting anything yet. I'm new on the site so might not have the proper permission as of yet.
So here goes. A photo of ole blue taken today.
Dynamo
ole blue 2020.jpg
 

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Hmmm. I thought I posted this...then it didn't show up??!!
Let me try again. Hopefully it won't be a double post. Sorry if it is.
Dynamo
 
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