A '69 Build... "Brought to you by Don Juan Productions" Full index added to page #1

[Z71paramedic]

Well I'm certainly no engineer ( I hate math) and my truck is far from perfect but I will tell you I moved my engine/trans forward 2" and have noticed no adverse reactions. I don't have a big block... Nor was I worried about a perfect COG or anything like that. I wanted things to fit. Having done this my valve covers have plenty of room, my distributor cap seems miles away from the firewall compared to stock and I may even be able to pull the distributor with the motor in the truck now My angles are pretty solid too and have no driveline vibes to report of.

Another COG argument is that you have hundreds of pounds of tube in the back for the cage/sliders. I'm sure you'll have seats, passengers, tools, a full (at first) 40 gallon gas tank and a big a$$ bumper in the rear too. The weight of sliding the motor 2" forward should be more than offset than all of that I would think. Plus you'd have the added space for the valve covers/dizzy with a metric $hit ton less work to do.


Just my 0.02, but again I'm no expert.

 

[NorCal69]

Mike,

I feel your pain on all of this.....


You are going through a lot of the same struggles I did initially, and will probably come to a lot of the same conclusions. In a short wheelbase truck like ours, it's really hard to install a doubler and still keep the driveline angles looking good.



Compromises:

Belly clearance - What is your current height to the bottom of the framerail? 24"? 26"? If you pull some lift out of the truck you can improve the rear angle.... you'll rub more, but that's what the rocksliders were designed to do.

You know, I have not measured that in awhile. My guess is that 24-26 though. I sure would like to leave the height that it's at.

Drivetrain angle - You can tilt the whole combo more steeply to improve the rear angle, but you'll cost yourself even more BOA clearance at the xfer case.

Rotate the 14BFF pinion - You risk starving the pinion of oil, but a lot of guys just overfill the pumpkin and call it good.

I'll do some more research on this.

Replace the Doubler with an Atlas - It's a really expensive way to gain a few extra degrees... but if you want to "buy your way out" it's an option.

Man, I wish. Just not in the budget this year. Been a pretty calm winter with very few claims coming in.

High Pinion rear axle - Maybe a Ford 9" Getting the pinion up higher is just as good as lowering the suspension down, but again it's a huge and costly change.

High Pinion with Portals - You'll get great operating angles, and the only thing you'll have to change is ........EVERYTHING ELSE!

I know a guy that has some almost done. There probably pretty dusty, but I don't think that he will be using them any time soon. Plus, I've bought from him before and seems like a good dude.


Take a few (hundred) more laps around the truck and I'm sure you'll figure it out. My prediction is that it won't be any one item that you change, but it will be a series of relatively minor adjustments that will help pull several degrees of angularity out of that rear driveshaft.

-G

Well I'm certainly no engineer ( I hate math) and my truck is far from perfect but I will tell you I moved my engine/trans forward 2" and have noticed no adverse reactions. I don't have a big block... Nor was I worried about a perfect COG or anything like that. I wanted things to fit. Having done this my valve covers have plenty of room, my distributor cap seems miles away from the firewall compared to stock and I may even be able to pull the distributor with the motor in the truck now My angles are pretty solid too and have no driveline vibes to report of.

Another COG argument is that you have hundreds of pounds of tube in the back for the cage/sliders. I'm sure you'll have seats, passengers, tools, a full (at first) 40 gallon gas tank and a big a$$ bumper in the rear too. The weight of sliding the motor 2" forward should be more than offset than all of that I would think. Plus you'd have the added space for the valve covers/dizzy with a metric $hit ton less work to do.


Just my 0.02, but again I'm no expert.

I hear ya, Z. Just moving the engine forward would solve a lot of problems. I need to get back in there and really start to check out my front driveline. If it screws that up, it just won't be worth it.

I have, I guess what would almost work now (rear), I just need to get some of that clearance on the firewall. So many options, and it's all over a couple of degrees here and there. Who woulda figured.

 

[NorCal69]

Hey, Sean. What did you end up with on your front. Now that I'm thinking about it, with the doubler, mine should actually be longer than yours.

I know that you have a taller lift, so moving the engine forward on mine, might not be that bad for the front DS.


Greg, where/how much, does the COG come into affect on moving it forward?

 

[ashman]

this is all way over my head, but I enjoy reading and learning. /thumbsup

So many options, and it's all over a couple of degrees here and there. Who woulda figured.

it's the details that kill ya!

 

[NorCal69]

this is all way over my head, but I enjoy reading and learning. /thumbsup

it's the details that kill ya!

Dude, I'm just a carpenter. This chit is way out in left field for me too..

 

[Z71paramedic]

Hey, Sean. What did you end up with on your front. Now that I'm thinking about it, with the doubler, mine should actually be longer than yours.

I know that you have a taller lift, so moving the engine forward on mine, might not be that bad for the front DS.


Greg, where/how much, does the COG come into affect on moving it forward?

Mike, I'll run out there in a bit and check it for you. All I know is Jess didn't seem too concerned about it when I called him

 

[bp71k5]

Why not consider a rear cv shaft? I'm running a doubler with the motor moved forward but you should still be ok at the rear with a CV with the stock motor position unless your lift is crazy big.

 

[Greg72]

Good point Brian.

What did Jesse say the max operating angle should be for the CV-side of his 1-Ton drivelines? Obviously with the double-cardan joint in there you split the angle between them and it should be easier to keep the operating angle at something more reasonable....

That still doesn't change the fact that that rear pinion needs to point straight at the 205 rear output, and THAT angle might end up steeper than you feel comfortable with.


-G


ps. Jesus was "just a carpenter" too.....as I recall he ended up accomplishing some pretty impressive things.

 

[bp71k5]

That still doesn't change the fact that that rear pinion needs to point straight at the 205 rear output, and THAT angle might end up steeper than you feel comfortable with.

True. Although you can point it back down a few degrees and assume axle wrap under throttle will bring the pinion back up a bit. That's what I ended up doing, but the axle does puke out some fluid during extended freeway speeds and high temp.

 

[NorCal69]

Why not consider a rear cv shaft? I'm running a doubler with the motor moved forward but you should still be ok at the rear with a CV with the stock motor position unless your lift is crazy big.

That was for HAD's CV shaft. I think there are a couple of things that are beating me up a little compared to your rig. Your 4500 is shorter, I believe and I'm running a 6" lift. How much did you move the engine forward? Did you notice anything that would make you not do it again?

Good point Brian.

What did Jesse say the max operating angle should be for the CV-side of his 1-Ton drivelines? Obviously with the double-cardan joint in there you split the angle between them and it should be easier to keep the operating angle at something more reasonable....

That still doesn't change the fact that that rear pinion needs to point straight at the 205 rear output, and THAT angle might end up steeper than you feel comfortable with.


-G


ps. Jesus was "just a carpenter" too.....as I recall he ended up accomplishing some pretty impressive things.

When I talked to him, he stated that the max that I would want to go would be the 20* for the DS and 18* at the pinion. I asked him if I ended up at 22*-23* how long the u-joints would last, I thought maybe 5k. He answered with 1k.

ps. you got me on the carpenter. I might need to change my bio to something a little more positive...

 

[bp71k5]

I moved the engine forward about 4.5". I used the existing holes in the frame that I assumed were for the BBC at the time, but doubt that's what they were really for.

My 205 also hangs down just under 4" from the bottom of the frame rail after it was clocked 2". It sounds like a lot, but is 2" better than stock.

I dunno if it helps, but my driveshaft angle is at 22deg at full droop and somewhere less than that at ride height. It's on jack stands so it's hard to get a real measurement at the moment but I estimate it at 15-16. If you rotate your pinion up just a little you will find the angle is reduced quite a bit. There might be a sweet spot somewhere in there.

 

[Greg72]

A few more thoughts for you Mike.....

Moving the driveline forward isn't the end of the world, and there are a few advantages (clearance at firewall, etc). Yes, you are shifting more weight over the front axle but if you also move the front axle forward, the penalty should be minimal.

Keep an eye on the front driveline too.... Moving the driveline forward is going to screw with your front angles, so be careful not to trade one set of problems for another.

Ultimately you can swap to a set of aluminum heads to remove front end weight (expensive), or relocate the battery to the rear to shave a few easy pounds from up front.

It's probably best to make peace with the fact that the transfer case is going to hang down a few inches.... Just come up with a nice tapered skid plate for it so that when it hits a rock it can easily slide up and over.

-G

 

[folkenheath]

I was assuming it was for a CV shaft, if you were not running a CV shaft then you need to crank the pinion way down parallel to the tcase and make your angles much worse, in which case you would probably need a 1410 and may still have vibrations.

 

[NorCal69]

Thanks for the help Guys. It's really pretty interesting stuff once you start to read about it.

I didn't even open up the garage last night. The plan was to try to figure out as much as I possibly could last night. I know from experience, once I get under the rig, more questions will come up.

It really does look like moving the drivetrain forward seems like the best option to go forward with. At least at this point. I think that I'll have some time tonight to get my front measured up. I'd like to have a lot figured out, so I can maybe get some tube/bar?? under the doubler this weekend.

Couple of things that I found out last night. The transmission measurement still has my head spinning. I just cant get over how all three components (engine, trans and transfer) are not at the same plane. I thought at least the trans and the transfer would be.

Tom Woods in his tech article says to measure off the trans to get you angle.

A quick scroll down and you'll see it.

http://www.4xshaft.com/

Then I came up to this on pirate. The guy just couldn't figure out his problem.

Post 11 is where he figures it all out.

http://www.pirate4x4.com/forum/showthread.php?t=984183&highlight=driveline+angle

 

[NorCal69]

I was assuming it was for a CV shaft, if you were not running a CV shaft then you need to crank the pinion way down parallel to the tcase and make your angles much worse, in which case you would probably need a 1410 and may still have vibrations.

Yep, it looks like a conventional 2 joint drive shaft can only run at a max of 8*. It's a completely different set up with the tranfer and pinion being parallel. At least that is what I'm getting out of it so far.

Just so you guys know, I have HAD's flange set up for the 14bff and for the back of the 205. Shouldn't need the pinion guard set up on this one.


Greg, I hopefully have a plan of a nice skid plate for under the transfer and trans. With those three mounting plates on each side of the frame, the forward plates would have a piece of tube that is a big "U" with a flat/strait area going under the bellhousing area. I could then cover everything with some kind of material (unknown) from the front of the trans, to the rear of the doubler and out to the sliders. At least it's in my head, don't know if it will really work out though.

 

[folkenheath]

The transmission measurement still has my head spinning. I just cant get over how all three components (engine, trans and transfer) are not at the same plane. I thought at least the trans and the transfer would be.

The crank shaft (and cam), transmission shafts, and tcase shafts are all parallel to each other, and the output flanges will be perpendicular to that. I think the confusing part is that the mounting flanges for the carb, tranny pan, bottom of the oil pan (not the mounting surface) are not perpendicular to the crankshaft centerline. If you thought what I think you thought, you are correct, there are just other dimensions that make it seem like it's not that way.

 

[NorCal69]

Haven't had a bunch of time on the rig lately. The rain stopped this last weekend and it was time to cut the grass and clean up the yard. I was becoming "that guy" on the block.

I did have a chance to move the drivetrain forward three inches though. Nothing is set in stone and no holes were drilled. It sure makes everything really easy with Kert's crossmember. I put a come-along around a piece of metal that wrapped the front frame horns and gave a couple of cranks. The entire thing was just to easy. I'm confident that I can keep playing around till I have everything just perfect. The engine crossmember still sits ~2" behind the axle. That is without moving the axle forward too. I'd say that 75% of the engine is still behind the axle.

The three inches sure made everything work out really nice. I have a ton of room for the firewall. Without cutting onto the floor (yet), I gained three inches worth of belly clearance. The 205 still hangs about 3" below still. But, it looks like with these angles, if I wanted, I could bring the rear up on the doubler.

I did get a chance to measure bottom of frame, 29 1/4". It came in a little tall for 38's but, that could just mean I need to step up to some 39.5's. Remember though. My super springs have not even came close to hitting a vertical on the shackle. I would like to think that with enough weight ( I have no idea on how much that will require ) I'll lose an inch, maybe.

The rear

So it looks like I have about 15.7* degrees on the rear. I can still come up almost 4.3 now, but that would require the floor to be cut.

The front

I talked to Jess, on Friday before he left his shop and gave him the run down. I mentioned that it's running about 27* and he told me this is about normal for the front and really not to worry about it. Made me feel a little better.

A pic of the shenanigans

 

[Z71paramedic]

Yeah, Kert's crossmember is definitely the *hit! Sounds like moving things forward will really make life easier. Looks good with that BB there!

 

[NorCal69]

Hey Sean, I know that I've asked you a bunch of measurements on this, but one more would be cool.

What do you have to the bottom of your frame rails?

Thanks, Brother!!!

 

[Z71paramedic]

Hey Sean, I know that I've asked you a bunch of measurements on this, but one more would be cool.

What do you have to the bottom of your frame rails?

Thanks, Brother!!!

Give me a bit, I'm actually still in bed I'll measure it up for you in a bit though.