4BTA motor mounts

[moesett]

I'm attempting to install a 4BTA in a 1957 ffpw. Can use your help with any advice and pictures.

thank you

[Desoto61]

It's going to be worth your time to subscribe to the magazine or at least the site so you can access the archives and search. There are a few different threads about this modification. Not sure anyone has done one quite the same. Mine work but there is quite a bit of vibration, I'm sure there's probably a better way to do it, but it will also depend on the exact setup you plan to use as far as what your design will need to be.

Also go look at the 4BT swap forum, you'll find way more information on designing motor mounts and such there.

[moesett]

motor mounts

First off, I must say you are an amazing craftsman. Thank you for responding so quickly. I am now a subscriber and have been poking around in the archives. I have gone through your build several times and found it fatastic. I have been a member of 4btswaps for a while, super site. I would think that this swap has been done so many times that there would be a somewhat common setup.

[overland]

motor mounts

Hi,

I'm also interested in the 4BT swap. So far, I have found the same as Moesett, many different ways to do it.

Desoto61, what do you think is the cause of your "excessive" vibration?


~james

[Desoto61]

Thanks for the kind words, but I started off with nothing but a bunch of hand tools and an ambitious nature, so it's mostly been a learning experience, and it's far from perfect. But that also means it's doable by anyone with a mechanical bent and a stubborn enough nature.

Well at it's most basic this is a big 4-cylinder commercial diesel engine, it is going to vibrate, NVH was secondary to the design. It makes a lot of noise too, I thought it might be my exhaust but no, it's mostly engine noise. Cummins did make a balance shaft set for these engines to try and tame some of that, but they're expensive if you find them and bolt below the crankshaft and so make the engine even taller, which is already an issue as the oil pan already sits low enough most have to clearance it.

My engine has the Chevy NV4500 setup which uses a really heavy flywheel, which should help some, but I have no idea how much as I've never run one with a different setup.

My motor mounts are the 6BT versions so they're designed for a heavier engine that has less vibration, different/softer mounts would probably help most. The liquid filled (but expensive) Lord mounts seem to be most popular but not as easily found. I think they also need to be installed vertical.

I think another thing that may have helped would have been to try and build more of a "cradle" type mount, e.g. with the motor mounts at an angle between the frame and engine, that way some of the side-to-side vibration would be transferred as the engine trying to "lift" itself, and partly as a horizontal force into the frame sides. By being flat and somewhat low on the block mine let the engine "rock" back and for the between the flat plates which transmits to the truck better.

The vibration is mostly at idle and high RPMs, which is somewhat expected, just off idle it smooth's out quite a bit, but I was surprised at just how pronounced it was at idle.

Unfortunately the only way to know for certain what works best is to experiment, and that's time consuming and expensive. On top of it the best design for vibration may not be the best for packaging, or strength, or simplicity, etc. I'm sure someone with better fabrication skills could come up with a more elegant solution. I've often wondered about using the front mounting holes and building something that bolts to the original engine mounting locations. Cummins offered a front mount like that, but then you need a more robust rear mounting as the single trans mounts wouldn't give you the best support against the engine twisting in the frame.

Charles Talbert probably has the best setup, but it's his secret sauce, and heavily dependent on his exact build, but it's also why people come to see him with big blank checks. For the rest of us it's a combination of what we have to work with and our resources to fabricate parts. There are so many different parts combinations that it's hard to give anyone "one way" to do it.

Determine what drivetrain you want to use (trans & transfer case) and go from there. That is probably going to be determined by what you can find or how much you are willing to pay. That will drive your path forward more than any other thing.

Good luck and make sure you share the build here too so other's can benefit too!

[overland]

Desoto61, thanks for the detailed response. I think it would be interesting to 'see' if your engine would be quieter with softer motor mounts. I'd be interested in hearing from folks cradle mounts.

I haven't read much about the Cummins ISB, but I am eager to know if that is a 'workable' option. The little I have read is that is a quieter engine then the 4BT. I'll need to spend a little more time reading on 4btswap.

[Desoto61]

I think the ISB probably would be quieter and smoother. The computerized common rail injection allows you to tame a lot of sins of the diesel. Tradeoff is the computers and complexity. Check out the carryall thread for Alex's build on one of those. He's got a lot of work in the computers and electronics ahead of him, plus the larger size. Charles Talbert has switched to them as well, but the cost is significant if you can find one.

If I was going to look for one of those I'd be tempted to look at some other options too. Banks once showed off a diesel kit built around the 3.0L V-6 from the Jeeps/RAMs, which would be a good little motor.

Personally if I were dreaming I'd want one of the V8 diesels that Nissan is going to put in the new Titan. But finding one...

The biggest problem is gearing. With a 2300 RPM governer, 4.88 axles, and a 0.73:1 OD, my final speeds are going to struggle to get to 65 with a 35" tire. I'd like to do 37" but not sure it's going to fit, and even then 65 is still at the high end. Without swapping axles the only other option is to try and find a lower OD, or an engine that can rev higher.

Not that I need to go much faster, but it puts normal highway speeds outside the ideal engine speeds for a diesel, but just about right for a gas engine or faster spinning diesel.

[tuko]

4bt, gm nv4500 2wd, dodge 2nd gen adapter plate, dodge nv4500 bell housing and input shaft with retainer, dodge 2nd gen 2500 5 speed pedals with a dodge master cylinder/brake booster and slave cylinder works very well! Also anchor 2859 make a great alternative to the lord mounts.

[moesett]

Tuko
How did you get around dodge starter? I am trying to use the 2859s . It looks like I would have to pull the mt to change the starter. Do you have any pics?
Thanks Andy

[tuko]

Are you using a power steering or vacuum pump? I am not, I covered with a blank plate, plenty of room. If you are using something in that location it may be more difficult.

[moesett]

I plan to use power steering, but there is no room for vacuum pump or the steering gear. I am going to go with a 92 dodge dana 60 and try to figure out the steering box placement.

[tuko]

Mine are very similar to these, allowing removal of the starter if need be

http://www.4btswaps.com/forum/showth...l=1#post154170

The frame side sits in a cradle I made up. The site won't let me upload my pictures as I am no longer a subscriber.

[moesett]

Tuko
Thanks, [show me your mounts] is one of my favorites, and what you suggest is what I am attempting.