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Vibration and Noise of 4BT

16K views 21 replies 12 participants last post by  camccardell 
#1 ·
Hi, I have been looking into swapping a Cummins 4BT into my 77 F150 and the only bad things i've heard about this is the added noise and vibration that im going to get. To me, the increased fuel economy, torque and longevity of the diesel would outweigh these drawbacks but i'd still like to know just how bad it is before hand and how to lessen it.
So is there any particular year or model 4bt that has less vibration or noise than the others? Is there a way to balance these engines better? How about motor mounts, what material is best at absorbing that vibration?
 
#2 ·
There are no versions of the 4B that vibrate less. That's because it's a 4 cylinder, but there are some things you can do that will help. First item is use the heaviest flywheel you can get, that would be the chevy version for the 4B, weighs in at 62 lbs, that is if your using a manual trans.
Some of the forum users swear by the liquid filled isolaters, I've found that the first gen Dodge isolaters with a couple of holes drilled in them combined with the chevy flywheel works great.
For noise theres some good threads in the stickys on that subject.
 
#7 ·
Well theres a website called fordcummins and they sell an adapter for the B series that will make it fit with the C6, so if I get that adapter it should work. I was just wondering if there was a heavier flexplate that could be used with the C6.

Some 4BT's have balancer shafts hidden in the oil sump.
Which 4bt's would have those balance shafts in them you think? Or could the balance shafts be installed on any 4bt?
 
#10 ·
You can put a c6 behind a 4bt if you have a ford adaptor. I have a ford small block windsor adaptor so if you had a small block c6 transmission you would be in business.
 
#11 · (Edited)
I did a 6BT Swap in my 89 and used the C6 that was bolted up to my original 7.3 Diesel. It is different bolt pattern than the small block.

The Cummins came out of a 85 F350 as my doner truck and it used a Waive Ring to take up the space between the flywheel and the Torque converter:


I thought it looked a little flimsy so I had a solid ring made at my buddys machine shop:


Not sure if it the same application for the 4bt's but it may be an option.

Here is a link to my webshots with the Cummins Conversion Pics:


ON EDIT,..I cant post any attachments until I have 10 Post,..Sorry,,pics to come later,..:confused:
 
#12 ·
I did a 6BT Swap in my 89 and used the C6 that was bolted up to my original 7.3 Diesel. It is different bolt pattern than the small block.

The Cummins came out of a 85 F350 as my doner truck and it used a Waive Ring to take up the space between the flywheel and the Torque converter:


I thought it looked a little flimsy so I had a solid ring made at my buddys machine shop:


Not sure if it the same application for the 4bt's but it may be an option.

Here is a link to my webshots with the Cummins Conversion Pics:


ON EDIT,..I cant post any attachments until I have 10 Post,..Sorry,,pics to come later,..:confused:
DarrinGT:
Post your links. I gave you the missing 2 posts credit needed to post your links.
 
#13 ·
Be careful making things too solid between the flywheel and torque converter. Automatic transmissions have what is called a flex plate for a reason. Torque converters are slight out of true and can expand under pressure causing alignment to the engine to change. The flex plate ( and wave ring ) take up this miss alignment.

Some 4B has a balance shaft that bolted to the main caps. I have one that is going on mine at some point. These add about 4" to the bottom of the engine.

Balance shafts do work, I've got a International backhoe with a 4 cyl diesel D239 that vibrates less than my old Leroi Tract air that uses a 225 ish CID 4 cyl gas. The IH has a smooth machinery type of vibration.
 
#14 · (Edited)
The balance shaft is used in low rpm applications. They are only rated for a certain amount of rpms(cant remember, but was lo) and not used in hiway apps. I dont know if anybody is using one in a vehicle but I wouldnt personally. With a gov spring upgrade you would probably be building a large, expensive grenade. Some Lord or marine jelly motor mounts help. If you use poly on trans/t-case it will bring it right back so try to use rubber or something soft all the way back to isolate vibrations.
 
#15 · (Edited)
Internal balancing of rotating and reciprocal parts is supposed to help smooth things up. Fluidampr says their's is not a balancer. A combination of things should help. Mounts are the main thing. Lord's are good. I called them and they didn't have a clue what I was talking about. If someone knows the Lord's part number for the 4bt please post it.
 
#19 ·
#16 ·
When making your motor mounts, it will help some if you position the isolators on a 45° angle. This way the "jumping up and down" of the pistons is not transmitted directly to the frame. Half of the forces are going down and half of the forces are pushing the mounts outboard.
 
#17 ·
Angles will work with solids but is not recommended for Lords/liquid mounts.
 
#18 ·
BobS

Quote Originally Posted by DarrinGT View Post
I did a 6BT Swap in my 89 and used the C6 that was bolted up to my original 7.3 Diesel. It is different bolt pattern than the small block.

The Cummins came out of a 85 F350 as my doner truck and it used a Waive Ring to take up the space between the flywheel and the Torque converter:


I thought it looked a little flimsy so I had a solid ring made at my buddys machine shop:


Not sure if it the same application for the 4bt's but it may be an option.

Here is a link to my webshots with the Cummins Conversion Pics:


ON EDIT,..I cant post any attachments until I have 10 Post,..Sorry,,pics to come later,..
DarrinGT:

Post your links. I gave you the missing 2 posts credit needed to post your links.
Sorry been a while, Here are the pics of the Wave ring.

Little hard to see it but it is installed on the flywheel here:



Here is is removed:



Here is the spacer my buddy made:



 
This post has been deleted
#21 ·
I was all worried about the vibration while building my Bronco . I just used those flat dodge motor mounts. I never even think about the vibration now. Mine has been running over a year. Now it is noisy but I have no AC so the windows are down most of the time, but after I'm on the road no problem hear either. Quiter than the box van.
 
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