Mack b62 frame question

[nam vet]

I have a 1957 b62sx that was originally equiped with a 464a gas engine with a triplex trans. Sometime over the years it was converted to a----according to the info on the timimg gear cover-endt673. Problem is the engine seems to long. The front radiator support was modified further forward because the balancer on the front of the engine was rubbing and the fan was hitting the radiator. Because the support was moved forward it threw all the front sheet metal out of position by 2/3 inches. Doesnt look right. Two questions. Are the truck frame rails for the gas motors shorter than trucks with diesel motors??? Are there different widths for the flywheel/clutch bellhousing that would possibly pull the motor back that 2/3inches? Thanks Bob

[mechohaulic]

#1- THANK YOU for YOUR SERVICE ..#2- frame rails length  aren't the critical issue compared to position of the mounts. possibly it was easier for someone to move things forward then to move trans back and cut driveshaft since the nose was already off to swap engines .  to me it's would be easier to move mounts back. a donor vehicle may have been there to provide  crossmembers etc. if the unit has offset mounts , swapping left to right  will give a couple inches difference in location. 

[nam vet]

Thanks for the response. So possibly the frame is not my problem. My b62 was originally built with an en464a gas engine. Over the years it was converted to a 673 but the installation wasn't 100% correct. Does anyone know if the 464a engine was shorter than the 673 diesel?  The 673 sits a couple of inches to far forward so the fan hits the rad and the crank balancer rubs the rad support

[D-Day]

If you look on the B model registry here and go to B model info and then Cab info you can see all of the different things they did to the different models as far as bumper to back of cab dimensions there was a lot of difference in hood length etc.

[terry]

3 hours ago, nam vet said:

Thanks for the response. So possibly the frame is not my problem. My b62 was originally built with an en464a gas engine. Over the years it was converted to a 673 but the installation wasn't 100% correct. Does anyone know if the 464a engine was shorter than the 673 diesel?  The 673 sits a couple of inches to far forward so the fan hits the rad and the crank balancer rubs the rad support

If the frame mounts on the side point towards the front, reverse sides and it might come out right.    terry

[nam vet]

Thanks for the info but the only engine mount is a cradle that bolts behind the crankshaft pulleys and damper on the engine and goes from frame rail to frame rail. There seems to be only location for the two trans mounts because the frame rails are not factory drilled with any extra holes to be able to move the mounts forward or backwards. Somebody suggested the B model registry and that it has a lot of useful info. I am going to give that a try.

[D-Day]

10 hours ago, D-Day said:

If you look on the B model registry here and go to B model info and then Cab info you can see all of the different things they did to the different models as far as bumper to back of cab dimensions there was a lot of difference in hood length etc.

My thought on this was maybe the front end got replaced with a different front end from one of the shorter hood trucks I remember locally here someone had a similar problem replacing the sheet metal up front.

[nam vet]

Ok two more questions. this is about B model trans mounts. On the top of the trans mount,not the frame mount,there is a part # cast in between the webs. Could somebody tell me what that # is? Could be right or left just tell me which side and the #. Also my B has the emergency brake drum on the driveshaft. Its a long frame with a twin screw. My drum seems to far forward. It looks like it should be pretty much under the rear frame mount for the cab because it looks like the mount has been notched for the drum to fit into. Thanks

[D-Day]

I have some out that I can look at maybe tomorrow I did notice the B755 I am working on the location of the frame side of the mount in relationship to the cab mount is a lot different than the B 73 I am removing the transmission from that is in the shop now they are relatively the same they both appear to come off the transmission at a 90 degree angle as opposed to being angled forward or aft I will get some pictures as soon as possible

[D-Day]

The transmission mounts look similar but are not the same from a B755 and a B73 also the frame side has a different bolt pattern but not the transmission side also you can see the location as compared to the cab mount on the other side of the frame 11 inches in difference probably similar difference in the B62-B61 

[D-Day]

Same thing with the front mount not only in a different location but different bolt pattern maybe a B61 mounts would move it back but you have to measure everything carefully 

[D-Day]

I was able to get a measurement from the B73 mounts the green one on the transmission side from the bottom they are actually offset about 3/4 of an inch so you could gain that way possibly could not find part number yet

[nam vet]

D Day thanks for your all your help and pictures.  Your second picture looks like my mount. I found the part numbers right on the top next to that middle web. They were covered in rust. Thanks again!

[nam vet]

Ok I have been doing some research. My problem with my drive line being too long is not the frame or wrong motor. My problem seems to be in the transmission area. I originally thought it was a triplex, but its a Mack 10 speed, 5 speeds with a hi and low. After looking at a ton of pictures on the internet it looks like there are two different widths for the flywheel housing and the clutch housing. One picture showed a very skinny housing for both of them, the trans was a duplex and has the drum on it for the emergency brake like mine, which looks like it will solve my problem.  In the other picture both housings were wide, and the flywheel housing had a small removable vent cover on the top, just like mine. and a drum for the e brake. This trans was also a duplex. Both were early 58/59/60's B model Macks. Anybody know why 2 different widths??. I would really like to fix mine correctly instead of moving trans mounts and shortening drive shafts etc. Any help would be appreciated. Thanks

[D-Day]

A lot of the early B models had a single plate push type clutch later the twin disc push type clutch came out then the twin disc pull type clutch took over different bell housings flywheels and input shaft for the transmission were used as well as all of the clutch linkage and other related parts

[nam vet]

Is this a common problem with B model owners that change to a twin disc? It makes the trans to long and either pushes the motor forward and hits the rad mount or it moves the trans back and the mounts need to be moved back and the driveshaft needs to be shortened? What solution is everybody using?

[D-Day]

No easy answer in the past I have redrilled the frame to relocate the rear mounts but sometimes that is not possible if there are other holes to close I have also fabricated mounts for the bell housing making an offset to move a small distance  and then shorten the driveline its getting difficult to find the right combination of parts that you need for engine swaps

[nam vet]

D Day Thanks again for your help. I decided to go for it and just push the engine/trans back the 3or 4in. I need to make the front rad support bolt up in the right place. I found a driveline shop that says they can shorten the driveshaft and it looks like the rest is fabrication mounts,exhaust,clutch linkage etc. Thanks again.

[Mean Green]

D day I see the yellow frame has budd wheels can’t tell if it has brakes or not I’m looking for a complete axle for my b42 wondering if you have anthing

[D-Day]

That truck was west coast had budd hubs all around 1965 yes no brakes up front I found studs for the aluminum wheels still available I will try to get a casting number or something for you axle is a FA 5071 should be the same spindle and bearings for 507 west coast is where to look that is the only one I have 

Edited February 22, 2023 by D-Day

[Mean Green]

Ok thank you I put a hub pilot air ride cut off in the rear of mine and it’s been tough finding something for the front some guys here used a fld freightliner axle I just try to keep my eyes often for anything 

[Mean Green]

My b 42 was converted to diesel and if I remover right someone had notched come vrossmember out in the front for the damper and my fan was so close to the rad you couldn’t change the belts 

[D-Day]

Looks like 6Qj417A maybe hard to find possibly used on early R or F models as well 

[mowerman]

i always thought the frame on a gas job was thinner,is that true??? bob

[Vladislav]

On 2/19/2023 at 9:24 PM, nam vet said:

Ok I have been doing some research. My problem with my drive line being too long is not the frame or wrong motor. My problem seems to be in the transmission area. I originally thought it was a triplex, but its a Mack 10 speed, 5 speeds with a hi and low. After looking at a ton of pictures on the internet it looks like there are two different widths for the flywheel housing and the clutch housing. One picture showed a very skinny housing for both of them, the trans was a duplex and has the drum on it for the emergency brake like mine, which looks like it will solve my problem.  In the other picture both housings were wide, and the flywheel housing had a small removable vent cover on the top, just like mine. and a drum for the e brake. This trans was also a duplex. Both were early 58/59/60's B model Macks. Anybody know why 2 different widths??. I would really like to fix mine correctly instead of moving trans mounts and shortening drive shafts etc. Any help would be appreciated. Thanks

Here you probably talk about 67 and 72 series transmissions. Both were used on B-models. The 1st was lighter series box with lesser torque rating. The 2nd is what you described as a clutch housing with a vent cover on the top (it has a similar one at the bottom either). I don't know were they used with different clutch sizes but it seems making sence. And I see no reason a man can not install one style in place of the other on a engine using different flywheel, clutch, mounts, prop shaft etc. Or just swap an engine together with a tranny making adaptations to the chassis.

Vlad

[Mean Green]

I never compared frame thickness between a gas or a diesel I know mine was a long chassis truck was built a a livestock truck and it had a plate that ran from behind the front spring mounts to the front of the rear spring mounts I ended up removing it because of rust jacking it was only on the sides and bottom not on the top