300+ rebuild

[mechohaulic]

6 hours ago, Freightrain said:

I've run valves, so I understand the procedure.  On my hot rods, I always do one cyl at a time.  They have cheat sheets on how to do multiple cylinders at a time but I never do it that way.  Ever.  Even after getting grief for it.  "Oh, you're taking too long".  Whatever.

This having so much lash surprised me.  Why does it require so much for a "dynatard" cam?  What is special about it?  I'm just glad it isn't a cam lobe problem.

I did the valves on my 237 and the Jakes without issues.  I know Jakes are different but I followed the sequence and they work fine.

I want to transfer the Jakes over to this engine, if possible.

one day if time allows. do the cheat sheet method of adjustment ; then go back to one cyl at a time see if any difference.  the better jacobs is an add on with jake unit holding down exhaust valves AT PRECISE cyl firing. the dynatard being built in has those over sized rocker adjusters which are simply small hyd slave cyl. that combined to a screwy cam make the Daynard "work". the dyna has to be on cyl TDC  for proper adjust. pushing down on rocker to completely expel all oil in slave cyl. short version the dyna ain't worth sh- - t ;makes some noise.  fred flintstones car had better braking. 

[fjh]

7 minutes ago, mechohaulic said:

one day if time allows. do the cheat sheet method of adjustment ; then go back to one cyl at a time see if any difference.  the better jacobs is an add on with jake unit holding down exhaust valves AT PRECISE cyl firing. the dynatard being built in has those over sized rocker adjusters which are simply small hyd slave cyl. that combined to a screwy cam make the Daynard "work". the dyna has to be on cyl TDC  for proper adjust. pushing down on rocker to completely expel all oil in slave cyl. short version the dyna ain't worth sh- - t ;makes some noise.  fred flintstones car had better braking. 

Yup yup a fart in the wind has better holding power!😂

[Geoff Weeks]

4 minutes ago, mechohaulic said:

one day if time allows. do the cheat sheet method of adjustment ; then go back to one cyl at a time see if any difference.  the better jacobs is an add on with jake unit holding down exhaust valves AT PRECISE cyl firing. t

That is only true for engine that use a rocker to work the injector. Engines with an injection pump (mech Cat and Mack) there isn't the rocker to trip the the exh valve at injection. So on those they have to use a valve on an adjacent cyl to trip and the timing isn't exactly right. It is why a mechanical Cat's Jake isn't as good as one on a Cummins. Once mfg went to electronic common rail with the cam pushing the injector and the electronics adjusting timing an duration, Jakes  matched those of Cummins. 2 stroke Detroits had there own problems, keeping a Jake on those limited.

[Freightrain]

3 hours ago, terry said:

Larry , i might have missed it, gonna run the triplex behind it?   Terry

My initial thought is NO.  Everyone says to but I don't want to worry about something going wrong.  These transmissions arent on every block anymore. 

 

My next thought is get rid of the 4.10s for a set of 3.55s if I can find a set for a Rockwell.  Then I can run a 13 spd.  If changing rear gears becomes a hassle, I want a true double over 13.  Not a homemade version.  I want more road speed at lower rpm(noise level).

I will be removing the little 6041 box I have hanging in there.  Much to fragile.(I'm a gearhead, I want something I don't have to drive like I have an egg under my foot).

I had thought of using the 5 spd that came with engine and find a 1241 and use it for splits, plus if I get a 1241C it has deep under like my 6041.

 

Lots of "maybes" and "ifs".

[Mark T]

4.10s and a 15 over. Used to work nice with a 300. And one of those shouldn't cost a fortune.  Good luck finding an RTOO thirteen. A RTLO 13 or 18 has a high final overdrive, and some of the smaller series don't cost a whole lot.  A direct 5 speed and a 1241 with 4.10s....might just as well use an RTO 13. Even a  FRO 10 would be nice with 4.10s. 

[davehummell]

Larry I have a freightliner air ride axle with a 373 ratio and I put in a 13 double over triplex I bought it not knowing it was a double over the junkyard guy just said it was a triplex it will go faster than I really want to drive anymore

[Freightrain]

I want to cruise at 14-1500 rpm @ 65 mph.  Not 1800 I am now.  Those 3.55s or a double OD like I basically have using that 6041 box.

 

I'm not worried about going fast, just fast enough without all the noise.

[Mark T]

FRO

[Geoff Weeks]

I wouldn't have a 15 in anything if I had a say. I have one in my Marmon and hate it.  If gearing for slow RPM at high road speed, steps between gears are critical to having something that works well.

If using an Eaton, then look are rear gearing and transmission as a package. What you choose in the axle will effect if you want a RTO or an RTLO 13 or 18

My use was different than your, a lot more weight and wind resistance, but also a lot more displacement at power (ATA 3406). Being able to drop a gear and gain ~250 rpm vs ~400 rpm is the difference between a 13 and 15. I know right now you are thinking "I'm going up in HP I will not need to drop a gear" but there will be times you will and going to 1650-1700 is a lot better than 1900!

 I still say what you have will handle what you are putting through it, I wouldn't put a driver in it, but driving it yourself it would take it just fine.

[BOBWhite]

I've never seen a 15 speed in anything but old oilfield stuff and haven't ever driven one. I can see why 15 speeds fell out of favor, same with super 10s. 

[fjh]

5 hours ago, BOBWhite said:

I've never seen a 15 speed in anything but old oilfield stuff and haven't ever driven one. I can see why 15 speeds fell out of favor, same with super 10s. 

I’m no truck driver just a dumb wrench turner ! But in my humble opinion the more gears the better! 18 sp fuller would be my choice ! Note modern easy to get parts lots of selection for almost any horse power! 
 

just my opinion!

[Mark T]

5 hours ago, BOBWhite said:

I've never seen a 15 speed in anything but old oilfield stuff and haven't ever driven one. I can see why 15 speeds fell out of favor, same with super 10s. 

15s went away because axles got so much faster. (basically)   That was the beginning of the end for so many of those once popular transmissions.  Super 10 ?  Technology outpaced them before they ever came close to catching on. Everything gets outdated at some point I guess 

[Joey Mack]

Ive only seen a few 15 overs, and am not a guru. The last one was 5 years ago in an 87 Superliner with 4.42 rears and an E-9 500.  I drove it a few times and it pulled good, but, i was just test driving it while i was working on the restoration of it.  It certainly would keep up at high speeds. Anyway, just my 1 cents of knowledge..

[Mark T]

4 minutes ago, Joey Mack said:

Ive only seen a few 15 overs, and am not a guru. The last one was 5 years ago in an 87 Superliner with 4.42 rears and an E-9 500.  I drove it a few times and it pulled good, but, i was just test driving it while i was working on the restoration of it.  It certainly would keep up at high speeds. Anyway, just my 1 cents of knowledge..

15 over was popular back in the '80s in tractors. Older trucks might have a direct 15 . Like back closer to the early '70s. ( a ten speed with deep reduction )  They could have been either directs or overs. I think the last ones went up to 15-7s.  I mentioned it cause I drove a  300 with one behind it. Even though it was a Maxidyne it still worked pretty good, and was nice for slowing down the truck with the engine brake.  After some thought, I think an FRO ten speed might b worth looking into for Larry.  ( low 1st gear and fast over gear )They're cheap and lots of CHs used them. I doubt the clutch housing is gonna be bolt for bolt though.

[Freightrain]

I'm not overly worried about a deep low. Like my deep under 6041 just for the slow truck race.  Beyond that I don't "need" it.

 

I know I am dealing odd pieces and trying to get something that works well together.  Decent splits and something like the double OD I have using my Triplex and 6041.   Gets me 65 mph at 1500ish.  Much quieter then 1800!  I don't like lugging it much with that 6041 and the 300 will be harder on it.

I wouldn't kick a 18 to the curb if I found one reasonable, even it it means paying full core for it?  If there is a DO version that would be a plus.  I have the Eaton chart saved, need to look around.

I need at least a single OD, period.  I will remove the 6041no matter.

As for clutch housing, Geoff and I were already poking around at those before I rebuilt the Triplex.

 

Using the Triplex?  I could, but I don't want to have to "baby it".  If I feel the need to let it rip, I want a transmission that will not flinch.  Just a note, I purchased a new $10k transmission for my race car.  It is the top of the line, badass, never have to worry kind of transmission.  I have no problem with doing that for the Mack.  I only want to do this once.

Thanks for all the input guys.  It will come together somehow.

[Geoff Weeks]

In my book a 15 is a 12 anyway, and it is a transmission looking for a reason to be.  I can see why fleets would spec them as it are a little more "idiot proof" than a 13 or 18. For me if I need the deep bottom end, I would choose 2 spd axles over an 18. 18 has the 15 beat any way you look at it, but in the wrong hands can get expensive quick

I have a RTO 14615 in the Marmon, and the only reason it is still there is I retired before I could swap it out.

Run what you came with until you have the money and time to change, but when you make the change, make it for the best possible spec's for how you are going to use it, or save your money. Just because it may be slightly better is not reason to jump from one compromise to another.  The difference in cost when buying a 10 vs. a 13 or 18 on the used market is going to be a few hundred, but you still have all the costs of the bell, mounts and clutch over what you have now.

 I would  sit tight with what I had and wait until the ideal set-up can be had.

Do the Math! crunch all the numbers, startability, top speed, cruising speed RPM, jumps between gears etc. 

[Joey Mack]

I wonder if Eaton has a bell housing for the FRO to fit his engine?

[Geoff Weeks]

Where you have to be careful is in the lower gears, that applies to any transmission, it the higher ranges it isn't going to damage something as easily. 

I would shy away from double overdrives, with the one exception of the RTLO's. 1st there is too much wasted in gearing up and back down, all that goes into heat. 2nd there is the driveshaft issue, have to do the math and make sure you are staying away from critical speed at all and 1/2 true critical at cruise.

The RTLO's are really a single overdrive front box with an underdrive splitter, where one stick position down is direct, and top gear is something like .76??? in the front, and when the splitter is in 12th is something like .86. Not a true "double over" where there are two gearsets over driveing the input to a faster output. It is all in how it is plumbed in the trans that makes it seamless, kind of like when the went to the Xbar top cover on the RTO's you can't tell by the shift pattern if it is an RTO or an RT 

[BOBWhite]

1 hour ago, fjh said:

I’m no truck driver just a dumb wrench turner ! But in my humble opinion the more gears the better! 18 sp fuller would be my choice ! Note modern easy to get parts lots of selection for almost any horse power! 
 

just my opinion!

I used to think that same thing until I got a truck with a Mack 6 speed (twin stick). You somehow are always in the right gear and have plenty of power without doing as much shifting. Biggest problem is at 2,000rpm doing 60, 45mph at 1600 is just right but I don't do much highway driving. 

[Freightrain]

The 300+ needs more gearing.  Like a Thermodyne.  The truck had a 5 spd, but I bet it was a real PITA around town.  But it was a fleet truck, so I assume that is why they used a 5 spd.  

[Geoff Weeks]

Spicer's sales pitch was "0 to top speed with only 5 stick movements".  14,16, or 20 possible selections.

[Freightrain]

55 minutes ago, Geoff Weeks said:

Spicer's sales pitch was "0 to top speed with only 5 stick movements".  14,16, or 20 possible selections.

That would be a cool set up.  Seen a few for sale but a bit pricey and not sure about rebuilding cost?  Availability?

[davehummell]

Many years ago I worked at a trucking company that ran the 285's with the 5 speed in several cabovers to the coast and they sent a R model with a 237 with 5 speed on a weekly run to Canada. I knew a guy that I used to do work for that had a R model running to Texas and back

[harrybarbon]

21 hours ago, Freightrain said:

I want to cruise at 14-1500 rpm @ 65 mph.  Not 1800 I am now.  Those 3.55s or a double OD like I basically have using that 6041 box.

 

I'm not worried about going fast, just fast enough without all the noise.

We have 2 V - 350 same set up as your engine in our B75. It has the Mack box TRDL 1070 10 spd overdrive and 4.17 tandem rears, at 100klms per hour at 1800 revs. I have pushed it to 120klms/hr, but revs up. Pulling a tri-axle 43 foot trailer with a hay load maybe 15 tons, it held comfortably cruising at 1750-1800 depending on wind, motor did not lug and occasionally I had to drop down to 9th, but revs can drop to 1400 (even 1300) on the flat and it still pulls because of the torque. Little noise with exhaust stacks on each side of cab.

We are limited to 100klms/hr, so a 3.7 diff would not be good for the engine.

As you want lower revs, a Mack diff at 3.7 would match your motor very well. Alternatively a Mack 12 spd would also marry up perfectly to your motor and 3.7 diff. All the best with your rebuild.

 

[Freightrain]

That Mack 10 spd must have similar OD as my Triplex.  I want more though.  A quiet, get home gear.  Even if I only used OD on level or downhill.

Not sure a 12 spd would fit under the cab in a B model?  I would love to have one.