"Big Al" truck engines

I know of a 72 Freightshaker  with a BIG AL still in the truck , also a 74  Dodge Bighorn with one in just sitting , guy SAYS  he dont want to sell them of coarse , BUT  every now and then he calls wondering if I,m still interested ;and of coarse I am ; but he wants to dam much !!!! we are in the negociations stage ; hopefully it,ll work out one of these days

This is just one  more of ALLIS CHALMERS big ,good ideas that they let fall through the cracks ; the owner of the trucks I know of said AC were really pushing Freightliner + KW  to market these and service these engines under AC contracts all over the US , BUT AC MOVED ON TO another good idea and it all fell slowly  apart ????? Way to go AC !! Like Walt B. said many times - once again ALLIS struck faliure at the brink of success !!!

a friend of mine ( a truck Guy) was telling me about this AC engine the other nite. he wanted to know if I'd ever seen one. No I haven't. I thought the purple people eaters were the mn. vikings.

Got my copy of the magazine today. No Big Al's for sale in the back. Sorry.

calvin-the 25000mark2 came out in 68,there was a number of improvements to these engines thru the years .the best engines with all the updates would be approx. 1975 up.serial #4700 &up.the 21000 is the same as 25000 except for the intercooler and fuel setting.serial #13500 and up on the 21000 would also have the same updates.the 6138 has the flange mounted injection pump,and piston cooling thru the rods instead of the nozzles on the bottom of the cyl.(21000-25000)if you have a engine give me the serial # and i can give you what you can do to improve it .also the 6120(8550-4w305) engine is a 6138 with a destroked crank ,so you can build a 6138 with a crank change and pistons.i would  have to look to see if if the connecting rods are the same length as the6138.

Did they use the R/Bosch P pump?

some 21000s-25000s used both robert bosch and american bosch

DougG wrote: I know of a 72 Freightshaker  with a BIG AL still in the truck , also a 74  Dodge Bighorn with one in just sitting , guy SAYS  he dont want to sell them of coarse , BUT  every now and then he calls wondering if I,m still interested ;and of coarse I am ; but he wants to dam much !!!! we are in the negociations stage ; hopefully it,ll work out one of these days

According to the article, there was ONE Dodge Bighorn built with the Big Al engine. So if that engine is was installed in that truck from the factory, then it is one of one.....very rare

Kcgrain wrote: To 427435, allis didnt build that engine for the class 8 truck market, the engine was being built for the HD 21 dozers, large scrapers, gen sets, wheel loaders, pumps , rock crushers etc, the truck market was just another venue for that engine, I have talked to some drivers that drove  these beasts, and they said thats Allis Gaurantee of the legal speed limit in all states was 100% accurate they had power to burn, and would blow any cat , cummins ,or detroit right off the road. To be fair though the "big AL" was 450 hp detroit was building 318V8, cummins had a hard time making 350 hold together and Cat was holding 300...barely. The flaw in the truck market for Allis CHlamers wasnt design, HP or reliability, it was a lack of engine support out in the country. Every little town had a cummins or detroit dealer, cat had service shops all over Allis Chlamers  had few if any. SO if your BIG AL engine needed service or parts you were screwed. Mack had the same problem untill recently west of the Mississippi, few Mack dealers to service the trucks or engines west of the Mississippi, and Mack was known more for voactional trucks, not class 8. Mack with Volvos help has over come that and Allis Chalmers didnt remain in the truck engine market long enough to over come it.

er... wasn't the 1693 cat available at 425 hp?  Hauled logs with one, turned up... lotsa power, but I still would go to the bank on a 350 cummins from that era any day.

jmm wrote: er... wasn't the 1693 cat available at 425 hp?  Hauled logs with one, turned up... lotsa power, but I still would go to the bank on a 350 cummins from that era any day.

Yes, there were some 425hp 1693, which was very conservative.  They were aftercooled unlike the lower hp 1693's.  I have seen several places state that it was 425 to the wheels which means 500+ at the crank. 

Of course in 74 Detroit released their 8V92 which could be a beast  turbocharged
There were some trucks with 12v71s

Also somewhere in there Cummins introduced the KTA 1150 with ~600hp.  Don't know the exact year there. 

Calvin Schmidt wrote: I would assume that a 21000 or 25000 engine would bolt into a 4W305 making a 450 hp super tractor. I'll get some serial numbers.

I think that reading this thread with regards to "Big Al" truck engines, I think that things are really much better these days by reading about it here or in other sources as well. In this way, i've got to learn a lot of things in order to compensate stuffs. Hope all is well by now.

Edited by armandjones82 - 17 Dec 2010 at 11:20pm

i talked to a friend this morning (he has a ac/fiat-allis construction salvage yard in mi.)he told me a story,that he got a call from a guy who drove a cab over pete with a big al for allis chalmers.after the plant closed,he bought the truck from the co.he said he never had a crank failure(other drivers did)because he always drove the truck between 1400-2100rpm.the truck had over a million miles.when the engine got tired he would take it to allis,put innew sleeve packs and bearings and head back out on the road.when he hit the mountains out west alot of guys would try to pass him-but few ever did.anyway he wanted a allis guy to buy the truck,and my friend at the time was'nt interested.my friend told me he still might have the guys info written down in his notes(10-15 years ago).i told him to see if he still had the guys contact info.i am relitivlely sure the truck is gone,but it sure would be neat to talk to the guy.

Ok, sorry for bringing this old topic up, but I must know more!  I am super intrigued by the rarity of Big Al engines, and I would love to see/hear one in person, or if not possible, at least on youtube.