New m715 engine project

I,ve had everything to build a N.O.S. m715,230 tornado engine now for quite a while now and my m715 now has 57k miles on it and starting to get weak in a couple cylinders so I figure now is the time to start assembly of my replacement engine. the truck is 99% all original and I,d like to keep it this way so as they say the apple is ripe ! I have a brand new short block but I also have a N.O.S. set of civy 230 tornado pistons and there 8.5 to 1 compression as opposed to 7.5 in the military engine so I,am going to swap pistons to the higher compression for a little more torque. when i get the short block out of my storage area I,ll post some pictures of the crate and of the unpacking. they seal the dickens out of these. i had 5 of them through the years and this is the last 1 i have. alot of folk have never seen one of these being built so it should possible be of help for someone down the line. it will be 100% new air filter hsg to oil pan, fan blade to pressure plate. more to come soon.
bob

p/s
I already replaced the transfer case and trans-pto combo with N.O.S. components. not that the originals was bad. it sure pays to keep road speeds at or lower than 45 mph.

As I understand, those are a strange unique engine. My dad had a mid-60's Jeep Wagoneer with the same engine (only the civlian model) . I was a 20 year old already-learned-all-there-is-to-know-about-engines kid. When he told me it had 7 lobes on the only cam, I thought he was crazy. Impossible I said.
Then he explained it had a rocker above and below each lobe (with an extra one for the fuel pump). Ingenious!

I had an ambulance with the Tornado engine (M725?). A water pump grenaded and I figured the local auto-parts discount store surely would stock a water pump for a Tornado engine. Correct, theyt did. Wrong, because as I quickly found out, the water pump on a military one has a different bolt pattern than a civilian one.

Good luck. Some day, I am going to get another M715.

Bob, have you ever heard of an aluminum head for the Tornado? Also, please post some pics of the short block in the crate, that is truly a rarity.

You're a better man than I am. Petty soon my 230 is coming out and a GM 292 is going in. Personally, I think rebuilding a 230 is like trying to polish a turd. I know you and others will disagree and I understand the desire to keep the truck bone stock.

The local FD has a m715 brush truck with a thrown rod (lead footed volunteers) and they want to buy my 230 for $1,000. When I was made that offer it was all I needed to swap it out.

Imo,
the 230 is the perfect engine for the m715 "if" you leave the stock 5.87 gears in it ! Also if you dont drive it over 45 mph. When you install that 292 you,ll have to keep your speed to 45 mph also f you want to make t live plus the long stroke of the 292 makes it a fuel hog but very torquey . I have a adapter kit for that engine to mate it to stock trans if you need it. From my experience the 230 is a very hi quality engine, steel crank,forged rods, hemi combustion chambers, tuned hi flow exhaust manifold, very fuel efficient just to mention a few things.
Bob

Yank the engine and drop a Cummins 4BTA or a Chevy 350 in there. The stock engine is great when it works fine and has low miles on it. When it wears out, don't bother rebuilding it or replacing it with same engine, upgrade.

I want to keep this truck original.

bcowanwheels said:

Imo,
the 230 is the perfect engine for the m715 "if" you leave the stock 5.87 gears in it ! Also if you dont drive it over 45 mph. When you install that 292 you,ll have to keep your speed to 45 mph also f you want to make t live plus the long stroke of the 292 makes it a fuel hog but very torquey . I have a adapter kit for that engine to mate it to stock trans if you need it. From my experience the 230 is a very hi quality engine, steel crank,forged rods, hemi combustion chambers, tuned hi flow exhaust manifold, very fuel efficient just to mention a few things.
Bob

Click to expand...

I'm mating a 3053 trans behind the 292 so that will help a little on speed. You could be right about the fuel mileage.

The main problem I have with the 230 is the cam. I've seen several worn out with relatively few miles. That and the cost to rebuild one when it does wear out. My old 230 does still run strong but I pull a trailer from time to time and mainly want a little more power.

The reason the cams goes bad are people dont know the only source of oil for the top end is the oil line from pass. Side of engine block to rear of cylinder head. These lines swell shut, crack open ( giving people the idea there rear main seal is leaking ). This line needs to be replaced with a teflon line or steel line then no more cam problems. I have 292's myself and in my pickups best i can get is 10-12 mpg. In fact i,am building one now. How do you plan on hooking up the 3053a trans to it exactly as there is no 12 or 13" flywheel for a 292.

maddawg308 said:

Yank the engine and drop a Cummins 4BTA or a Chevy 350 in there. The stock engine is great when it works fine and has low miles on it. When it wears out, don't bother rebuilding it or replacing it with same engine, upgrade.

Click to expand...

Evidently you don't know Bob very well.

Have fun with that Bob, sounds like a good project.

There should be a way to swap center hubs from one clutch disk to another. I know I've done that before in a different application.

Center hubs isnt the problem, all he can use is a 11" flywheel with that 292 as thats all that available unless you go custom billet steel and thats $$$$ if it was me i,d sell the 3053a if your stuck on useing the 292 and i,d put a nv4500 out of a 5.9 "gas" engine dodge pickup then you can use a advance adapter 1" plate and then bolt it straight up to a chevy bellhsg. With a recentered clutch disc. I'am doing this setup now for my new work pickup truck, 292,.060 over,.010/.010 crank, 194 cylinder head & lp pistons. All else in the is brand new. These 292's are like the 230's there critters of there own. Cost is up when you talk 292. Good to hear from you tom, i pray the lord is blessing you richly !!
Regards
bob

bcowanwheels said:

How do you plan on hooking up the 3053a trans to it exactly as there is no 12 or 13" flywheel for a 292.

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Bob, I didn't think this would be a problem. I assumed that since the 292 was used in 2-ton trucks that the proper flywheel would be available. Looks like I need to do some more research before I start this project.

even the c60 & c70's chevys had 11" clutches. this 292 i,am building now came out of a c60 and had a 11" clutch. also theres 2 different 11" flywheels for 292's. 1 had 1/2" flywheel bolts and one had 7/16" bolts. you,ll need to know year of your engine to make sure you match the flywheel to crank. some cranks have 6 counter balance lobes and some had 12. the flywheel needs to match. a sbc is alot less pain to work with
bob

Reading all your posts has started making me nervous. For over a year I've wanted to put my Chevelle 350 in the M715. I only know enough to get lucky or in trouble from time to time. All this talk of adapters, re-centers, swaps etc. makes me think I need to take it to a shop. No clue what that could end up costing me. My 230 runs but not great and I too want to jump on the more power train. I applaud you for refurbing the 230. Best of luck

Ft Worth Clutch can quote you a clutch with the large 10-spline hub to match the 3053 trans... I've discussed the possibility with them of making a 6.2 Diesel clutch disc with the 'Spicer' big 10-spline hub... they quoted me @ $125 for a custom disc ~ 2 years ago.

IIRC - you can use the big C60/etc bellhousing on the 292 - the 3053 should bolt to the 'big' truck bellhousing. I'm currently bolting a 3053 to a GM 6.2 diesel & using the GM big truck bellhousing & adaptor plate to do the conversion.

And NAPA shows a few 13" clutch options for the 292 engine - 10-spline by 1 1/2" hub... So there must have been a 13" flywheel for the 292.

Further searching shows that Medium & H.D. 1 1/2 ton Series 40 & up Chevy/GMC trucks in 80-86 offered the 292 with a 13" clutch (Spicer) with 13x10Tx1 1/2" splined hub.

91-98 vintage trucks with 366 engine & Spicer trans offered a 12.2" clutch x10Tx1 1/2" spline... same story for 427 engine trucks with 12.2" Spicer clutch -

HTH -

'Tanner'

By the time you round up all these special parts tanner you'd be alot cheaper to just install a common sbc

I've got a c-60 bell, a 292, and a 3053. I haven't looked at it all though to see what all else I'll need to mate it all up. The trans came out of a parts truck, got the bell for free, and paid $100 for the engine. It's just all been sitting there for over a year because I've been working on other projects (too many other projects).

I'm hoping to get to work on it over the winter because I have my 230 sold for good money. I won't highjack Bob's thread anymore and start a new one when I get ready for the repower.

bcowanwheels said:

By the time you round up all these special parts tanner you'd be alot cheaper to just install a common sbc

Click to expand...

... I gather that you hate the 6.2.

Parts aren't that hard to gather - I've got two sets of large GM truck bellhousings - std 6.X flywheel (not dual-mass) with 12" Reo clutch or custom clutch, and that's really about all that's required that would be considered 'exotic'.

For the 292 - I'd look at verifying that the 292 block will mate to the big 5-bolt bellhousing (it should be same pattern as the SBC) - get a 12" or 13" 292 flywheel, and a mating disc - what's not to love?

http://www.ottawaclutch.com/cmt.htm



'Tanner'