454 for towing

[dave brode]

Interesting [the 8.0 crate engine].

9.9 CR - pretty high for something that may use a carb and less than ideal timing curve.

I wonder why they chose the 4.25 stroke, vs the 4.375" from the 496 [8.1]?
I wonder why they chose the GEN6 style head, vs the tall port from the 496?

Is it a 4 ring piston like old tall decks?

2/3 - 4/7 swap. same firing order as the 8.1 [496 truck] engine?

I read a thread at ST in which a guy claimed that this is from 2015 trucks. True? If not, when was a tall deck engine last used?

[Newold1]

This engine was developed as a replacement for the older 454 propane and CNG commercial engine fleets used in great numbers around the world. It was not a replacement for the 496-8.1L engine that GM stopped producing in 2009. PSI bought all the tooling and rights to the old 8.1L -496 engine in 2010 and uses it for CNG-Propane use in medium fleet trucks and industrial engine applications.

This configuration was also a simple production part that GM had already most of the parts for on the shelf. The block is just the 10.2 deck Gen 6 block they already had in production for their 540 variant, the heads were just the late 98-2001 454 Vortec iron head and the forged crankshafts, long forged rods and all other parts where on the shelf. I think the only part they had to specially produce and use was the piston which is a very nice 3 ring 1.385 compression height hyper-eutectic piston with coated skirts.

This engine is also targeted at the marine engine packagers like Vovo Penta, etc where all iron saltwater use engines are in mass use.

Gm has never used any big block Gen 4, 5 or Gen 6 bigger than a 454 in trucks. The Gen 7 496-8.1L engine is the largest they have used to date. This 8.0L engine is not being touted as a high horsepower big block for performance upgrades as GMPP has lots of other variants to do that. GM wanted a crate type long engine (Less intake and such) that could be dropped into a lot of Propane -CNG fleets and such with a bolt in type installation.
I think the nice thing about this block is that you are getting a very nicely machined and assembled engine with a real warranty (parts and labor)with all forged internals and a change of camshaft that can retro-fit into a lot of older (pre-2000)trucks with the old all iron 454's and produce a nice big flat torque curve and reasonable higher horsepowers at a very affordable cost. This is a towing grunt type use crate engine> Much better alternatives for higher performance in rpms and horsepower are already abundant in the aftermarket.

[Dan Timberlake]

Chevy truck brocure ca. 1960
http://paintref.com/cgi-bin/brochuredis ... 11&scan=11

348 standard in the C80. No mention of diesel power.

GMC at least mentions diesel, but as an option
http://www.hankstruckpictures.com/pix/t ... page03.jpg

[user-612937456]

I hear a lot of talk about a quarter to a or an elder Brock carburetor butt if you're willing to take the time to do the tuning Holly can be far superior as far as power and fuel economy

[My427stang]

I think people tend to under power gasoline powered tow vehicles because they try to turn them at diesel RPM. I'd put good thought into tire size, gearing, transmission, and get an idea of the rpm you really plan to pull, although you won't be building a 6000 rpm engine, you likely won't get what you need at 1500 either. Also, don't expect diesel economy, but I have seen an LS Chevy van pull like a rock star, just need to be efficient at where you plan to run.

More gears are certainly better too

[Newold1]

I think a low rpm high torque properly powered big block in the 488-540 cubic inch variety can easily pull 12,000 to 15,000lbs with the right transmission, gear ratios and tire type. It just has to be configured correctly. It's not going to get the mpg of today's diesels or will it have the 600-900lb/ft of torque those diesels are producing.
I've been on the interstate many times and had Dodge Diesel duallies with a four vehicle hauling trailer full of 4 vehicles pass me cruising at 75mph in their overdrive gear not even making a sweat! Gas engines won't match their pulling power at decent mileage and no one should expect them to.

[Truckedup]

I've driven more than a few heavily loaded gas engine heavy duty trucks. To make speed you're running the engine wide open against the governor in all gears.And many had compound gearboxes and or multi speed drive axles with 12-18 gears...The OP here isn't grossing 45,000 pounds and may have 450 pounds of torque but he will have to spin that engine to climb the hills at highway speeds.

[Newold1]

What the heck were you driving. Govenor, 12-18speed compound gears, those sure were not an 86 one ton dually! Those sound like 2 or 3 axle dumps or such to get up in that 45,000 lb class GVW.

I know what you mean in those old 427-454 gas 250HP engines.

Years ago I used to drive a 3 axle Ford F700 weighed about 35,000 lbs with a 513 inch gas engine with a govenor, a 5 speed with a compound low followed by a 4 speed brownie. The thing was a turd and harder than hell to shift and get up to highway speeds over a mile or so, even on flat ground. If you showed it even a picture of a hill it would groan and stop!! I hated driving that truck! But I think your analogy might be comparing apples to onions here?

[Truckedup]

What the heck were you driving. Govenor, 12-18speed compound gears, those sure were not an 86 one ton dually! Those sound like 2 or 3 axle dumps or such to get up in that 45,000 lb class GVW.

I know what you mean in those old 427-454 gas 250HP engines.

Years ago I used to drive a 3 axle Ford F700 weighed about 35,000 lbs with a 513 inch gas engine with a govenor, a 5 speed with a compound low followed by a 4 speed brownie. The thing was a turd and harder than hell to shift and get up to highway speeds over a mile or so, even on flat ground. If you showed it even a picture of a hill it would groan and stop!! I hated driving that truck! But I think your analogy might be comparing apples to onions here?

I am referring to 10 wheel dump trucks....But the comparison is valid..The OP's truck will need rpm to climb hills and more than three speeds to keep up with traffic.Trucks used to have 105 HP engines and hauled all sorts of stuff.. They they had low gearing and it was slow going....

[Brian P]

Lets rough out some numbers for that gearing ...

The truck plus the trailer probably weigh 20,000 lbs together. If you want to get that up a 5% grade at 60 mph (88 ft/s) that's 20,000 x 88 x 0.05 / 550 = 160 horsepower JUST to lift the weight up at that speed.

Aero drag for something with as much frontal area as it could be, plus rolling friction for something that heavy with that many wheels, could pretty easily add up to another 160 horsepower, so it will take 320 horsepower to get up that hill. If this engine makes somewhere near 500 lb.ft of torque it's going to need to turn somewhere near 3500 rpm (and make that torque at that RPM) in order to do that. Ideally this would be in direct drive with at least one overdrive gear above this so that you're not wailing away at 3500 rpm at 60 mph all the time. If it doesn't make that much torque at that RPM, all it means is that it'll go slower (and maybe it'll have to gear down).

Dunno what tires you have so I'll guess 28.5" rolling diameter for no other reason than that's the size of the wheels on my van (>8500lb GVWR). Those turn 708 revs per mile i.e. 708 rpm at 60 mph.

To do 3500 rpm in direct drive at 60 mph would require a 4.94 axle ratio. Plausible. Pick the closest one you can actually get.

Now, the next challenge, getting up a steep grade at a low speed. There's a limit to what's realistic here based on how much grip the drive wheels have. If the truck is 4x4 that's basically the weight of the truck plus the tongue weight of the trailer, let's say 10% - probably somewhere near 7,000 lbs acting on the drive wheels. With good traction there's a fighting chance of getting up a 1 in 3 slope. How much torque ... ? ? ? 7000 x (28.5 x 0.5 / 12) = 8312 lb.ft at the wheels. Divide by our hypothetical 4.94 axle ratio and the transmission output needs 1682 lb.ft in order to do that. That's 3.36 times what the engine puts out.

First gear of a normal automatic plus torque converter multiplication will just barely do it. It will not be happy about it. If that steep hill is anything more than momentary it's going to melt down. Even starting off from a normal stop, it's not going to be happy.

An old school 3 speed automatic is not gonna cut it unless you want to live with that engine spinning 3500 rpm (plus torque converter slippage!) at 60 mph ALL the time.

This is why transport trucks have transmissions plus range boxes plus splitter gears - you need a really low 1st to get moving from a stop and you need a reasonably tall top to be able to cruise without screaming the engine and the gaps between gears have to be small enough that you can pick a good gear to be in at any speed.

The new 8 (soon 10) auto-boxes have a 1st gear around 4.7:1 and a top gear around 0.65:1 which solves this reasonably well, also. Good low 1st to pull away without relying on the torque converter, nice tall top for highway cruise, gear steps reasonably close together so that it can keep the torque converter locked to avoid meltdown.

The old pickup truck manual transmissions all had a "granny" 1st gear for getting big loads started from a stop. The engines in the old days didn't have the kind of power that's on tap nowadays ... so you just slowed down.

I think if the original poster still wants to use that gas engine, and presumably doesn't have access to a newfangled 8 speed automatic, it will be best off with a "granny gear" manual and probably a 2-speed range box behind it ... A plain old granny gear 4-speed will do but then it's going to be like this http://67-72chevytrucks.com/vboard/show ... p?t=343826

[Brian P]

And in that thread was a useful piece of information ... the gear ratios available in a couple of the plausible manual transmissions. There's no overdrive, but you can re-crunch the numbers as I did to see where you are. The wide-ratio 4-speed appears to have a big enough split between 1st (6.55:1) and top (direct) to get this job done. It won't be pretty, and it won't be pleasant, but it'll do it.

[pdq67]

I want to say that AP Greens in the '80's two Gunning Trucks were an F-600 361 FE engine with a 4-speed/2-speed rear end and an F-750 with a 391 FE engine with a 5-speed/2-speed rear end.

Damned good trucks EXCEPT they had a bad habit of knocking a wrist pin keeper out every so often which led to scoring of a cylinder wall. They were both governed to something like 3400 rpm and Charlie and I ran them wide open across country going from job to job.

We ended up with a new LN-7000 3208(?) V-8 diesel, 5-speed when the little F-600 got long of tooth. F** LN-7000 piece a shit that it was even though it really was a good truck..

It was governed at 72 MPH new and this was back when the speed limits were 55 MPH!!

On it's maiden trip, we went from South Bend to Renville, MN to a great big Sugar Beet Plant and coming back I was driving as we went under a country road, no access overpass, with a trooper sitting there on top of it monitoring traffic.

The CB broke clear as a bell and said, "Slow down", and that was all. I dropped her down to 55 for like 5 miles and kicked her wide open headed home via Chi-Town... I turned her over to Charlie when I hit north Chi-Town because I didn't have a f** clue about the roads in Chi-Town coming in from the north and then east around the lake to South Bend, IN.

Later, I ran the LN-7000 up to Alcoa, Massena, NY from Mexico. MO coming back to like 17 miles from the IN state line and never stopped it coming back to Mexico, MO! My f** worthless side kick, Dennis liked ta f** shit! he never road with me again! The old truck had two 50 gallon saddle tanks and got like 8 mpg running on the Hwy! I would top her off and never stop her until I had to fuel up!! 16 hours, no f** problem on my kidneys!!

One trip to Prattville, AL, my boss Jack was riding along because he had a plastic gunning job at international Paper there in a lime recovery rotary kiln with the crew from B'-Ham that we worked with at times and I dropped him off and went over to International Paper at Bastrop, LA. We had two gunning rigs in the truck... one for his job and the 2nd for my job!! Pat Sewell was a great guy as was Johnny and Clyde!

It was a hoot because we left Mexico MO at 7:00 AM and I never stopped the SOB until we hit the Prattville H/I. Jack looked over at me at like 5:00 PM as we went by Huntsville, AL and said, "I wasn't going to say anything, BUT, damnit boy, When are you gonna stop this SOB? Hell boy, its supper time!!"...

I looked over at him and said, if the wheels ain't rolling, we ain't making any miles! And he f** shut up. I stopped at the H/I at Prattville, AL.

I called my Buddy Harry that lived in Shelby County south of B'Ham and drove over and stayed with him over night and then I drove on to my job in LA.

I dropped My Boss Jack off at Prattville and his job went to hell as mine in Bastrop went from early mid week into Sat. night!! F** three days!

Shooting a Black Liquor recovery boiler!

I called Jack Sunday morning at 6:00 AM after my job ending at 2:00AM that night/morning and asked him if he wanted me to drive back to Prattville from Bastrop LA to help him and bless his heart, he said, "No, you've been up damn near all night so sleep in and go home!!

It was a real f** hoot because as I went through the scales at the state line from Arkansas to MO, it was dark so I had to dim my head lights and when I went to pull them back on the f** handle broke off !! No F** lights.

So I pulled over out of site from the scale house and climbed in back and cut a piece of wire I-off the lights in the box and I made several, "hair-pins", and figured out how to rig my headlights and go -t her going to Little Rock. Taped them up solid with black tape

I pulled into Little Rock at another H/I and just F** lucky they had a room because I couldn't drive any farther!!

Seems there was a football game in town and a n AM WAY convention so no rooms were available, I could have kissed the Lady that made my room up

pdq67

[MT Jeff]

How about a Gear Vendors overdrive/Underdrive? It will give the OP six speeds. But still no lock up. Just a thought. And a 496 would seem logical if building anyway. It will never be a new truck but a 496 with six gear choices would be a vast improvement I would think.

[Brian P]

Original poster hasn't given us a hint about transmission, the math says he's going to need a lot of it - a big range between the lowest gear (for starting off heavily loaded) and the highest gear (for cruising unloaded). Isn't a GV something like a 28% overdrive? It'll help but I was thinking more like a hi/lo 4x4 range box ... IF you can shift from low to high while moving. (I've never owned one, so I have no idea about that.)

[mgoblue9798]

Lets rough out some numbers for that gearing ...

The truck plus the trailer probably weigh 20,000 lbs together. If you want to get that up a 5% grade at 60 mph (88 ft/s) that's 20,000 x 88 x 0.05 / 550 = 160 horsepower JUST to lift the weight up at that speed.

Aero drag for something with as much frontal area as it could be, plus rolling friction for something that heavy with that many wheels, could pretty easily add up to another 160 horsepower, so it will take 320 horsepower to get up that hill. If this engine makes somewhere near 500 lb.ft of torque it's going to need to turn somewhere near 3500 rpm (and make that torque at that RPM) in order to do that. Ideally this would be in direct drive with at least one overdrive gear above this so that you're not wailing away at 3500 rpm at 60 mph all the time. If it doesn't make that much torque at that RPM, all it means is that it'll go slower (and maybe it'll have to gear down).

Dunno what tires you have so I'll guess 28.5" rolling diameter for no other reason than that's the size of the wheels on my van (>8500lb GVWR). Those turn 708 revs per mile i.e. 708 rpm at 60 mph.

To do 3500 rpm in direct drive at 60 mph would require a 4.94 axle ratio. Plausible. Pick the closest one you can actually get.

Now, the next challenge, getting up a steep grade at a low speed. There's a limit to what's realistic here based on how much grip the drive wheels have. If the truck is 4x4 that's basically the weight of the truck plus the tongue weight of the trailer, let's say 10% - probably somewhere near 7,000 lbs acting on the drive wheels. With good traction there's a fighting chance of getting up a 1 in 3 slope. How much torque ... ? ? ? 7000 x (28.5 x 0.5 / 12) = 8312 lb.ft at the wheels. Divide by our hypothetical 4.94 axle ratio and the transmission output needs 1682 lb.ft in order to do that. That's 3.36 times what the engine puts out.

First gear of a normal automatic plus torque converter multiplication will just barely do it. It will not be happy about it. If that steep hill is anything more than momentary it's going to melt down. Even starting off from a normal stop, it's not going to be happy.

An old school 3 speed automatic is not gonna cut it unless you want to live with that engine spinning 3500 rpm (plus torque converter slippage!) at 60 mph ALL the time.

This is why transport trucks have transmissions plus range boxes plus splitter gears - you need a really low 1st to get moving from a stop and you need a reasonably tall top to be able to cruise without screaming the engine and the gaps between gears have to be small enough that you can pick a good gear to be in at any speed.

The new 8 (soon 10) auto-boxes have a 1st gear around 4.7:1 and a top gear around 0.65:1 which solves this reasonably well, also. Good low 1st to pull away without relying on the torque converter, nice tall top for highway cruise, gear steps reasonably close together so that it can keep the torque converter locked to avoid meltdown.

The old pickup truck manual transmissions all had a "granny" 1st gear for getting big loads started from a stop. The engines in the old days didn't have the kind of power that's on tap nowadays ... so you just slowed down.

I think if the original poster still wants to use that gas engine, and presumably doesn't have access to a newfangled 8 speed automatic, it will be best off with a "granny gear" manual and probably a 2-speed range box behind it ... A plain old granny gear 4-speed will do but then it's going to be like this http://67-72chevytrucks.com/vboard/show ... p?t=343826

I know this is a very old post, but felt this needed mentioning.

"With good traction there's a fighting chance of getting up a 1 in 3 slope."

Where in the US would someone be driving a rig like that on a 1 in 3 slope? That is an 18.4% grade. I doubt that exists on any Interstate or major hwy in the continental US. Steepest in the Rockies is 9.4%, with a few at 8% or so.

Even if one does exist there would almost certainly be an alternate route to take.