I know it sounds strange but my dad is thinking of putting an older 8v-71 in his 95 International. It currently has a 7.3 in it. He has the engine but i was trying to find out if this has ever been done before. We are pretty sure it will work, :beatsmebut since there is so much knowledge on this board,:notworthy i'd like to hear anybody's ideas or opinions.
-
Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!
International 4700 + 8V71
- Thread starter Essayons
- Start date
Well Essayons,the engine coversion can be done with alot of work & fabrication.What is wrong with the 7.3 engine?After reading your thread I took a look at www.truckpaper.com to see what a 1995 IH 4700 was going for these days and it looks like they are around the 5,000 to 5,500 dollar range for the truck.Now I am a big detroit diesel 8v-71 fan,but you will need to pencil this one out on paper to see if it is cost effective for the job that you are using the truck for.
There is nothing wrong with the 7.3, it's just really weak.......and not cool. His truck has a flat work body type bed on it and he uses it to haul his travel trailer as well as his tractor. He doesn't ever go far........probably averages less than 3000 miles a year and a typical round trip is under 100 miles. Since he has a virtually new 8v-71 he thought it would be cool to stuff it under the hood. So i guess what i am trying to say is, cost really isn't a factor and this truck is more for fun than work.
I see.Essayons,sometimes you are better off staying with the engine that came with the truck.For instance take my gmc wrecker,it has the detroit 6v-53 and it is a little slow on the road but it dose its best work on winchouts.The IH DT 466 engines that I have been around pull great and look cool in a IH truck.But If dad is set on the 8-v 71 then all we can do is install it for him.Keep us posted and send us pictures Essayons.
amunderdog
Senior Member
Re: 8V71 Detroit Engine Jim McNaul 9-25-04
8V-71's are still manufactured by Detroit Diesel today. They are probably one of the most widely used diesels in the world in their horsepower class. They are a design that was introduced in the 1940's, so are naturally not up to modern noise, emission, and fuel economy standards. The most common HP rating for the 8V-71 was 318 HP (at sea level. They suffer from altitude just like a naturally aspirated gasoline engine. They ARE considered naturally aspirated even though they have a gear driven rootes type positive displacement supercharger on them. The displacement of the 'blower' is exactly the same as the displacement of the engine, so consequently no boost pressure is developed. There is no provision for 'overdriving' the blower. There is a turbocharged version of the 8V-71 which is called the 8V-71T. These do not suffer deration due to altitude and are much quieter. 8V-71 means 8-cylinders with 71 cubic inches each, or a total of (8 X 71) 568 cubic inches. This is not realy very big when you consider that almost all big trucks are powered by 855 or 893 cubic inch engines. But an 8V-71T in a motor coach is a hot son of a gun! Greyhound busses routinely got 500,000 miles between overhauls on these engines pulling 35,000 lbs gross weight. Most truckers are dealing with 80,000 lbs weight so consequently get considerably less longevity and less performance from an 8V-71 than they do other larger engines.
http://www.kingofobsolete.ca/8V71_DETROIT_DIESEL_TRUCK_ENGINE_WEBPAGE.htm
8V-71's are still manufactured by Detroit Diesel today. They are probably one of the most widely used diesels in the world in their horsepower class. They are a design that was introduced in the 1940's, so are naturally not up to modern noise, emission, and fuel economy standards. The most common HP rating for the 8V-71 was 318 HP (at sea level. They suffer from altitude just like a naturally aspirated gasoline engine. They ARE considered naturally aspirated even though they have a gear driven rootes type positive displacement supercharger on them. The displacement of the 'blower' is exactly the same as the displacement of the engine, so consequently no boost pressure is developed. There is no provision for 'overdriving' the blower. There is a turbocharged version of the 8V-71 which is called the 8V-71T. These do not suffer deration due to altitude and are much quieter. 8V-71 means 8-cylinders with 71 cubic inches each, or a total of (8 X 71) 568 cubic inches. This is not realy very big when you consider that almost all big trucks are powered by 855 or 893 cubic inch engines. But an 8V-71T in a motor coach is a hot son of a gun! Greyhound busses routinely got 500,000 miles between overhauls on these engines pulling 35,000 lbs gross weight. Most truckers are dealing with 80,000 lbs weight so consequently get considerably less longevity and less performance from an 8V-71 than they do other larger engines.
http://www.kingofobsolete.ca/8V71_DETROIT_DIESEL_TRUCK_ENGINE_WEBPAGE.htm
The engine he has is an 8v-71T, don't guess i have ever really noticed one without a turbo charger. All the engines i have seen in our part of the country are turbocharged, mainly marine engines. I fool with the 8v-92TA's rated at 500 hp in our military vehicles and they are naturally all turbocharged. Thanks for the info. BTW, i think his is rated at 350 hp, not 100% sure.
Last edited:
Essayons,when I Done a engine conversion on my dozer the engine that I installed in the dozer was a 855 cummins.I found it was more cost effective to buy the whole semi tractor with the cummins engine in it.Rather than buying a piece at a time for the project.I know you already have the 8-71 engine,but you will need the tranny ,driveline,engine mounts,exhaust system and so on.Look around your neck of the woods and buy a truck that has the 8-71 in it running or not ,you will get most of the parts you need for the job.These older semi tractors in my area go pretty cheap,maybe 1,500 to 2,000 dollars and drive it home to take it apart.
That is a good point because i think one of the hardest parts of the conversion will be finding an acceptable tranny, the motor mounts would be nice as well. Thats why i posted this thread because although my dad is a highly decorated freightliner mechanic and I used to be a welder/fabricator, there are still things that we haven't thought about. I plan on fabing the exhaust and i think he has some ideas for a suitable tranny. However, we aren't sure about the cooling system. The current radiator is way too small to support an 8-71 and finding one that will work might pose a problem. I definitely appreciate your input, keep the ideas coming.