Cummins 4BT & Diesel Conversions Forums banner
141 - 160 of 160 Posts

· Registered
Joined
·
179 Posts
Discussion Starter · #141 ·
Just threw some vids up I have been making on the process. I am much farther along but haven't done enough editing. Going to get a bunch of weather this week so no installing the engine this week while I have it off. But that's alright.
 

· Registered
Joined
·
7 Posts
So i have this 4.5 looks similar to what you have. I'm wanting to put it into my 86 Toyota pick up truck.. not sure if i should use this engine or use my other 4bt 3.9 since i have one as well. So right now I'm undecided on which one I should use. What are the pros and cons between them both to where I can make the right choice here to know which one to use.
 

· Registered
Joined
·
13,454 Posts
A far as power goes, the 3.9 can outdo the 4.5. You can only build the 4.5 so high due to its rods and pistons. You have to change the injection pump on the 4.5 for any upgrade because the one on it is computer controlled. The 99 HP was basically the limits Cummins put on that model of 4.5. The 3.9 can easily be built to 300 HP but I wouldn't dare try that on the 8 valve 4.5. The 16 valve 4.5 could do it but that one is a different animal.
 

· Registered
Joined
·
7 Posts
A far as power goes, the 3.9 can outdo the 4.5. You can only build the 4.5 so high due to its rods and pistons. You have to change the injection pump on the 4.5 for any upgrade because the one on it is computer controlled. The 99 HP was basically the limits Cummins put on that model of 4.5. The 3.9 can easily be built to 300 HP but I wouldn't dare try that on the 8 valve 4.5. The 16 valve 4.5 could do it but that one is a different animal.
So my 4.5 can easily put out 300hp then. What can I do to make it out out that much. Sorry I'm a newbie to all of this. So if you don't mind helping me out on what i need to do to make it 300hp i would greatly appreciate it.
 

· Registered
Joined
·
31 Posts
Just found this thread the other day. Lots of good info here. Thanks Char! I was given 4 worn-out long blocks a while ago. Two 3.9 and two of these weird 4.5’s. Decided to build the 3.9 because I knew nothing about the 4.5. Bored out the 3.9 0.5mm (0.020”), put a performance cam in it, 5X12 nozzles, nearly all assembled. Got to buy the expensive parts now. Injection pump, adapter plate and flywheel for GM transmission. Someday I may revisit the 4.5.
 

· Registered
Joined
·
13,454 Posts
So my 4.5 can easily put out 300hp then. What can I do to make it out out that much. Sorry I'm a newbie to all of this. So if you don't mind helping me out on what i need to do to make it 300hp i would greatly appreciate it.
I wouldn't recommend trying to make a 8 valve 4.5 do 300 HP. That's 3 times the power it was designed for. I'd worry about those skinny connecti4ng rods plus the rod angle with around 650-700 lb ft of torque that you'd have. I'd think 200 might be pushing the limit. The 3.9 can do it easily but that 4.5 is a different animal. I said the 16 valve 4.5 could be built to that power level. Two totally different engines. Also, I wouldn't recommend that vacuum/power steering combo in you photo. Those have a bad reputation.
 

· Registered
Joined
·
7 Posts
I wouldn't recommend trying to make a 8 valve 4.5 do 300 HP. That's 3 times the power it was designed for. I'd worry about those skinny connecti4ng rods plus the rod angle with around 650-700 lb ft of torque that you'd have. I'd think 200 might be pushing the limit. The 3.9 can do it easily but that 4.5 is a different animal. I said the 16 valve 4.5 could be built to that power level. Two totally different engines. Also, I wouldn't recommend that vacuum/power steering combo in you photo. Those have a bad reputation.
Sorry miss read that part. I'm i able to make mine into a 16 valve if so what's the max HP i can out of it and even worth doing so.because i have a 3.9 4bt is it worth me just using that motor instead since I'm reading it can get 400HP easy.?
 

· Registered
Joined
·
1,898 Posts
...because i have a 3.9 4bt is it worth me just using that motor instead since I'm reading it can get 400HP easy.?
Just because you read it on the internet does NOT make it true.

400 HP ain't going to be easy, is going to be expensive, and probably will live a short life.
 
  • Like
Reactions: eggman918

· Registered
Joined
·
2,623 Posts
Sorry miss read that part. I'm i able to make mine into a 16 valve if so what's the max HP i can out of it and even worth doing so.because i have a 3.9 4bt is it worth me just using that motor instead since I'm reading it can get 400HP easy.?
Once you are north of 200HP IF you have one of the turbos that come on well by 1,500 RPM you will have a mill that with proper gearing be a useful and fun rig.
Your choice of turbo and gearing is what makes of breaks the "Fun Factor" with the 4BT...$.02
 

· Registered
Joined
·
13,454 Posts
You can't make yours into a 16 valve. They have a different block that has a different bore and stroke than yours. Your engine was designed to be a high torque low horsepower industrial engine, not a high powered street model. Not much to be gained on yours by installing a 16 valve head. As the guys said, getting to 300 HP can be done reasonably easy on a 4bt 3.9. 400 HP is a whole different world. You'd need a P7100 injection pump, possibly another step up in injector size over the 5x.012, twin turbos, different pistons, one heck of good intercooler, and lots of mods to insure it all stays together. We have very few guys who go to the power level. You're talking about an engine with near 1000 lb ft of torque which can tear up drive train parts. To build a serious power engine like that can get into some serious money. Could easily go $10,000 or a lot more. May need 13mm bores in the injection pump which can be big money. Guys running that kind of power usually have an automatic transmission which might cost $5,000. There are only a few manuals that will handle that kind of torque. I've read articles about guys who run the 6bt to extreme power levels and they have $60-100K in an engine that might last one season. As the guys also pointed out, life expectancy becomes short at high power and rebuilds come often.
 

· Registered
Joined
·
7 Posts
You can't make yours into a 16 valve. They have a different block that has a different bore and stroke than yours. Your engine was designed to be a high torque low horsepower industrial engine, not a high powered street model. Not much to be gained on yours by installing a 16 valve head. As the guys said, getting to 300 HP can be done reasonably easy on a 4bt 3.9. 400 HP is a whole different world. You'd need a P7100 injection pump, possibly another step up in injector size over the 5x.012, twin turbos, different pistons, one heck of good intercooler, and lots of mods to insure it all stays together. We have very few guys who go to the power level. You're talking about an engine with near 1000 lb ft of torque which can tear up drive train parts. To build a serious power engine like that can get into some serious money. Could easily go $10,000 or a lot more. May need 13mm bores in the injection pump which can be big money. Guys running that kind of power usually have an automatic transmission which might cost $5,000. There are only a few manuals that will handle that kind of torque. I've read articles about guys who run the 6bt to extreme power levels and they have $60-100K in an engine that might last one season. As the guys also pointed out, life expectancy becomes short at high power and rebuilds come often.
Got you.. so answer me this then. What would you recommend on doing in my situation here.. because I'm wanting to install it into my 1986 Toyota pick up truck with and 6 speed Allison tranny i want it as an daily driver. Like i said i have the 4bt 3.9 engine and would it be just best to still that one then the 4.5 that i have . Because i bought the 4.5 and I'm able to return it so what would you do here?
 
141 - 160 of 160 Posts
Top