2.3 Mini Stock Engine Ideas
06-27-2012, 01:53 AM
#1
2nd Gear Member
Thread Starter
Join Date: Apr 2007
Location: Indiana
Posts: 215
2.3 Mini Stock Engine Ideas
Ok guys here is dilemma... I have had multiple fox body's all being 5.0's. I have built multiple fox body's all being 5.0's. I bought a notchback roller yesterday and mt plan is building a roundy round car for our local track. My first question is what year engine do i need to hunt for/ I want a carbed car with distributor. My buddy has a 2.3 buts a 8 plug engine and the oil pump is where the dizzy whole should be? I am going to run a five speed also. Any help on this will be greatly appreciated. I have no knowledge on a 2.3 at all. I dont care to convert a engine to carbed but the 8 plug engines wont work.
07-04-2012, 01:22 PM
#3
Join Date: Jul 2012
Location: PA
Posts: 2
You can use you 8-plug head for parts and once it's stripped it can be a nice door stop or a boat anchor.
My advice is to go find a D-port head from a 1980s car or Ranger. Use your EFI lower intake manifold and an adapter from Esslinger to mount a Holley 500cfm 2-barrel.
If the rules allow you to run a crank-trigger ignition, get a kit and use with the existing ignition. If you have to run a distributor I recommend buying a one for an early 1980s 2.3 and hooking it to a factory Duraspark control box.
That gives you the advantage of having variable advance instead fixed advance like guys running the TFI distributors. Plus the Duraspark system is not as prone to heat problems like the TFI system is.
If your engine is in good shape you can leave the bottom end alone. For the average mini-stock racer if you keep the rpms below 7500 there should be no problems if you start with a healthy bottom end.
Stock 2.3 rods start to break at 7800rpm, but by replacing the rods bolts you can get that up to 8200rpm. With aftermarket rods you can safely turn up to 8800 rpm and then you have to worry about stock crankshafts breaking.
That said, you need to do some head work to get a 2.3 to turn up past 6000rpm. First and the easiest power is to mill the head for increased compression.
And you have to mill it a seemingly insane amount to get the most power. It is not uncommon for some racers to mill a 2.3 head as much a .180. That will add a bundh of power but you will need to run race gas, because you'll have an engine with about a 13.5:1 compression ratio.
The second thing is to get the exhaust ports enlarged and the valve bowl areas cleaned-up. It really isn't need to have the intake ports ported, but the exhaust side of a 2.3 is very restrictive and can use help. Have larger valves installed if the rules allow you to do that.
The exhaust system is going to depend on the rules. If you can, go with an aftermarket header. I've run a Hooker header since 1887 and it was a cheap and easy pickup of 25hp.
If the rules say you must run a stock exhaust manifold you need to hunt for the Ranger tubular exhaust. It's like the 5.0 factory shorty headers instead of the cast-iron lump exhaust manifolds most 2.3s came with.
Cam selection is going to depend on you rules. If you're allowed order a solid lifter roller cam kit, go for it. Racer Walsh sells a good .608 lift cam, I've had one for 10 years now.
It's a very rev-happy cam and makes good power in the high rpm range. You will need to do some machine work to install the solid lifters and springs, as well as changing valves to match the cam. Also a good time to switch to the bigger valves.
You're going to run a T-5 so you need to research the rules for tire size to match the 2nd gear ratio so you can keep the engine in the 7500-8000 rpm range down the straights. You'll find that you'll probably want 3.55 rear gears
with a T-5, but you'll need to check the gear ration of the trans and know the tire size to be sure.
What you're looking for is a a final drive ration of about 7.25:1 when you in 2nd gear. You'll spend the entire race in 2nd, so if you can find an older 2.3L 4-speed trans, you can reduce the power lost of turning the T-5s extra gears.
I highly recommend you go to www.4m.net and check out the mini-stock tech forum there. There are a bunch of very clue-in guys there who will help with the engine and suspension issues you may have.
They've also got formulas to better determine what gears are needed depending on the length of tracks you'll be running, the tire size and which trans you use.
My advice is to go find a D-port head from a 1980s car or Ranger. Use your EFI lower intake manifold and an adapter from Esslinger to mount a Holley 500cfm 2-barrel.
If the rules allow you to run a crank-trigger ignition, get a kit and use with the existing ignition. If you have to run a distributor I recommend buying a one for an early 1980s 2.3 and hooking it to a factory Duraspark control box.
That gives you the advantage of having variable advance instead fixed advance like guys running the TFI distributors. Plus the Duraspark system is not as prone to heat problems like the TFI system is.
If your engine is in good shape you can leave the bottom end alone. For the average mini-stock racer if you keep the rpms below 7500 there should be no problems if you start with a healthy bottom end.
Stock 2.3 rods start to break at 7800rpm, but by replacing the rods bolts you can get that up to 8200rpm. With aftermarket rods you can safely turn up to 8800 rpm and then you have to worry about stock crankshafts breaking.
That said, you need to do some head work to get a 2.3 to turn up past 6000rpm. First and the easiest power is to mill the head for increased compression.
And you have to mill it a seemingly insane amount to get the most power. It is not uncommon for some racers to mill a 2.3 head as much a .180. That will add a bundh of power but you will need to run race gas, because you'll have an engine with about a 13.5:1 compression ratio.
The second thing is to get the exhaust ports enlarged and the valve bowl areas cleaned-up. It really isn't need to have the intake ports ported, but the exhaust side of a 2.3 is very restrictive and can use help. Have larger valves installed if the rules allow you to do that.
The exhaust system is going to depend on the rules. If you can, go with an aftermarket header. I've run a Hooker header since 1887 and it was a cheap and easy pickup of 25hp.
If the rules say you must run a stock exhaust manifold you need to hunt for the Ranger tubular exhaust. It's like the 5.0 factory shorty headers instead of the cast-iron lump exhaust manifolds most 2.3s came with.
Cam selection is going to depend on you rules. If you're allowed order a solid lifter roller cam kit, go for it. Racer Walsh sells a good .608 lift cam, I've had one for 10 years now.
It's a very rev-happy cam and makes good power in the high rpm range. You will need to do some machine work to install the solid lifters and springs, as well as changing valves to match the cam. Also a good time to switch to the bigger valves.
You're going to run a T-5 so you need to research the rules for tire size to match the 2nd gear ratio so you can keep the engine in the 7500-8000 rpm range down the straights. You'll find that you'll probably want 3.55 rear gears
with a T-5, but you'll need to check the gear ration of the trans and know the tire size to be sure.
What you're looking for is a a final drive ration of about 7.25:1 when you in 2nd gear. You'll spend the entire race in 2nd, so if you can find an older 2.3L 4-speed trans, you can reduce the power lost of turning the T-5s extra gears.
I highly recommend you go to www.4m.net and check out the mini-stock tech forum there. There are a bunch of very clue-in guys there who will help with the engine and suspension issues you may have.
They've also got formulas to better determine what gears are needed depending on the length of tracks you'll be running, the tire size and which trans you use.
07-05-2012, 04:24 PM
#4
2nd Gear Member
Thread Starter
Join Date: Apr 2007
Location: Indiana
Posts: 215
I am running t5 do to the rules. I can mill head nut can not change valves. I do want to put a cam in it though. The engine is out of a 88 mustang but I have converted it to carb. What would be a good cam to go with this head and stock valves? The track is 1/3 mile also and i was gonna run 185/60/14 tires. I have a 373 rear gear right now.
07-05-2012, 07:22 PM
#5
Join Date: Jul 2012
Location: PA
Posts: 2
I'm gonna refer you to www.4m.net for the cam selection answer. There are guys there who will know off the top of their heads.
If you can't change valves you may be restricted to something like a .408 lift cam that doesn't require a valve swap. Much larger and cams need to go to a reduced base circle which requires longer valves.
Running a 1/3mile track will probably mean you to switch out the 3.73 gears for something more long-legged. Something like 3.47s or 3.55s so you can keep the rpm in a range the engine can stand. Otherwise you'll over-rev or be on the rev limiter towards the ends of the straights.
You'll need to know standing height of your tires you'll be running so the math can be done to figure out a good cam and gears match to the T-5 and a stock bottom end. Then once you get the engine done you get to jump into the world of chassis set-up.
If you can't change valves you may be restricted to something like a .408 lift cam that doesn't require a valve swap. Much larger and cams need to go to a reduced base circle which requires longer valves.
Running a 1/3mile track will probably mean you to switch out the 3.73 gears for something more long-legged. Something like 3.47s or 3.55s so you can keep the rpm in a range the engine can stand. Otherwise you'll over-rev or be on the rev limiter towards the ends of the straights.
You'll need to know standing height of your tires you'll be running so the math can be done to figure out a good cam and gears match to the T-5 and a stock bottom end. Then once you get the engine done you get to jump into the world of chassis set-up.
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