"best" 2F
- Thread starter Mace
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Mace said:What is the benefit of closed chambers and flat top pistons?
And yes, this motor will get flat abused. I am looking at well over 200hp at the rear wheels...
And a 6500K redline..
So, every little bit of work will help
I assume you've read my engine thread?
https://forum.ih8mud.com/showthread.php?t=61396
Bathtub chambers are a much better design for LPG (you're still running LPG right?). Especially if you go to almost zero squish.
Over here, I've never seen domed pistons - everything was flat top.
I ran the head off a 1.5F on a 2F block for better compression. I guess for turbo work you wont want to get too carried away with machining for compression.
I've not had any problems with my rod bolts (have had the bottom apart once since the rebuild) - but I did loctite them!
With a turbo, I reckon you should be able to get 300hp out of it
Definately do some form of oiling mods though!!!! Mine are outlined in my thread, Mark W I'm sure has his written somewhere - I know they're on the LCML
Mark W
Yep, I really don't really care that much I guess.
Chef said:
I get rings, bearings, pistons, seals and gaskets from a local parts warehouse that sells wholesale only to the local parts stores... and guys like me who have made rhe right connections.
I get my cams and oil pumps and a few other items from different sources I have tracked down.
Mark...
Mark W
Yep, I really don't really care that much I guess.
Mace said:
With a starting CR of 7.8 (or possibly 8.5 in the later motor) yiou still need to worry about it even with a turbo.
I forgot that you were running a turbo. 200+ at the rear wheels should be easy.
A '76 block will work fine with a 3FE head. But '76 pistons will not.
I forget exactly which bolts I have looked into. I've got it written down at the shop. Made by ARP. Looks like they'll be about a .001 -.002 interference fit. A little heat and a press should get them in just fine...
Mark...
Mark W
Yep, I really don't really care that much I guess.
andrewfarmer said:
The domed pistons may be a US thing. I've only taken down one 2F that I knew for sure was a stock Canadian engine. It had flat tops with open combustion chambers.
Mark...
Mark W
Yep, I really don't really care that much I guess.
Mace said:
I tend to agree about likeing the longer stroke. Or more importantly the longer rods. But the biggest advantage of the 3F for higher rpm is not the shorter stroke but the lighter rod and piston combo. The 3F rod is a LOT shorter, as is the piston. The equates to a lot less weight. It's the weight as well as the stroke that creates the stress at higher speeds.
Mark...
the shorter rod also reduces torque (piston dwells for less time at TDC)and increases side loading of the piston...
chris
chris
- Thread starter
- #29
I wonder if the side loading of the piston is offset by the reduced weight of the rotating mass??DHONDAGOD said:the shorter rod also reduces torque (piston dwells for less time at TDC)and increases side loading of the piston...
chris
This argument could be an incredible display of bench racing
I need to roll the 2F I have in the garage over and see what vintage it is.
- Joined
- Sep 26, 2003
- Threads
- 117
- Messages
- 11,199
- Location
- Lancaster, Ohio, USA
- Website
- www.tlcperformance.com
Mace,
If you had to pick one 2F to build, the 85-end models are best. They have all the upgrades of the 81-85, plus in 85 they got:
-the 3F cylinder head, which gives the option of running the 3F manifolds
-the 3F head gasket with better coolant flow direction
-screw in oil galley plugs (I really like this)
-slight improvement w/ the 3piece thrust bearing
-torx screws in timing plate(which should be added to any engine).
However, if you start w/ a 4230cc engine that is 8.3:1, then punch it 1.5mm OS, the result is 4367cc at 8.57:1. Usually the head is milled a little to clean up the face, which will get up to 8.7:1. If the engine is gonna be blown on, that's a pretty high CR, without modern feedback control systems.
The lightened valvetrain came along in mid 1979.
On the rods, newer is definitely better. As Mark mentioned, it's marginally lighter, but it's also much stronger because of the extra finishing on the I-beam.
I've got a picture here of the 79-earlier rod vs. the 80-later rod, but can't figger out how to post it.
If the engine is gonna be spun, it should be balanced to zero. Early 2F and all F engines are often out by several OUNCES. No, not grams. Rods are out by 20 grams or more, cranks off by 50, flywheels off by 30. The only thing that keeps a 1971 F engine together at speed is sheer stubbornness. The 81-newer engines were destined for cushy FJ60 wagons, so they finally started paying attention to balancing. They are usually only out by an ounce.
HTH
If you had to pick one 2F to build, the 85-end models are best. They have all the upgrades of the 81-85, plus in 85 they got:
-the 3F cylinder head, which gives the option of running the 3F manifolds
-the 3F head gasket with better coolant flow direction
-screw in oil galley plugs (I really like this)
-slight improvement w/ the 3piece thrust bearing
-torx screws in timing plate(which should be added to any engine).
However, if you start w/ a 4230cc engine that is 8.3:1, then punch it 1.5mm OS, the result is 4367cc at 8.57:1. Usually the head is milled a little to clean up the face, which will get up to 8.7:1. If the engine is gonna be blown on, that's a pretty high CR, without modern feedback control systems.
The lightened valvetrain came along in mid 1979.
On the rods, newer is definitely better. As Mark mentioned, it's marginally lighter, but it's also much stronger because of the extra finishing on the I-beam.
I've got a picture here of the 79-earlier rod vs. the 80-later rod, but can't figger out how to post it.
If the engine is gonna be spun, it should be balanced to zero. Early 2F and all F engines are often out by several OUNCES. No, not grams. Rods are out by 20 grams or more, cranks off by 50, flywheels off by 30. The only thing that keeps a 1971 F engine together at speed is sheer stubbornness. The 81-newer engines were destined for cushy FJ60 wagons, so they finally started paying attention to balancing. They are usually only out by an ounce.
HTH
- Joined
- Jan 24, 2003
- Threads
- 144
- Messages
- 2,024
- Location
- Columbia, MO
- Website
- www.tornadoalleycruisers.com
Man, I love this thread...
- Thread starter
- #32
Now all I have to do is figure out what engine # they started doing all of these modsFJ40Jim said:Mace,
If you had to pick one 2F to build, the 85-end models are best. They have all the upgrades of the 81-85, plus in 85 they got:
-the 3F cylinder head, which gives the option of running the 3F manifolds
-the 3F head gasket with better coolant flow direction
-screw in oil galley plugs (I really like this)
-slight improvement w/ the 3piece thrust bearing
-torx screws in timing plate(which should be added to any engine).
However, if you start w/ a 4230cc engine that is 8.3:1, then punch it 1.5mm OS, the result is 4367cc at 8.57:1. Usually the head is milled a little to clean up the face, which will get up to 8.7:1. If the engine is gonna be blown on, that's a pretty high CR, without modern feedback control systems.
The lightened valvetrain came along in mid 1979.
On the rods, newer is definitely better. As Mark mentioned, it's marginally lighter, but it's also much stronger because of the extra finishing on the I-beam.
I've got a picture here of the 79-earlier rod vs. the 80-later rod, but can't figger out how to post it.
If the engine is gonna be spun, it should be balanced to zero. Early 2F and all F engines are often out by several OUNCES. No, not grams. Rods are out by 20 grams or more, cranks off by 50, flywheels off by 30. The only thing that keeps a 1971 F engine together at speed is sheer stubbornness. The 81-newer engines were destined for cushy FJ60 wagons, so they finally started paying attention to balancing. They are usually only out by an ounce.
HTH
In the long run it really looks like the newer the motor, the better the choice.
- Joined
- Sep 26, 2003
- Threads
- 117
- Messages
- 11,199
- Location
- Lancaster, Ohio, USA
- Website
- www.tlcperformance.com
The engine number doesn't help much, since it is not on the cylinder head or the crank or the rods....
Just go by the casting date and numbers.
Just go by the casting date and numbers.
- Joined
- Sep 26, 2003
- Threads
- 117
- Messages
- 11,199
- Location
- Lancaster, Ohio, USA
- Website
- www.tlcperformance.com
In the photo, the lighter rod is the one that *appears* to have the i-beam machined. It is not machined, it has been "forged" along the i-beam. While the rod is still red-hot, the beam gets smacked in a press which compresses and aligns the grain on the edges of the I-beam. The flat areas are not machined away, but are made stronger. The rod picks up fatigue resistance by dint of the edges of the I-beam being much more crack resistant. The actual tensile strength of the rod beam is not significantly improved, but it is much stronger/durable in use because failures usually start as a crack at the outside edge of the beam.
more resistant to edge cracking = more resistant to ultimate failure
Thanks Steve for posting the pics
more resistant to edge cracking = more resistant to ultimate failure
Thanks Steve for posting the pics
- Joined
- Sep 26, 2003
- Threads
- 117
- Messages
- 11,199
- Location
- Lancaster, Ohio, USA
- Website
- www.tlcperformance.com
You sure about the 61041?
Heads are 61030 or 61031, open chamber, or
61040, 61070 closed chamber.
blocks start off as 61011 in 75-76, then step upward to 61014 in late FJ60's
Should we start a sticky thread about dating parts, w/ pictures of all the components that have dates stamped or cast (blocks, heads, diff gears, carbs, fuel pumps, T-cases,etc.), and how to decipher them?
Where's the stupid noob thread about posting pics, I need to read that again?
Heads are 61030 or 61031, open chamber, or
61040, 61070 closed chamber.
blocks start off as 61011 in 75-76, then step upward to 61014 in late FJ60's
Should we start a sticky thread about dating parts, w/ pictures of all the components that have dates stamped or cast (blocks, heads, diff gears, carbs, fuel pumps, T-cases,etc.), and how to decipher them?
Where's the stupid noob thread about posting pics, I need to read that again?
