2F engine not powerful enough??? (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Feb 9, 2009
Threads
11
Messages
24
:crybaby:I just bought a 1978 fj40 but for some reason the beast won't go above 60 on the road. I have 33's on the frame and it is the original 2F with only about 125K original miles on it. It sounds great but I am not getting enough torque out of it. The only thing I can think of is that it is set up to pass emissions in AZ but I am now in NM and that is not required. Do you guys think this is the problem? I have a new carb, new tune up, new fuel pump, etc and it seems to run good but just cant get more power from it? Any ideas?? Please help.:crybaby:
 
2F

Welcome to Mudd :flipoff2:

If you like driving a LC well as many others have said, learn to love the right lane. I do, if you want something that goes fast, then buy it....

Good Luck:)
 
Hi All:

Well, if the rig has all of its original smog-junk on it the 2F is probably only putting out about 125 HP.

Things to check are the compression of the engine, and whether you have the appropriate jets in the carb for the altitude you are driving at.

The '78 vintage 2F in my '74 FJ40 pulls pretty good on the highway but admittedly it bogs down a bit when pulling a mountain pass (3,000 feet elevation) between the resistance of the grade of the road and the carb jets set for sea level.

But, if you really need a lot more power a GM V-8 is the "tried and true" solution. Do some searching here on MUD - lots of good info on doing a SBC swap.

Good luck!

Alan
 
what's the gearing in your axles ?

how do you know you are low on torque :confused: did you want torque or power ?

yes, the 2F will go faster than 60 - not that that is necessarily safe :rolleyes:
 
I would check compression first
 
:crybaby:I just bought a 1978 fj40 but for some reason the beast won't go above 60 on the road. I have 33's on the frame and it is the original 2F with only about 125K original miles on it. It sounds great but I am not getting enough torque out of it. The only thing I can think of is that it is set up to pass emissions in AZ but I am now in NM and that is not required. Do you guys think this is the problem? I have a new carb, new tune up, new fuel pump, etc and it seems to run good but just cant get more power from it? Any ideas?? Please help.:crybaby:

Is it pretty much stock?

Have you done a compression test?

Is the linkage bound in any way? Will it go wide open?

What are your rpms at 60?

Could always cap off the smog pump temporarely if you think it might be the issue.

Could it have been detuned to meet emissions?

What is the timing set at.

Is the advance working?

Is the pedal all the way to the floor?

What psi are your tires?

No brakes are dragging, right?

Choke is working correctly?

I can go on all night.:D Cause you don't need a v-8 to have a powerfull cruiser. All you need is to have a good running 2f.
 
There is something badly wrong! My guess is that the carb secondary is not opening or the distributor advance is not working. My 2F will take my spring over FJ60 to 75 easy.
 
Something's not right. I run a 78 with 33's (4.10's) at 6,000 ft and can run over 60. On a good day I can even pass a slow truck!

Anyway, it's no powerhouse, but it should do better than you're describing.

I agree with the compression check - as well as the other basics: valve lash, timing, carb set-up (is the secondary working???).
 
My question is who the hell goes above 60 with an original engine in their truck? It's not the safest thing, nor is it the best for engine and fuel efficiency. I'm good with right around 52-55. Where did I read that 100 km/hr or 62 mph was the top end? Factory literature somewhere, I think.

Brian
 
80mph:steer:
69 fj ad.jpg
 
Last edited:
There is something badly wrong! My guess is that the carb secondary is not opening or the distributor advance is not working. .

My thoughts as well. Check carb linkage for excessive freeplay, and try the secondary diaphram test [thread search required;)]

Best

Mark A.
 

I like the advert but "deep foam seating for seven men" - not for long in an FJ40 please!

That also says 145bhp which I think is right for a new '78, 125bhp for a F? (not sure because the picture is pre 2F). 2F might be 155bhp?

Even a good engine will be down on new spec after whatever years since it was new or had a rebuild but I would guess 100bhp should see you at 65mph in most FJ40's.
 
if you check what Trollhole suggests you wont be far from the problem,if it is so sick it wont be hard to figure the problem,my 77 kicks ass,its stock and will do the 80mph they say but i crooze on 60,just done 4000 kilometres no drama, its part of the fun of getting to know your rig too,let us know when its sorted
 
My question is who the hell goes above 60 with an original engine in their truck? It's not the safest thing, nor is it the best for engine and fuel efficiency. I'm good with right around 52-55. Where did I read that 100 km/hr or 62 mph was the top end? Factory literature somewhere, I think. Brian

Mine runs like a top and 50-55 is the best it will comfortably do. I could make the engine scream and get more speed if I wanted to... and then slam a tree...:eek: I think he has a pretty normal 78, but was expecting more.
 
Mine runs like a top and 50-55 is the best it will comfortably do. I could make the engine scream and get more speed if I wanted to... and then slam a tree...:eek: I think he has a pretty normal 78, but was expecting more.

He's saying his top speed is 60 and he has pretty much the same vehicle as I do and I cruise at 60 no problem. Something is not right. I don't have smog equipment but I have the tires and the motor he has.

Does the 78 have points?
 
Last edited:
I drive mine on 35's (4:88's) at 65-70 at 7000', 50-55 up steep grades. There is somthing wrong if it wont go 60mph on flat ground at sea level. Try fresh fuel, basline all the fluids and tune up. And check your vac advance. Also remeber with 33's and stock 4:10's 60mph on the speedo will be closer to 70mph.
 
Last edited:
Mine's a '78 on 33's..... 2F motor with all the smog crap. cruises at 65 with no problem. Haven't tried to go faster but could.

Maybe start with a tune-up. Valve adjust.
 
x2 vacuum secondary not working...
 

Users who are viewing this thread

Back
Top Bottom