Amazing what a properly tweeked engine will do for you

[trekker]

I took my 40 out on a road trip on I95 to visit family for Thanksgiving. About 1200 miles complete trip.

1968 cruiser with a freshly rebuilt F155. Stock tranny, 33x9.5's. I put a freshly rebuilt 1 bbl carb on it.

14.8 MPG for the first half the trip avg speed 69.2 MPH

I fiddled with the timing a little bit for the return trip and got the following:

An amazing 17.8 MPG and avg speed 77.8 MPH! I did do a little drafting with a really nice guy with an 18 wheeler for about 200 miles but overall I'm super pleased with the tight stock steering, and performance of the engine.

On some stretches, I was cruising at 80+ mph and my top speed was 88 with some pedal left SCAREY!!!! Calculations were done with a handheld GPS unit. My speedo is about 8 mph off because of the tires.

Will I ever do this again? NO! It was very loud as I have a soft top and driving a 40 at those speeds DEMANDS YOUR COMPLETE UNDIVIDED ATTENTION!!! I was completely wiped out at the end of each leg (600 miles).

I saw another 40 on a trailer headed north and that was it for 40 sightings along the way.


EDIT.... crap... 17.8 MPG seemed a little high so I refigured it and sure enough I was off a little ... 16.5 MPG Still amazing!

 

[IDave]

The amazing F engine! Sweet!

 

[trekker]

2F






meh

 

[IDave]

....

 

[Dusty 66]

Cool.... I can't wait to do the same......Dusty 66

 

[rsbcruiser]

Building an F155 for fuel economy, thanks for the encouragement. Curious as to your drivetrain and tire size.

 

[DSRTRDR]

I have done at least 500 miles each way to Moab twice fo0r the past two years, and at other times of the year, getting to a trail may require 100 miles either way....

does it need my full attention - yes, like any other vehicle should as well

am I wiped out by the end of the day - sure, but I smiled the whole time

also softtop here and so loud I can barely hear the others talking on the CB

I usually stop trying to push the speed by about 85mph (that is "criminal speed" in AZ anyway don't ask how I know, it wasn't in the cruiser )

now I-95 traffic that would be SCARY

 

[trekker]

Building an F155 for fuel economy, thanks for the encouragement. Curious as to your drivetrain and tire size.

Stock 3 speed. Stock drive train. 33 x 9.5 BFG's @ 35 PSI.

 

[MoCoNative]

Where was your timing, and what did you adjust it to? What is your elevation?

I generally get 15 pretty regular with my 40, daily driving, some town, some highway. But I'm running a 77 2F carb on my F155. I have my timing set at 11 degrees BTDC, seems to be about right for me, maybe I should go a bit higher. Also, what plugs you running, anything special, or original style.

 

[MoCoNative]

Oh, and are you deaf now. Last big roadtrip I took in my 40, that was dedicated highway time, I wore ear plugs, actually made the drive comfortable.

And I can't remember, but what kind of soft top do you have? Been thinking of getting one myself.

 

[brider]

Did you say that was a 2F? You rebuilt it and re-used the original 1-bbl carb? Good for you! How long did it take you to get up to that highway speed?

I mentioned in a recent post that at 85 mph with 33's and 4.11's, your engine is spinning at around 3,668 rpm. That's fast, more power to you if you can stand the scream, from what I read, the 2F is more tolerant of the sustained high revs than the F.

 

[trekker]

Where was your timing, and what did you adjust it to? What is your elevation?

I generally get 15 pretty regular with my 40, daily driving, some town, some highway. But I'm running a 77 2F carb on my F155. I have my timing set at 11 degrees BTDC, seems to be about right for me, maybe I should go a bit higher. Also, what plugs you running, anything special, or original style.

The truck is on the East Coast and when I did the numbers I was running on I-95 so elevation at about sea level to maybe 1000' at most.

My plugs are NGK BPR5EA-L

Regarding timing, I do not have a timing advance light so I set timing at the ball and then run it for a while, then advance the timing ever so slightly until I "feel" that it is running optimually. This takes some time to do.

I adjust the carb per the FSM. I also noticed that when my engine is not timed right, my engine temp is a little high but when set correct, it runs cooler. Not by much... perhaps the thickness of the red needle is all that is noticed when running at hwy speeds.

snip...

And I can't remember, but what kind of soft top do you have? Been thinking of getting one myself.

I'm running one of Eshan's OEM repos.

Did you say that was a 2F? You rebuilt it and re-used the original 1-bbl carb? Good for you! How long did it take you to get up to that highway speed?

I mentioned in a recent post that at 85 mph with 33's and 4.11's, your engine is spinning at around 3,668 rpm. That's fast, more power to you if you can stand the scream, from what I read, the 2F is more tolerant of the sustained high revs than the F.

Nope F 155. Yes we were screaming! It gets to hwgy speed quickly w/o hesitation and the pedal never needs to be "floored". The engine was running "cool" and sounded great with a completly stock set up (except for the tires). Keep in mind that the drive train only has about 35k original miles on it so everything is still "fresh" mileage wise. I did have a F145 in it but I threw a rod (#5) due to a plugged oil port.

Rather than repair the F145 immediatly, (I still have the original engine) I came across a F155 rebuilt using all OEM parts by a mechanic who has a great rep. Essentialy a new engine. I popped that in and rather than go with the 2bbl that came with it, I put on the 1bbl from the F145 to keep with the original look. I'm also using the 'oil bath" air filter.

So the truck is practically "new" save for a little bondo where the water pooled around the usual places when these trucks sit for a while (20+) years.

So essentially, completly stock, low miles and tuned per FSM it is running exactly as it was designed as it was supposed to when it was rolled off the line in Japan. I'm very happy with it ----- FINALLY!