I can't drive 55

[peesalot]

It is all clear now, although I have nothing against the GM straight 6 or it's carb, I think you will find unbolting that thing and throwing it very satisfying, search threads on here for pics of where all the ports on the Revisk carb go if he did not label them, find happiness. Before you do that and it still runs, have you put tcase in nuetral, moved lever only to driver and got engagement which would be Hi range ?

 

[MatthewMcD]

I’d try and block off that hose to the oil fill as I think it’s a big vacuum leak? Mine on my 45lv I just vent to atmosphere. I think it should vent to the air cleaner top (not used port in the pic) where it’s connected it will be a vacuum leak?My2c.

The vent on top of the air cleaner is connected to the port on the valve cover.

 

[MatthewMcD]

Seems like he’d be struggling with idle if that hose was a vacuum issue, Matt says the motor purrs and pulls up to a point. I’m not familiar with the F engines so I Googled images and that hose is common so I’m doubting that is the issue.

Do we know if the dizzy is advancing with vacuum?

Work got in the way yesterday, I'll try and get the distributor advance test in today.

• Distributor Manual Advance
• Drive without the gas cap
• Drive with oil filler line plugged
• Check for any other vacuum leaks around the carb

 

[knuckle47]

@MatthewMcD it appears you have very systematically ruled out many of the most critical components… and done a great job doing it. Frankly, take an EASY route, swap the carb…..if no change, dig deeper. Some of the things you’re checking on see to be long shots compared to fuel demands

Only my 2 cents… though

 

[charliemeyer007]

I have been watching best of House shorts - we need a "white board" post with all the symptoms and all the test run so far listed and kept up to date. I would have never guessed we be on page 11 with 200+

 

[MatthewMcD]

SOR lists a PCV valve from '58 to 9/71 which works with the oil filler neck. They don't have early valves or grommets in stock.

Interesting. I had not seen that. I'll look at the filler neck connection.

 

[MatthewMcD]

@MatthewMcD it appears you have very systematically ruled out many of the most critical components… and done a great job doing it. Frankly, take an EASY route, swap the carb…..if no change, dig deeper. Some of the things you’re checking on see to be long shots compared to fuel demands

Only my 2 cents… though

Totally agree, for me it's about time. I won't have the time to dedicate to the swap until tomorrow. I do have an hour here and there for some of these side investigations.

 

[MatthewMcD]

You can see that same line in my PFP on my 74, it restricts a bit when it goes into the intake to carb adapter. If your engine is all sealed up and the line is good It shouldn't cause a problem.
Any valve that I would imagine would just be in case of backfire and shouldn't really cause any sort of issue.

Totally agree...except...

Yesterday I had the epiphany, there is a hose to the oil filler...it's a new hose. But, the oil filler cap gasket is old and crispy. So I made a new one and now the cap fits very snug. No time for a test drive 'till later today. It may not be "the thing", but every idea y'all have had has led to incremental improvements and forced me to look wholistically at the problem. PO claims in this configuration, it reached 60-65.

 

[Grayscale]

I'm only familiar with late F and 2F. Can a 2-barrel carburetor be installed on a '68? Usually, it is an air cleaner assembly / intake manifold conflict.

 

[MatthewMcD]

It is all clear now, although I have nothing against the GM straight 6 or it's carb, I think you will find unbolting that thing and throwing it very satisfying, search threads on here for pics of where all the ports on the Revisk carb go if he did not label them, find happiness. Before you do that and it still runs, have you put tcase in nuetral, moved lever only to driver and got engagement which would be Hi range ?

I have shifted the transfer lever the way you describe, and it does engage.

 

[Toshi38]

I have shifter the transfer lever the way you describe, and it does engage.

Stupid question... If you put it in 4low with the hubs unlocked you go around half as fast, with similar engine sound /rpms?

 

[MatthewMcD]

I have been watching best of House shorts - we need a "white board" post with all the symptoms and all the test run so far listed and kept up to date. I would have never guessed we be on page 11 with 200+

Did someone say "Whiteboard"? I have to add today's tests to it.

 

[MatthewMcD]

Stupid question... If you put it in 4low with the hubs unlocked you go around half as fast, with similar engine sound /rpms?

No stupid questions.

Added to the list for today's test drive.

 

[77mustard40]

Man aren't these things fun!

 

[RevISK]

Man aren't these things fun!

So fun…

I’m trying as hard as possible to hurl my Weber as hard as I can against a wall, just need the linkage figured out on the new one first.

 

[MatthewMcD]

Man aren't these things fun!

So VERY fun. Very pretty, super fun, occasionally temperamental, sometimes a little crazy...sometimes the heights of ecstasy (solving a problem) and depths of heartbreak (when you find the next problem).

 

[peesalot]

So it seems it is not a low range issue, quite possibly, since it appears your PCV valve has been deleted it is a simple vacuum issue.

 

[Skreddy]

I can’t wait for the Weber results. For a Rochester B series carb, they average about 200 cfm, with the biggest variant being 250 cfm on the 292 engines. I seem to recall a stock Aisin is around 450 cfm? If these are all accurate, that Rochester is just choking that F engine.

 

[mrboatman]

It actually looks like you have a PCV valve installed already take a closer look at it

 

[MatthewMcD]

It actually looks like you have a PCV valve installed already take a closer look at it
View attachment 3747419

Yes, I do. I never looked at that connection thinking it was just an "L". This PCV valve is threaded into the block on the tube. It's not a press fit as shown on the parts diagram. I removed it and cleaned it. Replaced it and them deleted it by plugging the vacuum hose.

No change in performance, though it appears to have "enhanced" a few of my oil leaks.

How do I test a PCV valve? Finding a replacement is going to be interesting.