Timing Wandering

[RobertC]

I am confused -- I thought that the pcv valve was in the valley pan on this "vintage" engine (1975).

Michael mayben will have to address the correct setup of the pcv valve. (I know there are a number of "variations" over the years - including different variations "added" by pos.)

re: speed sensor -- michael mayben will have to address this, also.

My understanding of the speed sensor is that it "works" with the thermo vacuum switches ( which your engine does not have ) to "control" the vacuum advance under some engine conditions.

On a smog engine, vacuum lines run from the tvs swtiches (2 lines) to the speed sensor solenoid valve... These tvs switches are also "eventually" connected to the vacuum advance canister via vacuum lines.

Good luck

 

[smartin]

I've looked a couple of engine setups for scouts and have not really found any consistent vacuum setups and like you I am pretty confused at this point on what goes where. On a good note though, the truck runs much better with this new carb and I am sure that once the vacuum situation is corrected my mileage and power will increase.

Thanks Robert!

 

[smartin]

I believe that I now have the vacuum lines setup correctly. I looked at a few more engine setups and found that Robert was correct in that the pcv valve should be in the valley pan cover. I picked one up from the parts store and it fit perfectly.

I pulled and plugged the line from the speed sensor. This seems to have absolutly no affect on how the engine performs.

I ran a single vacuum line between the metering block and the vacuum advance.

Other than the above there are no other vacuum connections and the unused ones are all plugged.

Now I have one last thing...now that I removed the pcv valve from the valve cover, do I need to get a flame arresstor or can I just plug the hole? Does it matter? Btw in the photo it is on the passenger side as during the rebuild I swapped the valve covers to make it easier to access the oil fill cap.

 

[RobertC]

I believe that I now have the vacuum lines setup correctly. I looked at a few more engine setups and found that Robert was correct in that the pcv valve should be in the valley pan cover. I picked one up from the parts store and it fit perfectly. .

The pcv valve should be routed to the intake manifold -- where your "multi" connections are...

I pulled and plugged the line from the speed sensor. This seems to have absolutly no affect on how the engine performs.

Probably would not notice anything -- I think it affects ("changes") the vacuum advance during some combination of road speed and engine operating temp -- when all "pieces" are
in place (tvs switches, egr valve, etc).

now I have one last thing...now that I removed the pcv valve from the valve cover, do I need to get a flame arresstor or can I just plug the hole? Does it matter? Btw in the photo it is on the passenger side as during the rebuild I swapped the valve covers to make it easier to access the oil fill cap.

Yes, you need a flame arrestor - so that the engine itself "breathes" internally and does not build up pressure.

I thought michael would reply, but maybe his internet / phone situation is still a mess.

Imo, you have valve covers from an "earlier version" / earlier year engine (pcv plumbing wise) -- why I asked about the year of the engine.

There should be a driver's side valve cover without an oil fill cap with the same pipe fitting that your current pass side valve cover has.

The flame arrestor goes in the driver's side valve cover and a hose runs to the base of the air cleaner (where you had your pcv valve connected). You need to "construct" a connection (that does not kink the hose) as the stock "hard-formed" 90+ degree bend rubber hose is not available.

There also should be a pass side valve cover (version) with just the oil fill cap and no pipe fitting.

I guess you could put a flame aresstor in your pass side valve cover and run the hose that you had on the pcv valve to the air cleaner.

 

[smartin]

yes, you need a flame arrestor - so that the engine itself "breathes" internally and does not build up pressure.

I thought michael would reply, but maybe his internet / phone situation is still a mess.

Imo, you have valve covers from an "earlier version" / earlier year engine (pcv plumbing wise) -- why I asked about the year of the engine.

There should be a driver's side valve cover without an oil fill cap with the same pipe fitting that your current pass side valve cover has.

The flame arrestor goes in the driver's side valve cover and a hose runs to the base of the air cleaner (where you had your pcv valve connected). You need to "construct" a connection (that does not kink the hose) as the stock "hard-formed" 90+ degree bend rubber hose is not available.

There also should be a pass side valve cover (version) with just the oil fill cap and no pipe fitting.

I guess you could put a flame aresstor in your pass side valve cover and run the hose that you had on the pcv valve to the air cleaner.

There are many items that I have found since purchasing the truck in '95' that are not consistent with the year of the vehicle and the valve covers May be another one of those things. From what you said above it probably does not matter which side the arresstor is on as long as its there and connected to the air cleaner. Is that correct?

I've shecked a few parts stores and cannot find the arrestor. Where can I pick one up at?

 

[kyleandhisIH]

...
From what you said above it probably does not matter which side the arresstor is on as long as its there and connected to the air cleaner. Is that correct?

I've shecked a few parts stores and cannot find the arrestor. Where can I pick one up at?

The flame arrestor is just a fresh air inlet for the crankcase, and is a sister component to the pcv valve. That's why it is plumbed to the clean side of the breather oem. From my understanding, it is perfectly acceptable to replace the arrestor with a simple open-element filter. This gets done on many engines, and IH iron is no exception.

 

[RobertC]

I've shecked a few parts stores and cannot find the arrestor. Where can I pick one up at?

Suffering from brain fade... the flame arrestor is an IH part. Looks like they are on back order (light line).

You can call Jeff at ihon and see if he has a used one.

Or, you can do what kyle recommended, put a small filter on it.

Think I have seen a real small k&n filter used -- think they May be usually used for venting differentials / transfercase..

Found a picture in IH only buildups / pd's drivetain upgrade / post #24. There are probably other pictures posted - if you spend the time looking.

If you are curious:

IH engines (sv v8) have a build date -- stamped in a piece of metal attached to back (firewall) of the block -- "behind" the valley pan.

"somewhere" someone had posted / compiled a "translation" to an actual date...

 

[Scoutboy74]

Years ago I stupidly chucked my oe valve cover mounted flame arrestor thinking it would be super easy to get a replacement. Not the case at all. So what I did was buy a short chunk of copper tubing that was threaded on both ends. As long as one end is threaded I think you're golden. Threaded it into the valve cover fitting. Then I bought an el cheapo motorcycle crankcase breather filter in a chrome housing and attached that to the other end of the copper tube. It serves the purpose of the flame arrestor and adds a touch of bling not that it matters in my case.