Just a bit more than a puff on startup

Robert kenney said:
Craig if you determine the engine is not broken in enough to seat the rings find the longest steepest hill you can find and run the heck out of it. 3000 rpm and 25-27" manifold pressure for at least 2 hours. Don't lug it let it turn up for cooling. Then leak the motor down. If you find a low cylinder pull the oil filer cap and listen for ring leakage. If you still hear hissing take to the hills again.
Robert
Click to expand...

As for the driving in the hills, the hill would not need to be 2 hours long but an accumulation of hours.


Craig,
hope you didn't take all of this talking the wrong way . Early on in this thread I did say that I thought it was broken-in as 500 miles has been enough for my situations. Sounds like you have put your rig through enough abuse to seat the rings.
 
Robert kenney said:
sorry tiny.... I respectfully disagree. factory intake stem to guide .001-.0035 (.0035 is service limit not perfered) exhaust .0015-.004 (.004 is service limit not perfered). :icon_eh: :nono:
my IH is running exactly that .001-.0015 stem to guide clearance. No problems. It will even be receiving a turbo and 8-10 lbs.


You run what you want but I'll tell you from many many engines I have running around in everything from boats ,race cars and dd's IH fiat GM Ford toyota supercharged and turbo charged. .001-.002 on honed bronze guides works great on the intake. Period..... With a properly oiling valve train you won't stick a valve.

Bronze has a higher cte that steel. As the valve and guide assembly heats up the clearance actually gets larger. Large stem to guide clearances also transfer heat more poorly.

Robert
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that was my experience using the f**d umbrella seals on the valve stems. I went back to stock IH valve stem seals had have not had a problem since.
 
Ok went to the snow again today, I held it wfo up every hill and the map sensor would be 88-91 the highest reading I got was 94.1

I ran it in second gear for a while climbing up out of placerville and keep it at 3900-4000 rpms and it ran fine.

I drove faster than normal going up the mountain today and kept the rpms at 2,900 which is 65 mph the whole way.

In the snow there is a lot of resistance, so that take's some throttle too.

Rk, I was looking in a mag today and noticed that royal purple has a break-in oil. It's possialbe the swepco oil is extra slippy which means it will even take longer to break-in the engine.

The new part comes in tomorrow :gringrin:

I check the plugs a while back and they looked fine. I did not check the compression. Maybe this comming week I can get those numbers too.

How do I do the leak down you talked about with the oil cap off?
 
Craig,

I have been following your scenario since the beginning, and I have learned a lot from it. I now know that IH stuff is sometimes a lot more "different" than conventional, but just to stick my two-cents worth in, I have never had a problem with ring break-in using swepco oil in the past.

It's my humble opinion that maybe you should research some of the things Robert, Jeff and greg (to mention a few) have suggested.

I'm sure you will keep us posted!

Dick
 
Craig said:
ok went to the snow again today, I held it wfo up every hill and the map sensor would be 88-91 the highest reading I got was 94.1

I ran it in second gear for a while climbing up out of placerville and keep it at 3900-4000 rpms and it ran fine.

I drove faster than normal going up the mountain today and kept the rpms at 2,900 which is 65 mph the whole way.

In the snow there is a lot of resistance, so that take's some throttle too.

Rk, I was looking in a mag today and noticed that royal purple has a break-in oil. It's possible the swepco oil is extra slippy which means it will even take longer to break-in the engine.

The new part comes in tomorrow :gringrin:

I check the plugs a while back and they looked fine. I did not check the compression. Maybe this comming week I can get those numbers too.

How do I do the leak down you talked about with the oil cap off?
Click to expand...


Craig,
I would do your pcv change and drive it.

To answer your "leak down" question.
A leak down test comprises placing the cylinder to be tested at exactly tdc compression stroke. Removing the spark plug and installing a hose like a normal compression tester into the plug hole. The hose is attached to a special gauge and manifold designed to put compressed air into the cylinder through a calibrated orifice. The source air is regulated at say 80-120 psi. The lester has a gauge calibrated in % that reads how much air pressure the cylinder can hold of the air allowed through the calibrated orifice. If the cylinder will only hold 80% of the air being blown in it is said to have a 20% leak down. The 20% of the air that is leaking can usually be heard leaking through one of 3 places. 1) the crankcase breather or in the case of a closed system like yours, from the oil filler opening if the rings are the cause. 2) the carb or intake if the intake valve if the cause 3) the exhaust if the exhaust valve is the cause.

Typically no more that 5% leakage is considered good. I like to see less than 3%. To each his own.

A leak down tester can be purchased from many places including summit racing.

Aircraft use an different system but the same basic test. As I have been told scouts don't fly so I won't go into it here.

To be absolutely honest I would leave it alone and just drive it.
 
Got the new pcv, compared it to the old one and they look the same. But when blowing on it, the old one is a one-way valve. The new one I can blow into and get air to go both ways. One was blows easy the other harder, but leaks a bunch. After mess it with them I reinstalled the old one. As a pcv should only allow flow one way.
 
Found that the 73-75ih have a different pcv then the 76-80

before that I think the where just open vent on the valve cover


these are from rockauto and they are all the same for the different models

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Craig said:
got the new pcv, compared it to the old one and they look the same. But when blowing on it, the old one is a one-way valve. The new one I can blow into and get air to go both ways. One was blows easy the other harder, but leaks a bunch. After mess it with them I reinstalled the old one. As a pcv should only allow flow one way.
Click to expand...

If your old valve is acting like a one way valve in the direction of flow "out" Of crank case it is bad. This is by mouth not using compressed air. The poppet spring is probably bad on the old one you just put back.

The operation of your pcv valve was hashed over early on in your thread.

The valve is "not" A one way valve. Under high manifold suction the vacuum overcomes the spring sealing the poppet off to a low metered flow. Under power or reduced vacuum the spring pushes the poppet open Allowing the engine to draw air out of the valve burning the blow by and relieving the crankcase pressure.
 
Robert kenney said:
if your old valve is acting like a one way valve in the direction of flow "out" Of crank case it is bad. This is by mouth not using compressed air. The poppet spring is probably bad on the old one you just put back.

The operation of your pcv valve was hashed over early on in your thread.

The valve is "not" A one way valve. Under high manifold suction the vacuum overcomes the spring sealing the poppet off to a low metered flow. Under power or reduced vacuum the spring pushes the poppet open Allowing the engine to draw air out of the valve burning the blow by and relieving the crankcase pressure.
Click to expand...


Robert I was told a pcv valve is a one way device. It's designed to close in the reverse direction, like in the case of a back fire through the carb. I trust your experience and will go with it's not a one-way device.

Repeat of what was said early in the thread.

"for the pcv valve to operate properly the supply vacuum needs to be large like the 3/8 fitting into the base of the carb. @ idle it is drawn /sucked closed so no leakage occurs." Or maybe just a small metered amount as stated above.


To finish your thought
when the engine is under throttle the vacuum is reduced the spring inside the pcv pushes the valve open allowing a controlled / meter amount of air to flow out of the engine crankcase and into the intake manifold so the blow by gases can be re-burned.

I will install the new pcv and verify the suction with my thumb at idle and rev the engine up and check that the spring pushes the valve open. ( or pinch the hose and listen for the valve to drop open) I'm just a bit leery of replacement parts, even when they come from napa. I will do the same test with the oem pcv to see if my calibrated thumb can the difference.

Anybody know why they change the design in 76.

edit.. To clarify the old one only allows air to flow from the crankcase to the manifold.
 
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Dam we're beating a dead horse here!

Pcv was first intro'd inna 'bout 1955 on inboard marine engines! Same dam pcv valve as used on all ihc apps up through about 1967 or so. That was the open pcv system.

The closed pcv system was mandated by the fookin' feds beginning with m/y '63 light duty vehicles.

Imho, all engine "ventilation" issues are caused by either lack of proper maintenance or jury-rigged/changed vent plumbing. And if the blowby is so severe that the ventilation/pcv system can't handle it, then engine service is the solution.

Every engine manufacturer had a somewhat different pcv scenario, and that could greatly vary depending upon the engine family and production date. There are no "only one ways" for this stuff, just like there are no "only one ways to fix stuff".

And as I post nearly every day...the ihc-produced service literature is very poor in regards to changes made over the 40 year production cycle of this stuff. Many changes were made, most especially in the early/mid '70's as all manufacturers struggled with emissions-related drivability problems on new vehciles. And we still deal with that stuff today since none of that crap was truly "fixed" back in the day.

This explains the "pcv" deal inna nutshell in generic format:

http://www.filtercouncil.org/techdata/tsbs/94-2r1.pdf
 
michael mayben said:
dam we're beating a dead horse here!

http://www.filtercouncil.org/techdata/tsbs/94-2r1.pdf
Click to expand...

Maybe so, but then maybe this is why some engines run hotter than others. If the controlled air leak is not the same, maybe this induces a lean mixture and cause the engine to over heat when under a load. Just a wildass guess there, but food for thought.

I was just trying to figure out what Robert was saying.

Robert kenney said:
edit..
The valve is "not" A one way valve.
Click to expand...

Your article states exactly how it works, I'm thinking Robert meant it's Not just A one-way valve?.
 
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A lean a/f mixture that is "lean" enuff to induce elevated engine temp at any single throttle plate angle/manifold vacuum reading, is an engine with major drivability issues to the point it "won't go"!!!

Again...this stuff wasn't broke from the factory...it gets broke when we screw with it.
 
Craig,
in the event of a back fire yes the valve is in some cases designed to prevent fuel from being blown back into the crank case. In the context of your oil burning/ smoke issue the valve does not act as a one way valve under a normal operational regime. Some pcv valves (depending on mfg) are allowed unrestricted poppet travel to shut off in the event of an induction system backfire event. Like the valves you received not all do, some have a spring to prevent the unrestricted poppet movement. Seeing as your reference to one-way valve was vague I assumed you had an understanding of pcv function/theory. Sorry for making that assumption.

Either way the valve you purchased will/should run ok. If your start up smoke is because of the old valve being defective the new valve will fix it.

Robert
 
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