Just a bit more than a puff on startup
- Thread starter ihpartsjeff
- Start date
Robert Kenney
Super Moderator
hey ace
most of us don't fly scouts. That would convert to 5 to 2 in. Hg. Vac?
Ohh come on!!! I've seen scouts fly..
sure if 29.92" is full throttle then 2-5" vac would work.
but what about driving at altitude? Subtract 1" vac per 1000feet.
Rk
Attachments
Craig
Active member
There are no hills that I can climb for two hours at 3,000 rpms.
Tahoe is only 70 miles from my house. 7,000 foot climb
unlike air planes we have cops and stops signs.
I ran the FI for some time on the previous motor, not a new thing. In fact everything was working and dialed in. The new engine does generated more heat then the old one, and I have been working on changes to resolve that. The water pump was just one change. I've always had a shroud, now there might be photos not showing one, as I might have removed it going though the many mods in the cooling system. But when you having over heating issue, the last thing you do is leave the shroud laying in the garage. I currently have the biggest rad you can get, and that required cutting several inches out of the front end to make it fit. Dual 1 1/4" tubes. Massive to say the least, plus a dodge viper cooling fan. No cooling issue currently.
I did not baby it, Jeff said to drive it like you stole it. But when its new you need to make sure everything is working right before you go flying. You need to make sure you don't have any water or, oil leaks, etc. This is why you drive around the block and check to make sure every is working as it should. The only new item would have been the exhaust.
We drove it between 2500-3000 rpms all the way to hollister. Which is about 200 miles one way. ( I have the windalda data if that helps) there is one good long hill climb going there. But not like going to tahoe
my drive to work has a real good climb too, and I would drive up and down that hill.
Most every time I drive it, we head up into the mountains, you have to push it hard to just make it up the steep hill climbs.
But you bring up a good point, if I replace the pcv and it's still sucking oil then the rings might not have seated all the way. Which has been Jeff's point, these engines take a long time to break in. Last weekend was a good hard run, as we climb to about 6,000 feet and the last 2,000 was plowing through snow, but not at 3,000 rpms. I could put a trailer hitch on the Scout and pull my 4,400 rv trailer around. We have some hwy's that wonder up and down though the foothills that give you a lot of opportunity to gas it, but you have to stop at the lights, as they won't accept flight plans.
I can drive it up the hill (tahoe) in second gear and keep it at 3,000 the whole way. I drive about 50-60mph most of the time.
Tahoe is only 70 miles from my house. 7,000 foot climb
unlike air planes we have cops and stops signs.
I ran the FI for some time on the previous motor, not a new thing. In fact everything was working and dialed in. The new engine does generated more heat then the old one, and I have been working on changes to resolve that. The water pump was just one change. I've always had a shroud, now there might be photos not showing one, as I might have removed it going though the many mods in the cooling system. But when you having over heating issue, the last thing you do is leave the shroud laying in the garage. I currently have the biggest rad you can get, and that required cutting several inches out of the front end to make it fit. Dual 1 1/4" tubes. Massive to say the least, plus a dodge viper cooling fan. No cooling issue currently.
I did not baby it, Jeff said to drive it like you stole it. But when its new you need to make sure everything is working right before you go flying. You need to make sure you don't have any water or, oil leaks, etc. This is why you drive around the block and check to make sure every is working as it should. The only new item would have been the exhaust.
We drove it between 2500-3000 rpms all the way to hollister. Which is about 200 miles one way. ( I have the windalda data if that helps) there is one good long hill climb going there. But not like going to tahoe
my drive to work has a real good climb too, and I would drive up and down that hill.
Most every time I drive it, we head up into the mountains, you have to push it hard to just make it up the steep hill climbs.
But you bring up a good point, if I replace the pcv and it's still sucking oil then the rings might not have seated all the way. Which has been Jeff's point, these engines take a long time to break in. Last weekend was a good hard run, as we climb to about 6,000 feet and the last 2,000 was plowing through snow, but not at 3,000 rpms. I could put a trailer hitch on the Scout and pull my 4,400 rv trailer around. We have some hwy's that wonder up and down though the foothills that give you a lot of opportunity to gas it, but you have to stop at the lights, as they won't accept flight plans.
I can drive it up the hill (tahoe) in second gear and keep it at 3,000 the whole way. I drive about 50-60mph most of the time.
Well sir, I reckon I be up fer a learn'in in that department!
Craig, the intent here is guidance. I don't think we're saying anything was done wrong. What I think I'm see'in is the break in appears interrupted, unless I'm missing something. From long distance that's easy to do. Hopefully it'll just take time. I still think a compression and plug check for baseline stats is a good idea.
Thanks for posting the chart.
Robert Kenney
Super Moderator
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.
Tiny Yokum
Member
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.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).
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
Craig
Active member
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
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?
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
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?
DF Sales&Marketing
Oil Tech Moderator
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
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
Robert Kenney
Super Moderator
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
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 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.
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
I use the hf leakdown tester...works beautifully, don't need to spend mucho dinero for one!
harbor freight tools - quality tools at the lowest prices
But I always do the following in order:
1) cold (dry) compression test.
2) hot compression test.
3) hot cooling system pressure test (with appropriate equipment).
4) hot leakdown test.
That is "leakage" diagnostics.
harbor freight tools - quality tools at the lowest prices
But I always do the following in order:
1) cold (dry) compression test.
2) hot compression test.
3) hot cooling system pressure test (with appropriate equipment).
4) hot leakdown test.
That is "leakage" diagnostics.
Robert Kenney
Super Moderator
I have an old version of this one. 2e | aircraft tool supply
Not that I like to blow money but my tester needs
to conform to faa standards.
Robert
Not that I like to blow money but my tester needs
to conform to faa standards.
Robert
Craig
Active member
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.
Robert Kenney
Super Moderator
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.
Tiny Yokum
Member
Robert, thanks for the heads up on this.
Craig
Active member
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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Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
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
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
Craig
Active member
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.
Your article states exactly how it works, I'm thinking Robert meant it's Not just A one-way valve?.
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