Just a bit more than a puff on startup

ihpartsjeff

ihpartsjeff

Administrator & Owner
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Re: 392 exhaust valve guides

Pull off the pcv hose and see if there is evidence of oil. That should clue you in on a possible bad pcv valve or one with the wrong orifice.

If the pcv checks out fine then I would have to point at the guides leaking oil past. As I have said in the past that is how the guides stay lubed and last. I agree it is somewhat bothersome when you dump a cloud of smoke in a busy parking lot but at least I know my guides are getting lubed. We can go with umbrella seals and that should help considerably on the puff of smoke at start up.

As for the oil consumption your motor is having I still say these motors taking upwards of 5000 miles or more to seat the rings especially since the IH blocks are harder to due their hi nickle content. Combined that with chrome rings and it takes longer. There will be differing opinions on this subject but this is my opinion. I would rule out the rocker tower bolts leaking into the intake runners as I always seal those.

I have a lot more information on this subject but right now I am tight on time. When I get back after the new year I will post up what IH has written in their manuals in regards to oil consumption and diagnosis.

Bottom line is if something is wrong then bring it back as we stand behind all the work we do here at ihon.
 
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Re: 392 exhaust valve guides

quote:
originally posted by Craig
yes lot of hills. I live at about 58 feet and we head into the mountains and run fire roads or hardcore trails. The puff of smoke at start up can be a lot, in fact I can just stop for a couple minutes and get a hugh cloud. Other times no cloud just a puff. I was reading Jesse post on the valve guides, but looks like he had machine work done to fit some other parts. I don't want to pull the heads on a new motor. Was just hoping to find something that could be done with just the valve covers removed. I suspect the oil sitting in the valve cover near the rear and when a valve is open, allows oil to drain into the camber might be the cause?

The down hill sections will cause a lot of oil to be sucked by the intake guides. Also on the 9 stand rocker assemblies where 4 bolts penetrate the intake port can be another source of oil usage. The 4 bolts need a thread sealer to be applied or oil will be drawn by the threads and into the engine.

The standing oil at the rear of the head is well below the stems and not a likely source of your smoke. Assuming the drain back hole are clear.

If you built the engine you will know what steps were taken during the build. Hope this helps.

RobertI copied this from the oil form for every bodies reference.

Now for the new stuff
Jeff is right the engines are designed to oil the guides that way. IH has there own way about things that works. But if the stem to guide clearances are in spec they are going to allow oil by and cause the start up puff. Kinda got to live with it.:(

the following is how I set up all valve guide - stem clearances. This is how I do it not how it has to be done. I do it to limit oil burning beyond any IH standards. And have better valve train dynamics. Valve wobble in a sloppy guide can induce harmful spring harmonics. I always install bronze guides on the exhaust side for optimum heat transfer. I except all risks for my setup method. So a shop will need to let you know if they will have issue should you chose to follow my guidelines. I also always assemble my own heads and double check the setup.

Intake guide to stem clearance .001-0015 period no matter what engine except for shim valve overhead cam engines where I use .0005 - .0010. On those basically when a valve is allowed to drop by gravity only with no oil it should close all the way by it self. If that is achieved I don't allow any more clearance. On a street engine I always install stem seals. The soft rubber kind on non emission apps and the teflon kind on emission apps.


Exhaust guide to stem clearance .0015-.0025 no matter what engine. Except for shim valve overhead cam engines where I use the gravity drop standard and limit clearance to .0015. No seal on non emission apps but do have on emissions apps.

If you are having a severe start up smoking issue I don't think the pcv system is at fault from too much suction but excessive crankcase pressure could/might be an outside cause due to not enough venting. The small fittings you show May be to small to handle high throttle settings. That is only a observation that I would have no way of proving from here.

Robert
 
Re: 392 exhaust valve guides

Sorry maybe I thought I said that. Anyways that's why I move the topic to the valve guide thread and said Jeff built the motor so you would know, because you ask if I remembered to seal those bolts. I had Jeff do the work for that very reason. Jeff's knowledge of motors and IH stuff is tops. If I built it I would have missed about 25 little things lol

I'm still stumped by the fact I can let the Scout sit for 3 days and get a puff or a cloud, or stop for 15 minutes and get a puff or a cloud. After I get some testing done next week, I can take all this data to Jeff for him to evaluate. I will workout a time with Jeff when he can have the Scout for a few days so he can look at it too.

I going to delete all my posts from today and make a concise post about valve guides as I want this thread to be about the guides
 


Ok looking for ideas. My 345 was professionally rebuilt by Jeff. So there are no issues with assembly. The valve guides were not replaced as they were within spec. I'll make a video so you can see the amount of puff!! But it smokes pretty good on startup. I'm running a pcv with the stock valve cover spark arresters attached to the air filer box. Is it possible the pcv is creating two much of a vacuum? I could try disconnecting the pvc from the base of the TBI and just put a plug on the TBI.
I've noticed that if I get some fast food and turn the engine off for a minute or two waiting for my order, there will be a nice cloud of smoke when I restart. Same as when it's been sitting for a couple days. I asked Jeff and he said that the IH designed the guides to allow oil past to lubricate the stem. So some puff on startup is normal. This I know to be true, but mine seems to be a bit more than normal. Just looking for options on what might be the cause.
 
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Pulled the pcv hose off the base of the intake, then stuck a tool in there and it was covered in oil. So this means oil is coming up the through the pcv valve. I pulled the pcv valve and shook it and it sounds fine. Yes its install in the correct direction:dita:

napa is closed today, so I will get a new one tomorrow.
I googled the part number on the old one, but no info. Found

edit... When I installed the breather's in the valve cover I cleaned them with carb cleaner, as they have some steel wool looking stuff inside.
 
I never run the pcv into the base like that. I always run it into the air filter. Sucking from the crankcase (black hole) is a huge vacuum loss.
 
I thought that was the stock location? I can look tonight in the manual. I argee you need to tune for such a loss.
 
tiny yokum said:
I never run the pcv into the base like that. I always run it into the air filter. Sucking from the crankcase (black hole) is a huge vacuum loss.
Click to expand...

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. A driving speeds it needs to flow sufficient volume to compensate for blow by and scavenge all combustion leakage into the crank case. The return supply that hooks into the valve covers is right as it receives clean air from the air filter. The location of the valve as far as I have seen on other CA Scout II's is into the lifter valley cover like it is in craigs photo.

Robert
 
As usual, Robert's analysis of a pcv system's hook up is korrect-a-mundo. Some engines have the valve's outlet on the manifold, some are at the base of the carb. It's basically a normally open spring loaded valve that's driven by manifold pressure. At low manifold pressure(high vacuum) the valve is pretty much drawn shut. Some valve elements will have an orifice in them for low load and idle operation. Under larger and larger loaded operation, or wot acceleration, the valve's spring allows it to open and draw in more crankcase vapors. The make up air for the crankcase is sometimes through a fitting in a rocker cover, or the induction's air filter housing, or some engines will have a tube or pipe to the crankcase fitted to the filter housing. Some Scout 800's with the 266 had a tube arrangement in the front of the block that went to the timing cover. That one was repeatedly mistaken for an old dipstick recepticle when the hose to the air cleaner was missing. Proper operation is essential to minimising external oil leaks in old engines, and drivability. Some transition from idle problems and carb tuning issues can be influenced by a defective or plugged valve as they were part of the over all induction set up. All valves are not the same. Some of the older ones like from ac were take apart and clean, many more followed that where disposable. Also, they are sized to engine and application, the main differences being in the volume they passed and spring rate. Most of the time ya didn't fu** with it, ya just cleaned or changed it. Back in the day of auto school, say 69-71, ac had a tool you could check pcv operation. You ran the motor, and put the tool with adapter on the oil fill port, or some access to the crankcase. The indicator showed green, green/yellow, yellow, red indicating a good, dirty, or bad pcv valve. It looked similar to an air filter's change gauge. You were really checking the crankcase's negative pressure the pcv system puts on it.
Oil in a pcv could indicate excessive piston ring blow by, or oil not meeting voltality (noack) requirements and the vapors condensing in the system. I would think it would have to be a really cheap oil in a neglected hot running motor to get that kind of gunk unless some one had some ring issues.

As to smoke on start up: that is normal For IH engines. All my IH sv engines do that to one degree or another, and it's not Consistent. Sometimes it's more, some less; some after parked for months, some after a quick grocery grab. The point is, if Jeff says the guides were within spec; so be it. My neighbor, (ex farm boy, rancher, etc), stopped by when I was tuning one of my first internationals. I started it up and wow, what a cloud at first. Gene says, "yep, typical innernashional!"
in today's culture, smoking is a bad thing. When my 1210 or Scout puff, I get strange looks; similar to when I pull out my pipe in public:dita: 'course that depends on the town. College town it's not so good, a mill town is not so bad.
Craig: 2 other checks you should try. Check the spark plug color. Problems in oil control will have a color and pattern on them. Also do a leak down test. That can direct ya to either a ring seating or top end in relation to your oil consumption you mentioned in another post.
 
It's the normal oil blue white smoke color. I got some video, but its hard to see as the smoke goes up and out of the carport, plus when cold you get some stream too.

Napa had to order the part and it should be here on Monday. The pcv valve is one of those maintenace items that just never got replaced. Not sure how I misssd that, as I put all new parts on this motor. But some how I did :(
I run swepco oil which is a top of the line oil. The rebuilt engine is also top of line.
I'm sure the new part will cure the issue.

For the bored click here.
 
As mentioned before, a small amount of oil is designed to lube the valve stems and guides. With the guide to stem clearance of only .001"-.002" a drop of oil between is a good thing.
Fmoe, re-engineering this will result in stuck valves and bent push rods.
 
I looked at your u-tube clip. That didn't look excessive or abnormal by IH standards. It blew smoke for a couple seconds then switched to steam. Just my .02:icon_mrgreen:
 
I musta be bored, I looked at the clip. Not all that out of the ordinary, a tad more than mine.
What's been your break-in procedure on the new motor?
 
tiny yokum said:
as mentioned before, a small amount of oil is designed to lube the valve stems and guides. With the guide to stem clearance of only .001"-.002" a drop of oil between is a good thing.
Fmoe, re-engineering this will result in stuck valves and bent push rods.
Click to expand...

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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Yes I was also bored. Seemed like it was loaded up like overly Rich upon start up. That will make it blow more oil smoke as it washes the cylinder walls of oil. Just an observation.:gringrin:

Robert
 
greg r said:
I must be bored, I looked at the clip. Not all that out of the ordinary, a tad more than mine.
What's been your break-in procedure on the new motor?
Click to expand...

That why its taken soon long to find, it's just a tad over normal. But the pcv should not be sucking oil, just fumes.
Yes the valley cover pan has the tin shroud in place.

Break-in, when new new, I start it up and varied the rpm's letting the cam break in. 20 minutes? After that I drove it around the neighborhood. Short trips and let it cool for bit and go again. I was letting the rings cool in between runs as they tend to get real hot on the fresh motor. Took is easy for the first few miles just rev it up and let the compression slow me back down. Once I felt everything was looking good, I took it on some longer drives and then up the freeway into the hills to put some load on the engine. I drove to and from work and around town for about 500 miles and then off to hollister hills (200 miles away) did some wheeling for the weekend. Back home I changed the oil with about 1,000 miles on the motor. Motor running great, that was March last year. Today it still runs great. Even Jeff is amazed at how smooth it idles
 
Robert kenney said:
yes I was also bored. Seemed like it was loaded up like overly Rich upon start up. That will make it blow more oil smoke as it washes the cylinder walls of oil. Just an observation.:gringrin:

Robert
Click to expand...


Ya is was kinda hard to start the Scout and video it too. I pumped the gas as it was a cold morning. ( your right extra gas) still need to fine tune the FI for cold starting. Moates stuff in route.:winky: I had the vid so I tossed it out there. I'm "working" today, but will drop that vid and post one once its warmed up.
 
Yes, I've also scanned your other posts. You've done a tremendous amount of work on this motor! I see you've put a lot of time into the fuel injection as well. On top of all that, you had over heating issues from a poorly assembled pump,(in my opinion poorly assembled), and maybe some air flow and shroud problems. All this onna freshly Rebuilt engine. Too many balls for me to juggle if it was my show. On rebuilt engines I try to plan what I want to do, and then have sum kinda strategy to do one thing at a time. All my overhauls have been stock, but say I want to upgrade a carb as part of the rebuild. I go with what works now or get the carb in order before The project. That way I have green light so to speak for a proper cam break-in and not fiddling with the sob to get it to idle. After all is broke in, then I start on mods.

Now take this as my opinion, and my opinion only: frankly, on what I've read, I think the motor has been babied. Those hard chrome rings ain't all the way seated in yet. It's my advice and experience that you need the highest sustained Mep(mean effective pressure) to rightly seat rings. In real world, wot as long as possible without over revving it. Here's an example: last spring I overhauled the motor in my daughter's car. Right after she fired up and run good, I took it out for several hours of wot long assed high climbs on roads in the hilly areas of our county. Now, and some 15k miles later, there's still top compression and no oil consumption. Granted the car is a rice grinder and the ring technology is different, but it wasn't that much different from some of the other engines. However, tempered with that the break-in followed the method of not going over 50 or so for the 1st 500 miles, and varying the speed. After the 500 mile oil change, little was used by the way, it was drive as usual. Punching it from stop to stop sign won't to help a whole lot.
It's always easy to offer advice after the fact, and when some else is do'in the work; but I'll bet a plug check and compression check would give some baseline stats for future problem solving.
 
Greg, I could not have said it any better my self. New engine needs to run right and run the first time it is started for both cam break in and seat the rings especially chrome on iron. If you don't generate sufficient cylinder pressures or a greg wrote mep you will only glaze the rings and cylinders and they May never seat correctly. Piston rings are actually a dynamic device. They require combustion pressures to get behind them and push them against the walls. The cylinders machined or honed finish

for reference: standard break in procedure for all reciprocating aircraft engines. Fill crankcase with 50wt mineral oil(pure mineral oil with no detergents friction modifiers). Start and run for a minimum time on ground to assure all systems are operating correctly. Run up and fly it. Once flying, maintain 75 % of rated power for several hours the time will vary based on manufacturer but usually 4 hours.

The point I am trying to make with this reference is to never baby a new engine. I am not saying to beat it but drive it firmly.

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
 
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