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And never, never ever ever, buy a new head. You're ending up with the same junk that failed you in the first place.
You really never need to replace a head unless you find one with an extensive crack. If you have one that has to be replaced and simply get a used one off of another engine from eBay or swing by a local small engine shop and buy one out of their junk parts. Popped out valve c or slipped valve guide is an easy fix that cost zero money. A new head is like $150 plus. You would be better off to take your head to a machine shop and let them fix things which would result in a better quality head than a brand new one.
Edit: Looks like heads are coming down in price like carbs and pressure washer pumps....GOOD!!

Still, they are not new and improved. Briggs hardly ever does that. Kohler on the other hand had a head gasket blowing issue on the twin command they put out a kit albeit overpriced that FIXED the problem. GREATLY improved head gasket and new bolts/studs.
Briggs still give us the same old lousy single ohv blowing out head gasket that failed the first time...or 2nd.

I will put my cleaned, grooved, and loctited repaired head up against any new one in a overheat challenge to see which guide will slip first.
We could heat them in an oven and have a press with scale on the guide and see at what temp and pressure one moves then the other.
 

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Discussion Starter #22
Been thinking about the normal operating forces that might cause the valve guide to move where pressed into the cylinder head. Just two come to mind.
One would be the movement of the valve stem as it opens and closes. That movement is equal distance in both directions and the number of movements in each direction is equal.
The other is pressure of the exhaust gases through the port each time the valve opens. If full throttle engine speed is 3600 RPM, the number of pressure pulses is 108,000 per hour. For 570 hours on my engine, the total number of pressure pulses on my engine is over 61 million. So even with the pressure being low, the cumulative effect of such a large number of pressure pulses is significant.
 

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That's where you need to step back about 13 steps and not worry about it. My brain does the same thing sometimes and delves deep into the whys and stuff all in all it doesn't matter too much. But pondering does occasionally help me come up with some out-of-the-box fixes.
Lots of things are- or are not in theory or on paper but don't work out that way an actual practice or real life.
Very very few engines run at 3600 RPMs anymore anyways. It is amazing how they have lowered the specs over the years. Most of these engines respect from the factory between 3150 and 3450. With most being on the lower end.
Still though, there's a lot going on in a short period of time.
From my experience with these in many many occasions I would have to say it must be the pulses and the vibrations. I have seen a good number of valves stick in the valve guide where they couldn't even be moved by hand and to where they were so slow to close from the valve spring pressure ,the piston smacked them before they could get out of the way on with valves in a position where the piston can hit them.
This would be a lot more pressure exerting on the guide to make it move one way or the other or to at least loosen it up and these were never loose.
After the valve stem was cleaned and lubricated or run on a wire brush to let everything slide freely, there were no future problems with the guide moving out of place.

It's really just more about the heat. When they overheat the aluminum expands so much you could push the guide with your thumb. Then, when it cools back off it tightens back up. Every time it moves or slips even a little bit it wipes a little bit of the aluminum off and makes it a little bit easier for it to move the next time it gets hot and at an even lower temperature.
I believe the explosive pressures inside the engine, even though the valve should be totally shut when the explosions are occurring oh, but there is the movement which is fairly fast of the air blowing out of the open valve and out the exhaust port, I feel this pressure and movement is what causes the guides to always move out away from the head of the valve.
I could certainly be wrong about this as it's just a guesstimate. It very well could be the effects of fast movement or inertia. The guide that is sitting still and the valve is being pushed quickly and repeatedly so therefore the guide could be pulled up just like a hammer handle is if you hold the handle on the bottom with the head towards the floor and take another hammer and smack the bottom end of the handle. It looks like you are pulling the hammer head up onto the handle and that is the end result but in reality the heavier hammer head is staying exactly where it is and you are quickly and forcefully moving the handle so fast that the heavier metal head cannot keep up with it so a little bit of movement occurs. This could be the forces at science involved with the guides coming out and asked if which way they slide.
But as I started this reply, none of it really matters. The science involved for the reasons aren't going to help us fix the problem or prevent it. We're not going to be able to slow the speed or the impact Force down on the tip of the valve stem or make the guide what would be the engine whole head move at the same time and speed as the rocker arm. All that matters in these situations is the quickest, easiest way to fix that is a long-term or permanent solution
 

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Bus, you been here what, 10 minutes, and are questioning Toby who's been for 'round 6 years?
This is the FRIENDLIEST web site, so those posting at least try to chill when they get bothered or disagree with a given post. Not worth the heartburn.
We all are here to help one another with problems and solutions gained over years, or accumulated to centuries of experience. No need to get bothered at a suggestion. It's just that, a suggestion.

By posting a question, quandry or problem, you are asking ALL site members for their input, so don't be bothered when someone answers. OR, don't ask...

tom
 

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"That's where you need to step back about 13 steps and not worry about it. "

So very helpful.
... you, me, whoever. Notice I said I do the same thing.. Over-analyze, but as I mentioned it can be good for unique fixes.
Not picking on you just saying that while you and me might think all about the pressure forces under a valve head on the guide.... we are like 13 steps beyond what most owners ever consider.
Kind of a plus for us.
I have found though that on many situations I have stopped worrying about the why's ~some~ and just do what I know works.
That's how the guides and seat repairs are to me. I guess I've done too many.
Sorry if it brushed you the wrong way but clapback will get you nowhere.
The rest of the post had a lot of good info following along with what you pondered in your post.
I'm here to help others, learn stuff, go off topic and tell stories, make small talk, and tell people when they are doing something the hard or wrong way-- HELLO YOUTUBE!
 

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Discussion Starter #27
Had opportunity to look at the Briggs repair manuals for the Intek and Vanguard engines-- separate manuals. Will paraphrase the info to avoid copyyright issues. Just 4 lines of text for valve guides for the Intek. Briggs gauge #19381-- apparently if it fits into the guide, the guide is considered to be worn out. Replacing the cylinder head is the repair. That's it.
Vanguard uses similar gauge #19382. Valve guides are replaceable for the Vanguard-- using tools and techniques specified by Briggs. Reaming the guide to size is the final step.
So our home-brewed remedies are what I call "farmer-fixes".
 

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Had opportunity to look at the Briggs repair manuals for the Intek and Vanguard engines-- separate manuals. Will paraphrase the info to avoid copyyright issues. Just 4 lines of text for valve guides for the Intek. Briggs gauge #19381-- apparently if it fits into the guide, the guide is considered to be worn out. Replacing the cylinder head is the repair. That's it.
Vanguard uses similar gauge #19382. Valve guides are replaceable for the Vanguard-- using tools and techniques specified by Briggs. Reaming the guide to size is the final step.
So our home-brewed remedies are what I call "farmer-fixes".
I've been telling people for years there is no Factory or manufacturer authorized repair for this. I say it's the backyard mechanic and old guys who know what they're doing repair. I fully believe when you fix one with a Groove around the guide peening it nicely and use Loctite, it is better than any new head you could put on there. The only Advantage people have to put a new head on and the reason it doesn't break or slip quickly is the new head is nice and clean with no debris or buildup or greasy Grime to hold in the heat. If you clean them off properly when you have them apart a good repair is better than a new head.
 

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I've been telling people for years there is no Factory or manufacturer authorized repair for this. I say it's the backyard mechanic and old guys who know what they're doing repair. I fully believe when you fix one with a Groove around the guide peening it nicely and use Loctite, it is better than any new head you could put on there. The only Advantage people have to put a new head on and the reason it doesn't break or slip quickly is the new head is nice and clean with no debris or buildup or greasy Grime to hold in the heat. If you clean them off properly when you have them apart a good repair is better than a new head.
Since new head has no improvements I'm thinking it might be a good idea to do the peening repair on the new head right away.
 

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PHP:
You could also drill through the aluminum and into the guide but not all the way through and cut a short pin to drive into there and then peen the aluminum from the hole back over on top of the pin. You can do this on two spots if you wanted to at like at 9 and 3.
It's just more work and I've never had one fail after fixing by just peening so I haven't ever worried about doing it a different way.
Went back and forth for quite a bit either in this thread or another one about someone wanting to remove the head and weld on both sides from a YouTube video they found. That could make it substantially stronger than just peening also but you still could have a little bit of movement because it would be hard to get the weld tight on the aluminum as it would melt some of it because you're having to weld to a steel guide. Also it could warp the guide slightly and you have to make sure the valve slides smoothly in the guide with no tight spots.
Between both of these types of over the top repairs oh, I feel that Drilling and pinning would be the best way to prevent any possible movement but I just don't think either one is necessary. They're both over the top and one requires you remove the head. I just did one of these Monday without removing the head in about 40 minutes start to finish.
The two most time-consuming parts of the job are getting the valve Keepers back in and cleaning off all the debris on the head under the shroud. You could fix one of these and never even take the shroud off but that's kind of a gamble since majority of the time the reason they fail is because of lack of air flow and proper cooling.
 

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Discussion Starter #31
For the valve guides that move out and interfere with valve action, moving them back to original position is best done (my opinion) by pressing them. I suggest that a hammer should not be used used directly on the end of the valve guide. The video shows a vise being used which works well if the available vise is large enough. I used the shop press.
Note the sleeve used in the video to transfer the force to the guide. If one needs to make a similar sleeve, a drill, Letter Size B makes a good clearance hole for the valve stem which keeps things aligned while pressing the guide. I used a 5/16" deep socket, 1/4" drive, which did not have a through hole, drilled it with the "B" drill and it worked fine for the purpose.

 

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For the valve guides that move out and interfere with valve action, moving them back to original position is best done (my opinion) by pressing them. I suggest that a hammer should not be used used directly on the end of the valve guide. The video shows a vise being used which works well if the available vise is large enough. I used the shop press.
Note the sleeve used in the video to transfer the force to the guide. If one needs to make a similar sleeve, a drill, Letter Size B makes a good clearance hole for the valve stem which keeps things aligned while pressing the guide. I used a 5/16" deep socket, 1/4" drive, which did not have a through hole, drilled it with the "B" drill and it worked fine for the purpose.

https://www.youtube.com/watch?v=5wPVwt9mHbQ
Here's how this usually plays out: If a tech in a shop is going to remove a head for a slipped valve guide (or popped seat) they are going to replace with new head to make more money for himself or the shop.

The backyard techs and tinkerers that have been fixing these for decades usually don't bother wasting the time (and headgasket) to pull the head for a guide.

I do as many others do and have over the years and fix them the quickest easiest way possible. The end result of durability of repair is the same.
There are many techs that would tell you you should NEVER do a repair without a new head but more of us with repairs done years ago that are lasting just fine.

You wouldn't even be able to hammer on the guide itself because with the head still on the valve would be sticking out of it so you cannot hit it.
You use the socket method mentioned. I cut a groove around the guide or at least file some lines into it to where it will be just below the surface and then clean well with carb or brake cleaner then remove any residue.
Then I coat with red loctite and then tap it into place with a deepwell socket that contacts on the outer 1/3 of the guide and lets the valve go through the center.
Then I stake it around the aluminum into my groove. Many use a punch but I prefer a #2 square drive tip. But staking is probably staking.

I just see no reason to pull a head for this repair and the quality and durability is the same.

In regards to the video. He should not use the valve to line it up and press it in. Was that an old valve or the one he was going to use??? You should never press on a good valve.
Also the welding is not needed and and many people who can still fix their own mowers don't have a welder.
Yous could also drill and pin it but again not necessary.

Do he address the reason this happens? I can't watch a complete video. I hate them too much.
Does he talk about the almost full cooling fin channel on the end and the reason it happens in the first place?

As I have said over and over....Every youtube video I see either does things the wrong way or the hard way.

People call me literally EVERY day who have gone to videos and screwed things up more or taken a lot apart that was unnecessary instead of going to a repair manual style picture tutorial and doing it by a know method that works instead of taking Double D's or billy joe's one time youtube "repair" (how long did it last) as correct and some sort of gospel.

Many have different ways of doing things and there is more than one way to achieve the desired results...but I trust forums where I can see multiple similar ideas and opinions or online repair tutorials that I trust will work.
 

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I'm thinking that filing some groove on the part of guide that goes back in would provide more contact area for the loctite and wonder how jb weld work work in place of loctite. As for videos I've seen good and bad. Challenge is knowing the difference.
 

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I have no proof that the loctite actually makes the repair any stronger or more durable but it makes me feel better. I have to look up the specs on what temperature you have to heat it to to release it according to their information but I think it's higher than what J-B Weld is rated to.

I feel more comfortable with Loctite because it is an anaerobic curing sealer that works in the absence of air and oxygen who has J-B Weld is a two-part chemical reaction epoxy and I think most of it will get squeezed out as you slide the guide in anyways and I think Loctite has a little bit higher temperature to still have some holding effect.
Like I said, I have no proof that either one works better or is he even needed as most people don't even use Loctite. I have never had one fail that I have repaired so luckily I am currently at 100% and very happy with those results.
A large majority of people just tap them back in and don't even use any Loctite or even steak them in because they don't know to do that. Often they will last a long time or sometimes just for a while. Sometimes it's just that someone was cutting a large field with a mower and really over working it and it was stalling out in the tall grass and that's what causes the head to overheat and the guide to just slip in the first place. If they tap it back into place and don't overheat the engine it very well could last for a long time.
 

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I think the extra groove would be necessary for jb and they have a high temp and extreme temp now

Even though I regularly use JB Weld in several types, I find their products to be mostly hype and advertising and never perform up to what they claim.
I find Loctite to do exactly if not more than I expect.
 

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Discussion Starter #37
The socket or home-made tube used to press against the guide ideally will have end surfaces that are perpendicular to the axis of the valve. For the tube, drill a rod of cold-finished steel in the lathe with the B drill and then face the ends of the tube to make them perpendicular. The resulting wall thickness should be 1/4" or a bit more. The valve stem, if used for alignment, serves to align the parts until the pressing force is applied. Thus the valve never has any axial load and the bending moment is limited to just the weight of the parts aligned. No damage to the valve-- less force than when operating normally in the engine.
The already-mentioned socket works about as well as the custom made pressing tube.
 

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The socket or home-made tube used to press against the guide ideally will have end surfaces that are perpendicular to the axis of the valve. For the tube, drill a rod of cold-finished steel in the lathe with the B drill and then face the ends of the tube to make them perpendicular. The resulting wall thickness should be 1/4" or a bit more. The valve stem, if used for alignment, serves to align the parts until the pressing force is applied. Thus the valve never has any axial load and the bending moment is limited to just the weight of the parts aligned. No damage to the valve-- less force than when operating normally in the engine.
The already-mentioned socket works about as well as the custom made pressing tube.
I couldn't tell if he left the valve in there or not since as I said I jump around on videos because I can't stand them. It just seems Pennywise and pound-foolish for someone like him to worry about pressing the valve in with a vise or anyone else to worry about tapping in with a hammer if they're not going to do anything to prevent it from coming back out. I have heard people talk about tapping guides back into place for years but if you just tap them back in it's kind of a waste of time. The odds are it will come back out in the future. This gives the overall thought of repairing a slipped valve guide a bad image. If you repair them the better way that we have found works by grooving, Loctite and staking, the repair is in my opinion stronger than what was originally from the factory. People out there go around saying you can't fix them because they will slip again. This is because people have simply pressed them back into place and they have slipped again.
 
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