Valve guide (exhaust) seems loose HSSK50-67394S 5hp

#1
I'm on a small tablet so its hard to search these things so I'm hoping someone knows off-hand.

I removed this engine from my snowblower because I thought the head gasket was gone, but nope...it seems to be the absence of any valve lash (exhaust valve only)..which i think i can handle.

Whats really troubling me is what seems to be excessive side to side movement of the valve...a strong .020"

Recommendations ?
 
#2
Sounds like the guides are pretty worn. Here's what the L-Head Manual says:
Oversize Valve Guides

The valve guides are permanently installed in the cylinder block. If they get worn excessively, they can be reamedoversize to accommodate a 1/32" (.793 mm) oversize valve stem.
The guides should be reamed oversize with a straight shanked hand reamer or low speed drill press. Refer to the"Table of Specifications" (Chapter 10) to determine the correct oversize dimension. Reamers are available throughyour local Tecumseh parts supplier. Consult the tool section in Chapter 11 for the correct part numbers.
The upper and lower valve spring caps must be redrilled to accommodate the oversize valve stems.After oversizing the valve guides, the valve seats must be recut to align the valve seat to the valve guide.

Specifications: Oversize guide min 0.3432 max 0.3442




 
#3
Sounds like the guides are pretty worn. Here's what the L-Head Manual says:
Oversize Valve Guides

The valve guides are permanently installed in the cylinder block. If they get worn excessively, they can be reamedoversize to accommodate a 1/32" (.793 mm) oversize valve stem.
The guides should be reamed oversize with a straight shanked hand reamer or low speed drill press. Refer to the"Table of Specifications" (Chapter 10) to determine the correct oversize dimension. Reamers are available throughyour local Tecumseh parts supplier. Consult the tool section in Chapter 11 for the correct part numbers.
The upper and lower valve spring caps must be redrilled to accommodate the oversize valve stems.After oversizing the valve guides, the valve seats must be recut to align the valve seat to the valve guide.

Specifications: Oversize guide min 0.3432 max 0.3442




Dr. Shop Teacher - thank you for such a detailed answer, I appreciate it sir !
Looks like I'm buying more tools......
 
#4
Dr. Shop Teacher - thank you for such a detailed answer, I appreciate it sir !
Looks like I'm buying more tools......
So it sounds like the valves sit vertically(not an angle) in the block so I could put the block on a bridgeport mill for the reaming part ?

I've seen information out there where people have used Briggs #19269 to install bronze bushings in place rather than put oversize valve in....to me this makes more sense.
 
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#5
My H60 has the valves canted...I don't know about the H50, though I suspect they are the same. Somebody with way more knowledge than me should respond and give you better advice as to the best solution.
 
#6
He said it was a hssk50 Which is a small frame and it does not have angled valves like the h50. I may have a oversize exhaust valve for you, but you need to measure the valve head as Tecumseh went to a smaller diameter exhaust valve in the later years.
 
#7
He said it was a hssk50 Which is a small frame and it does not have angled valves like the h50. I may have a oversize exhaust valve for you, but you need to measure the valve head as Tecumseh went to a smaller diameter exhaust valve in the later years.
^^^^reads better than me, and is way smarter^^^^^:smile:
 
#8
Oversized exhaust valve.....

He said it was a hssk50 Which is a small frame and it does not have angled valves like the h50. I may have a oversize exhaust valve for you, but you need to measure the valve head as Tecumseh went to a smaller diameter exhaust valve in the later years.
Yes thats correct, I have the small exhaust valve version.

The stem measures around .243". I left the valve at work, but the seat diameter is approximately. 780"

I took a closer look at the seat and it almost looks like a pressed-in guide...i'll try and upload a photo of it....havent figured out how yet.
 
#10
So you have a choice use a briggs tool or a 1/4 inch tap and tap the guice then use a bolt with a few 1/4 inch fender washers over the seat and pull it out, replace it or ream it if you can get the oversize valve. I will look for the one I have and let you know what size it is. Either way you should also recut the valve seat. Need to find or make a guide to fit. I was going to replace mine but someone on the forum (ATK rider maybe) told me about briggs valves being a few thousandths larger in the stem diameter so I tried one and it fit great. Had to cut down the valve length and cut a new retainer groove though. I think I have a thread on that on here.
 
#11
So you have a choice use a briggs tool or a 1/4 inch tap and tap the guice then use a bolt with a few 1/4 inch fender washers over the seat and pull it out, replace it or ream it if you can get the oversize valve. I will look for the one I have and let you know what size it is. Either way you should also recut the valve seat. Need to find or make a guide to fit. I was going to replace mine but someone on the forum (ATK rider maybe) told me about briggs valves being a few thousandths larger in the stem diameter so I tried one and it fit great. Had to cut down the valve length and cut a new retainer groove though. I think I have a thread on that on here.
Thanks Ole, appreciate it.

It looks to me like the valves sit vertically on this engine (thank God!) so thats going to make it so much easier to fixture when the time comes. I have a couple of Briggs engines for my kids minibike an the valves sit at some kind of angle...wish I knew what the angle is ????
 
#12
The latest plan......

I'm thinking about reaming the steel guide oversized (or removing it all together) and pressing in a solid bronze rod, and drill/ream to size for a stock exhaust valve (#36471). Then have my local shop recut the seat for the new valve.

What do you guys think of this plan ? Let me know !
 
#13
That would work if you have the correct reamer and guide to do it. Otherwise you still need the same tool to ream the worn guide to 9/32 nd's to either fit a bronze thinwall guide or the Tecumseh oversize valve. I tried to find mine but no luck but did find a bunch of other stuff that may help explain some more of your options. One thing to note the early larger exhaust valves had a thicker stem. In this picture the two small exhaust valves have a stem dia of .243. The three larger head exhaust valves are between .245 and .2465.


Which sixe valve do you have? small head is .825 large is .972.

Next two photos are the briggs valve guide repair kit.


You can see the 45 degree cone guide as well as a 9/32 piloted reamer. They are used together to keep the reamed hole straight and centered in the guide so after reaming to 9/32nds it is still concentric with the seat. I found a couple of guide inserts that are 9/32 od and .249 ID. These are pressed in after reaming or in your case you could just get the OS Tecumseh valve. Just make sure it is the right sized valve head size.



If you have a milling machine you could tram the deck to maike sure it is 90 degrees to the spindle then use a 1/4 inch mill chucked in a collett to locate it in the guide then lock down the table, lower it then get a 9/32nds piloted (.250) reamer to ream it to size without the briggs guide tools.
 
#14
Ole - thanks for the good info and photos.

My valve has a .243" stem, so it must be the smaller one (Which makes sense, the engine is a later model).

I think I'm going to put in the bronze guide rather than try and put the 1/32" over-sized valve in.....I just think its worth the extra work.

I've ordered a 12" piece of .375" bronze rod. The plan is to machine the existing steel guide oversize and press the bronze rod into it, then machine the hole into it once its in.

I haven't decided if I should buy the Briggs kit or purchase the reamers separately ?? All I'm really after is the reamers.
 
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