Thanks for the video. A good reminder to us that when we lap or replace a valve it is likely we'll need to deal with the valve length like you showed us. A suggestion... perhaps go on ebay & find an old v-block (you can find small ones) so that yu can use it to keep your valve squared-up to the surface of the grinding wheel. Plus, v-blocks are just a handy thing to have. Find one with a clamp. Thanks, again.
Nice video! Just wondering, would it better to lap the valve before grinding? My thought is that if you grind first (to get the desired clearance), then lap, wouldn't lapping after cause the valve to sit 'lower' thus messing up the clearance you initially set?
I have a Tecumseh HM80-155404L like this but with a tapered crankshaft so there's not really a replacement. I spent $500 on parts and machine work and the rod threw the block. Turns out the crankshaft key sheared off and timing was way advanced. I bought a new block but poor now so can't afford machine. Are Tecumseh engines known for bottom-end failure? I'm kinda afraid to do this if a spec gets into the oil... (running fine with my original worn parts, but lacks Torque at full load. Rings and hone new)
Did a rebuild (new block, piston, rings, valves, gaskets) on my 2003 MTD Snowblower Tecumseh hssk50 5hp and I set the intake at .004 and the exhaust at .008 and set the coil airgap with a business card. Now regretting I didn't set the intake and exhaust a little more.
Yeah, while you should be ok at .004 it is on the lower end of the spec. I typically try to shoot for the middle range of the specs. Is it giving you trouble?
@@kbssmallenginerepair2615 ... some history on the machine and why I rebuilt it; when I say this machine still looks like new I'm not joking...I would wax it! I purchased new in 2003, used very little but it did work well. I made/added the rubber impeller attachments which greatly improved the machine ability to throw snow much further, always changed the oil and never saw any metal in the oil. Again, never really used it every winter with lighter snow accumulations. But last heavy storm time I used it in 2015 I noticed it was having a hard time even getting through 4" of light snow and was difficult to start. I did a compression test and sure enough it dropped. Pulled the head and the cylinder walls were wiped out! Sever score marks and gouges you could feel with a fingernail yet, the piston skirt was fine. Ordered a new block, pistons, rings, valves and gaskets total parts $200 and change. I was meticulous with the rebuild and back then I didn't realize the valve spec for my Tecumseh HSSK50 5hp was between .004 / .008 I THOUGHT it was .004 for the intake and .008 on the exhaust...kinda like how I would set up the valves on my race cars with solid lifters...the intake was a different spec vs the exhaust. When I rebuilt it back in 2015 I never even started it and here in SE Pa we haven't had significant snow to where I needed it. Until a few days ago... I did the first start, fired right up a little smoke because there was oil on the cylinder from rebuild and within several minutes of warm-up it started acting odd. I pulled the carb, all passages were clean and open, needle and seat were working as should so then I pull the valve cover and double check the clearances... they was as I grinded them to be .004/intake and .008/exhaust. but now I realize I'm on the extreme low/high margins of the specs. For giggles I'm going to double check the coil air-gap.
@@kbssmallenginerepair2615 ... I tinkered with the governor adjustment...all seems good. I may order a $15.00 adjustable carb for it to dial it in more.
I have a 5 hp tecumseh now the more they run and warm up the worse they run. Can even hear the valve issue. The newer ones the head gaskets come apart upon removal so you need a head and a few more gaskets if they break
What exactly wears to allow the clearance to be reduced to zero, or less? Cannot see it being the valve face or you would have to regrind it, not just a fast lap job. Nobody addresses this on YT. They should have originally installed adjustable lifters like they did in old cars and trucks with flat head engines, would save a lot of work. .008" (in) and .012" (exh.) is what I see on other sites. More is better is what I think.....allows longer intervals between adjustments. I really like your style, I am subscribed, thanks. Geo.
Hi Geo, Thanks for watching and subscribing! Typically the valve seat wears down which causes the valve to sit lower therefore losing all valve clearance. For this particular model Tecumseh calls for .004-.008 on both sides, but you are correct, a lot of guys like to use .008in & .012ex across the board.
@@kbssmallenginerepair2615 Thanks for that speedy reply. But I think you mean the valve sits higher thus never closing. I have a 5HP Tecumseh that needs a look-see at the valves, but it can wait. My neighbour had a 10 1/2 HP that I have been eyeing and he finally gave in. It is now on my 24" MTD and performing admirably. These have the extended camshaft to drive the wheels. Geo.
@@geobrown9413 Yes, I can see how that sounded confusing. When the valve seat wears down or sinks in the engine block, this in turn will also drop the valve (causing the valve to sit lower in the engine block than from the factory) Because the seat AND the valve is now lower (losing all valve clearance) the valve sits above (higher) than the valve seat and does not seal properly causing loss of compression.
I am old school and like physical copies of things especially to look at while I am working with greasy hands instead of pulling out my phone or using a computer. You can pretty much find anything online, but I prefer the manuals and books. You can look those up on amazon or eBay. Otherwise just do a google search for the specs of the engine you are working on, save it to your computer in a file, or print it off...
I'm not sure that you put the piston in TDP right position? Before to make the job for gap valves all these must be very whell close and the piston in the right compression position. After this you can begin to fix the valve gaps. Put before the job the some think in room valve (rug) to protect this versus griding grease. Clean correctly after the job the valve room.
Thanks for the video. A good reminder to us that when we lap or replace a valve it is likely we'll need to deal with the valve length like you showed us.
A suggestion... perhaps go on ebay & find an old v-block (you can find small ones) so that yu can use it to keep your valve squared-up to the surface of the grinding wheel. Plus, v-blocks are just a handy thing to have. Find one with a clamp.
Thanks, again.
Great suggestion. Thank you for sharing!
Thank you I want to do this.
Great video thanks for sharing
Nice video! Just wondering, would it better to lap the valve before grinding? My thought is that if you grind first (to get the desired clearance), then lap, wouldn't lapping after cause the valve to sit 'lower' thus messing up the clearance you initially set?
I have a Tecumseh HM80-155404L like this but with a tapered crankshaft so there's not really a replacement. I spent $500 on parts and machine work and the rod threw the block. Turns out the crankshaft key sheared off and timing was way advanced. I bought a new block but poor now so can't afford machine. Are Tecumseh engines known for bottom-end failure? I'm kinda afraid to do this if a spec gets into the oil... (running fine with my original worn parts, but lacks Torque at full load. Rings and hone new)
Did a rebuild (new block, piston, rings, valves, gaskets) on my 2003 MTD Snowblower Tecumseh hssk50 5hp and I set the intake at .004 and the exhaust at .008 and set the coil airgap with a business card.
Now regretting I didn't set the intake and exhaust a little more.
Yeah, while you should be ok at .004 it is on the lower end of the spec. I typically try to shoot for the middle range of the specs. Is it giving you trouble?
@@kbssmallenginerepair2615 ... some history on the machine and why I rebuilt it; when I say this machine still looks like new I'm not joking...I would wax it! I purchased new in 2003, used very little but it did work well. I made/added the rubber impeller attachments which greatly improved the machine ability to throw snow much further, always changed the oil and never saw any metal in the oil. Again, never really used it every winter with lighter snow accumulations. But last heavy storm time I used it in 2015 I noticed it was having a hard time even getting through 4" of light snow and was difficult to start. I did a compression test and sure enough it dropped. Pulled the head and the cylinder walls were wiped out! Sever score marks and gouges you could feel with a fingernail yet, the piston skirt was fine. Ordered a new block, pistons, rings, valves and gaskets total parts $200 and change. I was meticulous with the rebuild and back then I didn't realize the valve spec for my Tecumseh HSSK50 5hp was between .004 / .008 I THOUGHT it was .004 for the intake and .008 on the exhaust...kinda like how I would set up the valves on my race cars with solid lifters...the intake was a different spec vs the exhaust. When I rebuilt it back in 2015 I never even started it and here in SE Pa we haven't had significant snow to where I needed it. Until a few days ago... I did the first start, fired right up a little smoke because there was oil on the cylinder from rebuild and within several minutes of warm-up it started acting odd. I pulled the carb, all passages were clean and open, needle and seat were working as should so then I pull the valve cover and double check the clearances... they was as I grinded them to be .004/intake and .008/exhaust. but now I realize I'm on the extreme low/high margins of the specs. For giggles I'm going to double check the coil air-gap.
@@kbssmallenginerepair2615 ... I tinkered with the governor adjustment...all seems good. I may order a $15.00 adjustable carb for it to dial it in more.
@@hmdwn perfect! Glad it worked out for you.
I have a 5 hp tecumseh now the more they run and warm up the worse they run. Can even hear the valve issue. The newer ones the head gaskets come apart upon removal so you need a head and a few more gaskets if they break
What exactly wears to allow the clearance to be reduced to zero, or less? Cannot see it being the valve face or you would have to regrind it, not just a fast lap job. Nobody addresses this on YT. They should have originally installed adjustable lifters like they did in old cars and trucks with flat head engines, would save a lot of work. .008" (in) and .012" (exh.) is what I see on other sites. More is better is what I think.....allows longer intervals between adjustments.
I really like your style, I am subscribed, thanks.
Geo.
Hi Geo, Thanks for watching and subscribing! Typically the valve seat wears down which causes the valve to sit lower therefore losing all valve clearance. For this particular model Tecumseh calls for .004-.008 on both sides, but you are correct, a lot of guys like to use .008in & .012ex across the board.
@@kbssmallenginerepair2615 Thanks for that speedy reply. But I think you mean the valve sits higher thus never closing. I have a 5HP Tecumseh that needs a look-see at the valves, but it can wait. My neighbour had a 10 1/2 HP that I have been eyeing and he finally gave in. It is now on my 24" MTD and performing admirably. These have the extended camshaft to drive the wheels.
Geo.
@@geobrown9413 Yes, I can see how that sounded confusing. When the valve seat wears down or sinks in the engine block, this in turn will also drop the valve (causing the valve to sit lower in the engine block than from the factory) Because the seat AND the valve is now lower (losing all valve clearance) the valve sits above (higher) than the valve seat and does not seal properly causing loss of compression.
@@kbssmallenginerepair2615 Gotcha. Thanks for clarifying.
I enjoyed the video
Would it run if it were .009-.010. ????
Yes it would. A little more is ok, depending on the engine. This particular model calls for .004-.008.
@@kbssmallenginerepair2615 Even 9 or 10 would be OK. tecumseh valves are known for stretching.
What do you use to obtain specs and technical data on all types of small engine?
I am old school and like physical copies of things especially to look at while I am working with greasy hands instead of pulling out my phone or using a computer. You can pretty much find anything online, but I prefer the manuals and books. You can look those up on amazon or eBay. Otherwise just do a google search for the specs of the engine you are working on, save it to your computer in a file, or print it off...
I'm not sure that you put the piston in TDP right position? Before to make the job for gap valves all these must be very whell close and the piston in the right compression position. After this you can begin to fix the valve gaps. Put before the job the some think in room valve (rug) to protect this versus griding grease. Clean correctly after the job the valve room.