Tecumseh spark plug thread repair on 5.5HP LH195 engine
Вставка
- Опубліковано 29 вер 2024
- 5HP Tecumseh snow engine repair of stripped spark plug threads without removing the cylinder head. Sometimes you can't remove the head to repair the threads so your only option is to thread a new heli-coil insert with the head in place. I'll show you how.
Well done!
A couple of suggestions that don't all apply to your special situation but for the normal thread replacement procedure: 1) Make sure the piston is not at TDC when you do this otherwise you may run the tap into the piston. 2) Contrary to the directions that come with the product, I would not use RTV sealant. That's really a rubber-based gasket sealant. I would use Loctite Red instead which gives you the added advantage of locking the coil in the head so it won't be removed when you take out the spark plug which is often a problem people report when they use RTV. RTV simply makes no sense to me. 3) Use Anti-Seize on the plug threads. That will also help to make sure the coil isn't removed with the plug but you should always use it anyway when installing spark plugs. In fact, I would never even think of installing spark plugs with coating the threads with Anti-Seize, especially with aluminum heads.
Don't remove spark plugs from an aluminum head when the engine is hot. When it's hot, both the head and the spark plug metal is expanded, making the plug very tight. If you remove the plug when the engine is hot, there's a good chance you will rip the threads right out of the head.
Don't try to blow the metal shavings out of a cylinder with compressed air. It won't work. The nozzle will block their escape anyway. Use a tiny vacuum attachment for your Shop-Vac or other vacuum device. They sell little assortment kits on Amazon, etc. There are very tiny vacuum nozzles that will get in tiny places and they are ideal for this. Also, coat the tap with grease and remove it frequently during tapping to clean off the shavings that will stick to the grease. That will eliminate most of the problem right up front. As you know, the spark plug does not actually go into the cylinder on your engine. Blowing compressed air into the spark plug hole will actually push the shavings into the cylinder.
In your case, I would have first tried to heat the bolts with a torch but if that didn't work, your method is fine. To avoid problems like this in the future, coat all threads with Anti-Seize. That's especially important with aluminum heads. Of course, you almost certainly never removed the head bolts before so that's not an issue here but, when you do remove bolts, use Anti-Seize when you reinstall them. I think a little heat on each bolt would have freed them up, though.
+Bob Miller
Agreed with Bob. Good post.
+Bob Miller would using anti seize on a head bolt not throw off the specs when torquing the head bolts down? I'm not a small engine tech,but I am an automotive tech and I am just using the logic I would apply with a gasoline automotive engine. Everything else you stated I agree 100%. Great post
+jamie buchanon I think Bob was saying apply anti-seize to the spark plug threads when you install a plug in an aluminum cylinder head. I think most folks do this because the aluminum heads can oxidize and the plug can get "rusted" (oxidized for aluminum) in place and difficult to remove without damaging the head. Be careful when using anti-seize on your spark plug, don't use an excessive amount and keep it away from the center electrode. I generally apply it a few threads back from the end of the plug to prevent it from getting on the electrode and causing misfires (or not fire at all). Don't forget, that anti-seize has very tiny aluminum particles, graphite , nickel , etc in it... it will allow some electricity to flow down the center insulator and short out if you get a decent amount on the inner insulator cone/center electrode - possibly preventing a good spark. So, use it on the threads but be careful not to get it all over the plug. When I use it in the shop, it gets on everything even when I'm very careful... stuff is messy.
+Dan Small Engine okay I gotcha. Hey Dan You have a new subscriber
You're correct. I see I wrote that incorrectly but I've fixed it. I did mean to put an anti-seize compound on the spark plug threads, not the thread insert. Thanks for pointing that out.
When doing a job like this do not use any impact tools
You don't need to remove head to fix.With piston up you can insert a air nozzle into cylinder to plow anything out after threading.
The phrase 'Shit Storm' at 1:50 made me decide to like this video.
No need to worry about a few small shavings of aluminium, as normal combustion temperatures will ignite and burn small shavings of aluminium, yes aluminium will burn very much like magnesium does, so it leaves the engine as exhaust, now cast iron or steel requires higher temperatures to burn so cleaning out the shavings is recommended
All wrong procedure even though you made the thread
I did a similar procedure on a old Jari snow blower that was a freebie for my nephew. It worked fine. Would not do it this way if head was cast iron.
You shouldn't have removed the end. It guides the tap. Lower the piston down. Tighten and loosen the tap repeatedly and clean off the shavings. Put wheel bearing grease on the tap. Use Locktite high strength sealer on the insert. Let it dry and harden. Use the swager to expand the knurl. A medium insert would be better than the short one so it'll have more bite. Use a ratchet instead of power. If you don't tighten the plug enough, the insert can come out! Then you have to use a Big-sert. A Time Sert is better but it's expensive. Run a cylinder leak-down test to check rings and valves. A piston stop tool can lock an engine to remove crank bolts etc.
Marty Stevens Piston position does not matter. Most of these engines position the plug over the block, between the valves and piston.
Larry Fine I have that kit and sometimes you might can screw it down onto the piston. Those inserts work but if you have limited space, the swager might not hammer it enough to lock it in. That kind of insert can loosen and widen the hole. Then it pops out! A Time-sert is better because it locks in. It costs more. If the insert comes out, a Big-Sert may be needed. Use a screw extractor to remove inserts. To gauge the size, use a drill bit and drill to a maximum of 3 bits to the size of the insert size. Use Loctite High strength sealer. Screw the plug in loosely when installing the insert to dry. Install an insert matching the depth of the reach. Tighten the head bolts on small engines.
where do I get the kit sir
Nice job done. Wonder if the alloy bits will exit. Cheers 🦘🇦🇺
I blew out the cyl with my air gun to get it all out. The repair was a last ditch effort on that old 5hp TEC engine before we just scrap'd it.. Most of the 5 or 5.5 HP flathead snow engines are pretty much dead by now. The blocks on most of the 5hp and some 8hp L-head engines will "settle" or shrink a bit over time and this prevents the valves from full closing. You will have to remove the breather cover and grind/file back the valve stem to increase the clearance to let the valve actually close. (Or remove the head and pull the valves and grind them as needed) Check the spec for the proper valve to lifter clearance. Too much clearance give you an annoying tappet sound!
how did you get the metal shaving out of the cylinder?
Compressed air. When I did the work, I had both valves closed on the compression stroke. I used a blow gun to blow all the chips out. These chips were large (not like dust from grinding) so they were all large enough to get picked up and blown out. I also slowly rotated the engine while blowing air into the spark plug hole to force out any chips that I missed through the exhaust and intake valves. Not perfect but fine for this old machine.
where do I get the kit sir
Manuel Rapalo Amazon or parts stores have it.
I'm the same on a scooter
ABSOLUTELY PROFESSIONAL It would be better to use a Time-sert kit. They lock in. Save-A-Thread can loosen up if you don't swage it properly. Use a screw extractor to remove inserts.
Most Tecumseh engines are a "shit storm" anyway.
I have one of these snowblowers the engine always starts on the first pull. I don't use it much anymore since they got a bigger machine with an 9 horse Tecumseh.