Your Shirtless Neighbor 2 #1 Posted March 13, 2016 I just got her all back together. New piston, rings, connecting rod, and rebuilt the carb... so far $120 into this "free" motor. Filled the oil to the middle of the full marks, and it fired up. Instantly it was smoking. I can't adjust the carb worth a damn and it won't rev. I did remove the governor.... and I checked my vent valve, all seem to be OK. I let it run. For a good 5 minutes billowing smoke. The cylinder was in spec at 2.6" diameter.... What am I missing?! Just a bad motor? After 5 minutes the side of the carb and air cleaner were black... The oil has a slight haze to it, but it's clean. Also, piston rings are staggered.... just to rule that out. The ONLY difference between the old and new piston is the new one didn't have that wavy spring ring. The old piston had it under the lower compression ring. Is this supposed to go under the oil ring? Share this post Link to post Share on other sites
illinilefttackle 399 #2 Posted March 13, 2016 Was this engine block bored?, Clearances checked?- Al 1 Share this post Link to post Share on other sites
squonk 40,740 #3 Posted March 13, 2016 I beleve it needs that wavy spring under the oil ring 2 Share this post Link to post Share on other sites
AMC RULES 37,102 #4 Posted March 13, 2016 Should just replace the carb... find 'em cheap enough on Ebay. Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #5 Posted March 13, 2016 It's blowing oil boys.... the carb isn't the issue. It's a blow by issue. And the bore was checked. Standard size. Share this post Link to post Share on other sites
buckrancher 2,679 #6 Posted March 13, 2016 is the crankcase vent in the valve cover open Brian 1 Share this post Link to post Share on other sites
squonk 40,740 #7 Posted March 13, 2016 How was the bore checked? An old Tecky that still is standard size is probably out of round. I blew a bunch of them up back n the day. Never fixed one so what do I know. 3 Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #8 Posted March 13, 2016 (edited) Crank case vent/valve vent is working. New gaskets, cleaned the mesh. It's venting to the carb, no excess oil really. Bore was checked with vernier top and bottom. Center was checked with a ring and shims. Edited March 13, 2016 by AimlessMoto Share this post Link to post Share on other sites
squonk 40,740 #9 Posted March 13, 2016 (edited) Bore really needs to be checked with a bore gauge or inside/ outside micrometers. Cyl. Is probably out of round and tapered out of spec. Edited March 13, 2016 by squonk 3 Share this post Link to post Share on other sites
Howie 885 #10 Posted March 14, 2016 What was said above, a vernier caliper is not a good tool to check the bore. One can make those come up with all different measurements depending on how one uses them. Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #11 Posted March 14, 2016 I'll grab a bore gauge from work tomorrow and double check it. What about that wavy ring? Where should that go? Also.. if worse comes to worse. Can this be bored to receive a 7hp piston? Share this post Link to post Share on other sites
can whlvr 993 #12 Posted March 14, 2016 even if its in spec you MUST hone her to set the new rings,sounds like the rings arnt seated yet and if you are sure its in spec it should have been honed Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #13 Posted March 15, 2016 5 hours ago, can whlvr said: even if its in spec you MUST hone her to set the new rings,sounds like the rings arnt seated yet and if you are sure its in spec it should have been honed It was honed... I'm sorry, I didn't add that to my original post. This is my issue, is everything was done by the book on this rebuild. But, I don't have the correct book it seems.... And how come no one can tell me where that WAVY RING GOES?!?!?! Is there supposed to be a ring UNDER the oil ring?!?!?! Share this post Link to post Share on other sites
Molon_Labe 731 #14 Posted March 15, 2016 If your wavy (expander) ring is the same width as the oil ring groove it should go under the ring as in figure GO below Share this post Link to post Share on other sites
sorekiwi 761 #15 Posted March 15, 2016 59 minutes ago, AimlessMoto said: And how come no one can tell me where that WAVY RING GOES?!?!?! Is there supposed to be a ring UNDER the oil ring?!?!?! Its a little hard to tell what you are talking about. Your ring set should have come with instructions. If the oil ring is a "4 piece ring" then yes there should be 2 scraper rings, a spacer ring to seperate the 2 scrapers, and another ring to tension the scrapers against the bore. A little more information about what you have would be helpful. Share this post Link to post Share on other sites
slammer302 2,155 #16 Posted March 15, 2016 Here's a pic of a tecky piston maybe it will help you out. You may want to check that all ur rings are facing the correct direction so they pull the oil back down the cylinder. Good luck keep the teckys alive! Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #17 Posted March 15, 2016 (edited) Ok... my piston that came out had 3 rings and 1 spring. An oil ring with large holes on the bottom. The middle ring with a square notch cut out of the bottom section and the spring under it. And the top ring, which is solid. The way it came out was EXACTLY like that picture, EXCEPT for the spring under the oil ring.... which is probably what led to the original failure. ... The new setup is a slotted oiler ring on the bottom... double bevel center ring... single chamfer top ring... I think I have to pull this thing apart, maybe use the stock rings if they're in spec, and put the damn spring correctly under the oil ring. Edited March 15, 2016 by AimlessMoto Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #18 Posted March 15, 2016 This is the original as it came out. Share this post Link to post Share on other sites
squonk 40,740 #19 Posted March 15, 2016 (edited) I see enough scuffing on that old piston to tell me that block probably needed boring. Every engine I ever worked on had the wavy expander under the oil ring. I just never worked on Tecky innards.Looks like someone got in there before you and meesed things up Edited March 15, 2016 by squonk 1 Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #20 Posted March 15, 2016 I have a feeling that's what caused the original failure of this engine was someone else's intervention. When I took the head off there was a PILE of carbon around the exhaust valve and burnt oil in the intake... the carb was coated in black... Hopefully I can get this sorted. It starts REALLY easily, so I know it's worth saving... just have to get this oil issue sorted. Share this post Link to post Share on other sites
Wishin4a416 2,190 #21 Posted March 15, 2016 Probably already mentioned, but the Oil Scraper ring is not upside down correct? Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #22 Posted March 16, 2016 (edited) 3 hours ago, Wishin4a416 said: Probably already mentioned, but the Oil Scraper ring is not upside down correct? Correct. It's in according to the diagram and how the original mounted. Quick clip of it running at www.instagram.com/aimlessmoto , it's the first vid that pops up. Edited March 16, 2016 by AimlessMoto Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #23 Posted March 16, 2016 HAHA! I think I got this. I put the center ring in upside-down! Attached is a pic of the piston as it came out... I also double checked all my rings at 4 different heights in the bore... on average all gaps came out to .010, the bore with a gauge spun 3 times at 3 depths averaged 2.623. The piston itself is 2.607. All seem to be within spec, and the bore was only out of round by less than a thou. I'm still going to take it to a local small engine shop so the can check the engine code and see if it needs the spring under the oil ring. Hopefully it's just the stupid wiper ring. Share this post Link to post Share on other sites
squonk 40,740 #24 Posted March 16, 2016 I would have him check that bore if I were you. Using a ring is not accurate. 1 Share this post Link to post Share on other sites
Your Shirtless Neighbor 2 #25 Posted March 16, 2016 4 hours ago, squonk said: I would have him check that bore if I were you. Using a ring is not accurate. You should your coffee before posting. I clearly have a pic of a bore gage, and stated my measurements. I also checked ring gap. Share this post Link to post Share on other sites
