procharger Posted March 2, 2016 Report Share Posted March 2, 2016 I still have oil leak after Lockwood resurfaced head and cyl. 175 hours ago, exact same place as before on top of number 2, called and they said to use 242 loctite on sealing surface and put it back together so that's what we did, finish it up Wed. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 2, 2016 Report Share Posted March 2, 2016 Are you sure it's the cyl. head and not the valve cover? Link to comment Share on other sites More sharing options...
procharger Posted March 2, 2016 Author Report Share Posted March 2, 2016 yep you can see the place where it was on sealing surface Link to comment Share on other sites More sharing options...
Roger Lee Posted March 2, 2016 Report Share Posted March 2, 2016 If this area is where the head meets the cylinder then this is supposed to be lapped in place with some compound before final assembly. This is all it may need to stop the leak. There is a special tool for this. There is a picture of this tool in the Heavy Maint. manual. This is usually done at first engine assembly, overhaul or if there is a leak. We demo this tool in the Heavy Maint. class. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted March 2, 2016 Report Share Posted March 2, 2016 It sounds like Lockwood already tried to resurface/lap the area once already. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 2, 2016 Report Share Posted March 2, 2016 Forgot to read the first post again and missed the already lapped part. Still might not have been done right and may need a second lapping. Link to comment Share on other sites More sharing options...
procharger Posted March 2, 2016 Author Report Share Posted March 2, 2016 Yea they did all that, anyone heard of loc tite for sealing it up?? Link to comment Share on other sites More sharing options...
Roger Lee Posted March 2, 2016 Report Share Posted March 2, 2016 Send your inquiry here. This would be the definitive answer. techsupport2@kodiakbs.com Link to comment Share on other sites More sharing options...
pappa Posted March 5, 2016 Report Share Posted March 5, 2016 Yea they did all that, anyone heard of loc tite for sealing it up?? Procharger, I think I'd contact Locktite also, as there is some chance they may have heard a related question previously. Though not aviation, I had a related question to myself years ago on a 1988 T-bird 3800 V-6 engine made in Mexico. Ford had a recall (they kept as secret as possible) for leaking head gaskets. When I tore it down, I found the gasket so out of place that less than 1/16" width had ever been effective in places. Positioning pin holes were way oversize but also the gasket itself wasn't straight fore-and-aft. I had the heads milled and a valve job. The new gaskets were also sloppy on positioning pins. Having knowledge of people having gone through this more than once, I decided to improve results. Here is where it relates to you. The use of JB Weld, Devcon might also work but I am not sure of it's. temperature data. No shop mechanic would do this because of extra time involved and he is paid from flat-rate book I first squirted oil on top of pistons to soak rings and smeared oil almost all of way up on cyl walls. I installed several positioning studs in block headbolt holes. Cleaned surfaces on top of block, and surfaces of gaskets good with LT. Doing 1 bank at a time: I mixed epoxy and applied THINLY with my finger to sealing surfaces of block, and appropriate side of gasket. I then slid gasket down in place , pressed gently and checked with my finger for any excess epoxy run-out. Then I slid head (NO EPOXY ON TOP OF GASKET AND NONE AT ALL ON HEAD) over studs and installed several head bolts just a little beyond finger tight. NO COMPRESSION OF GASKET AT ALL. Did the other bank, and let both sit 24 hours. Then I took off heads and did top of gaskets and the heads same as I did the bottoms and the block. But tho time I installed all the head bolts and tightened using twice the number of normal sequence increments as normal AND stopped about 15 pounds short of final torque. Let it sit 24 hours, then did two rounds on torgue to final torque value. Ran the car hard fo years. I have 24 acres and started using it for woods car. Eventually developed "freeze plug" leaks and I would forget to put water in it. Ashamed to say but more than once it got so hot before I got back to water ,you could have fried steak on it. Still never a leak for 10 years of that until I junked it out. Sorry this was so long, but don't know of anyone else who has done this and thought it might help you. Epoxy sure is great stuff. Pappa Link to comment Share on other sites More sharing options...
Anticept Posted March 5, 2016 Report Share Posted March 5, 2016 If this area is where the head meets the cylinder then this is supposed to be lapped in place with some compound before final assembly. This is all it may need to stop the leak. There is a special tool for this. There is a picture of this tool in the Heavy Maint. manual. This is usually done at first engine assembly, overhaul or if there is a leak. We demo this tool in the Heavy Maint. class. Uhhh what tool? I asked LEAF for a head lapper, and they said there is no such official tool; they had to have one machined 10+ years ago. The guy who did it isn't around anymore and they haven't had a need to make a new one. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 5, 2016 Report Share Posted March 5, 2016 Look at Eric Tucker's next time you go to school. He used to make them. It isn't an official tool. You could lap with the two mating surfaces and some compound. It works, but not as easy. Link to comment Share on other sites More sharing options...
pappa Posted March 5, 2016 Report Share Posted March 5, 2016 d several positioning studs in block headbolt holes. Cleaned surfaces on top of block, and surfaces of gaskets good with LT. Doing 1 bank at a time: I mixed epoxy and applied THINLY with my finger to sealing surfaces of block, and appropriate side of gasket. I then slid gasket down in place , pressed gently and checked with my finger for any excess epoxy run-out. Then I slid head (NO EPOXY ON TOP OF GASKET AND NONE AT ALL ON HEAD) over studs BEING SURE TO VISUALLT CORRECTLY POSITION GASKET AT THIS TIME. I SUGGEST - DO NOT USE QUIK- SET EPOXY-IT WII SET BEFORE YOU ARE DONE............................. Then I took off heads and did top of gaskets and the heads same as I did the bottoms and the block, COATING TOP OF GASKET AND BOTTOM OF HEAD IN LIKE MANNER TO BOTTOM OF GASKET AND BLOCK. Tried to edit things I may have not been clear on. But with Windows7 smartphone it "corrects" LOL Bill Gates, you - not letting you have freedom of correction, but kindly changing your correct words to totally not the right words. Also great at leaving out words a lot. Maybe I'll go back to Android. Sorry about the rant. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 5, 2016 Report Share Posted March 5, 2016 Hi Pappa, If you do these things on a Rotax you will pay a price and it's costly. Link to comment Share on other sites More sharing options...
procharger Posted March 5, 2016 Author Report Share Posted March 5, 2016 Brought it home today will take a few hours to see if it is still leaking. Roger are you saying I could lap it in with compound by hand I have done many motorcycle heads like that?? Link to comment Share on other sites More sharing options...
Anticept Posted March 6, 2016 Report Share Posted March 6, 2016 Brought it home today will take a few hours to see if it is still leaking. Roger are you saying I could lap it in with compound by hand I have done many motorcycle heads like that?? How about pictures? Link to comment Share on other sites More sharing options...
Roger Lee Posted March 6, 2016 Report Share Posted March 6, 2016 It can be done that way. Then the metal mating surfaces should match up better. I wouldn't go that route unless it is necessary. Link to comment Share on other sites More sharing options...
Runtoeat Posted March 7, 2016 Report Share Posted March 7, 2016 Curious about lapping. Is maybe a bluing painted on the surfaces and then these are lapped until the bluing shows the surfaces are flat and no longer have low spots? Interesting that Lockwood recommends LocTite and Roger says don't go there. Roger, you must have interesting conversations with Dean Vogel when you two see one another! Procharger - did the LocTite stop the leaks? Link to comment Share on other sites More sharing options...
Roger Lee Posted March 7, 2016 Report Share Posted March 7, 2016 Lapping is the accepted method for joining and mating of the heads. I have never seen or heard of anyone using Loctite to seal this surface. Before I did that I would lap them again.. It may have been a poor job or not lapped long enough. there isn't any way to know. It could even be they were clean at that mating surface and has a poor seal. using Loctite seems like a bandaid approach to doing it right. I do know 2 special someone's to ask. I'll send an email. Update: I got call backs in about 5 minutes.. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 7, 2016 Report Share Posted March 7, 2016 Okay here is what two top Rotax authorities say. First no Loctite to seal heads. I told you I had never heard of such a thing and that would be a bandaid approach. This leakage is caused by two things. The first would be from an overheated head which caused warping. This can't be fixed and needs new heads. The real way to test for this is to send heads in and have them hardness tested. There is no oil in the head to leak. Second: The huge majority of people that think heads are the problem are wrong. It is the head studs that are allowing oil seepage to migrate. If you have a mid 2006 or earlier engine you use the green double "O" rings to seal these. If you have a newer engine than that then it is a black "O" ring to seal and stop this oil migration. This leakage is from the crankcase compression and causes oil to migrate up a stud. If you remove the head and then the stud you will find oil. Last is that lapping can make a difference, but if you have a soft head it will eventually leak again after about 100 hours. Rotax factory assembles the heads and applies a very thin film of the silicone heat transfer paste to the head sealing surface. As the heads get tightened down this allows the head to move ever so slightly to find it's position and not bind up from the metal to metal surface seating. Bottom line is if it hasn't been overheated then replace the stud "O" rings. There is an SB on this for earlier engines. Link to comment Share on other sites More sharing options...
Tom Baker Posted March 7, 2016 Report Share Posted March 7, 2016 I did mention the SB about the O-rings on one of his other post about this problem. I had a set of heads off to clean the exhaust valves, and Brett at Leading Edge Airfoils said I should comply with the SB while the engine was apart. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 7, 2016 Report Share Posted March 7, 2016 Here is a little more background. Many years ago Rotax did have in the manual that adding a VERY thin film of 243 was acceptable. Then it was taken out of the manuals. Allowing people other than the factory seemed to cause more issues than it solved. If the mechanic or owner used the wrong type or didn't apply a VERY thin film then the Loctite ended up in the cylinder and it caused some good damage. A thin film can be a little subjective. Then we have people that believe they know more than Rotax (who would have known) and they figured if a little was good more is better. Then you have expensive repairs. Rotax hasn't used nor wants any Loctite to seal a cylinder any more. Link to comment Share on other sites More sharing options...
procharger Posted March 8, 2016 Author Report Share Posted March 8, 2016 Lockwood told us to use loc tite they said rotax used it when overhauling engines so who knows what is right guess I will find out soon?? I was thinking copper coat may be better if I need something on surface, anyway the head and cylinder at top had a little dark spot on sealing surface just like last time about 3/8 inch long so something is going on there not sure what. Roger Do o rings for studs go on front studs on number 2 cylinder. Anyone know why the torque on studs was changed to 120 verses 180 ? Link to comment Share on other sites More sharing options...
Roger Lee Posted March 8, 2016 Report Share Posted March 8, 2016 "Anyone know why the torque on studs was changed to 120 verses 180 ?" Because 180 was too much torque and caused leaks. Rotax does not use Loctite to assemble engines. That is old school and they don't use it or recommend it any more. The dark spot is either from a leaking stud or a crack in the head. There was an SB out on this. "I was thinking copper coat ". This is why Rotax quit recommending Loctite to seal heads. people use either the wrong things or too much which causes expensive repairs.may be better if I need something on surface, Link to comment Share on other sites More sharing options...
ZZ Top Posted October 10, 2016 Report Share Posted October 10, 2016 Is there a sequence in tightening the studs? Have an oil leak that is getting worse. Think this may be the problem. Right side back cylinder. Engine has not overheated, however it has been in the high yellow often. On warm days during a long climb have to level off to let the engine cool down. Link to comment Share on other sites More sharing options...
Roger Lee Posted October 10, 2016 Report Share Posted October 10, 2016 Yellow temp ranges will not harm heads. The sequence and values for torquing the heads is in the Heavy maint. Manual. Link to comment Share on other sites More sharing options...
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