oil leak at base of cylinder

[T41pilot]

I'm looking for a best practice or easiest way of dealing with an oil leak at a cylinder base. I've got the jug pulled back about as far as I can without exposing the piston rings at this point. It appears that to do a proper job of cleaning off the old aviation gasket #3, that I should probably pull the cylinder all the way off and just completely clean off both the bottom of the jug including the shims and the block side and start over with a fresh install of sealer. I'm guessing I just didn't get enough on there when I built the engine or the cylinder got moved during the drying process and hosed it up that way. At any rate the leak was pretty bad. I'll probably do both cylinders since I have the engine torn down that far anyway. My question is can I use my ring compression tool with the piston still attached to the rod and reinstall the cylinder over the top of the piston or do I have to remove the piston pin and pull the cylinder and piston off together? It's been rather frustrating so far since I am so close to getting it certified and just having bad luck with oil issues. First an oil pump that was never drilled out and blowing oil out every orifice that it could find and now this. I've got another week of warm weather on the menu to try to get this back together so any help would be appreciated. I don't have any local buddies with VW experience to help.

Regards

[mike.smith]

I'm looking for a best practice or easiest way of dealing with an oil leak at a cylinder base. I've got the jug pulled back about as far as I can without exposing the piston rings at this point. It appears that to do a proper job of cleaning off the old aviation gasket #3, that I should probably pull the cylinder all the way off and just completely clean off both the bottom of the jug including the shims and the block side and start over with a fresh install of sealer. I'm guessing I just didn't get enough on there when I built the engine or the cylinder got moved during the drying process and hosed it up that way. At any rate the leak was pretty bad. I'll probably do both cylinders since I have the engine torn down that far anyway. My question is can I use my ring compression tool with the piston still attached to the rod and reinstall the cylinder over the top of the piston or do I have to remove the piston pin and pull the cylinder and piston off together? It's been rather frustrating so far since I am so close to getting it certified and just having bad luck with oil issues. First an oil pump that was never drilled out and blowing oil out every orifice that it could find and now this. I've got another week of warm weather on the menu to try to get this back together so any help would be appreciated. I don't have any local buddies with VW experience to help.

Regards

That's the right gasket stuff to use. I have not experienced a leak at that location, so hopefully resealing and resetting will work. Sealant should be the second line of defense to hold back fluids. Flush and torqued mating surfaces are your first line of defense. If you need to add a lot of sealant then there is something else amiss, like uneven mating surfaces. You should not have to completely remove the cylinder. I would think you'd be able to clean and reseal without needing to open up the gap too far.

[Area 51%]

Perfectly acceptable to leave the piston on the rod then reinstall using the ring compressor......but it can get messy. Probably equally messy either way.

A couple of things to look out for- Verify that the length of the cylinders are the same, from the base where they sit on the case, to the surface that contacts the head. Next, verify that the shim stacks are the same height and make sure the sharp edges of the shims all face the same direction. Finally, check for a case-saver that is above the mating surface that might be interfering with the shims.

[pappas]

I just did exactly the same thing. Some people like Permatex aviation #3. I hate it! Smelly, drippy, runs all over the place and leaves ugly marks on the motor, really difficult to clean up. I'm out on #3.

I just resealed 4 cylinders with Hylomar Universal Blue. Awesome for me. Easy to apply, no leaks from the jugs or cylinder studs for the first time in 125 hours. Doesn't really harden and is a breeze to clean up even after it has set up.

I will never use #3 again.

[T41pilot]

I just did exactly the same thing. Some people like Permatex aviation #3. I hate it! Smelly, drippy, runs all over the place and leaves ugly marks on the motor, really difficult to clean up. I'm out on #3.

I just resealed 4 cylinders with Hylomar Universal Blue. Awesome for me. Easy to apply, no leaks from the jugs or cylinder studs for the first time in 125 hours. Doesn't really harden and is a breeze to clean up even after it has set up.

I will never use #3 again.

Did you coat the push rod tube seals as well or leave those dry?

[pappas]

I have not had good luck with pushrod tube seals. I have put them in dry, with a light coat of oil, with RTV, with Dowsil 3145, and now with Permatex Ultra black for oil.

I recently installed them with Ultra Black on the seals and then "painted" the base of the tubes at both ends around the bottom halves of the tubes. So far, this has been the most effective method for me. Others have not had any problems with the standard methods. I replaced the original pushrod tubes long ago because I was tired of loosening the heads to replace seals. I now use EMPI spring-loaded tubes. If I have more trouble with them seeping, I will remove all of that and try the Hylomar Universal Blue. I like the way that has worked on the cylinder bases and studs. Experiment on!

[T41pilot]

I have not had good luck with pushrod tube seals. I have put them in dry, with a light coat of oil, with RTV, with Dowsil 3145, and now with Permatex Ultra black for oil.

I recently installed them with Ultra Black on the seals and then "painted" the base of the tubes at both ends around the bottom halves of the tubes. So far, this has been the most effective method for me. Others have not had any problems with the standard methods. I replaced the original pushrod tubes long ago because I was tired of loosening the heads to replace seals. I now use EMPI spring-loaded tubes. If I have more trouble with them seeping, I will remove all of that and try the Hylomar Universal Blue. I like the way that has worked on the cylinder bases and studs. Experiment on!

I ordered some Hylomar and will give it a try. The information I found on it looked quite good. If Rolls Royce uses it in their jet engines, it must be good right? Trying my glass half full instead of my usual half empty on for size. I'll try the Hylomar on my tube seals and let you know. At this point I would like to get it good enough so that I can get the plane certified. The plane is done except for this.

[pappas]

Let us know how the Hylomar works on the tube seals.

BTW, your plane does not need to be flight-ready before it is inspected. The airframe inspection covers the cowl need to be off. The seats should be out and any inspection covers that allow access to any components or control linkages under or around the seat pan need to be off as well.

You don't even need any fuel in it. The inspection from the DAR or FAA is not a flight inspection. I have only heard of 1 inspection where the DAR even asked for the engine to be started. They don't want the liability.

They will check to make sure all of your paperwork is correct, that you have the W & B done and he might ask you to calculate one for him as well. I built 5 planes and no one even asked me to fire up the panel or any avionics. They will check for cotter pins, to see if there are 3 bolt threads showing past locking nuts and that type of thing. Don't sweat it just be glad you are getting yet one more set of eyes to check your work.

[wlarson861]

In regards to the inspection, check with the inspector as the condition he want's the plane in when he arrives. My DAR wanted the cowl on and all inspection panels in place with the plane in flight condition.
He said he needed to see the plane in both conditions, ready to fly and open. He said his experience was that it took less than half the time to open it up than it did to put it back together.
He is right as far as my plane goes. So I would ask the inspector how he want's it.

[pappas]

Good advice, better to ask than guess.