cylinder to case seal
Posted: Wed Aug 14, 2019 9:09 am
by Johns
Having a problem with #1 and 2 cylinder side of motor leaking from the base of cyl to the case at higher rpms.(Above 2,000) Looks more like # 2. I recently had the motor home and cleaned everything, resealed everything with Permatex aviation form a gasket #3 and it still leaks. Not as bad as before but enough to keep me grounded.
Anyone else have this problem? Maybe a different sealer? Ideas? John
Re: cylinder to case seal
Posted: Thu Aug 15, 2019 7:22 pm
by wmbarber
I have the same problem but mine appears to be the number one cylinder and has occurred with both Permatex and RTV red. Hopefully someone has some suggestions. Otherwise how many have had success with the Permatex verses sucess with RTV?
Pete
Re: cylinder to case seal
Posted: Thu Aug 15, 2019 8:44 pm
by Onex107
Crazy suggestion. If you have shims under the cylinder you have to seal each one also.
Re: cylinder to case seal
Posted: Fri Aug 16, 2019 6:39 am
by Johns
Yes, I have shims and I did seal both sides. That is what so frustrating, I am sure I did it correct. Ready to bring it home and try again.
John
Re: cylinder to case seal
Posted: Fri Aug 16, 2019 7:51 am
by kmacht
If it is a new issue have you taken a good look at the crankcase vent? Building up even a slight positive pressure in the case can cause leaks.
Keith
Re: cylinder to case seal
Posted: Fri Aug 16, 2019 8:13 am
by Area 51%
Are you sure the leak isn’t coming from the hold-down studs?
Re: cylinder to case seal
Posted: Fri Aug 16, 2019 9:01 am
by Johns
I am pretty sure they are all blind holes on that side. Correct me if I’m wrong. John
Re: cylinder to case seal
Posted: Fri Aug 16, 2019 11:26 am
by Area 51%
The back 2 studs on #1 cylinder go all the way through into the case. PM me your email address and I’ll send you a picture.
Re: cylinder to case seal
Posted: Sat Aug 17, 2019 2:07 am
by lutorm
Johns wrote:Yes, I have shims and I did seal both sides. That is what so frustrating, I am sure I did it correct. Ready to bring it home and try again.
John
On my case, the cylinder stud “case saver” inserts protruded slightly above the cylinder base, so the shim would not lie flat against the base. I had to (very carefully) dremel down the inserts where they run under the shim. It’s described, with a picture, here. Are you positive yours don’t have the same issue?
Re: cylinder to case seal
Posted: Sat Aug 17, 2019 10:53 am
by Johns
Lutorm, I have the engine home and that is on my list of things to check although I did check them already. There has to be something I am overlooking.
Thanks everyone, John
Re: cylinder to case seal
Posted: Fri Aug 23, 2019 12:43 am
by lutorm
On the advice from several people I used Loctite 618 and hylomar when sealing the case. Hylomar is only for very well fitted surfaces so I’m pretty sure I used 518 on the cylinder base, studs, etc. I still have some leaks, but not at the cylinders…
Re: cylinder to case seal
Posted: Thu Aug 29, 2019 2:16 pm
by Johns
UPDATE: Started motor up with no leaks! Woo Hoo!! Been fighting this battle for a long time. Kieth had the right idea. Previous owner had different set up than the Aerovee manual. Rubber grommet with a 45 degree bend, with a smaller tube (reducer) to fit inside the grommet, then another hose to that. The smaller tube had collapsed to the size of about a no. 2 pencil. Without removing the smaller tube you couldn’t see it. Pete, double check your vent.
Cheers, John