Baffle plugs - is there more elegant solution?

[Vlad]

Little details here. Spark plug access holes on newer baffle kits are of oblong shape. Plans say use two Tinnerman washers AN3235 screwed together. There is still a gap and it doesn't look right because metal is thinner than the washers. I was looking at others builders' websites and nobody has those spark plug access holes. Can somebody comment on these or post a picture?

[Bushcaddy]

Vlad,

I used a Van's o-320 baffle kit to do my O-235. I cut a piece of .032 aluminum the same shape as the oblong hole you describe, but bigger so it overlapped the hole on all sides and used an avex 1601-410 rivet (any pop rivet would do) at the top of it and can now slide the larger piece back and forth to expose the sparkplug access hole whenever necessary. Works great.

[jonbakerok]

Originally Posted by Vladyspassky

Little details here. Spark plug access holes on newer baffle kits are of oblong shape. Plans say use two Tinnerman washers AN3235 screwed together. There is still a gap and it doesn't look right because metal is thinner than the washers. I was looking at others builders' websites and nobody has those spark plug access holes. Can somebody comment on these or post a picture?

The new Lycoming that I had put in my RV6 in 2003 came with round grommets to fit a round hole in the baffle. There were two plug wires to a grommet. Apparently, that style of grommet is no longer made, which is probably why your baffle kit has oblong holes.

When I was helping a friend with his baffles recently, he had the opposite problem you describe. The grommets he had were oblong, figure-eight-shaped and the hole in the baffle was round. We searched all over to find round grommets like mine to fit his round holes but couldn't find them. Spruce only had the oblong ones.

So I think if you look in the Spruce catalog, you'll find some oblong grommets to fit your holes. I'd give you a link but I couldn't find them on the web site. They were hard to find in the book.

[dhall_polo]

Vlad,

Do you have the baffle material on yet? You can't almost, but not quite, cover the hole with the tinnerman, but the baffling helps out. Between the baffling and the tinnermans, I was able to plug the hole. A pic probably doesn't help much, and it's a lousy pic at that. I cut a slit in the baffling there, and the lower edge of the baffling is sandwiched between the tinnermans.

[Vlad]

Thank you all gentlemen. All examples are very useful and now I have an idea what to fabricate.

[roadrunner20]

One other issue you need to be aware of if not done, will give you an elevated temp on #3. Not sure whether the instructions have been updated.

Make sure you add a washer between the #3 cylinder backside to the baffle. Without the washer, air can not pass over #3 and the back of the cylinder/baffle.
Someone on this list gave me the fix. I had been chasing this for quite some time. Once done, it lowered my #3 cht by 20-25 degrees.

[trackdom]

Hi,
I am wondering what those spark plug access holes are for? I don’t understand the interest of those holes . That’s rather a leaky point .

[riseric]

Originally Posted by roadrunner20

One other issue you need to be aware of if not done, will give you an elevated temp on #3. Not sure whether the instructions have been updated.

Make sure you add a washer between the #3 cylinder backside to the baffle. Without the washer, air can not pass over #3 and the back of the cylinder/baffle.
Someone on this list gave me the fix. I had been chasing this for quite some time. Once done, it lowered my #3 cht by 20-25 degrees.

Yep, I put 3 washers there... #3 is now 30F cooler. Even cooler than #1.
I might remove 1 washer...

As for the Spark Plug holes, I used what Vans suggested and there was still a gap.
As I don't have to go through these holes to install/remove the plugs, I filled the gaps with Red RTV.