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Dipstick access when using a plenum

SMO

Well Known Member
Friend
When building my Rocket I made a plenum to assist with cooling. To provide access to the dipstick I put a cone around it, and then attached some scat to the plenum directly above the cone. When installing the plenum the scat is compressed down around the cone - this maintains the seal around the dipstick so the plenum does not lose pressure.

Now I want to install the CPI electronic ignition, and want to put the coil packs inside the plenum. However one plug boot interferes with scat.

My question is: Regardless of the electronic ignition, is there a better way to provide access to the dipstick when using a plenum? How have others done this?

Here is the top of my engine with the plenum off - the CPI coilpack is roughly in position:
Dipstick.jpg



Here is the bottom of my plenum with the scat attached:

Plenum%20Scat.jpg
 
Here's what I did. I stole the idea from from Deems Davis. Probably not a solution to your problem, but you could do something similar.

Lenny

plenum1.JPG

plenum2.JPG

plenum3.JPG
 
I am confused as to what engine you have that has the oil dipstick at that location. I have O-320 and the stick is outside of my plenum. I haven't seen the O-360 so I didn't know that is how they were.

I am impressed with the way you made the dipstick cover. Nice glass work.
 
Last edited:
When building my Rocket I made a plenum to assist with cooling. To provide access to the dipstick I put a cone around it, and then attached some scat to the plenum directly above the cone. When installing the plenum the scat is compressed down around the cone - this maintains the seal around the dipstick so the plenum does not lose pressure.

Now I want to install the CPI electronic ignition, and want to put the coil packs inside the plenum. However one plug boot interferes with scat.

My question is: Regardless of the electronic ignition, is there a better way to provide access to the dipstick when using a plenum? How have others done this?

Here is the top of my engine with the plenum off - the CPI coilpack is roughly in position:
Dipstick.jpg



Here is the bottom of my plenum with the scat attached:

Plenum%20Scat.jpg

I believe that Ross makes a coil mount integrated with the Mag cover plate. Spark plug wire is cheap and you have the pass through holes already. I mounted my coil on the firewall. It works just as well there with no interference.

Larry
 
I believe that Ross makes a coil mount integrated with the Mag cover plate.

Yep, he surely does. I was just hoping to keep it inside the plenum if I could - would really like the extra space between the accessory case and the firewall if I can have it.

Nice solution Lenny!
 
Lenny, nice looking piece of work but aren't you afraid that engine movement might tend to break your fiberglass piece as it appears that it is rigidly attached to both the engine and the cowl?
 
I like Lenny's method. Should be pretty easy to build a piece that accomodates the coil tower and boot. Short of that, you might move the coil forward or off to the side. Looks like you are using one of Ross' slick coil mounts, but it might work on another pair of bolts forward, or creative use of spacers might work to move it off to the right of the backbone.
 
Lenny, nice looking piece of work but aren't you afraid that engine movement might tend to break your fiberglass piece as it appears that it is rigidly attached to both the engine and the cowl?

Engine and plenum - not the engine and the cowl. The plenum moves with the engine.
 
Lenny, nice looking piece of work but aren't you afraid that engine movement might tend to break your fiberglass piece as it appears that it is rigidly attached to both the engine and the cowl?

Take another look------the square flange is mounted to the plenum cover, not the cowl.
 
I do this so rarely that I struggle posting pics but I will give it a try. I have done this both on a metal and carbon fiber plenum and both work well. No tools needed. simply push down and rotate to one side. No restrictions for space or air deflection.
vpb9fn.jpg
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Hope thats plain enough. I dont have any pics of the finished product without removing the cowl but I think you can see what I have done.
Ryan
 
Thanks Ryan, I can see how you have done that - would work nicely. I will have another look tomorrow and see if I can make that work for me - I may have another problem in that my "hidden hinge" depression might also get in the way.
 
I wanted to do the hidden hinge as well. I settled on a standard hinge on each side of the door. One for a hidden release at the front inlet of the cowl. The standard hinges leave the clearance required between the cowl and plenum without changing the plenum and it still looks pretty nice. If needed I can take pictures later today.
Ryan
 
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