Pre-Crossflow Valve Cover/Bonnet Conflict

[Rodnok]

My valve cover, a generic finned alloy unit, has a center mounted filler with vent cap that sits too tall, preventing bonnett closure. It has a large threaded hole in the rear with a plug in place. I'm considering finding/making a cap for the filler and using that rear hole in the valve cover as a vent with appropriate piping. Is this a reasonable solution or am I overlooking something?

[7Westfield]

go for it

that's how mine is vented, and also most of the Formula Fords in the world

it's probably 1/2" npt     or maybe 3/8

[Joe Petty]

There is not a lot of room!

 

I had interference with the breather, radiator cap and the corner of the front carburetor.

 

Problem with these Kent motors is that parts get swapped in that are not quite the same as original and you have to make adjustments.

 

Good Luck - Joe

[Origin7]

6 hours ago, Rodnok said:

My valve cover, a generic finned alloy unit, has a center mounted filler with vent cap that sits too tall, preventing bonnett closure. It has a large threaded hole in the rear with a plug in place. I'm considering finding/making a cap for the filler and using that rear hole in the valve cover as a vent with appropriate piping. Is this a reasonable solution or am I overlooking something?

 

 

I just installed one of these; it's the most low-profile cap and breather I could find. Still very close to the bonnet. If I had a threaded hole, I'd do it your way. 

 

 

[IamScotticus]

9 hours ago, Rodnok said:

My valve cover, a generic finned alloy unit, has a center mounted filler with vent cap that sits too tall, preventing bonnett closure. It has a large threaded hole in the rear with a plug in place. I'm considering finding/making a cap for the filler and using that rear hole in the valve cover as a vent with appropriate piping. Is this a reasonable solution or am I overlooking something?

Yes. check burton for a blanking solution for dry sump application.

Is that a magnet on the freeze plug?

[Christopher smith]

I do not remember where this unit came from but it works and gives great clearance

[Rodnok]

On 8/17/2026 at 11:35 AM, 7Westfield said:

go for it

that's how mine is vented, and also most of the Formula Fords in the world

it's probably 1/2" npt     or maybe 3/8

thanks for confirming my thoughts, I'll get to work on it.

[Rodnok]

On 8/17/2026 at 2:45 PM, Origin7 said:

 

I just installed one of these; it's the most low-profile cap and breather I could find. Still very close to the bonnet. If I had a threaded hole, I'd do it your way. 

 

 

I just ordered an alloy weld-on bung and low profile cap on e-bay. We'll see how that works out. Now to practice my aluminum welding. 

[Rodnok]

On 8/17/2026 at 11:41 AM, Joe Petty said:

There is not a lot of room!

 

I had interference with the breather, radiator cap and the corner of the front carburetor.

 

Problem with these Kent motors is that parts get swapped in that are not quite the same as original and you have to make adjustments.

 

Good Luck - Joe

 

[Rodnok]

It may be busy but is sure is pretty. Looks like new!

[Rodnok]

On 8/17/2026 at 6:37 PM, IamScotticus said:

Yes. check burton for a blanking solution for dry sump application.

Is that a magnet on the freeze plug?

The freeze plug does not have a magnet. It was in the motor when I got it. I've done searches  but am unable to identify it...

[7Westfield]

this is similar to the can I used on mine

mount it as high as possible

 

https://www.ebay.com/itm/286815733808?_skw=oil+catch+can&itmmeta=01M0DPEJP41N0H19G0E1EH6CAT&hash=item42c78cc830:g:9LcAAOSwQuFkEXpI&itmprp=enc%3AAQALAAAA0GfYFPkwiKCW4ZNSs2u11xDvAUbi4%2FCnjDXpZqkVb1vQelnDIxAnNV%2BwJKZvcVbLyVoySB96KTaDMxkd8rQwn%2Fzabj%2B56mc8DNsyef%2FC22q5CTCr0lkgAJ86DmVfVNX85TEJxY2raRpAHUkrLLeecOUUr18N%2F7BJeaIU00RWnOoQLId%2BIvczoabQmBiJKRgCaJtuzuSuUIiqnTOpHihUMWfzNIoqMleUKQJ87lyvab4s%2FLfB1Lk6aI1xi%2BCnF6FFRRVq83CqO0Vlq1CtgW18qWM%3D|tkp%3ABlBMUMqruraDaA

[IamScotticus]

12 hours ago, Rodnok said:

Now to practice my aluminum welding. 

there must be easier options. 

JB weld? Friction fit plug? a plug with a bar under the top?

I don't know if you have clearance for that. 

 

have you touched that nut on the freeze plug with a wrench to see if it's magnetic? I suspect it's one of those oil drain pan plugs wirh a nut holding it on the other side.  that or some water temperature sensor, which makes more sense,  but I don't see a spade.

Edited Thursday at 03:35 AM by IamScotticus

[Rodnok]

17 hours ago, IamScotticus said:

 

 

have you touched that nut on the freeze plug with a wrench to see if it's magnetic? I suspect it's one of those oil drain pan plugs wirh a nut holding it on the other side.  that or some water temperature sensor, which makes more sense,  but I don't see a spade.

[Rodnok]

I've just learned that the freeze plug has a low temperature center section that will melt when overheated. These are commonly employed by cylinder head rebuilding shops to cover their butts in the event of a warranty claim. Regarding the filler cap, I'm still not sure as to how I will resolve the clearance issue. If the alloy cap and bung appear appropriate, I'll use em. I know there are simpler fixes but I'm not a big fan of adhesives although I have used JB weld with great success. I have a lot of money invested in tools and am always looking for an opportunity to further my limited skills by doing something that's a bit of a stretch, thus the weld-on bung. 

[7Westfield]

FWIW   you can get valve covers without a hole/cap

 

Burton has them   pricey

Dave Bean or Ivey  ??

[Rodnok]

Thanks for the heads-up. I'll keep that in mind if my modification appears unrealistic when the cap arrives.