Navarro aftermarket heads
 

I know a lot of discussion has taken place about spark plugs and Aluminum after market heads but I have not been able to find an answer to my specific problem. I have Navarro heads from H&H Flatheads on a 1950 8BA V8 with an L-100 cam (.375 lift). H&H recommends Autolite 216 spark plugs for these heads. When I use 216 plugs I find that exhaust valve in cylinder #8 crunches the electrode almost closed. None of the other spark plugs show any hits. I'm sure my problem is due to the L-100 cam lift. Has anyone encountered this problem with Navarro heads and a high lift cam and what did you do to overcome it? I know I can double washer the plugs but if someone has found a better solution I would love the hear it.
Thanks, Tony

Re: Navarro aftermarket heads
 

Tony since you have a new set of heads and only one spark plug that's hitting a valve in cylinder number 8 that tells me that the spark plug hole in the head for that cylinder was machined deeper than the other seven.
Any cam with lift will at times require the spark plug be spaced out a bit so the valve will not come in contact with the plug electrode. There's only one solution to this problem. Add another spark plug washer to the plug. Since you only have one that hits add one spark plug washer to cylinder number 8.
Well there is possibly one more option return the heads to H&H and try another set.

Ronnieroadster

Re: Navarro aftermarket heads
 

Thanks Ronnie, that's what I thought.

Re: Navarro aftermarket heads
 

Your welcome ;)

Re: Navarro aftermarket heads
 

One more option, try a better brand of heads.

Re: Navarro aftermarket heads
 

Pete, got any preferences? I’ve got a pair of Navarro heads on my 59 A and they’re good. I did have them machined to achieve.040 clearance above the piston . I bought these heads back in the 1990’s from Barney himself. I don’t know about the repop stuff.

Re: Navarro aftermarket heads
 

On the few street engines I have built with stock type chambers, I used either Edelbrock or Sharp.
I used those also on the race engines because they always welded reliably for the flat pistons.

Re: Navarro aftermarket heads
 

At the risk of sounding like a broken record, I will repeat my recommendation of those (formerly) cheap ol' Edmunds heads. They are unlike any others in that they have the spark plug moved juuust enough to miss the exhaust valve. This allows the use of extended tip spark plugs that seem to be an advantage. I put a set on the '51 Merc engine in my '51 Ford in 2016, and they haven't missed a beat yet. I pulled the plugs last summer to check their condition and they still looked great. I'm a true believer.

Here's my original thread : https://www.fordbarn.com/forum/showt...hlight=Edmunds.

Re: Navarro aftermarket heads
 

Keep in mind that the reproduction Sharp heads also come from H&H, so they're just as likely to have machining issues as the reproduction Navarro would be.

Re: Navarro aftermarket heads
 

I am aware of all that. I was talking about 50 years ago.
We make our own heads from billets these days.

Re: Navarro aftermarket heads
 

I has a question of compression related to this issue.
Why don use a thicker head gasket.
Is compression related to a stronger engine or is lower compression get more flow, so more power ?

I has a set of the ’10 to 1’ L&S heads and Ross domed pistons.
Heads is 59 CC and measure 10.5 mm or 0.413” deep chambers.
They get 10 in compression with 1/8” bore and a 0.04” thick gasket in a 59BA.
My cam is a Potvin 425 so I might get away with this but I might has to mill up the heads or go with a thicker gasket.

-So question is, do this engine need compression or do they make more power less compression.
That would cure all spark plug issues aswell.

I got my ears up on this as I heard a guy went very fast in in a non blower FH at Boneville using under 6 in compression.

Me, I has zero experiance on the Flatheads chambers/compression ideas.

Re: Navarro aftermarket heads