DOOE-R deck thickness

Ran across a set of DOOE-R's that have been raced for years. Heads are bare and in fairly good shape, however it looks like the heads have been milled quite a good bit. Combustion chambers are in the high 50 - low 60cc range. I think the heads have been milled about 0.100". Question is: What kind of compression ratio would be ok to run with these heads being milled that much? Will we have issues w/ blown headgaskets or something similar?

Thanks,
Jon

In most cases, compression ratio ought not be a problem with heads milled 0.100" and used in a naturally aspirated engine. You might run into other custom engine building issues such as intake manifold alignment, piston-to-valve clearancing, etc.

Paul

If I were guessing I'd say that they have likely been angle milled, although the last set I ran across that were angled milled a hundred were in the 49-50 cc range if I recall. High 50s to low 60s may be more like .050 or so flat milled.

Bret

Below is how to measure how much the heads been milled.

Posted: Sun Nov 26, 2006 10:09 pm Post subject: Check the "button" depth in the combustion chamber

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In every Ford combustion chamber there is a small flat round pad that the chamber casting depth is measured from deck face. Often this 0.25" diameter pad is called the chamber button. Listed below are some common cylinder head part numbers with the appropiate depth measurement.

D0OE = 0.740"
D0VE = 0.740"
D3VE = 0.840"
D2OE = 0.780"

Please note that these are a dimensions will have a tolerance of +/- 0.010". Hopefully this helps you.

Jay from Eliminator Products and IDT
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Eliminator Products and IDT
(810) 395-2779
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The engine we are considering would be these iron cj's and some 2443's. So about 17:1. And an alky Carb. Does that change anything?

FORDMUD wrote:The engine we are considering would be these iron cj's and some 2443's. So about 17:1. And an alky Carb. Does that change anything?

With those thoughts in mind... Good luck!

Bret

FORDMUD wrote:The engine we are considering would be these iron cj's and some 2443's. So about 17:1. And an alky Carb. Does that change anything?

It might be necessary to whack down the dome of the L2443s for clearance and/or for good flame travel. Also, I think you're going to be pushing a paper head gasket around between cylinders and will need copper head gaskets (0.050" thick minimum). It might be a good idea to install some 1018's paper gaskets first, torque to spec, leave overnight, disassemble in the monring and mic the gasket all the way around its perimeter and also around the fire rings, and map your findings. Adjust torque at each head bolt accordingly until you get uniform thickness all the way around the paper head gaskets, then install the copper head gaskets using the noted bolt torque for each individual head bolt. It will likely be a very high maintenance engine and most people would grow tired of messing with such a program. But if you will be using alcohol as a fuel, you may simply install a 0.100" copper head gasket so that compression ratio drops to about 14:1 and you'll be fine.

Paul