eBay Cool Head - 1970 170 on eBay

[TrickSix]

1970 170 head for sale on Ebay. Has the 1-3/4" inlet and the intake log looks bigger than the older versions. Not sure about actual flow efficiency. Also has small combustion chambers, so no need for lots of milling if used with a 200. Kind of expensive but looks in good shape.

https://www.ebay.com/itm/1561961419...uid=yPAA4oA3Qxu&widget_ver=artemis&media=COPY

 

[bmbm40]

I think those are good ones and kind of rare.

 

[MaverickAddict]

I asked them questions about that head. It does have 7 out of 11 exhaust port bolt holes with broken off bolts or studs in them. It has only been visually inspected for cracks & not magnafluxed. It has not been rebuilt. $449.99 is kind of high priced for what they have in my book. Machine work for extracting 7 broken bolts adds up even before the cost of rebuild if it checks out okay for cracks. That doesn't include the $152.79 cost for shipping either.

 

[DON]

That is the same head I have. Mine has the two barrel conversation done

 

[MaverickAddict]

Also the same head that Farron made such good power with on a 250 converted to a tri-power setup. Just a little high in price with no guarantee that it is not cracked. If they would magnaflux it or guarantee it not to be cracked or refund if cracked, then it might be worth the price.

 

[drag-200stang]

What they want and what they will take, are two different things.

 

[DON]

What they want and what they will take, are two different things.

What they want and what they get are two different things too!

 

[PSIG]

You have to specify the part number D0DE-6090-A when you contact head re-manufacturers. They can find one for you, rebuild it with warranty, and ship it to you free for that price. I have no idea on wait time or anything, but that's what they do for a living, so I'd give it a shot.

 

[powerband]

related data from archive:

....WHAT YOU NEED TO CHECK IS THE LAST LETTER ON THE HEAD. YOUR DOXX - 6090 A OR B. THE A WILL GIVE YOU A GOOD JUMP IN COMPRESSION. YOU WOULD BE IN THE AREA OF 9.25 TO 9.75. WITH JUST A BOLT ON. THE B WILL DROP YOUR COMPRESSION TO 8.0 TO 1.:
.
early Maverick 170 heads were 'closed chamber' vs 200 and 250 heads but with later - larger carb port and log runners.
.
DODE 6090 - A 170 :
. .
.
D7BE 6090 AB - 250;
.

have fun

.

 

[DON]

Just to be clear, the “A” head has smaller chamber volume as well as the smaller carb port and smaller log runner?

 

[drag-200stang]

Just to be clear, the “A” head has smaller chamber volume as well as the smaller carb port and smaller log runner?

No, large log, high runner, large carb opening 1-11/16'' they call it 1-3/4'' and small chamber, but the other letters and numbers have to be right, not any ''A" head.

 

[DON]

Just a thought, how would the “A” head be for quench? Piston is zero decked. I don’t know how much has milled off the head.
I just don’t know much about quench

 

[PSIG]

AFAIK, all these heads were closed-chamber, with some having smaller CC chambers, no? Open-chamber typically has no quench pads or area (circular bowl). This example using the classic Cleveland closed/open chambers, where #4 is "open" with no quench:

 

[drag-200stang]

It is the best you can get in an Iron head. Flat top pistons would be more better, ha ha. The way I see it, quench is the area that is not combustion chamber and cools the air/fuel charge and squish is the area that is not chamber that squishes the air/ fuel charge to the combustion chamber for a faster well mixed burn. Both fight detonation and need to be close to the piston to much gap is no good, to tight the piston will hit at high RPM.
This is for NA, now for boost, open chambers with no tight parallel surfaces work better because the air/fuel charge is dense enough that there can be to much mixture motion. That is why the open hemi head was favored for boost and the wedge head for NA, well that is how I see it.

 

[PSIG]

Quench is the technical term for both descriptions, and 'squish' is a common slang for quench. You are correct of the proximity and effects (literally quenching and limiting initial burn radius from the plug), with common street engines of our description striving for roughly 0.035" to 0.05" max piston-to-head clearance, in order to minimize end gasses that lead to detonation on det-limited fuels.

A chamber does not care about pressure from atmospheric (NA) or boost for burn, and there is no special benefit from it due to that. Non-quench is more prone to detonation no matter the pressure or density, as exhibited by hemi and open-chamber examples. There are design preferences for certain chamber shapes (e.g., hemispherical to allow high valve angles and/or central spark plug location), but they are not applicable to our designs. To some degree, "it is what it is" at this point.

 

[DON]

To be clear, is that clearance for what part of the head? I am assuming an open valve?

 

[pmuller9]

To be clear, is that clearance for what part of the head? I am assuming an open valve?

The flat part of the head that is not part of the combustion chamber.

 

[drag-200stang]

Quench is the technical term for both descriptions, and 'squish' is a common slang for quench. You are correct of the proximity and effects (literally quenching and limiting initial burn radius from the plug), with common street engines of our description striving for roughly 0.035" to 0.05" max piston-to-head clearance, in order to minimize end gasses that lead to detonation on det-limited fuels.

A chamber does not care about pressure from atmospheric (NA) or boost for burn, and there is no special benefit from it due to that. Non-quench is more prone to detonation no matter the pressure or density, as exhibited by hemi and open-chamber examples. There are design preferences for certain chamber shapes (e.g., hemispherical to allow high valve angles and/or central spark plug location), but they are not applicable to our designs. To some degree, "it is what it is" at this point.

We will have to agree to disagree. Chamber ''Softening'' is done on high power boosted engines. A 7 degree cut on the Quench pads so they are not tight and parallel, kind of like a hemi but not that much.

 

[PSIG]

I don't think we disagree, as there is still quench across the area, decreasing towards the chamber, as opposed to no quench at all (open chamber). This is not exclusive to boosted engines and other techniques are also used, such as slotting or grooving (two-angle), or expensive but claimed effective spiral as Smokey Yunik (or was it Penske) patented.

 

[DON]

The flat part of the head that is not part of the combustion chamber.

Is not that clearance determined by the thickness of the head gasket? Assuming flat top piston.
And thanks for the opinions guys. It does help my brain to get a grip on chamber design. when I was in school my professor observed I was the kind of person that needed to know HOW something worked to understand it. I think he was right and I am learning how the combustion chamber works.
Thank you!