440 Closed Chambered question ?

[mguesto]

I will soon be sending out an XS29 440 engine to be "freshened" up. Nothing done to it but
bearings, rings, etc. That is my goal anyway. I got this engine back in 2009 for a spare for either my Dart or my GTX.

I was told that this was never apart, (it looks like the factory paint on the timing chain cover anyway) so i should consider
different heads to put on it because the original 69 heads should be done for unleaded gas anyway. Cost comparison
would be better off purchasing new heads.

Here is the quesiton. I have an oportunity to pickup a set of 440Source heads that have very few miles on them for a
good price of $600 for the pair. I was told that the heads were closed chambered. Probably way overkill for a stock engine
but I can't see me doing any damage to it if i buy it. Can I ?

If I do purchase these heads, am i forced to do other work to the engine or can i just leave it alone and stock? My goal is
to do it stock and not go crazy.

Looking over my "library" of books i can't find anything that says it would be a wrong purchase for a stock engine. All i find are passages that say when they were used.

So I am asking for some input here.

Thanks for your input.

Matt

 

[ykf7b0]

Go for those heads!!! If you decide against them I sure would like a shot at them for that price.

 

[Pops1967GTX]

Nice tech Article with some good information............


[video]http://www.moparmusclemagazine.com/techarticles/5115_cylinder_heads/[/video]

 

[Meep-Meep]

The closed chamber heads will bump your compression about 1/2 point, but as long as the compression is not over 10:1 you should be OK for pump gas. Ideally you would want to cc everything to know for sure. It's the combination of static compression ratio and cam timing that can make or break your build.

 

[Photon440]

The extra heat transfer from aluminum heads is going to offset about a point of compression gain. It might balance out.

 

[Hemirunner]

Here is the quesiton. I have an oportunity to pickup a set of 440Source heads that have very few miles on them for a
good price of $600 for the pair. I was told that the heads were closed chambered. Probably way overkill for a stock engine
but I can't see me doing any damage to it if i buy it. Can I ?

If I do purchase these heads, am i forced to do other work to the engine or can i just leave it alone and stock?

If you buy them, have an engine shop look them over. There's probably a reason they were taken off with low miles on them and being sold cheap.

 

[mguesto]

The guy told me that when the shop first put the engine together, they did not clean up properly
and there was some junk around the crank. When he ran it in, he said it was o.k.

Then when he put it through some good pulls on the road it tore up the bottom end. So he got another engine
that was already put together and ran with that.

He also has a set of inline 2- 4's for sale. (I am not interested in the 2-4 setup) I have yet to see any of this, since i am waiting for my engine to be inspected first. If all turns out to be fine, then i will have the heads looked at first before buying them for my build.

He says it will be after the 4th before it can be taken in the shop. I should point out that the two shops are NOT the same people.

Thanks for the information.

Matt

 

[IQ52]

The extra heat transfer from aluminum heads is going to offset about a point of compression gain. It might balance out.

Bologna!

- - - Updated - - -

If you buy them, have an engine shop look them over. There's probably a reason they were taken off with low miles on them and being sold cheap.

Very good point.

 

[Meep-Meep]

If you buy them, have an engine shop look them over. There's probably a reason they were taken off with low miles on them and being sold cheap.

X3!

 

[Meep-Meep]

Bologna!


I have heard both arguments regarding alum vs iron head materials, but you having tested the theory and finding no difference between the two is worth more than anything I have heard. Do you have data? It would be nice to put this to rest at least on here. If I follow your logic that debunks the following: "you must have one point more compression when using aluminum heads vs. iron to keep the power equal" or "use aluminum heads to cure detonation" because - "aluminum has better heat transfer properties that cool the chamber faster" I can only explain that even though aluminum has better heat transfer properties than iron, the heat of the expanding gas in the chamber (although much hotter than aluminum can tolerate) happens so fast that even the aluminum can't conduct fast enough. So you end up with an average temperature the soaks into the water jacket and things just take care of themselves from there.

 

[Photon440]

Bologna!

- - - Updated - - -

You may well be right, as I'm not usually building engines and certainly haven't done a steel/aluminum back to back comparison. So I have to go by common consensus in what I read. Other builders and head manufacturers seem to think that you can run a bit more compression with aluminum.
http://www.hotrodders.com/forum/aluminum-vs-cast-iron-heads-61610.html
http://www.speedtalk.com/forum/viewtopic.php?p=52602&highlight=

It gets mentioned in the Mopar Performance site:
http://mopar.ca/en/partsandaccessories/pure-performance-heads.html

Also this Chevy article that I think I found from one of your links:
http://www.chevyhiperformance.com/techarticles/83858_iron_vs_alloy_engine_heads/

While the above article is encouraging to me - I love the idea of the lightness of aluminum and the slightly higher torque that their test results came up with, I wish they had gone further. They started the test with an engine compression ratio that the iron heads could use. I would have been more interested if they had a higher compression aluminum head, and then tested to see if an equivalent iron head would run without backing off the timing. Maybe it would, maybe not, but it wasn't tested.

And that answer would have been more in line with the original question of whether the higher compression aluminum heads would be a viable replacement.

I'll be quiet now.

 

[Cranky]

Here's what one guy on Speedtalk said about his experience and I've heard the same said from others that did the same thing over the years....

"Many years ago I tried an aluminum version of the iron heads I ran on a B/G dragster, the iron heads made enough more power that it overcome the weight differential. The aluminum heads were tried on another car with the same results. That can only point to heat retention, and that the additional heat is beneficial in creating power."

That kinda tells me that iron heads hold more heat and heat is power....to a point. If you keep your engine cool then you'll have a better possibility of keeping it from pinging. There's a lot more at play than just having a cool enough engine to avoid ping. Heck, I had an 8-1 motor that pinged it's butt off even when the thing was at 170 and floored but forgive me for letting it reach 190 and part throttle! Yeah, it had an RV type cam in it and most that know about cams know what those things do.

 

[IQ52]

http://www.carcraft.com/techarticles/ccrp_0602_iron_versus_aluminum_cylinder_heads_test/viewall.html

"Many years ago I tried an aluminum version.........." Un huh, it HAD to be the iron.........r-i-g-h-t. How much difference? What heads and part numbers? Did they flow the heads? Was there ANY difference in compression ratio? It doesn't sound like there was any real control over the test........a back yard bolt on and wing it.

The general consensus of opinion comes from those who are repeating what they have heard. The only tests where they have flowed the heads prior to testing, have resulted in greater power from the aluminum heads at the same compression ratio and air flows as the iron. Even then, the testers refused to believe their own findings and said, "Well, we must have screwed up because the iron heads should have made more power." Though I have seen no tests of higher compression ratio, say those 12:1 or higher with the same heads, the Chevy iron and aluminum heads WERE tested at the same spark advance at different loads and no descernible detonation resistance difference was detected.

And to this point there are no Chrysler heads to test this on unless someone has some old 440-C and 440-1 Indy heads to sacrifice to the cause.

Somebody...........show me a test where the same flow rates and compression ratios were verified and the iron heads made more power or the aluminum heads made less.

- - - Updated - - -

I will soon be sending out an XS29 440 engine to be "freshened" up. Nothing done to it but
bearings, rings, etc. That is my goal anyway. I got this engine back in 2009 for a spare for either my Dart or my GTX.

I was told that this was never apart, (it looks like the factory paint on the timing chain cover anyway) so i should consider
different heads to put on it because the original 69 heads should be done for unleaded gas anyway. Cost comparison
would be better off purchasing new heads.

Here is the quesiton. I have an oportunity to pickup a set of 440Source heads that have very few miles on them for a
good price of $600 for the pair. I was told that the heads were closed chambered. Probably way overkill for a stock engine
but I can't see me doing any damage to it if i buy it. Can I ?

If I do purchase these heads, am i forced to do other work to the engine or can i just leave it alone and stock? My goal is
to do it stock and not go crazy.

Looking over my "library" of books i can't find anything that says it would be a wrong purchase for a stock engine. All i find are passages that say when they were used.

So I am asking for some input here.

Thanks for your input.

Matt

There should be some detonation resistance improvement with the Stealth heads because they have a better COMBUSTION CHAMBER SHAPE than the factory iron 906 heads. But before you replace the 906 heads with the Stealth you should calculate what static and dynamic compression ratios you have with the pistons, deck height, gaskets, camshaft, and cylinder heads you intend on using. Don't make these guys guess, do some measuring. The Stealth heads "should" work with your engine. But it would be silly not to first measure the things I have suggested.

 

[Meep-Meep]

I have made these points before about detonation. It's not just compression or the head material but a whole list of stuff that may or may not be controlled. So to pin detonation on just one or two factors is ludicrous. In no particular order this is what you have working with or against you:

Compression ratio
Cranking PSI
Cam timing
Chamber shape (including the piston top)
Fuel octane
Ignition timing
Inlet charge temp
Fuel distribution
Bore size
Spark plug location

And I'm sure I left something out.