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| Closed chamber head.... https://slantsix.org/forum/viewtopic.php?t=65770 |
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| Author: | MadScientistMatt [ Wed Feb 17, 2021 10:18 am ] |
| Post subject: | Re: Closed chamber head.... |
Quote: I think MSM meant that as an OE head, Mopar may have intended to use a special piston to generate a -0- deck at the squish pad, and enough dish to have the same cyl.volume...thereby ensuring if somebody scrapyardf the new head it wouldn't jack the squeeze on say the '68 3/4 ton 4x4 . As far as modern engines goes, most of these are Al-U-minimum, 4-valve headed, & the cam timing is actually -0- overlap... Yet take a new 2.5L Hyundai 4cyl....192hp NA, & 13:1 squeeze. On pump regular...try that out!
Correct - my guess is that they decided to develop the head and pistons as a combo that were optimized to work together, but would allow mixing and matching the heads and pistons to avoid something like the scenario with Cadillac V8s where the wrong combo could end up giving you compression in the 6:1s or 12:1s. The advantage I could see for the factory is that they'd only need to stock one sort of service replacement and wouldn't need to keep multiple parts on hand.
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| Author: | StrokerScamp [ Wed Feb 17, 2021 10:34 am ] |
| Post subject: | Re: Closed chamber head.... |
Quote: Quote: Quote: I would be interested in seeing how that head would work on a 170 (factory zero deck spec.) and a .022 shim gasket. I'm havin fun and that's all that matters, right? Next time you're up, I should have a hot 225 in it and we can go for a cruise. |
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| Author: | StrokerScamp [ Fri Feb 19, 2021 8:17 pm ] |
| Post subject: | Re: Closed chamber head.... |
Richie said it took only .010" to clean it up. That's a blessing on a long inline six head. They normally take more than that. As you can see, he's also starting to fit the 318 valves as well. Wasting no time. https://www.youtube.com/watch?v=fnBL27FdjT0 |
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| Author: | DynoDave [ Sat Feb 27, 2021 10:40 am ] |
| Post subject: | Re: Closed chamber head.... |
Wow, interesting piece StrokerScamp. Thanks for sharing all of the pics and info. That part was right in my neck of the woods, too. I have a set of 915 casting closed chamber big block heads from '67. Not rare or special, but Ma had certainly played with that chamber shape in the past. It will be interesting to see how this engine of yours runs. |
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| Author: | StrokerScamp [ Sun Mar 21, 2021 8:57 pm ] |
| Post subject: | Re: Closed chamber head.... |
Got the 318 valves installed in the head. Figured out the valve spring height. Going to setup at 1.8". Dropping the head of at the head porter probably Wednesday. Will update with pictures when it's done. |
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| Author: | StrokerScamp [ Wed Mar 24, 2021 8:51 pm ] |
| Post subject: | Re: Closed chamber head.... |
My porter has the head and it should be ready before too long. Will update with pictures and flow sheets. |
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| Author: | Doctor Dodge [ Thu Mar 25, 2021 8:25 pm ] |
| Post subject: | Re: Closed chamber head.... |
Quote: Got the 318 valves installed in the head. Figured out the valve spring height. Going to setup at 1.8"...
Be sure to check the rocker arm pad to valve stem tip contact pattern with longer valves installed at the 1.8 height. You will likely be on the "heel" of the arm's contact pad and on the inner edge of the stem tip. The longer valve stems can be helpful when running high lift cams but usually needs to be re-centered / adjusted when running lifts under .500 DD |
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| Author: | StrokerScamp [ Fri Mar 26, 2021 8:28 pm ] |
| Post subject: | Re: Closed chamber head.... |
Quote: Quote: Got the 318 valves installed in the head. Figured out the valve spring height. Going to setup at 1.8"...
Be sure to check the rocker arm pad to valve stem tip contact pattern with longer valves installed at the 1.8 height. You will likely be on the "heel" of the arm's contact pad and on the inner edge of the stem tip. The longer valve stems can be helpful when running high lift cams but usually needs to be re-centered / adjusted when running lifts under .500 DD |
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| Author: | StrokerScamp [ Thu Apr 01, 2021 3:51 pm ] | ||||
| Post subject: | Re: Closed chamber head.... | ||||
Got the head back today. Jerry did an awesome job on it.
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| Author: | DadTruck [ Thu Apr 01, 2021 3:56 pm ] |
| Post subject: | Re: Closed chamber head.... |
Rob, can you post the flow numbers? I would like to see the whole range, not just the big lift numbers. Thanks. |
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| Author: | StrokerScamp [ Thu Apr 01, 2021 5:04 pm ] | |||
| Post subject: | Re: Closed chamber head.... | |||
Quote: Rob, can you post the flow numbers? I would like to see the whole range, not just the big lift numbers.
Sure. I was just coming back to do that. The first sheet is after and the second is before. Keep in mind, these numbers are without any back cuts on the valves at all. Just a single 45. Also this is without the valve seats retouched. Both of which will add a bit more flow, once I get that done. Jerry said this head was the hardest iron head he's ever seen. Said it has a very high nickle content because it was constantly showering sparks the entire time. This is the last iron head he said he'll ever do.
Thanks.
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| Author: | volaredon [ Thu Apr 01, 2021 6:03 pm ] |
| Post subject: | Re: Closed chamber head.... |
Probably said out of frustration. Surprised at the single angle valve job, everyone and their brother who has ever done head work says at least a 3 angle valve job is essential with some telling you that you gotta go 5 angle. If that head is so hard, that much nickel content, (almost) sounds like stainless. Being as how that head is so hard, I doubt you'd need to add hardened seats then. The ones that I have been messing with had minimal sparks when grinding, and the material peeled away alot faster than I would have expected. |
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| Author: | StrokerScamp [ Thu Apr 01, 2021 6:29 pm ] |
| Post subject: | Re: Closed chamber head.... |
Quote: Probably said out of frustration. Surprised at the single angle valve job, everyone and their brother who has ever done head work says at least a 3 angle valve job is essential with some telling you that you gotta go 5 angle.
I'll never add hardened seats to anything as light as this Valiant or anything that doesn't spend the majority of it's life towing or hauling heavy loads. They are much less important than people think. If that head is so hard, that much nickel content, (almost) sounds like stainless. Being as how that head is so hard, I doubt you'd need to add hardened seats then. The ones that I have been messing with had minimal sparks when grinding, and the material peeled away alot faster than I would have expected. Oh and it has about ten angles on the seats. Was done with an almost new rottler. That will get touched up in a few days along with the valves getting a 30 and 15 added to smooth out the transition. |
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| Author: | StrokerScamp [ Fri Apr 02, 2021 7:52 am ] |
| Post subject: | Re: Closed chamber head.... |
Quote: Probably said out of frustration. Surprised at the single angle valve job, everyone and their brother who has ever done head work says at least a 3 angle valve job is essential with some telling you that you gotta go 5 angle.
I don't know.....I don't think that it was frustration. I think it was "tired of cast iron". I asked him about doing another slant six head for me over a year ago. He said then he wasn't doing cast iron anymore, but that since he had done one for me in the past and like them because they were something different, he'd do another one when I was ready. I've been keeping in touch with him ever since....he is a friend too after all. Then I came across the closed chamber head. I was just going to take him one of my nicer stock cores, but since I got this one, I took it instead and it turned out really nice. This is going to be a cool build with the closed chamber and solid roller cam.
If that head is so hard, that much nickel content, (almost) sounds like stainless. Being as how that head is so hard, I doubt you'd need to add hardened seats then. The ones that I have been messing with had minimal sparks when grinding, and the material peeled away alot faster than I would have expected. |
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| Author: | GregCon [ Sat Apr 03, 2021 5:51 am ] |
| Post subject: | Re: Closed chamber head.... |
It's interesting that the exhaust side is a more responsive port than the intake. On the intake, it's pretty much all done by .400 lift. |
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