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Welded combustion chambers.
https://slantsix.org/forum/viewtopic.php?t=20588		 Page 2 of 3
Author:  Joshie225 [ Thu Nov 02, 2006 11:07 pm ]
Post subject: 
Quote:
Is there going to be an issue with valve shrouding? :?:
I really don't think so. The valves open away from the closed side of the chamber toward the spark plug. The filled part on the plug side of the chamber is well away from the valves.

Sam,

I think most of your questions are answered in the thread I linked to earlier in Racing Q&A.

This is going to end up as something of an engine builder's thesis. If I can pull together enough knowledge and can afford to implement enough of it I feel I have a very good chance of running near 150 MPH. A 150 MPH record should stand for a while as long as a V6 Pinto or some other significantly smaller American car doesn't sneak by.
Author:  LUCKY13 [ Fri Nov 03, 2006 2:31 am ]
Post subject: 
WoW, who put all that JB weld in the combustion chamber of your heads, that stuff will fall out. LOL j/ken.


That looks sweat, who ever welded that it looks like they knew what they where doing. Just wandering will the cryo treatment nutrilize the stress in the metal? I have really been doing alot of research on fixing a set of heads this way. Although I was going to weld alittle more on the plug side than you had done ( not sure how much ). The price for what you have had this done for I believe I will just get them to do mine instead of trying myself. A reworked chamber like this could totaly change the /6. It will be interesting to see your results for sure.


Good Luck with your project, sounds like a fun adventure.


Jess
Author:  gearhead [ Fri Nov 03, 2006 7:08 am ]
Post subject: 
Nice Work!

I have been discussing a similar head buildup with Lou and even the Drakes while I was in NC.

I hadn't planned on welding on the plug side, and instead would weld only the far side, then mill to achieve the combustion chamber volume. But then, I wasn't as ambitious as you, and was only shooting for some squish, not an actual heart shaped chamber. Be careful, as part of what makes the chamber shape work is "squishing" the mixture into a turbulated and homoginized mass, squeezing into the smallest portion of the chamber where the most heat is, and why they bias the spark plug toward the exhaust side of the head these days. So I would try to blend the spark plug "hole" into the floor of your new chamber to open it to the plug.

My plan had been to run a reverse dome in the piston on my 198 rod engine. When building engines with squish, it is important to run zero or even a positive deck, or you can lose the detonation resistance created by good squish, and instead create horrible inefficiency by trapping mixture in areas not very available to the comustion process. Hence, the reverse dome...you have the piston made with a milled dish, the reverse shape of the combustion chamber. In this way you retain the squish, while providing comustion space appropriate for the compression ratio desired.

I am concerned about the warping...what do you thinks its affect will be on the valve seats and the angle to the guide? I know it can and will be remachined, but if the guide to seat face move much, standard techniques for valve grinding and guide installation could create valve geometry that is not consistant. That said, if the work is done on something like a Serdi machine that can cut the seats and guides like a mill, then no problem, but hand valve grinding would put any warping into the valve angle.

Even more important, what about the cradles in the towers that support the valvetrain? I realize these can be machined as well, but have you measured the warpage?...and figured how a shop would do the machining?...not an easy setup to machine those rocker shaft towers without a horizontal mill...rarely found in an automotive machine shop...

Anyway... Josh, if theres any way I can be of service, I would be more than willing to help. I'd work for trading stock or similar help with some of my stuff. My mill would help on those chambers, and I just started porting my slant head myself. I have valve ginding equipment, and stones already cut to open the throat of the slant for bigger valves. Could probably save you some cash...

Planning on starting a thread today discussing some cam research I've been trying to do that you may find of interest, so keep your eye on the racing forum today or tomorrow.

Gearhead, aka Karl Boe
Portland OR 503-669-2135
Author:  Joshie225 [ Fri Nov 03, 2006 1:36 pm ]
Post subject: 
Karl,

Thanks for the support. From what is posted in the tech section on KB-Silvolite.com any more than about .055" clearance between the piston and head eliminates the benefit of quench. With zero deck pistons and a Fel-Pro head gasket the clearance should be .039". I set up a 318 with the same quench distance and it worked great. With the RPM this little motor is expected to turn I don't want to go any tighter for fear of the piston hitting the head.

The warping isn't that bad. .020" is where it stands now and I hope it ends up better before the machining. As much as will be cut for the oversize valves I'm not worried about the seats at all. I've thought of every issue you raised and have plans to address everything including the rocker stands.
Author:  argentina-slantsixer [ Fri Nov 03, 2006 4:57 pm ]
Post subject: 
this is my new head project for the big cubes slant

Image

it's from a race car from the '70's, the way they used to use their heads when heads mods was non restricted by the rules.
Author:  argentina-slantsixer [ Thu Nov 23, 2006 7:34 pm ]
Post subject: 
progress pix? :wink:
Author:  gmader [ Thu Nov 23, 2006 7:59 pm ]
Post subject: 
yes, please!
Author:  Joshie225 [ Thu Nov 23, 2006 9:29 pm ]
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Sorry, nothing other than the one picture. I recetly bought a Honda CB650 so it's getting more attention now than the cylinder head. I doubt I'll have anything to share until February. If someone would buy my '67 Valiant that would help speed things along.
Author:  Slant6Ram [ Thu Jul 19, 2007 3:34 pm ]
Post subject:  Digging up bones.
So I did a search on welding up chambers on a cylinder head and this is the only thread I found. I was wondering what ever happened to the project head in question?

His picture of the chamber is not a slant six head, but rather an example of what he was aiming to achieve. Wish the first pic was still working.

The reason I ask is because I have a head that I am working up like the one shown in argentina-slantsixer's photo. I am doing the welding myself and although it is of poor quality, I have taken steps to prevent warpage and cracking by doing small portions and immediate stress relief.

This is progressing nicely and I am excited about the fact that I haven't screwed anything up yet, after hearing years of "don't even try it" and multiple refusals from experienced welders.

I have about half of the total amount of filler (weld) already in and it is evenly distributed, not all on one end like my first porting attempt. After, I will be using a rotary file to clean things up and try to make size/ shape even between chambers. It's harder than you might think to fill all that space without burning a valve seat or the head gasket sealing surface. I'm sure I'll need to get it milled when I am done, but just a clean up at .040 or .060 is all I'm planning for the moment.

Pics are taken, but I've got to get them hosted and I'll post again next week here or in a new post if no replies show up in this one.

Paul
Author:  runvs_826 [ Mon Jun 09, 2008 10:12 am ]
Post subject: 
Can I get some more info on all this? The picture disappeared, also what does the "heart" shape look like? What special wire do you need to be able to weld on these cast heads? We have a MIG set-up and I was think I would be able to better weld it up because I could weld a dab on 1 and 3 chamber walk away for an hour, ect.
Also, how are the Cryo guys? I was going to try these guys out for the crank and rods.
Author:  Warren@PDX.com [ Mon Jun 09, 2008 2:50 pm ]
Post subject:  SL6 chamber weld-up
This is what I've been talking,theorizing & planning ever since I learned of the long-rod 225 4 or 5 years ago. Mucho kudos to Josh225 for sharing info,tech and problems pertaining to this project,paving the way for the less gifted and/or resourceful SL6 guys trying to bring their SL6s up to more modern standards.
My planned chamber shape will be similar to "Gearhead's"with material added opposite of spark plug & leaving the spark plug side "open",mostly to keep the C.R. down.I'm aiming for 9.7:1 C.R. with 198 rod/K.B.268 dished pistons set positive deck .009 to give .030 quench with a Fel-Pro "Blue Permatorque" head gasket(.039 thick) Will use MSD 6al w/5200 rpm chip.Cam specs 260/220-.515(I) 255/218-.535(E) 110 degree
1.70/1.44 "engnbldr.com" valves.Want roller(tip)rockers, don't want aluminum-stock rockers will do untill I find steel/ductile iron rollers.
Also considering reverse-cooling & thermal/ceramic powder coatings,budget permitting, for (added) detonation resistance.Has anyone out there heard/tried reverse-cooling SL6s? Warren@PDX.com
Author:  Volare4life [ Tue Jul 08, 2008 1:26 am ]
Post subject: 
*BUMP* just trying to keep an intresting thread alive, would there be any issues with the weld "Breaking free" ? would you leave the chambers rough cast, or would you smooth them out before welding ?
Author:  Warren@PDX.com [ Tue Jul 08, 2008 3:02 pm ]
Post subject:  Old topic:Welded SL6 chambers
Joshie 225 sold that welded-up head some time ago,that's why no more
info has been posted.We're on our own here unless some old-timer comes along that has already done this. :roll:
Author:  tophat [ Tue Jul 08, 2008 5:36 pm ]
Post subject: 
I thought long about this during my last build, but didn't want to risk a good engine. I would really like to try it one day, but it will be quite a while before I get to it.


TopHat
Author:  Volare4life [ Wed Jul 09, 2008 11:54 pm ]
Post subject: 
but would the welds hold against the compression, vibration and shear abuse ?

would it just be easier to shave the head, and polish the chambers ?

Maybe adding a little dome to the pistons ?

-Mike
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