Quote:
Rick likes cast Iron, It's what he knows
He also knows there ain't no .100 over aluminum blocks out there. If I'm going racing I'm in need of a bigger bore and one that stays put. 
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| Aluminum Block Cylinder Support https://www.slantsix.org/forum/viewtopic.php?t=65591 |
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| Author: | Rick Covalt [ Wed Dec 02, 2020 5:16 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
Quote: Rick likes cast Iron, It's what he knows
He also knows there ain't no .100 over aluminum blocks out there. If I'm going racing I'm in need of a bigger bore and one that stays put.
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| Author: | GregCon [ Wed Dec 02, 2020 6:25 pm ] | ||
| Post subject: | Re: Aluminum Block Cylinder Support | ||
Aluminum weighs about 1/3 as much as cast iron. A cast iron block (225) weighs 156lbs. Add in some extra lbs. for things like the caps and liners I'd guess the savings at.....75lbs.
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| Author: | Tim Keith [ Wed Dec 02, 2020 7:03 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
Quote: If the head could be mirror relief cut to the cylinder sleeves inside and outside diameters and O-ringed, you could lock the cylinder wall into the head for rigidity. The block would need to be decked and the cylinders left a little taller than the casting. Some tolerance would be needed, and how much would need to be known before cutting. That sounds interesting. Is there welding technology to weld the deck solid? I suppose that there is some shop that can do that, if the heat of the block can be controlled - like maybe a small weld, let it cool, then another weld ? |
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| Author: | GregCon [ Wed Dec 02, 2020 7:26 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
I'd guess welding is a dead end, if for no reason other than the blocks are over 50 years old. I've welded transmission cases and no matter how many times I cleaned them in a commercial machine (Graymills heat/pressure washer using Sta-Brite #33 detergent), it was impossible to get the oil and crud out of the pores. And that stuff bubbles out when you start welding. It worked OK on a transmission bellhousing, but no way would I guarantee it produce a leak free weld that sees temp swings and combustion pressures. |
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| Author: | AndyZ [ Wed Dec 02, 2020 7:50 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
How about new bigger liners, Siamese, 4” bores? 
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| Author: | Joshie225 [ Thu Dec 03, 2020 6:52 am ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
Quote: If the head could be mirror relief cut to the cylinder sleeves inside and outside diameters and O-ringed, you could lock the cylinder wall into the head for rigidity. The block would need to be decked and the cylinders left a little taller than the casting. Some tolerance would be needed, and how much would need to be known before cutting.
That's an interesting idea. The head couldn't be cut to the cylinder's ID as that's open space, but support on the outside of the cylinder is all I'm looking for anyhow. I'm not 100% certain that I like this better than my thought of putting grooves in the head and cylinder tops and joining them with a metal o-ring. Welding distorted Dutra's block quite a lot. I want to avoid putting stress into this lightweight casting. Because HardBlok isn't reversible, nor as thermally conductive as aluminum or iron I'm leaning toward a press-in support. Search "Honda block guard" to see what's available for those engines. New liners sound like a good idea, but with 3.98/4.0" bore centers the bore limit is around 3.7". And I don't know that enough structure exists to handle the liner OD or the torque increase. |
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| Author: | Tim Keith [ Thu Dec 03, 2020 12:53 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
Quote: How about new bigger liners, Siamese, 4” bores? Maybe cut out the old liners and use adhesive to seal a wet liner support plate in the bottom. As its been said that welding is out of the question, but maybe the bottom could be modified so that a wet liner support plate with o-rings could be glued in there well enough to not leak. Its only money! How to get studs to work if its milled out?
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| Author: | GregCon [ Fri Dec 04, 2020 4:46 am ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
It might work best to take an iron block and have it aluminum coated on the outside. |
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| Author: | Rick Covalt [ Fri Dec 04, 2020 9:16 am ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
Quote: It might work best to take an iron block and have it aluminum coated on the outside. I paint my block aluminum color- $9.95 and done! |
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| Author: | Joshie225 [ Fri Dec 04, 2020 12:50 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
Gee, thanks. 
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| Author: | Rick Covalt [ Fri Dec 04, 2020 2:05 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
Just kiddin with you! I really do hope you guys can work something out. It is way above my head.
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| Author: | slantzilla [ Fri Dec 04, 2020 6:01 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
I have seen a few threads lately about the perils of aluminum blocks when building V-8 race motors. They won't hold the cylinder walls round enough to keep the rings sealed, costing horsepower. That's on blocks with decks. Will a Slant block with no deck have the same issue? 
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| Author: | CNC-Dude [ Sun Dec 13, 2020 7:48 am ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
Quote: The working theory for the aluminum engine seems to be that for high performance use the cylinders need more support at the top. I've seen block braces for Honda engines, but making such a brace means an awful lot of measuring and machining. An idea presented to me which seems to meet to goal economically is to make a plate to seal the top of the block, invert the block and add enough HardBlok filler to form about a 3/4" thick deck. I am having a hard time coming up with drawbacks to this method so I'm throwing this out for the hive-mind to consider. Cooling is about the only question that comes to my mind. What do you think might go wrong?
Aluminum Devcon would be a better choice since it has a thermal expansion rate more closely matched to the block. Something that the GM guys are doing with the newer Atlas 4200 blocks is boring out the existing liners and having Darton make flanged sleeves to replace them. There are several YouTube videos of them making over 1000 HP with forced induction and having zero reliability issues. Having a flange at the top would allow the block to be machined in the deck to have the flanges fit into the surrounding deck area or added support. This is the same style sleeves used in all aftermarket aluminum blocks such as Rodeck and Donovan, so its tried and true and works. Its just expensive at about $125 per sleeve though, but I bet it will come closer to making an improvement than anything else that's been done before.
Thankfully my block is very nice around the cylinder tops. My concern isn't initial head gasket sealing, but that the cylinders aren't rigid enough to stay put and hold the head gasket at the desired ~220 hp. Has anyone o-ringed the aluminum block and can share their experience? Thanks! Edit: The maker of HardBlok says a guy in California has successfully used HardBlok to form a top deck on Cadillac engines. I assume this Cadillac engine is the HT4100/4500/4900 engine family. |
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| Author: | GregCon [ Sun Dec 13, 2020 12:13 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
$125 per sleeve is pretty cheap.....that's only $750 for the whole engine. A project like this can swallow a grand in no time. |
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| Author: | CNC-Dude [ Sun Dec 13, 2020 1:46 pm ] |
| Post subject: | Re: Aluminum Block Cylinder Support |
Could be a little higher than the Atlas engine because the Slant has a taller deck, but if it can improve the longevity and durability of the aluminum block it's worth it. |
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