2110cc Detailed Build Thread - Now 2276 Super Squish Build

[theastronaut]

We used to polish the entire inside of the case with HD motors back in the day...
While you got all of the polishing stuff out...

With the oil slinging off the crank, it can't hurt.
(Maybe hurt your fingers from all that polishing)

I'm definitly not done smoothing the insides of the case, still going to do some more porting and reshaping of the main webs. Also thinking about rounding the edges of the cylinder openings inside the block to smooth the internal air flow behind the pistons. As far as smoothing the whole insides, I've been tempted to do it since I first got the block but that would be quite a bit of sanding!

I worked on prepping the block a lil more saturday and took about 20 pics, I'll sort through and pick the best ones and load them up. Also need to find some sort of cutting tool to spot face the small perimeter case bolts as they aren't exactly flat. Anybody have any suggestions about what to use?

[Clatter]

The Bergs sell a tool for that very purpose.

They also recommend an increase in the size/thickness of washer,
And an increase in torque values for these bolts.

the increase in torque has been debatable, though.
And, if it were my engine, I'd only up the torque by a pound or two...

Now, polish the inside of that whole case so it shines like a mirror!

[Clatter]

Oh, and also polish the crank and rods too...

Lots of HP lost by those rough castings cutting thru the oil.

Plus, stress risers...
Stress cracks start at surface imperfections!

[theastronaut]

You're not helping me with my OCD problems! I'm contemplating having the crank knife-edged and since it would have to be rebalanced anyways... would be a good time to polish it too. The CB rods are already pretty smooth, and don't need much to make them balanced so I'll run them as-is. I'm going tomorrow to a shop that should have the tool to spot face the case hardware areas, if not I'll check into the one Berg sells.

[James2]

Case porting is often over looked and the purpose is often not understood. Details like these is the difference between a 180 hp and 200 hp engine, even though they use the same parts.

I have removed quite a lot of material behind #3 to smooth flow of air with no case problems. I would make the sharp corner about a 1/2-3/4 in radius.

[theastronaut]

Case porting is often over looked and the purpose is often not understood. Details like these is the difference between a 180 hp and 200 hp engine, even though they use the same parts.

I have removed quite a lot of material behind #3 to smooth flow of air with no case problems. I would make the sharp corner about a 1/2-3/4 in radius.

That's one of the areas that I was worried about taking out too much. I'll round it off more now that I know that, thanks! The block is welded behind number 3, so I'd think it should be stronger back there to allow a little more grinding...

[James2]

Had time to find pictures from my last build. Before and after. I polished the whole inside with a 80 grit flapper after I got done porting, well the parts I could reach

before



after

[theastronaut]

Had time to find pictures from my last build. Before and after. I polished the whole inside with a 80 grit flapper after I got done porting, well the parts I could reach

before



after

That looks like an aluminum case?

If so, there may not be as much material back there to remove on my mag case. And after looking the pic of my case back there, it doesn't show how rounded it already is. I'll still take a second look at it tho next time I'm grinding on it. Thanks for the input, those kind of details are really helpful!

[James2]

Yes, it's aluminum. As you can see it does not machine as well as a magnesium case.

[theastronaut]

Got some more porting done to the case. Worked the area above the center main bearing web to ease the airflow through that area. As with the porting shown before, a carbide burr on an air drill was used to do the rough shaping, a sanding drum, and finishing with a flap wheel on a dremel was used to smooth the block.

Before pics:

Thats the opening that I wanted to open up, right above the center main web.


Another shot:


With the case split:


After opening it up, went the same depth as the rod notches but wider:






With the case back together and only one side ported:



These are upside down but still shows the difference:







I'll scribe the other side of the block and port it to match next. Also have a few more areas inside the block that I want to rework and smooth.

Been eyeballing the crank's counterweights to get an idea of how I want to reshape the leading and trailing edges so that they'll be more aerodynamic; hopefully will be working on this in the next few weeks.

Another thing that has really caught my attention is combustion chamber designs. I'm really leaning toward buying a bare set of head casting and having the chambers welded up and reshaping them myself. Looking to accomplish a "fast burn" style chamber, with more quench area than normal and also trying to introduce swirl into the air/fuel mixture as the piston compresses the mixture on the compression stroke. Take a look at the pics on this thread to get an idea of the process involved with reshaping chambers. I may also relocate the plugs depending on what location the base castings come with. Buying bare castings will also let me buy the individual components such as valve springs (considering beehive) and valves to compliment this particular build combination.

Here's a link of interest with alot of info on the subject of fast burn technology:

http://www.theoldone.com/articles/

The "July 1985 Hot Rod" articles and The Soft Head 1999 article explain alot of the theory and modifications behind fast/lean burn engine designs.

I'll admit that I don't fully understand all that is involved to make this work effectively, but I'm convinced that it works and will be researching further on how to apply these principles to the engine I'm building.

[theastronaut]

A quick update to keep up with what I've been planning lately.


The next steps for the build will be:

Finish porting the block.
Smooth the inside of the block.
Oiling mods inside the block, described here: Bob Hoover's HVX Oiling Mods

I called Darren @ DRD Racing and will be purchasing a pair of bare 043 castings from him in the next few weeks. He was very supportive of the use of fast burn style chambers and encouraged me to persue their development for my engine.

Some of what I'm looking to get out of the quick/lean burn chamber design:

Better average HP and torque (not necessarily higher peak hp, but that's not the point), better gas miliage, lower head temps. I think the bottom end should last longer as the ignition timing (and therefore peak cylinder pressure) occurs later than in a normal engine, so the crank has rotated farther before the rod starts pushing down on it. The rod's angle is farther away from straight up when maximum cylinder pressure occurs so it isn't pushing straight down on the crank as much at TDC, and the bearings aren't as loaded. This also means the push from the piston/rod (maximum cylinder pressure) is timed when the rod is closer to a 90 degree angle to the crank - when maximum mechanical leverage is at it's greatest. Because the mixture burns faster and more completly, there is lower EGT's; the gas is finished burning (or atleast closer to being completly burned) before the exhaust vavle opens. Less heat in the exhaust port equals lower head temps.

In an aircooled engine with it's limited ability to shead heat, not producing extra heat to start with is much more effective than adding extra ways to get rid of it.

I've thinking maybe I should get some slip-in 94's so I could use a set of Aircooled.net's Super Squish pistons....

Fast burn 2276cc, FK-45, 13 /1 static CR, 48 IDA's...

Hard to imagine that it started off as a simple 1776 build a couple years ago!

[theastronaut]

Got the other side of the case matched up:

[theastronaut]

It's officially a 2276 build now The Squishies are in the mail, should be here next week.

I'll order 94mm cylinders from Brother's this week, not sure if i'll go the slip in route or have the block bored.

Since deciding to go with squishies, I'm still undecided on the cylinder heads. Welding up chambers like I'd wanted destroys the heat treating, and makes the alloy soft enough that the valve seats can sink, so thats out of the picture. Anyways, it's not needed with the super squish pistons. Wedgeports with some hand work seem to be a good choice, and alot of guys have had great results with them.

Dad had knee surgury, so I've been busy taking care of alot of the things he hasn't been able to do. He's back walking now so I'll be able to spend more time on the mock up and prep work. I hope to tackle the deck height once the parts arrive and as usual, I'll take pics and explain the process in detail.

[hotrodsurplus]

Just a tip from someone you don't know (apologies for not formally introducing myself).

When profiling the case, resist the urge to truly 'polish' the case. Very smooth surfaces have less surface area than rougher ones and any increase in surface helps the oil transfer heat to the case. Likewise, the greater surface area offered by a rougher case outer surface transfers more heat to the air. It's the same principle behind fins: they offer more potential cooling area because of their greater surface. Some may call it geekery and total overkill, but I've taped off the critical tolerance areas inside a case and blasted it with glass bead. I've done the same to the fins on cylinder heads.

Does it work? Hell, I don't know. Theoretically it can help, but I don't know if it's quantifiable.

[theastronaut]

Just a tip from someone you don't know (apologies for not formally introducing myself).

When profiling the case, resist the urge to truly 'polish' the case. Very smooth surfaces have less surface area than rougher ones and any increase in surface helps the oil transfer heat to the case. Likewise, the greater surface area offered by a rougher case outer surface transfers more heat to the air. It's the same principle behind fins: they offer more potential cooling area because of their greater surface. Some may call it geekery and total overkill, but I've taped off the critical tolerance areas inside a case and blasted it with glass bead. I've done the same to the fins on cylinder heads.

Does it work? Hell, I don't know. Theoretically it can help, but I don't know if it's quantifiable.

Good info and I completly agree.

The inside of the block won't be "mirror" polished (when I say polished I mean prepped and buffed to bring out flawless reflections like a mirror, or chrome) but only smoothed with a sanding drum and a flap wheel. The peaks and valleys of 80-120 grit sanding scratches should leave plenty of surface area for heat transfer. The outside of the block will be painted with either black or dark grey wrinkle paint so it will have more surface area than normal, although I'm doing it for looks more than heat transfer.

From my research, by using the Super Squish pistons the head temps will drop about 100 degrees, so the oil returning from the cylinder heads will be much cooler. In some cases power pulleys and even dry sump pulleys are needed to slow the fan down enough to let the engine get up to propper operating temps. I'm not too concerned with it running hot.

Thanks for posting! As I've said before, all relevant info is welcomed and appreciated!