Brencuda,

Realize my application is in a 4500 pound 64 d100 with a A833OD and a 3.91 positraction with P275 60R 15 tires, but the Edelbrock performer 500cfm (1404) on a 4bbl offy intake with custom exhaust (2 inch pipes out of Dutras to 2 1/2 muffler in and out) runs incredibly well. All it does is accelerate, no bog, no missing, no pinging. I brazed up and filed a 13R governor to make it a 9R with stock springs and a Pertronix module and stock coil with Accel 8mm plug wires. I, too am not sure exactly why it rus so well with the carb bolted on out of the box and idle screws set to idle at 600 RPM, but now that it is roadworthy I am beginning the tuning and analysis and cure plotting. Just bought a Sun machine to aid the process.

for what it's worth,
rock
'64d100

So to be clear - the artical that Doug D wrote about "Stroking the Slant 6" does not mathamaticaly work and should be removed from the articals list as it is faulty information?
If I am understanding the artical it use a stock crank that has been welded and reground (which the shop does do but hasn't done the slant crank before), uses stock length connecting rods (6.7"~) and uses a 2.2L turbo piston.
Now I am not going to get in to exact measurements at this point with you (because I don't know them). I'd like to just talk about the relationship between the parts on the lower end.
Doesn't the 2.2L piston have a wrist pin that is mounted closer to the top than the stock piston? Can't this distance be added to the length of the stroke of the crank (by welding and regrinding) as long as this added stroke does not hit the sides of the block (adding some dips for a little more clearance as talked about in the artical)? CR can also be adjusted 3 ways. First milling the head or block. Second added or subtracting some stroke. Third selecting one of the three different 2.2L pistons available. And for a fourth massaging all three to maximize stroke and hit target CR. Am I wrong in thinking that the 198 rod is the long rod, the 170 is the short rod and the 225 rod is the meduim rod that I'll be using.
You talk about doing the math in parallel. There are many number I don't yet (deck height in relationship to crank center line, wrist pin height to piston top, ect) and yes more homework is needed. Asking questions on this forum is homework. Being kicked in the face sometimes seems more fun than homework.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Perhaps it was a misunderstanding. In the past I have talked about building a "long rod" engine. In this thread I did not. To me it seemed that you were convinced that I could not stoke this engine and use 2.2L pistons. I felt that you were wrong. Did I take an aggresive tone- Yes, but not first. We will likely never know what you really thought since you've gone back and edited and deleted most of your text.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

IIRC, the limiting factor on stroke is the sides of the block. There is only so much room in there.

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Official Cookie and Mater Tormentor.

I know you can go 4.5" stroke with a stock 225 rod and 12pt rod nuts. Seen it...

Lou

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Home of Slant6-powered fun machines since 1988

The long stroke (4.5") with a 225 (6.7") rod and a 2.2 piston (appx. 1.59 compression height) Slant Six is a proven combination, I have built 2 of these engines, one is a low compression version (8 to 1) that is a real "workhorse" in one of my daily driver cars.

The second engine has much higher compression (13 to 1) and that engine breaks the off the shelf 2.2 pistons. I am ready to buy stronger custom pistons to make this engine "work" in a race application.

As noted, there are a few different versions of the 2.2 pistons and there are a number of other measurements that need to be taken to get the compression where you want it, this holds true for any special engine combo.... heck, even the factory built stuff had the "stock" engine's compression all over the map, due to wide open manufacturing tolerances.

So yes, a stroked SL6 works but it is expensive to build. (a welded and reground crank cost $$$)
I feel you will get more "value" from a properly built .060 o/s 225 or better yet, a "long rod" version of the .060 225

Note:
If you do a "stroker" go for 4.440 (appx 4 7/16") just because that stroke fits the RG block without a lot of extra grinding work.
DD

I know that there are a few of our European guys who have used the 88mm VW piston. Not usre what rod and stroke though.

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Official Cookie and Mater Tormentor.

DD
What part of the piston is breaking?

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Broke a big chunk of top ring land off.
DD