Cubes on an 84DA

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Speedy

Cubes on an 84DA

Post #1 by Speedy » Sun Oct 31, 2004 9:09 am

Reading up on GASSED260's engine has really been a delight. It really gets the gears turning and brings all sorts of questions to mind. I thought I would throw a couple of things out that I've been thinking about. I was wondering how he got his 260 inches. First off, How many cubic inches can you actually get out of one of these crossflow engines? I would like to speak in terms of an 84GA which is what I have. Is anyone making cranks for these? Is there enough meat on a stock crank to offset grind it to get a little longer stroke?

After asking the question, I realized, I don't even know what the stock stroke and bore is. Suppose I find someone to make a crank for me. How much extra stroke can I add before you run into clearance problems?

Coupled with the extra stroke, how much over bore can you safely get away with.

Looking for every bit, Do the pistons come all the way up flush to the deck or is ther a couple thousands to be had there?

Then after all this is complete, will it actually buy me any extra horsepower? Torque? Would it give me negitive returns on my rpm'S?

I read in one of my car mags where a company's making full circle cranks for V8 chevys. Running a full circle crank in my 2 cycle kart years ago as a kid made a huge difference. I always thought it would be cool for your car. Now there actually doing it. :) Now I'm dreaming :) I want a full circle stroked crank for my Aussie plant. Can you help me?

GASSED260

Post #2 by GASSED260 » Sun Oct 31, 2004 6:28 pm

Hey Speedy
My engine's not quite 260ci its 258ci
Ignore the specs in "My 250" for bore size as my callipers where no good and gave the wrong measurment

My bore is 3.74 not 3.76 and is 60# over :oops:
I don't think you can go much more than 60# as there is no off the shelf pistons bigger than 60# for the 250

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Up size Me (250)

Post #3 by xctasy » Mon Nov 01, 2004 4:35 am

If US or Aussie, the 250 isn't an engine to bore and stroke like a 300 I6, 225 or 250 Chev engine is, there isn't enough meat in the block


Aussie 250 uses a US 200 block with an extra 1.577" of deck, another link in the timing chaion in each direction, another half inch of block width, taking it to 9.58" wide at the pan, from memeory. It has better bore quality than the US engines, because the Aussie factory never had to push the thinwall casting techniques like the Ontario and Ohio boys had to on there Windsor and Cleveland engines. The Aussie ones can hack 60 thou over, but the US ones don't like more than 30 or 40 thou safely.

The Aussies made it significantly narrower than the US 250, which is 10.625" wide, not 9.58", with the Aussie cam sitting 400 thou lower in the block, and without the big US 250 cam and crank gear which is unique. The Aussie log and x-flow 250's are very much a minimum metal engine in comparison to the US 250. The top of the block is well over 1.3 " wider, however, to cope with the expansive canted valve head.

If I was doing a stroker, I'd use the US 250 because there is so much more room for an offest ground crank. You could go to 4.125", without needing a new crank, or grinding the sump, block or cam daimeter down. With a 40 thou over bore, the US 250 could bring in 270 cubes with some 1.9" journal rods and a good lower deck piston.

The Aussie 250 isn't like a Chrylser Slant 225, which has a huge crank case, and can be taken out to 4.5" stroke from 4.125" by welding the existing steel crank, and re-using the stock rods. You can go up to 260 cubes with 100 thou over pistons, up 35 cubes!

The only way you can get close to that stroke in an Aussie 250 it is by getting the piston and cylinder skirts notched further. They are already notched on the existing Aussie 250 just to get the 3.91" stroke. The con-rod parks very close to the cam and bottom cylinder wall. There were guys who would wind down the stock 2.124" crank pin to 1.899", and use Holden rods in the 221 Falcon sixes they had here, good for another 18 cubes. If you used the thinner small journal 4-cyl Honda B18 or Toyota 2.4 Previa/Camry or Nissan S15 rods, you might get to 272 with 60 thou over ACL pistons. Inliner has acces to 1.04" deck forged pistons, a whooping 490 thou thinner than the stock US and Aussie 200/250 pistons. As I say, a safe 272 cubes, a 9% upsize.

There are reports of 280 cube strokers in Australia, but there isn't lots of details. These are reported to have Nissan rods and Toyota pistons. They suffer from poor rod ratios, and are just freek motors for burnouts.

GMdestroya and I had a chat over the options late last year in the Aussie forum. tags281 had some information too.

Option 2 is to get some Aussie 5.75" Chrysler 265 Hemi rods, 2.0" pin, and stroke the crank to 4.03". You'd get 266 cubes with 56 thou over Chev pistons.
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XEC Ltd ICBE's Inter Continental Ballistic Engines-
FAZER 6Bi (M112 & EEC5) or FAZER 6Ti (GT3582 & EEC5) 425 HP 4.1L/250 I-6
FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
X-Flow Engine Components Ltd http://www.xecltd.info/?rd=10

GASSED260

Post #4 by GASSED260 » Mon Nov 01, 2004 6:09 am

This is just a pee in the ocean
If it could be done (aus 250) an over bore of 120# im sure it would need sleeves and an 80# off set stroke would give 279ci (I think) thats about 475cc bigger , Slightly bigger than the cans of Red Bear Iv just had
MMMMMmmmmm Vodka :nod:

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Post #5 by addo » Mon Nov 01, 2004 6:24 am

Vodka? Here's the ACTU looking after you!
Unions acknowledge that workers under the influence of alcohol or other drugs may pose a danger to fellow workers. They also realise that the reasons for the drug or alcohol problems may be complicated and therefore oppose a punitive approach to dealing with the employee effected. This is recognised in drug and alcohol policies developed by unions. The ACTU policy is available at http://www.actu.asn.au/national/about/p ... aldrug.htm


The whole stroking business can easily become just that... I can't see any of these things as cost-effective compared to running higher compression and Avgas or nitrous, or forced induction. This application is just too difficult for decent strokage.

GASSED260

Post #6 by GASSED260 » Mon Nov 01, 2004 6:43 am

addo wrote:The whole stroking business can easily become just that... I can't see any of these things as cost-effective compared to running higher compression and Avgas or nitrous, or forced induction. This application is just too difficult for decent strokage.


Yep a big pain in the back
Just bottle feed your baby

Speedy

Post #7 by Speedy » Mon Nov 01, 2004 8:00 am

Addo said:
The whole stroking business can easily become just that...


I realize that, But I like to know the limits and boundaries of my engines. And on a lazy Sunday afternoon, it's a nice topic of conversation preventing us from stroking our buisness.
It's a stroke of luck, that I even have one of these 250's all the way over here in Allen, Texas. :lol:
Last edited by Speedy on Mon Nov 01, 2004 8:01 am, edited 1 time in total.

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Post #8 by addo » Mon Nov 01, 2004 8:01 am

How much is your nitrous setup costing you? Or did you get it at mate's rates?

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