Where? dish pistons 200 rods in 250?

[Anonymous]

Anyone know if you can get "dished" pistons for 200 rods to go in a Aussie 250.
I know ACL make 221s for this but I think they only come in a flat top

 

[xctasy]

Some have said they exist, but I'll bet they don't. Remeber, the 188/200/221 log I6 was about 100 thou shallower than the Aussie tall deck 200/250. But a 6.275 inch rod is forcing you to take off 392 thou from the piston top. Bummer.

Look through Floridaphatman's later posts. He has a piston chart there. I'd look at Subaru Liberty/Legacy 2.0 RS pistons, and run a thicker gasket or deck them 40 thou. They may be cheaper, and then pins would only need a 7 thou hone to suit the Falcon piston pin. An L/r ratio of 1.61 :1 is much better than 1.50 or 1.53, eh?


Better than the 2002 250 Pursuit 5.6 Windsor at 1.59:1 l/r, but only equal to the good ratio 1.61:1 that the forged steel cranked Chrysler Slant 225's had since 1961. At least you don't have a four bearing crank

Save money, and get the info. Someone else care to help. I don't want to tell you how much I spent on my combo. Just check my old posts

 

[Anonymous]

What is that engine youve got. Tell us about it, its got a 3.5 inch stroke I believe. Why did you do it and what sort of performance did you end up with. Execute Expert!
Oh I do seem to remmember someone on this forum stating that you can get dished pistons for the 250. Oh well might just have to find some of those six inch rods in the latter Falcon. Although it hardly seems worth the trouble apart from the rods perhaps being better quality.

 

[xctasy]

NOTHING YET!

It's still with my friend Paul getting the adaptor made for the supercharger and 21 degree tilt.

At the moment, I have 3 engines.

1.My wifes daily driver, which she just loves! The stock 4.1 with +30 thou pistons, repro Heatseaker cam from previous rebuild from former owner, stock tail pipe, NZ Heatseaker brand header, single 2-bbl Holley #2300 throttle body on 5200 to 2300 Redline adaptor, 10 mm spacer plates to fit the carb without needing a Holley 2-bbl intake, and gas flowed 34ADM intake mainfold, 432 CFM Impco A5 carb and Kand N filter. 2.77:1 open wheeler diff, drum rear brakes, and 14X8's and 235/245 60's. It's still using a BW35 gearbox, and really gets off its butt. Around town, it's first out of the starter block. It's original aside from XB bench seat. Not a glamour machine, but its never let me down...aside from the headgasket cobbled up by the former owner. :fume:

2. A spare carby 4.1 x-FLOW DA83block from late XE. Not running. In basement. Has all the consumables on it.


3. The 228 Project engine mentioned above. Swept volume is 3.736 by 3.46, which is around 3729 cc. Block is stock 250 at 9.48 inches. Now this is my present for completing my study this year. The reason I built it is because I was prejudiced against short rod, long stroke sixes. The 250's always work well on the street, better than short stroke engines, but they lack some of the screaming shunt of a V8.

For years, supercharged V8's have got my attention. Kiwis are car crazy. It's some kind of isolation backlash! 6/71 351 Clevelands are my favs. But the cost and drama of having one survive is the issue. Split bores, the still too heavy block and heads, broken tranny and diffs, expensive gear. My friends XY 351 had the fire to hook me when I was 19, but he had to rebuild an 8 grand engine twice! That's clearly a bad choice of engine. I've half a dozen friends with Clevos, and the only one that is still going without problems is a 4.9 XD ute on propane. 300 000 km with heads done for ULP. Every 351 I've seen trashed has run bearings or bore splits.

So I guess I wanted a great rev range, and a solid base which I could Turbo or even Supercharge. The 250 was it. It's cheap, strong, and if you blow it, theres 10 in the town for each 1 you see for sale!

I read every Street Machine article I could, every engine building book I could get. The bad points was lack of smoothness and restricted rev range. So I decided to trade of some cubes for a boost in rev range. I also hoped to loose some torque so I didn't have to run an exoitic diff and trans when a boost was added. This is why guys get into trouble. A turbo or blower provides so much grunt it'll blow the bits around it.

I wanted a 1.8:1 stroke to rod ratio to reduce side loads and frictional losses to a minimum. (My David Vizard theoretical bull puky again), and didn't want to blow the game on bad pistons and rods. I had an old 221 lying around, one of two I've picked up for nothing. The 221 crank is similar in most regards to the 250, but the main bearings are 100 thou smaller, and the stroke is 3.46".

I had to get it down hand welded in a jig by a local firm, and the fillet radii done. I've been told the strength is in the micro surface finishing, not the grain structure primarily. Flange and thrust bearings must copy the 250 exactly. Then it has to be rebalanced for the rods and pistons. The 200 x-flow rods are ok, not really tough, but once pined for bearings, closed , ground and cleaned up of stress risers, they should be ok to 6200 or so. And there weren't any 300 I6 rods around.

Pistons had to be 1.475 " tall. My 2.3 Cortina had a 2.8 V6 brother which had 3.66 inch pistons which were 1.59 tall, but they were cast and too small. I couldn't find any thing the right height unless I got the last of the Speed Pro US Falcon pistons. I couldn't find any, but a friend got some TRW 305 forgies from a mate. They were std size, useless for a 305, so I got 'em cheap. They can be shaved right down to well under 1.45" if you are brave. I settled at 1.475", for a perfect 0 deck. Then the pins needed rod honing to fit.

Then I wanted a rev range to 5500 rpm, maybee 6000 rpm or more on an over rev at the drags. But it has to have torque at 3500 rpm. The need for a great set of gears ment a 4-speed auto, either Chevy or Ford, would have to be used. The AOD got the nod because of its cheapness. The faults are well known, so I've saved up for a kit to replace the convertor and clutch.

The crank flange PCD about 250 thou less than the 250, so a different flywheel/flexplate is needed (351C, modified to suit the crank). I'd been looking at an AOD, and an e-mail from Jack in November 2002 confirmed that the bell area on Oz I6's was lots different. I went and got an AOD anyway, knowing that the 6 bolts of the US trans are all outside the four bolts of the Aussie block. So a simple steel plate was made. Fine untill I changed ideas to the 21 degree slant to fit the blower .This was forced by they cheap aquisition of a low- miles Commer TS3 blower.

I hope to have it completed by early next year.

 

[Anonymous]

Impressive

 

[alloydave]

Tim , ACL make 2 types of piston for the 250 using 200 rods.

6mkry9412...has a 1.85mm dish (8.6cc) which is 10.0:1 @77cc

or a 6mkry9413..this is a 2 ring piston, flat top which is 11.2:1 @68.5cc

on the 200 rods you may have to remove some metal from the top to clearboth the underside of piston.

both are quite light 368g and 402g and both use a light tapered pin.

cheers dave

 

[xctasy]

Cool Dave, sorry for:nono:
me being such a skeptic Tim. When were they released?

Shame I never knew earlier, but I guess forged pistons will last longer.

But a 250 with 200 rods will produce bulk torque and rev. Often its forged pistons that do damage...they rattle when cold in many cases, despite the advances.

 

[Anonymous]

Great.
Thanks Alloy Dave. With my cam (as with a lot of others) on aussie fuel they recommend no more than 9.5 comp. KB auto tell me than they sell a thicker head gasket for pre-cross 2V. If this isnt enough or not desirable would machining the pistons to get a bigger dish bring it from 10.1 to 9.5 or less comp without taking too much off. Sorry this is all new to me.

 

[alloydave]

hey dudes, these pistons from acl auzzie have been out for about 2 years.
the 6mkry9412 dish type is recommended for offroad use only with a fuel
of 100 ron minimum ,do not exceed 10.0:1 adjust head volume to 60cc minimum. i dont know about machining the piston it has a 1.85mm bowl depth allready and has a crown thickness of 6.75mm .i dont think you would want to go any thinner in crown thickness.average thickness in 250
pistons is between 8-9 mm .A minimum thickness at any one point of 6mm should be retained and a general head thickness 7mm.
im not 100% positive on the idea, but may an offset grind 020" on your bigends to slighty shorten the stroke? maybe .......whatya reckon Deano.

CHEERS DAVE

 

[xctasy]

Geese you've done yer homework!

Well, any thing which is forged is able to be decked with ease...as long as its not a pop-top piston. But cast or so-called semi-cast pistons are pared back material wise, by some boffin who enjoyes destroying pistons in a dyno-cell...they have a minimum of metal, yet are still fit for big revs. Deck them, and the suface finish goes out the window, pinking can occur due to ridges on the annular edge, and you are in the poo, I'd guess. The late Repco technician Phil Irving, in his book Tuning for Speed, had a piston thickness depth verses compression calculation, and the ACL pistons are right on the limit as it is.

The offset grind is okay if your machinist is happy. He has to make a call . If the indexing of the crank to a 3.89 stroke is going to be taken care of by undersize bearings in the 40 thou zone with some CBA3808 bearings, then its all good. Easy enough to do.

The issue is, preseve the piston at all costs. My under standing is that forged pistons are not more reliable than a set of semi-hypereutectic pistons...they rattle when cold and have to run extra clearnce. The ACL stuff will look after the bore and shouldn't break if given a cane.

A loss of stroke from 3.91 back to only 3.89 is nothing...and you could go to 3.87 and lose a paltry 42cc's or 2.54 cubes.

If you go this way, you'll be happy.

Just a few pointers on selection. The stock chamber is about 62 cc, the dish is 8.6cc, the deck register is 20 thou below, or 0.05 cm, the gaskets are normally 41 thou, or about 0.1 cm, and the stock swept volume per cylinder is 681.49 cc. With the 6mkry 9412, thats a 9.37:1 compression.

Lowering the piston 20 thou in the bore by a 40 thou journal grind results in a 9.28:1 compression. That's with a 3.87 inch stroke.

The stock 2v's had over 10cc of trough in the piston.

I think you'll be ok. Any problems, look for crank work or chamber work rather than a thicker head gasket. The gasket must be the best for the job, not a stand in which has the right depth to reduce compression. Check it out in the tech section, under the Bowlings formulas or in the Ford Six Performance section.

 

[addo]

A 10cc dish? Wow. The chambers can spec from 56-60 based on wot I have seen. Guess you can plug in standard and offset strokes to get some interesting numbers on the calcs.

Adam.

 

[xctasy]

Hmmmm I should have said about 10 cc.

From previous posts by AlloyDave
all suit 4.1 250 engines
4.1 x-flow leaded petrol pistons have a 22cc bowl

4.1 x-flow unleaded petrol pistons have a 27.9cc bowl

4.1 x-flow hi comp pistons from acl auzzie have 15.3cc bowl

4.1 x-flow stock rod 5.885"6mkry9411, these are reduced weight (bare 488 grams) tapered pin 115 grams , highly scuff resistant and ductile molybdenum sg top ring,
pressure balance groove delays build up of interring pressure to reduce
ring flutter at high rpm , these have a 8cc bowl 38.86mm comp height, crown thickness 8.36mm,1.8mm bowl depth .

4.1 x-flow 6.275" rod hi comp/performance acl auzzie pistons have 8.6cc bowl (6mkry9412)

4.1 x-flow super duper flat top i (think these are 6.275 " rod pistons too -xecute) (6mkry9413)

3.3 x-flow the 15.3cc seems to be the 3.3 200 piston


The original log headed 221 your working on , Adam, has 6.08 cc dish spanning 56.90 mm at the top, and 52.10 mm at the base with at 2.6 mm dish.

Dunno what the blueprint head cc's are. Piston is the stock 38.86 mm tall.

From my measurements of my last of two 221 engines.

Oh, the rods are 5.14 inches (130.56mm), not 5.41. Deck is 8.425"
(214 mm).

Deck of piston is 25 thou short of block (0.64mm).

Nice stuff.

My pistons are the ancient L2432F, or a defunct forged 229/305 piston.

The +56 bigger Chevy piston I used is 1.56 tall (39.62 mm), with a 110 thou dish (2.79mm). I shaved it to 1.475" (37.47mm), leaving a small 25 thou dish (0.64mm).

The line refrence is still available for the basic part , but the part number has changed, and theres no flat -top avalilble anymore. There are also a couple of engines it can be found on...229 or 305.

L2487F is the newer flat top 229 V6; it has replaced the older L2432F. Both have a 13 cc dish, and are 30 thou taller than the US200 /AU & AR221/ US 250 piston, but shallower than most Aussie 200/250 pistons.

L2486F is the so-called flat top 305V8 piston, and its been the same for years. It is more expensive than the 229 piston these days.


whew, now we can all get some sleep!

 

[addo]

The 221 head has a chamber around 59-60cc.

 

[Anonymous]

I contacted ACL. Tony Sidoti tells me that the 6mkry9412 and can have bottom of the bowl reduced my 1mm at the most to give around a 9.5 comp. He says 1mm would remove 4.75 cc. Although 4.4cc is all that would be needed to get it to 9.5 comp.
Next time I rebuild my engine I will most certainly do this to see if I notice any difference in the way the engine feels and performs.
The 250 is most criticised right or wrong for its "rod to stroke ratio". Fix this and no one would have sufficient reason to bad mouth it. It would be very close to a 351 Cleveland 4V Phase 4. Which from the factory was expected to go to 6000-7000 rpm.

 

[Anonymous]

Ill ask Phil Irving. about this he works just down the road from me.

 

[Anonymous]

This is the E-mail reply to below

Dear Tim,

Thanks for your enquiry.

The 6mkry9413 is a flat top whilst the 6mkry9412 has a 8.6cc bowl.

The crown thickness on the 9412 piston is 6.75mm and at most one could
machine 1mm from this crown. To drop your comp ratio by half a ratio down
to 9.5,
you would need a bowl volume of around 13cc which is 4.4cc more than the
nominal 8.6cc on the 9412 piston. Increasing the bowl depth by 1mm will
give around an extra 4.75cc which should do the trick.

The ACL Race Series pistons are in Eutectic material and not in
Hypereutectic. Please contact one of our distributors or stockists (see web
page for details.) for pricing.

If you need any further info. please do not hesitate to contact me.

Regards,

Tony Sidoti
Product Planning Engineer.

Mahle ACL Piston Products Pty Ltd.

2 - 8 Oxford Road, Laverton North. 3026. Victoria. Australia.
Fax: +61 3 99311573 Ph: +61 3 8368 1848
E-mail: Tony_Sidoti@acl.com.au
Website: www.acl.com.au


RHH Security
<rhh.security@dhhs. To: "'webmaster@acl.com.au'" <webmaster@acl.com.au>
tas.gov.au> cc:
Subject: Pistons to fit 3.3 rods into a 4.1 ford
29/05/2003 08:51 PM







Can I enlarge the dish in the piston slightly at a machine shop.
If so what is the safe limit.
I am told the part no is 6mkry9413 has a 1.85 mm dish (8.6cc
whichs
gives 10.0.1 comp. I want 9.5 or less comp.
How much are they and do they come in Hypertec (silicon impressed
aluminium)
I suspect there might be more people who whould use these if they
were lower compression, not just the racers.

Regards Tim

 

[xctasy]

Tim said

Ill ask Phil Irving. about this he works just down the road from me

.

.

I read he had passed on. If hes still alive, can I have his signiture?He must be about 93 now!

Phil Irving used to get cabin blowers of Spitfires, and throw them on bored out 1200 cc v-twin Vincient Black Shadow blocks. The man is a legend. He is a David Vizard with a FIGJAM complex. Flip I'm Good Just Ask Me. But his mouth was in fact less boastfull than his creative genius.

He had no formal engineering degree, but he designed and created uttely dependable stuff that rocked the Antipodes. Repco heads for grey and Red Holdens, Buick blocks converted to make the Repco SOHC V8 which won the Formula One race for a year with the Repco Brabahm, did Vincients design work and got it under written by other so-called engineers.He left Repco in the late 60's to work with Chambelin or do freelance work. He was totally irreverent and laconic in the manner of Gelignite Jack Murry/ Dick Johnston. A true Aussie hereo.

 

[xctasy]

I'd follow ACL's advice. No-one makes four different non-forged types of piston to suit a small market like Australia to stuff up with poor advise!

There is possibly too much made of the rod length issue, but with ACL making it so cheap that you can correct it using standard components, you'd be a fool not to take these ones.

And no-one does 3500 ft/second all the time on the street, do they?

PS:

I'll go over some calcs for compression. It would seem that the volumes given are clearance volume above the piston (68.2cc, 77 cc, 70 cc etc).

I'm pretty exited about all this new ACL piston stuff. The Americans will love it

 

[Anonymous]

If you were to follow the shape of the EFI Crossflow chamber and cut the dish (reverse dome) how deep would the cut have to be to equal about 15cc's?

You mentioned that the new pistons have a dish, is it round?
If it is round could it be opened lateraly to match the shape of the chamber?

I just emailed Keith Black about the thickness of their piston domes. Maybe they are thick enough for a little surgery

It wouldn't be the first time I cut reverse domes with a template and a router! Man, I've got to get a milling machine.

John

 

[Anonymous]

Phil Irving might well be dead but if hes dead then Ill just ask Henry Ford. Just kidding. Apologies you may well be right.