Alternative Piston For 250 Other than the 255 V8

People who have read "The Ford Falcon Six Performance Handbook" know that a performance upgrade when rebuilding the 250cid
is to use pistons from the 1980-82 255cid V8. The 255cid V8 piston has a CH of 1.585" vs. 1.50" of the 200/250cid, and a piston
recess of only 1.5cc vs. 8.0cc of the 200/250cid. An advantage to using the 255cid V8 piston is to reduce the deck recess from the
stock 0.134" to 0.052", increasing compression and helping quench.

Unfortunately, 255cid V8 pistons are getting difficult to find. Another alternative piston, although not as beneficial as the 255cid V8,
is the inline four 2.5L HSC from the 1986-90 Taurus. The 2.5L piston has a CH of 1.556" with a flat top (no recesses). This piston
will reduce the deck recess to 0.078", can be found in several oversize, has the same pin diameter, and uses the same rings as the
200/250cid piston.

Hope this helps

I have scoured through several hundred pages of piston catalogs looking for a suitable swap, but can't find anything better than the one's you've mentioned. I found several new one's that had a taller compression hgt. than the stock 250 piston, but shorter than the 255 pistons. So no real advantage unless the 255 pistons completely went away. I did however find some that would be good for using with longer rods. The 3.68" bore size and 1.585" to 1.600" compression hgt is just not real common to many manufacturers I've seen in the piston catalogs.

then I C alota:

machined

/OR/

custom

on here. That opens another whole cana worms (^ da $ too).
What's the low & high price points (don't need range per se` just the 2 end points)? would you just need the same pin location & boar dia to keep the machining minimum? are custom an advantage (cast/alu/forged/hyperb/other options) for anything beside turbo? - just 4 compression & burn dynamics (swirl)?

. from a 2012 forum discussion:
The US 250 performance engine I'm running, uses TRW/SealedPower # 470NP's pistons. The application is 79-89 AMC 4.2(258).

Ford 250: bore = 3.68 / comp distance = 1.5 / dish volume = 13cc
AMC 258: bore = 3.75 / comp distance = 1.633 / D-Sump = 21cc's

This utilizes the bore at @ .070 over and raise the piston toward the deck .133 . The specs list the pin diameter of the ford rods at .9122 and the AMC's at .9310 which the rod bore can easily accommodate.

The cc volume of the recess is 21ccs. With the .070" overbore the bore is 3.75", stroke of 3.91, a Felpro head gasket at .050", a zero deck height, chamber volume of 60ccs and a piston recess of 21 ccs, gives a street compression ratio of 8.8:1 with @ OEM deck/head before any milling. milled head chamber volume , gasket crush variable will raise CR.

http://www.ebay.com/itm/AMC-Jeep-4-2-4- ... zG&vxp=mtr

2016:
I've been running the .070 overbore 250 for @ 10 years to local cruises, interstate trips and quite a few trips to Lebanon Valley Dragstrip.The 250/AMC piston .070 overbore seems quite manageable. 8)

have fubn

PS > Looking for FORGED pistons for 250 forced induction project.

Hi powerband, as far as forged pistions go about the best deal is from Auto Tech (see link below) which will custom build you a piston (even set them up for modern low tention rings (i.e. Metric) at no extra charge too) and built to your specs. Prices are quite reasonable, this is what I plan to use if I can get the funds togeather to build an engine. Good luck

http://racetecpistons.com/pages/autotec.php

Great info powerband! The 255 pistons have gotten so expensive it makes more sense to have them custom made by Racetek. I used the 2.5 HSC pistons and had 8cc D dishes milled into them by calspec. Had about $200-220 in them total iirc. Btw, if anyone finds they need a .040" over bore and is planning to use the 2.5 pistons, I have 2 left over from the 2 sets I picked up. Silvolite #1192+.040's

FYI there is a much better piston then the 255 stock cast piston, they also work in 200 3.3L

UEM pistons (make Sil-o-lite and Keith Black) make a replacement piston for the Assie guys that work well, they are a Hypereutectic piston so stronger then cast and tighter then forged.
The pin height is 1.53 so a little taller then stock (US) 200/250 pistons. They have 3 listing, flat top (3327H), 0.071 dish (3328H) and 0.276 dish (3332H)
I'm building a 200 using the Flat top pistons, only down sides are, need a uncut block if building a 200/3.3L and the ring pack is modern (1.5MM/4.0MM) Hasting sells ring sets in moly, I called perfect circle and got a zero gap set put together for me for a little over $100
Link if you want it. http://www.uempistons.com/catalogs/silv ... atalog.pdf
Walt

fast64ranchero":10n45md4 said:

FYI there is a much better piston then the 255 stock cast piston, they also work in 200 3.3L

UEM pistons (make Sil-o-lite and Keith Black) make a replacement piston for the Assie guys that work well, they are a Hypereutectic piston so stronger then cast and tighter then forged.
The pin height is 1.53 so a little taller then stock (US) 200/250 pistons. They have 3 listing, flat top (3327H), 0.071 dish (3328H) and 0.276 dish (3332H)
I'm building a 200 using the Flat top pistons, only down sides are, need a uncut block if building a 200/3.3L and the ring pack is modern (1.5MM/4.0MM) Hasting sells ring sets in moly, I called perfect circle and got a zero gap set put together for me for a little over $100
Link if you want it. http://www.uempistons.com/catalogs/silv ... atalog.pdf
Walt

Click to expand...

For the 200, you'd be better off getting the pistons for the 2.3L HSC from the Tempo; CH of 1.50", flat top, and oversizes are still available. Silvolite Part No. 1185. You wouldn't have to worry about the deck height with these.

I saw those Aussie pistons but they weren't as desirable as the 255 pistons because they had a shorter compression height. I was only looking for options that were equal to or better than what Rocklord mentioned.

follow up w/the details of the 4 cyl Tempo piston. it's been a go-to w/the 255 for yrs. it just may B 4 U...

http://www.crankshaftcoalition.com/wiki ... e_building

"The only difference is the 2.3L HSC pistons have a 0.090" pin offset, and the 200 pistons have a 0.060" offset. However, they still work fine, and are available oversize up to 0.080" from Speed Pro".

Utter nonsense...I wouldn't be using any 90 thou gudgoen pin offset 4 cyl piston in any i6 based on the ForSix performance guys experiences with all early HSC Sivolites under the earlier and later part numbers, and I'd be certain that includes the 2500 piston as well. They are not performance pistons in any shape or form.

/viewtopic.php?p=75817

MustangSix":277ea07i said:

US pistons will physically fit, but they don't have the dish necessary for a 250. The originals have a big 12cc dish in them, but the US pistons only have a 6.5 mm dish. The 2.3 HSC Tempo has flattops, so the difference is greater. Compression gets to be hard to manage. If you need an overbore, get the ACL versions with moly rings and shoot for no more than 9.0:1 with a carbed engine and non-computer mapped ignition.

Click to expand...

The problem is skirt cracking, piston head loss, and gudgoen pin freezing.

Its not related to the ring cleaarnces.

Its an issue they first fixed in Australia by tig welding up the pistons nasty cast in oil relief slots. In sedan racing in Australia, these pistons were notorius for piston top loss. After a piston change to drilled oil reliefs, the pistons are safe.
From our Parkwood60

Although these are not HSC pistons in the phots, he has blown up an HSC piston engine as well.

http://vb.foureyedpride.com/showthread. ... tura/page3

BRWSaver":277ea07i said:

So I pulled the motor apart, and it is the most blown of any motor I have ever seen.

http://piledriverz.com/2013/01/13/we-really-blew-it/

Click to expand...

And a terriable tendancy to break shirts, freeze the gudgoen pins and loose to piston tops.

The 86-90 2500 HSO piston has the same design.

There is not any longer a good record with the Sivolite replacement piston in any way. Our four board members have had a very bad reliablity record with these kind of pistons.


viewtopic.php?f=1&t=72474

Australian experiance says "Don't use slotted oil relief pistons in an I6 your going to accidently over rev, even if they are high silicon".

Back in the dark ages, Holden XU1 GTR 202 engines got triple CD 175 Strmbergs, 312 degree racing cams, and in 1973, triple DCOE 45's with one barrel taken out, bascially three 45 mm carbs with 40 mm chokes. The engines went from 216 hp to 235 hp flywheel , and pistons (already marginal) then started to fly appart all the time, An ex Ford development engineer Harry Firth remembered Mahale from Germany made slipper skirt cast alloy pistons with drilled oil holes that didn't come apart at 7500 rpm, for the RS2600 Cologne Capri. Through Repco, these High Performance # 9931326 / # 9931327/6KRY 2585 pistons were made. They gave sensational results

See the similarity to the 2800 Colgne pistons.





V4'S, V6's and I6's don't have the same ability to run V8 style pistons...a V8 isn't subject to the torsional vibration an I6 is under, and I6's tend to have harmonic vibrations of a low to medium order that V8's don't . The common I6 cranks aren't really that good, and a piston in an I6 is under different loads to a 90 degree crankpin counterweighted five bearing crank. So the German Mahale based casting became the high performance Holden and Ford 6 in line piston.


The Silvolite cat lists the Aussie 3327H and 3328H hyper flat tops as American made on page 29 and 33. http://www.uempistons.com/catalogs/silv ... atalog.pdf

See http://www.gmh-torana.com.au/forums/top ... 1-pistons/

and another view of the type of piston skirt differences.

Replacement Speed Pro pistons are designed to run with tighter piston-to-wall clearance than typical forged pistons. This is largely due to the slots running the length of the piston, isolating the skirts from the crown (left). The Speed Pro race pistons are much more ridged, with drilled oil-return holes (right), and therefore need to be looser in the bores.

Click to expand...

http://www.hotrod.com/how-to/engine/mop ... z3M3ahKM7n

Click to expand...

Thanks for the discussion, all the info!

"...They are not performance pistons in any shape or form…."
I have to rely on others real world experience as I am not a racer or HP runner.
(I did/am finishing up with a less recreation/race type "work truck" vehicle). At any
rate:
Would this 4 cyl piston be alright in non-performance situations? ie street/DD applications?

The cites (all of them?) have been about severely stressed conditions & I wonder if that environment to B too different from what some of us are asking in this/other situation? Is this too different a situation or should 'we' also be concerned about this proviso?

I think that the end user needs to be truthful with themselves to make a viable piston selection. I'm my years working in a race shop, most hotrodders always wanted to have their cake and eat it too, and always tried to mislead the shop as too their true intentions for their engines. In many cases, the 4 cylinder pistons mentioned can work fine if the person is truly looking for a rebuild piston to function in a stock street driven car with little expectation of been driven like a performance build. One thing to consider is that a cast four cylinder piston isn't designed for use in a longer stroke six cylinder engine, even though the bore may be the same. The longer stroke automatically increases the piston speed even at the same RPM by some higher amount and can easily exceed the limit it is designed for in the four cylinder engine. Meaning, that some safe guard factors in piston design aren't recognized when swapping pistons around from one engine to the other.

Right on CNC Dude!

At a personal level, I could make the Silvolite piston work in those high rpm, high hp 200 and 250 circumstance. The old timers just welded the slots up and drilled oil relief holes like the Cologne and XU1 GTR solid skirt pistons. Then you could freekin stand on it for 6 hours at a 100 mph average.

The Germans made Mahale pistons, and they won many races for Fords RS 2600 and Holdens XU1 GTR 3000

This "weld it up" tip is technically illegal in showroom stock racing, but it used to be done all the time in the 60's Showroom Stock 500 mile racing in the Antipodean countires.

The history of these pistons isn't that its a" useless" or "bad" piston, its just that its a regular replacement piston with no more attrbutes than a stock part. Its not a performance part, BUT A GREAT ENGINE BUILDER CAN WORK MIRICLES WITH A MODIFIED STOCK PART.


You have to read the advice of old timers, and get the first hand experience.

KB and Sivolite are really awesome suppliers, and back there product 100%, but you must verfifiy reliabiity, and these pistons don't stack up for the engines we them in. Mustangroo and his son Jason had HSC 2300 piston problems, so did Parkwood60.

I have to recheck with Does10's, but he had some issues, but it may not have been the piston.

Its not a performance part unless you either TIG or Eutectic alloy weld and check for cracks with die penrate and Zyglo. You then have to go up a few thou on what the ring supplier recomends as the midle of the road clearance to ensure you don't get ring butting on an engine which will be under a lot more BEMP than it was stock.

And the bore hatching and plaeau hone sizing needs to suit all the wonderfull devlopements over the last 52 years since the first 200 came out in 63 Fairlanes.


Things have moved on, and your engine builder will be able to find a great piston, and if you buy an engine or engine rebuld, get a waranty. If there is none due to end use issues, then get the best pistons you can afford and clearance them to suit the RA and average requirements.


American forged pistons are still the best in the world, but you have options on Hypereutectics, but most really good ones are made for overseas cars from American suppliers. Don't discount using the HSC or HSO pistons, but talk to a builder about ensuring skirt failure ever happens.

If you do nothing, a Silvolite HSC 2300 or HSO 2500 piston will fail based on other peoples experiences.

I should start a post "Has there ever been a Silvolite HSC 2300 or HSO 2500 piston that hasn't failed in a Ford I6?"

So,
I think rocklord may have been contimplating a piston change with the return of the Alu Head?
Would there B the same advantages with this as with the 255 piston in a standard (iron log) 250 or 200 build (w/da alu head)?

Hey, here's a thought - Will the 'new' head (too expensive 4 this use, but an 'idea') go on a 170? a 144?

chad":1bxmmfxf said:

So,
I think rocklord may have been contimplating a piston change with the return of the Alu Head?
Would there B the same advantages with this as with the 255 piston in a standard (iron log) 250 or 200 build (w/da alu head)?

Hey, here's a thought - Will the 'new' head (too expensive 4 this use, but an 'idea') go on a 170? a 144?

Click to expand...

Yes, but only if valve lift is more than 450 thou at the valve. You'll be better off cutting the block and use a 200 head gasket. The bigger intake valves hit the block at 3.5", there is 90 thou less clearance before the a higher lift cam is added. Ring lands park at about 250 thou below the deck at TDC, so you can easily die grind an extra amount.

Bank on diligent die grinder work. As you over bore the block 60 thou, it becomes less of an issue, or if you use a less than 450 thou lift camshaft.

None of this relates to OP questions, but just FYI 'cause you asked.

chad":nd2z6cix said:

So,
I think rocklord may have been contemplating a piston change with the return of the Alu Head?
Would there B the same advantages with this as with the 255 piston in a standard (iron log) 250 or 200 build (w/da alu head)?

Hey, here's a thought - Will the 'new' head (too expensive 4 this use, but an 'idea') go on a 170? a 144?

Click to expand...

If using the new aluminum head is the plan, I for one would want something more sufficient than a set of $80-$90 dollar pistons in an engine.

Hope I'm not stealin away yer thead rocklord… was this ur original intent? a choice for the return of alu head?

I'm thinkin from the responses the oem 200 / 250 piston is fine. The (expensive/rarer) 255 for compression changes,

and one of these (2 me) more exotic 1s (the Tempo is not either exotic or 4 use here) for stressful apps... ?

My original intent was if someone was rebuilding a 250 and wanted the 255 V8 pistons
but couldn't find the size needed, there is an alternative (though not exact) piston
to reduce the deck height and increase compression.

*