• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

cast vs hypereutectic pistons


lzarnch

New Member
Joined
Dec 17, 2007
Messages
58
Reaction score
0
Points
0
Location
California
Vehicle Year
1987 & 1986
Make / Model
FORD
Engine Size
2.9l & 408ci
Transmission
Manual
what is the differences between the two types of pistons? what is better?:dntknw:would a bigger compresion distance give a lower compresion ratio ?:dntknw:
 


almostclueless

New Member
Joined
Aug 6, 2007
Messages
1,403
Reaction score
3
Points
0
Vehicle Year
98
Make / Model
ford
Transmission
Manual
hyper has a silicon content that makes them slightly stronger than cast pistons and nowhere near as strong as forged pistons.


a bigger compression height should mean more compression all other things being equal.
 

AllanD

TRS Technical Staff
TRS Technical Advisor
Joined
Jun 1, 2001
Messages
7,897
Reaction score
134
Points
63
Age
62
Location
East-Central Pennsylvania
Vehicle Year
1987... sorta
Make / Model
Ford
Engine Size
'93 4.0
Transmission
Manual
Actually hyper eutectics are made of an alloy that has a smaller coefficient of expansion.

The point being that the pistons expand less so that they may be fitted
more closely to the bores. This closer fitting means the engine can be
"tighter" when cold so theoretically the engine will run cleaner when cold.

Unfortunatly hypereutectic pistons are more brittle than conventionally
cast pistons.

Forged pistons are the strongest, but to allow for their greater expansion from cold to hot they must be set more "loosely".

Some performance engines "back in the day" were famous for sounding like a garbage pail full of bricks rolling down a staircase after a cold start and until they warm up.
One of the noisiest was the 289Hi-Po engine.

AD
 

almostclueless

New Member
Joined
Aug 6, 2007
Messages
1,403
Reaction score
3
Points
0
Vehicle Year
98
Make / Model
ford
Transmission
Manual
Some performance engines "back in the day" were famous for sounding like a garbage pail full of bricks rolling down a staircase after a cold start and until they warm up.
One of the noisiest was the 289Hi-Po engine.

AD
Not trying to argue with you, but I don't remember the K code having forged pistons.....it DID have solid lifters, which would be noisy.
 

bottledgt

New Member
Joined
Aug 22, 2007
Messages
619
Reaction score
0
Points
0
Age
47
Vehicle Year
94
Make / Model
ford
Transmission
Automatic
hypers are not as bad as people give them credit. i bet most people who down them have never used them. ive been running them for over 10 years on a couple motors and spraying them with up to a 250 shot and 0 failures. just gotta know how to tune
 

lzarnch

New Member
Joined
Dec 17, 2007
Messages
58
Reaction score
0
Points
0
Location
California
Vehicle Year
1987 & 1986
Make / Model
FORD
Engine Size
2.9l & 408ci
Transmission
Manual
so would hyper pistons hold up to a 50-100 shot with the right rings or would cast be better?
 

bottledgt

New Member
Joined
Aug 22, 2007
Messages
619
Reaction score
0
Points
0
Age
47
Vehicle Year
94
Make / Model
ford
Transmission
Automatic
yes they will hold up as long as you dont lean it out or detonate
 

lzarnch

New Member
Joined
Dec 17, 2007
Messages
58
Reaction score
0
Points
0
Location
California
Vehicle Year
1987 & 1986
Make / Model
FORD
Engine Size
2.9l & 408ci
Transmission
Manual
what about cast pistons with a gapless second ring allowing for mild nitrous or boost
 

bottledgt

New Member
Joined
Aug 22, 2007
Messages
619
Reaction score
0
Points
0
Age
47
Vehicle Year
94
Make / Model
ford
Transmission
Automatic
i would not run anything gapless or cast
 

lzarnch

New Member
Joined
Dec 17, 2007
Messages
58
Reaction score
0
Points
0
Location
California
Vehicle Year
1987 & 1986
Make / Model
FORD
Engine Size
2.9l & 408ci
Transmission
Manual
if i wasnt to use nitrous would cast pistons be ok with chrome iron rings
 

lzarnch

New Member
Joined
Dec 17, 2007
Messages
58
Reaction score
0
Points
0
Location
California
Vehicle Year
1987 & 1986
Make / Model
FORD
Engine Size
2.9l & 408ci
Transmission
Manual
or any good set of rings
 

shadetree

New Member
Joined
Sep 9, 2007
Messages
1,794
Reaction score
9
Points
0
Age
84
Location
East Texas
Vehicle Year
1994
Make / Model
Explorer Sport
Engine Size
4.0
Transmission
Automatic
if i wasnt to use nitrous would cast pistons be ok with chrome iron rings
Chrome rings are very hard, and this make them very hard to seat. If they don't seat properly, they will use oil. Usually, chrome rings are for vehicles used in harsh conditions such as dust, severe duty, etc.

Moly or cast iron rings work fine for normal useage. Plasma moly are good for durability without the seating/hardness problems associated with chrome. They are, however, a bit pricey.
would a bigger compresion distance give a lower compresion ratio ?:dntknw:
Define compression distance. Anything that gives more volume to the combustion chamber lowers the compression ratio. shady






shady
 
Last edited:

lzarnch

New Member
Joined
Dec 17, 2007
Messages
58
Reaction score
0
Points
0
Location
California
Vehicle Year
1987 & 1986
Make / Model
FORD
Engine Size
2.9l & 408ci
Transmission
Manual
on the pistons specs it says compresion distance. for the pistons i plan on using its 1.511" for the stock pistons its 1.461", thats what i found on a website (motorsports svo catalog) was the sorce they used. i believe compresion distance is the distance from the piston pin to the top of the piston, thats what i heard
 

bottledgt

New Member
Joined
Aug 22, 2007
Messages
619
Reaction score
0
Points
0
Age
47
Vehicle Year
94
Make / Model
ford
Transmission
Automatic
that would usually mean your pistons are higher in the deck...probably higher than the deck which would be bad. at any rate, even if it fit, your compression would be higher
 

AllanD

TRS Technical Staff
TRS Technical Advisor
Joined
Jun 1, 2001
Messages
7,897
Reaction score
134
Points
63
Age
62
Location
East-Central Pennsylvania
Vehicle Year
1987... sorta
Make / Model
Ford
Engine Size
'93 4.0
Transmission
Manual
Factory Ford Rings are chrome.

OK those that had the coin to buy a ford with a hi-po 289 would also rebuild them with forged pistons

I can't actually claim to have seen an unmodified 289.
mostly because back then nobody left things alone.

AD
 

Sponsored Ad


Sponsored Ad

Staff online

Today's birthdays

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Truck of The Month


Kirby N.
March Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top