Pistons types
Thread Starter
|
Junior User
Joined: Feb 2002
Posts: 95
Likes: 0
From: Winnipeg, MB.
Pistons types
What are the pros and cons of dome, flat and concave pistons? and if you replace your pistons with high performance ones should you change your connecting rods too?
Junior User
Joined: Oct 2001
Posts: 94
Likes: 0
Pistons types
There aren't really pro's or con's. Concave pistons decrease compression to run blowers and turbos. Flat top pistons maintain an OE compression ratio. Domed pistons increase compression for high horsepower naturally aspirated engines. The domed pistons may also require the use of high octane gas to prevent pre-igntion.
You don't neccesarily have to change the rods when you replace the pistons, but if you are building a high horsepower engine you will want to put in stronger forged or powder metal rods.
-Jon
You don't neccesarily have to change the rods when you replace the pistons, but if you are building a high horsepower engine you will want to put in stronger forged or powder metal rods.
-Jon
Thread Starter
|
Junior User
Joined: Feb 2002
Posts: 95
Likes: 0
From: Winnipeg, MB.
Pistons types
How high a compression ratio can you go on regular pump gas without pre igniting the fuel? and about how much valve lift can a guy get away with, on a 351w, without using pistons that are cut for valve clearance?
Elder User
Joined: Jan 2002
Posts: 692
Likes: 0
Pistons types
>How high a compression ratio can you go on regular pump gas
>without pre igniting the fuel?
Depends on the design of the combustion chamber, but
9.5:1 to 10:1 is about the max...
>and about how much valve lift
>can a guy get away with, on a 351w, without using pistons
>that are cut for valve clearance?
Depends on the piston manufacturer, not all pistons
are built to the same specs, but .450" lift is about
max without clearancing...
Steve & the Rockette
'63 F100
'68 F100
'72 Capri 2L
'73 Capri 2.6L V6
'73 MG B GT 2.6L V6(Ford)
'98 Contour SVT 2.5L V6 (Mods)
'01 ZX2 (No Mods yet)
>without pre igniting the fuel?
Depends on the design of the combustion chamber, but
9.5:1 to 10:1 is about the max...
>and about how much valve lift
>can a guy get away with, on a 351w, without using pistons
>that are cut for valve clearance?
Depends on the piston manufacturer, not all pistons
are built to the same specs, but .450" lift is about
max without clearancing...
Steve & the Rockette
'63 F100
'68 F100
'72 Capri 2L
'73 Capri 2.6L V6
'73 MG B GT 2.6L V6(Ford)
'98 Contour SVT 2.5L V6 (Mods)
'01 ZX2 (No Mods yet)
Thread Starter
|
Junior User
Joined: Feb 2002
Posts: 95
Likes: 0
From: Winnipeg, MB.
Pistons types
Valve trains and especially the camshafts are still a mystery to me. What exsctly is a valve event and are there different grinds for different applications? Also how come some cams give you a lopey idle while other high perf cams have a smooth idle? 
Senior User
Joined: Jan 2002
Posts: 303
Likes: 0
From: USA
Pistons types
Well...I don't know much about pistons but I have heard that the dome style ones can lose you about 10+hp. Just a thought.
James
James
Trending Topics
Thread Starter
|
Junior User
Joined: Feb 2002
Posts: 95
Likes: 0
From: Winnipeg, MB.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe KucinskiGuest
Posts: n/a
Pistons types
Valve timing events are measurements of valve actions. Like intake valve open, intake valve close, ex valve opens, ex valve closes. These are commonly shortened to IVO, IVC, EVO, EVC. Lobe seperation is the degree of seperation between the max lift of the opposing valves. More seperation is peaky power at a higher RPM, like a 114 degree. Comon is a 108-110 lobe sep. Stay away from dome pistons until you know enough to go there. You can run a flat top, or slight dish with cut heads and get up to 13:1, maybe a little more. Cutting the head makes a more violent squish in the wedge head, and ands decreases the chamber CC's. This makes compression and a better burn. Run a good Venolia or similar piston, have them make them light, and you'll be set. Ballance it, and go!
Thread
Thread Starter
Forum
Replies
Last Post
Aaron-71
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
1
Jul 12, 2017 08:12 AM
BigBlocker0248
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
1
Jan 17, 2016 03:20 PM
Oldyeller75
1973 - 1979 F-100 & Larger F-Series Trucks
1
Mar 15, 2011 10:20 AM
turboman24
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
6
Mar 31, 2007 01:36 PM
