331 or 347?
4th Gear Member
Joined: Jan 2006
Posts: 1,527
From:
RE: 331 or 347?
4th Gear Member
Joined: Nov 2004
Posts: 1,724
From:
RE: 331 or 347?
I don't understand everyones issue with stroke length of 347. No one seems to be scared of 351 which is even longer stroke with same bore.
The issue of the 347 was, and I say was, the position of the wrist pin and oil rings. The original kits had the oil rings on top of the wrist pins and some say this caused higher oil consumption. The new kits, have just a bit shorter rods which gets the oil rings off the the wrist pin area, so problem solved.
The issue of the 347 was, and I say was, the position of the wrist pin and oil rings. The original kits had the oil rings on top of the wrist pins and some say this caused higher oil consumption. The new kits, have just a bit shorter rods which gets the oil rings off the the wrist pin area, so problem solved.
5th Gear Member
Joined: Jul 2005
Posts: 2,450
From:
RE: 331 or 347?
ORIGINAL: angcobra
I don't understand everyones issue with stroke length of 347. No one seems to be scared of 351 which is even longer stroke with same bore.
The issue of the 347 was, and I say was, the position of the wrist pin and oil rings. The original kits had the oil rings on top of the wrist pins and some say this caused higher oil consumption. The new kits, have just a bit shorter rods which gets the oil rings off the the wrist pin area, so problem solved.
I don't understand everyones issue with stroke length of 347. No one seems to be scared of 351 which is even longer stroke with same bore.
The issue of the 347 was, and I say was, the position of the wrist pin and oil rings. The original kits had the oil rings on top of the wrist pins and some say this caused higher oil consumption. The new kits, have just a bit shorter rods which gets the oil rings off the the wrist pin area, so problem solved.
2nd Gear Member
Joined: Feb 2006
Posts: 271
From: Florida!
RE: 331 or 347?
The 331 is the way to go, in my oppinion. The 331 from DSS offers the best combo of rod ratio, piston design, and ring package for the 8.2 inch deck height engine. The larger strokes create frictional losses, poor ring seal, and compromised piston design. That problem can be easily fixed with a taller 8.7 inch deck, but it costs more. Actually a 331 is about 40hp better at 6,000 rpm than a 347. The 347 is good for heavier cars that need extra low-end torque.
4th Gear Member
Joined: Nov 2004
Posts: 1,724
From:
RE: 331 or 347?
ORIGINAL: Sleeper_Stang_89
The 331 is the way to go, in my oppinion. The 331 from DSS offers the best combo of rod ratio, piston design, and ring package for the 8.2 inch deck height engine. The larger strokes create frictional losses, poor ring seal, and compromised piston design. That problem can be easily fixed with a taller 8.7 inch deck, but it costs more. Actually a 331 is about 40hp better at 6,000 rpm than a 347. The 347 is good for heavier cars that need extra low-end torque.
The 331 is the way to go, in my oppinion. The 331 from DSS offers the best combo of rod ratio, piston design, and ring package for the 8.2 inch deck height engine. The larger strokes create frictional losses, poor ring seal, and compromised piston design. That problem can be easily fixed with a taller 8.7 inch deck, but it costs more. Actually a 331 is about 40hp better at 6,000 rpm than a 347. The 347 is good for heavier cars that need extra low-end torque.
I always thought friction loses and ring seal was based on ring; material, thickness, and cylinder wall tension.
What about the piston design is compromised?
How does a 331 create more HP than 347 is all else is equal?
5th Gear Member
Joined: Feb 2006
Posts: 3,915
From: Southwest VA.
RE: 331 or 347?
that would be a first of many that i heard an equal 331 produce more hp than a 347. i want to see this info too. and also ive been runnin my 347 pretty hard and its doing great so far, and i just like to have the bigger engine....lol, mines bigger than yours.
1st Gear Member
Joined: Jan 2006
Posts: 70
From:
RE: 331 or 347?
The org. 347's did have oil burning problems, but not now. Most use a 5.315 lenght rod and the oil rings are now moved up out of the wrist pin as angcobra has stated. The deal with the stroke is relative to the rod ratio. A stock 302 has a rod ratio of 1.69, 331 with 5.4 rod is 1.66 347 with a 5.315 rod is 1.56 AND the mighty 351 Windsor stock is 1.70. The smaller the rod ratio, the more side load on the piston and cylinder wall. That is why most people say go 331 instead of 347. In the LONG run you have less piston and cylinder wear. But if you like tearing down your engine allot build a mountain motor...average 1.35 rod ratio.
Now go with the 331 LOL
Now go with the 331 LOL
ORIGINAL: angcobra
I don't understand everyones issue with stroke length of 347. No one seems to be scared of 351 which is even longer stroke with same bore.
The issue of the 347 was, and I say was, the position of the wrist pin and oil rings. The original kits had the oil rings on top of the wrist pins and some say this caused higher oil consumption. The new kits, have just a bit shorter rods which gets the oil rings off the the wrist pin area, so problem solved.
I don't understand everyones issue with stroke length of 347. No one seems to be scared of 351 which is even longer stroke with same bore.
The issue of the 347 was, and I say was, the position of the wrist pin and oil rings. The original kits had the oil rings on top of the wrist pins and some say this caused higher oil consumption. The new kits, have just a bit shorter rods which gets the oil rings off the the wrist pin area, so problem solved.