Questions on building a 451...
#337255
06/03/09 03:31 PM
06/03/09 03:31 PM
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Joined: Jan 2003
Posts: 408
Tampa, Fl
valiantboy
OP
super gas
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OP
super gas
Joined: Jan 2003
Posts: 408
Tampa, Fl
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Going to build a 400 based 400 based 451. i know This debate has been hashed before. Long rod or short? i know the better rod ratio is with the long rod motor. But the piston is shorter, the wrist pin is in the oil ring.. this is going to be a pump gas street motor and im just thinking longevity. Does the wrist pin effect the oil rings, being theres a "hole" going thru them? Does that raise the oil consumption? So will the short rod motor be better for a street application?
I'm WAY too baked to drive to the devil's house.
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Re: Questions on building a 451...
[Re: AndyF]
#337257
06/03/09 04:05 PM
06/03/09 04:05 PM
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Joined: Jan 2003
Posts: 75,082
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,082
U.S.S.A.
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Quote:
The wrist pin doesn't have to be in the oil ring on a 451 piston, there is plenty of room there for both.
What he said , the wrist pin would only get into the oil ring if you used a rod longer than the std RB length .
Off the shelf piston for that combo as long as you have the right bore size , 4.375 , rings readily available ...
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Re: Questions on building a 451...
[Re: JohnRR]
#337258
06/03/09 05:19 PM
06/03/09 05:19 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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I dont like the oil pin in the oil ring deal for the street. IMO, it's amistake to use it. But, if you look at a quality forged piston, you will find ones that don't have that feature. Pay more for the pistons and you'll be happier. KB hypers have the pin in the rail. They are strong enough, but IMO they are not good for this application.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Questions on building a 451...
[Re: moper]
#337259
06/03/09 05:25 PM
06/03/09 05:25 PM
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Joined: Jan 2003
Posts: 75,082
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,082
U.S.S.A.
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Quote:
I dont like the oil pin in the oil ring deal for the street. IMO, it's amistake to use it. But, if you look at a quality forged piston, you will find ones that don't have that feature. Pay more for the pistons and you'll be happier. KB hypers have the pin in the rail. They are strong enough, but IMO they are not good for this application.
I try to avoid KB hypers at all cost , didn't realize their piston has the pin in the oil ring , but it doesn't surprise me I guess ...
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Re: Questions on building a 451...
[Re: valiantboy]
#337264
06/04/09 11:22 AM
06/04/09 11:22 AM
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Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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I would use the rb rod which would give you #1 a shorter piston(lighter) & a better rod/stroke ratio & nowhere near a problem w the oil ring/pin or the piston being too short to where it rocks but now that you need a rb crank I'd use rb rods and an off the shelf KB 451 piston & still wont have any of the above problems
live every 24 hour block of time like it's your last day on earth
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Re: Questions on building a 451...
[Re: RapidRobert]
#337265
06/04/09 11:36 AM
06/04/09 11:36 AM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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I used J&E. But all the good piston places have them. KB Hypers all have a huge gap between the top and 2nd rings, so for that reason it pushes into the pin bore on that model. I was going to say, it's not worth having a crank offset ground or eevn cut down any more unless your family's into crank grinding. Use the 440 Source one for the conversion. It's a bit cheaper than having all the stuff modified to fit. Make sure you get a forged crank core... or you have to grind down the counterweights to fit in the block too.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Questions on building a 451...
[Re: RapidRobert]
#337267
06/04/09 11:54 AM
06/04/09 11:54 AM
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Joined: Jan 2003
Posts: 17,904
S.E. Michigan
ZIPPY
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 17,904
S.E. Michigan
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I used a stock 440 steel crank and modified the counterweights to 7.25 OD by hand (angle grinder + die grinder) which also gave me the opportunity to detail and deburr the part.
Core crank-80
Mag-50 (if memory serves)
Grind and polish-90
I used 6.76 Manley H beam rods and Diamond pistons. The wrist pin is nowhere near going through the oil ring land.
Rich H.
Esse Quam Videri
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Re: Questions on building a 451...
[Re: valiantboy]
#337268
06/04/09 01:02 PM
06/04/09 01:02 PM
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Joined: Oct 2005
Posts: 4,956
WI
Dcuda69
master
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master
Joined: Oct 2005
Posts: 4,956
WI
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Quote:
Well come to find out the block has been line bored to use the 440 mains. evidentally the guy i got it from thought itd be better. so i have to use a 440 crank. not that this is a huge problem.
That's good news! 440 crank,RB length rods,4.375 bore. If the Ross piston is only $125.00 more that would get my vote.Should be lots of piston options for that combo that will keep the pin out of the oil ring. 
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