At what point do you need beefed up engine parts ?
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Topic: At what point do you need beefed up engine parts ?
Posted By: DougG
Subject: At what point do you need beefed up engine parts ?
Date Posted: 24 Aug 2012 at 8:56pm
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At what point do you need hardened connecting rods , steel crank,double valve springs etc ? I kno of a few 426,s around here with 450 pump heads , big turbos and all stock stuff still running , but at 3000 rpm,s ; seen Bobs hole in the engine ,just wondering were the point is ?
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Replies:
Posted By: mlpankey
Date Posted: 31 Jul 2013 at 8:37pm
alot of times unfortunately its after it breaks. optimism over shadows reality at times and sometimes we just simply overthink it with rationalization.lol
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people if they don't already know it you can't tell them. quote yogi berra
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Posted By: DrAllis
Date Posted: 01 Aug 2013 at 9:16pm
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I've been involved with several Pullers over the years. My last was a 220 tractor with DB450 Roosa pump (leaf spring removed) with 4 hole x .020" injectors set at 2500 psi. Turbo was a Holset HX50 and would make 45 to 47 psi of boost with a 3000 rpm limit. Stock crank, cam, main caps, piston & sleeves, connecting rods and valve springs. Did not have water injection as the Rules did not allow it. I knew of a D21 with similar components that ran open rpm's and one time bent two connecting rods because the driver stalled the engine and did not turn off the water injection soon enough and the rods bent, not broke. Saw a 180 with excess water injection do the same thing. All crankshafts are steel. I know of only a handful of "billet" crankshafts as they can run upwards of $10 grand and are over 2,000 HP. Double valve springs are needed over 3500 - 3800 rpm. Stock main caps are good for 800 HP on a 301....426's may need a girdle before that. I do think later years the rods weren't as strong as the very early 70's and older....different vendors.
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Posted By: 2wise4agm
Date Posted: 01 Aug 2013 at 9:33pm
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So you think a 301 with stock rods will survive quite a while at 35-40 pounds of boost? That's what mine makes and it concerns me quite a bit. It makes about 8 hooks a month in the summer time.
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Posted By: rowcropmafia
Date Posted: 01 Aug 2013 at 11:16pm
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My 301 has been making 50-55 lbs boost 1400-1600 egt. With stock rods pistons and crank and its still living
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Posted By: O.P.S. Heads
Date Posted: 02 Aug 2013 at 1:38pm
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It has a lot more to do with HP and Ft lbs. produced than it does boost. An engine making 50 lbs. of boost that will effectively burn 600 cc's is much different than 50 lbs. of boost burning 250 cc's. Think of it more from a weight to gear ratio, if you can run 7th gear with a 190 driveline @ 6500 lbs. and spin it out with authority, you better have done something with your conn rods. Yes there are many other factors, but use that for a benchmark to go from. Yes the older rods (in a 301 anyway) can be harder / stronger than some of the later rods. Do a Rockwell test and find out. The better rods are 30 - 32 from the factory. These will hold up very well up to a point. If you can have someone (Max Simpson)heat treat them and get them to 38 - 40 Rockwell they will put up with 1000 HP or so. After than something other than OEM should be used.
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Posted By: Bob C IL
Date Posted: 02 Aug 2013 at 4:18pm
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Mine ran fine for 2 years till it went to 60 psi at 320cc... DAMN IT WAS A RUNNIN GOOD BEFORE THE BANG
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Posted By: Larry W.
Date Posted: 02 Aug 2013 at 4:41pm
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Bob, I sent you a message in your pm box
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Posted By: 2wise4agm
Date Posted: 02 Aug 2013 at 8:54pm
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My pump only flows 200cc and sixth is about the highest gear it can spin out in, so I'm probably ok for a while. I just see 1600 egt and 40 psi and start thinking too much I guess.
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Posted By: Bob C IL
Date Posted: 03 Aug 2013 at 9:01am
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That's a major problem with us low budget Pullin teams.... We worry to much about what's goin to come apart!!!! IN MY OPINION THE CHEAPEST PERFORMANCE YOU CAN GIVE YOURSELF IS.... Ask questions!!! They might sound stupid to some people and great to others but hey IT DON'T COST A DIME TO ASK SOMEONE ELSE WHO DON'T MIND SPENDING THERE INHERITENCE.... Bob C. Pres of the penny pinchin Pullin team...
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Posted By: rowcropmafia
Date Posted: 03 Aug 2013 at 7:36pm
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Bob is exactly right. I bet you would be suprised how many people are willing to help with any questions you have. Alot of the guys who help me keep mine running are guys I pull against
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