|
Re: 408 stroker build educate me
[Re: RangerDan440]
#310902
05/08/09 10:45 AM
05/08/09 10:45 AM
|
Joined: Aug 2003
Posts: 2,682
Clinton Twp. Michigan
coronet1966d
OP
master
|
OP
master
Joined: Aug 2003
Posts: 2,682
Clinton Twp. Michigan
|
Quote:
I'm running a fairly mild 408 in my truck with a cast crank, no problem but I would definitely stud the lower end. Ive also heard that Scat has a better reputation than Eagle. Keep the cam around .500 with a mellow duration since its going in a truck.
Mine is also a Magnum engine and when I built it, intake options were pretty much limited to the MP M1 so thats what Im running; its great over 4000 rpm but Im lacking the low end punch a stroker should have; Im going with more gear when I go into the rear later and hopefully that will cure it. I believe theres an Performer intake out there now for the Magums and thats what I would recommend for an RV-style cam in a truck.
Anyway, the 408 puts my 4400-lb 96 Ram into the mid 13s with 17 mpg (518 trans) so I cant complain. You'll have fun dusting off Mustangs and Hemis. 
i cant believe your truck weighs almost 1000lb more than mine
|
|
|
Re: 408 stroker build educate me
[Re: Crizila]
#310903
05/08/09 11:40 AM
05/08/09 11:40 AM
|
Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
|
I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
|
Quote:
Fact is Moper Mean speed is best way ( and the norm )for measuring piston strength and durability. At peak speed there is very little stress on the piston, so just measuring at one speed ( especially peak ) tells you very little about piston/rod/crank strength. The big hurter is at TDC / BDC, when the piston is at zero fps and changing directions. Yes, it is my engine, and I have had great results 100% of the time. Anyone who limits their stroker motor to 5K should go to their room!
Again, I disagree. Peak is the maximum force the piston, pin, and rod will face. The ratings we typically read are for mean speeds, yes. that's correct. But, pistons and rods dont break (from rpm stresses) at TDC or BTD. They break when either accelerating away or slowing down to those places. Cranks dont have torsional stress, not acceleration and dont figure at all in anything other than generating the acceleration rate. In any event, hypers are a favorite of mine in strokes up to 3.75. After that, they shoudl be replaced with forged for durability. Liek anythign else, a part has a finite number of cycles before it breaks. The closer you are to the limit, the fewer cycles it can take before it breaks. Lighter pistons let the rods live. But longer strokes are a beating on cast or hypereutectic pistons. AS far as rpms.. My truck doesnt see over 3500 with its' 360. It might hit 4K with a trailer up a hill in 2nd. So the sstroker for it will have cheap hypers in it. I'm not sure where that rpm remark came from other than a narrow singular viewpoint.
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.
|
|
|
Re: 408 stroker build educate me
[Re: coronet1966d]
#310904
05/08/09 11:51 AM
05/08/09 11:51 AM
|
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
|
Quote:
Quote:
I'm running a fairly mild 408 in my truck with a cast crank, no problem but I would definitely stud the lower end. Ive also heard that Scat has a better reputation than Eagle. Keep the cam around .500 with a mellow duration since its going in a truck.
Mine is also a Magnum engine and when I built it, intake options were pretty much limited to the MP M1 so thats what Im running; its great over 4000 rpm but Im lacking the low end punch a stroker should have; Im going with more gear when I go into the rear later and hopefully that will cure it. I believe theres an Performer intake out there now for the Magums and thats what I would recommend for an RV-style cam in a truck.
Anyway, the 408 puts my 4400-lb 96 Ram into the mid 13s with 17 mpg (518 trans) so I cant complain. You'll have fun dusting off Mustangs and Hemis.
i cant believe your truck weighs almost 1000lb more than mine
4400 isn't too bad. '79 LRE's were listed at 4000 I thought. my '96 ram SLT 5.2L, NVG3500 5 speed, 2wd 8' bed was 4700 w/1/2 tank of gas when I weighed it (without me).
had PS/PB/PW/PL A/C and some heavy 17x8 cragar SS's with 275/60R17's on it.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
|
|
|
Re: 408 stroker build educate me
[Re: moper]
#310905
05/08/09 08:47 PM
05/08/09 08:47 PM
|
Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
|
master
Joined: Oct 2003
Posts: 7,506
Az
|
Quote:
Quote:
Fact is Moper Mean speed is best way ( and the norm )for measuring piston strength and durability. At peak speed there is very little stress on the piston, so just measuring at one speed ( especially peak ) tells you very little about piston/rod/crank strength. The big hurter is at TDC / BDC, when the piston is at zero fps and changing directions. Yes, it is my engine, and I have had great results 100% of the time. Anyone who limits their stroker motor to 5K should go to their room!
Again, I disagree. Peak is the maximum force the piston, pin, and rod will face. The ratings we typically read are for mean speeds, yes. that's correct. But, pistons and rods dont break (from rpm stresses) at TDC or BTD. They break when either accelerating away or slowing down to those places. Cranks dont have torsional stress, not acceleration and dont figure at all in anything other than generating the acceleration rate. In any event, hypers are a favorite of mine in strokes up to 3.75. After that, they shoudl be replaced with forged for durability. Liek anythign else, a part has a finite number of cycles before it breaks. The closer you are to the limit, the fewer cycles it can take before it breaks. Lighter pistons let the rods live. But longer strokes are a beating on cast or hypereutectic pistons. AS far as rpms.. My truck doesnt see over 3500 with its' 360. It might hit 4K with a trailer up a hill in 2nd. So the sstroker for it will have cheap hypers in it. I'm not sure where that rpm remark came from other than a narrow singular viewpoint.
Apologize for the RPM remark moper - obviously that wasn't necessary. I probably am pushing the hi side of the envelope for my combo, but I think i'm still in the safe window. Some times I fall pray to the "happyness is a low ET" syndrome and lose sight of my original build goals - usually results in broken stuff. There is a lot of dynamics going on with the crank, rods & pistons that make the topic wide open for discussion. All these components don't see max stress at the same time during a 720 degree 4 stroke cycle. I happen to like and use my mean speed example and so far so good. I'm sure eventually I will break stuff - through fatigue, over stressing, what ever. Thats what mechanical things do. Just hoping it doesn't happen - tomorrow. 
Fastest 300
|
|
|
|
|
