My 427 dyno, analyze this graph
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TECH Junkie
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From: Republic of Texas
Originally Posted by Beast96Z
If the smoke is coming from blow by, it should be minimal upon crank up, but if it is coming from the top end, it should smoke pretty good upon startup due to seepage while it sat.
Originally Posted by 11 Bravo
It doesn't smoke on cold starts that I've seen. I've seen smoke only when I nail it. Didn't know it puffs smoke between shifts until someone on the road told me today. I'm thinking of fabbing up a catch can and see what it gets.
Is that the 427 from JPR from several years ago FINALLY living?????
My JPR motor blew up at 10K.....
Anyway, you can get the Harland rebuilds direct too, local company to me and great folks there.
My JPR motor blew up at 10K.....
Anyway, you can get the Harland rebuilds direct too, local company to me and great folks there.
Originally Posted by Viper
Anyway, you can get the Harland rebuilds direct too, local company to me and great folks there.
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From: Republic of Texas
Originally Posted by Viper
Is that the 427 from JPR from several years ago FINALLY living?????
My JPR motor blew up at 10K.....
Anyway, you can get the Harland rebuilds direct too, local company to me and great folks there.
My JPR motor blew up at 10K.....
Anyway, you can get the Harland rebuilds direct too, local company to me and great folks there.
I would include the Darton block he sent me, but it was cracked. I just moved up here, and little does he know I live only 2 miles from him. Suprise, suprise. Actually I think word has probably gotten to him. Gonna be calling him out shortly, I just didn't want to come into town and start **** the first month here when I'm the new guy with the local crowd. He is even working on cars again after he told me he joined the navy a year ago. Plenty of hot rods sitting at his house right now. Thread Starter
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From: Republic of Texas
Originally Posted by Pro Mouse
My New 408 was going through oil like that.I see you have a 99 ,I went to a LS6 Valley cover on my 99 ,My Oil drinking was PCV related.I would fill my catch can in about 100 miles and every time I nailed it was a freaking Smoke screen ,couldnt see the cars behind me(Very imbarrising)...You may wanna check into that.
I'll be damned, you know I heard Joe Prince was not even his real name!!!!! I can't believe he's got the nerve to work on these cars again, there's people still looking for his azz. Hope he doesn't have the cajones to join the board again along with the shady shop in PA (which will remain unnamed). I'm also stunned he joined the Navy at his age, plus having 2 kids at home.
Last edited by Viper; Jul 2, 2006 at 08:12 AM.
"How is the valley cover different? I'll have to look into that."
It pulls oil from the valley instead of the valve covers.
http://www.ls1howto.com/index.php?article=18
It pulls oil from the valley instead of the valve covers.
http://www.ls1howto.com/index.php?article=18
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TECH Junkie
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From: Republic of Texas
Originally Posted by Viper
I'll be damned, you know I heard Joe Prince was not even his real name!!!!! I can't believe he's got the nerve to work on these cars again, there's people still looking for his azz.
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Hello. I dont know alot of you here, but I do have some input on your rocker arm decision. The Comp Cams Pro Magnum Rockers are heavier...yes. But The extra weight is in the trunion area to decrease deflection. The valve spring itself doesn't see anymore weight than it would with a Harland Sharp. You wont see a difference in power or what you might think is valve float. The harland sharps will 'deflect' or bend more under higher spring pressures thank the comp pro mags. Your choice, but I wouldn't waste my money when you already have a better setup. About the oil consumption, block off all hoses to the intake from the crankcase. If it doesn't stop it is definately valve related. Some engine builders do not put valve seals on heads because of high lift and better lubrication. My Brodix came assembled, no seals on the exhaust. Smoked. Double check that. Thanks
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Great curve, but out of a 427 you should be making more power a lot sooner. Also a lot more power. Why are you burning so much oil? 1 qt every 100 miles??? On another post a guy was using a lot of oil with his DART 225's but after he switched to the AFR 225's he lost a few hp, but stopped using oil. Maybe your heads are the issue. Just my opinion.
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From: Southern California
If you're burning that much oil, you will definitely kill low-end torque. Oil of course kills octane.
Abnormal combustion on NA motors (with a free flowing exhaust) is most likely to occur at low engine rpms because there's plenty of time for abnormal combustion to take hold (that's why there's less timing advance at low rpms at WOT load than high rpms).
Combine the two factors and you can see why you can't make good low-end torque for the cubes.
Burning a lot of oil?
In addition to the PCV diagnosis made above, check:
Angle of the heads with the block to the mating angle of the intake manifold. All you need is a bad flycut on the heads and/or resurfacing of the block deck and you have additive effects that doesn't match up with the manifold. If it doesn't match up, you're sucking it from the lifter valley through the intake gasket. Symptoms: you can see it smoking a lot at long periods of idle. Other than the PCV problem, this will definitely get you 1 qt/100 mile consumption while generating at least 80-90% of intended power and running smooth.
I cannot see bad valve seals/guides burning 1 qt/100 miles although the intentional lack of an valve seal comment above is interesting. Bad guides or seals may have symptoms of a puff of smoke upon sudden load transients.
If the top two rings are sealing poorly then you'd blow out crank and rear main seals with the blowby to burn 1 qt/100 miles...plus it wouldn't make 489 rwhp however disappointing you feel that # to be.
It could be an abnormally low tension oil control ring from a defect. But I doubt it.
Abnormal combustion on NA motors (with a free flowing exhaust) is most likely to occur at low engine rpms because there's plenty of time for abnormal combustion to take hold (that's why there's less timing advance at low rpms at WOT load than high rpms).
Combine the two factors and you can see why you can't make good low-end torque for the cubes.
Burning a lot of oil?
In addition to the PCV diagnosis made above, check:
Angle of the heads with the block to the mating angle of the intake manifold. All you need is a bad flycut on the heads and/or resurfacing of the block deck and you have additive effects that doesn't match up with the manifold. If it doesn't match up, you're sucking it from the lifter valley through the intake gasket. Symptoms: you can see it smoking a lot at long periods of idle. Other than the PCV problem, this will definitely get you 1 qt/100 mile consumption while generating at least 80-90% of intended power and running smooth.
I cannot see bad valve seals/guides burning 1 qt/100 miles although the intentional lack of an valve seal comment above is interesting. Bad guides or seals may have symptoms of a puff of smoke upon sudden load transients.
If the top two rings are sealing poorly then you'd blow out crank and rear main seals with the blowby to burn 1 qt/100 miles...plus it wouldn't make 489 rwhp however disappointing you feel that # to be.
It could be an abnormally low tension oil control ring from a defect. But I doubt it.
Something about.. the 427's???
"And FWIW, it is seriously using oil, probably 1 qt every 100 miles and smokes out the tailpipes after each shift, as someone at a red light informed me. Smokescreen when floored, not sure if that is normal with this setup."
Just read a post on the Vette forum. The guy was complaining that his 427 was smoking, and he used 2 1/2 qts in 500mi, filled it up, and used another qt in 200 mi..He reported that his setup included a catch can system..
Are we seeing a pattern here??
Don't know who did the build, but have asked the ?....
Wasn't there also a thread about Dart heads, ported by another shop, having oil issues?? Didn't see the results of that investigation.
"And FWIW, it is seriously using oil, probably 1 qt every 100 miles and smokes out the tailpipes after each shift, as someone at a red light informed me. Smokescreen when floored, not sure if that is normal with this setup."
Just read a post on the Vette forum. The guy was complaining that his 427 was smoking, and he used 2 1/2 qts in 500mi, filled it up, and used another qt in 200 mi..He reported that his setup included a catch can system..
Are we seeing a pattern here??
Don't know who did the build, but have asked the ?....
Wasn't there also a thread about Dart heads, ported by another shop, having oil issues?? Didn't see the results of that investigation.
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From: Republic of Texas
Originally Posted by btwarrior
Hello. I dont know alot of you here, but I do have some input on your rocker arm decision. The Comp Cams Pro Magnum Rockers are heavier...yes. But The extra weight is in the trunion area to decrease deflection. The valve spring itself doesn't see anymore weight than it would with a Harland Sharp. You wont see a difference in power or what you might think is valve float. The harland sharps will 'deflect' or bend more under higher spring pressures thank the comp pro mags. Your choice, but I wouldn't waste my money when you already have a better setup. About the oil consumption, block off all hoses to the intake from the crankcase. If it doesn't stop it is definately valve related. Some engine builders do not put valve seals on heads because of high lift and better lubrication. My Brodix came assembled, no seals on the exhaust. Smoked. Double check that. Thanks
Originally Posted by RAMPANT
I have a similar set up but with a 412 LS2.
I do have AllPro heads and Kooks 1 7/8 headers with cats. Plus a steel DS and 12 bolt with 3.73 gears.
It made 512rwhp with 1.75 Pro Magnum rockers. It nosed over at 6100 rpm like yours. We put the stock rockers back in and picked up 40rwhp at 6500rpm. Still the same peak at the same rpm. It suggests valve train issues at the higher rpms. I went from .628 lift to .610 with the rocker change and gain hp under the curve.
BTW I have a set of Jesel J2k's on the way to replace the Pro Magnums.
The rockers will help, IMO.
Anyone want to buy a set of very low mileage rockers?
I look forward to seeing if you get the same type of results.
Rampant
I do have AllPro heads and Kooks 1 7/8 headers with cats. Plus a steel DS and 12 bolt with 3.73 gears.
It made 512rwhp with 1.75 Pro Magnum rockers. It nosed over at 6100 rpm like yours. We put the stock rockers back in and picked up 40rwhp at 6500rpm. Still the same peak at the same rpm. It suggests valve train issues at the higher rpms. I went from .628 lift to .610 with the rocker change and gain hp under the curve.
BTW I have a set of Jesel J2k's on the way to replace the Pro Magnums.
The rockers will help, IMO.
Anyone want to buy a set of very low mileage rockers?
I look forward to seeing if you get the same type of results.
Rampant
Originally Posted by Viper
"How is the valley cover different? I'll have to look into that."
It pulls oil from the valley instead of the valve covers.
http://www.ls1howto.com/index.php?article=18
It pulls oil from the valley instead of the valve covers.
http://www.ls1howto.com/index.php?article=18
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From: Republic of Texas
Originally Posted by TunedPower
If you're burning that much oil, you will definitely kill low-end torque. Oil of course kills octane.
Abnormal combustion on NA motors (with a free flowing exhaust) is most likely to occur at low engine rpms because there's plenty of time for abnormal combustion to take hold (that's why there's less timing advance at low rpms at WOT load than high rpms).
Combine the two factors and you can see why you can't make good low-end torque for the cubes.
Abnormal combustion on NA motors (with a free flowing exhaust) is most likely to occur at low engine rpms because there's plenty of time for abnormal combustion to take hold (that's why there's less timing advance at low rpms at WOT load than high rpms).
Combine the two factors and you can see why you can't make good low-end torque for the cubes.
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From: Republic of Texas
Originally Posted by allngn_c5
Why are you burning so much oil? 1 qt every 100 miles??? On another post a guy was using a lot of oil with his DART 225's but after he switched to the AFR 225's he lost a few hp, but stopped using oil. Maybe your heads are the issue. Just my opinion.
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From: Republic of Texas
Originally Posted by Old Geezer
Don't know who did the build, but have asked the ?....
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Yall tell me what you think. I believe before my calculation was a little off. The cam lift on the intake is .635 (.625 exhaust). I come up with .635 / 1.7= 373.5294 x 1.75= .653. If this is correct, I am actually over my valve spring limit.