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| Doc - Too Much Advance - Cont'd https://slantsix.org/forum/viewtopic.php?t=3027 |
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| Author: | XMAN [ Sun Dec 23, 2001 9:34 am ] |
| Post subject: | Doc - Too Much Advance - Cont'd |
Doc - Here's the engine layout: 225, 9.5 to 1 compression (140thds total off head & block), Flat Tops, bored .030 over, oversize Ford Valves, ported & polished head, Offy intake with 1" spacer, 650 Carter & Electric Pump, 6 to 1 Headers, MP Elex Distributor (Hi Perf Advanced Curve)#P3690785, MP Blaster Coil, Hughes Cam,Hughes Solid Tappets & Hughes springs with dampners, 1.5 Rocker Ratio (No spacers on shaft), Smith Bros shortened Push Rods,MP Double Roller Chain, etc. Cam specs:Lobe Separation 110, Centerline 107, Lobe Lift .294, Valve Lift .441 (Intake & Exhaust), Duration @ .050 Tappet Lift 224 and 265 Advertised, Camshaft Timing @ .050 Tappet Lift: Intake Opens 6 Degrees BTC and Closes 38 Degrees ABC; Exhaust Opens 46 Degrees BBC & Closes -2 Degrees ATC. Valve Lash Hot is .018 Intake & .020 Exhaust. Non symmetrical ground cam. Cam was installed at 105.5+ centerline working off #1 Intake Lifter. This was close as I could get it since I was at a 8 Degree bushing on cam gear (Max) and 2 degree offset crank key. This may account for some increase in timing 18-20 degrees and 40-42 total. The 18-20 degrees is at 1,000-1,200 rpm since it doesn't want to idle correctly below 1,000. Don't know why I not getting vacuum advance but it appears to be the carb not a pod problem, but without vac adv I'm at 40-42 total, so more vac advance would probably too much. Will have to checkout carb vac ports but otherwise carb performs fine. Engine seemed to perform well on street - No pinging, backfiring, stalling, etc. Each time I try retarding timing further the engine starts to get rough and will barely run at less than 10-12 Degrees BTDC. Should it idle less than 1,000rpm?? What if anything should I do with the distributor?? Or is it a case that she "Runs where she Runs"?? I've always been a V8er, thus, as I have found out this /6 world is a totally different ball game. I don't know how a Hi Pro /6 is suppose to run or sound. Lastly the car has a built up 904, GER Converter and 8 3/4 with 391 posi and 9X15 Hoosiers (Street/Strip intentions). Any and all comments and help greatly appreciated. usclstaffingnet@sprintmail.com |
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| Author: | dschumers [ Sun Dec 23, 2001 10:42 am ] |
| Post subject: | Re: Doc - Too Much Advance - Cont'd |
Quote:
: Doc - Here's the engine layout: 225, 9.5 to 1 : compression (140thds total off head & : block), Flat Tops, bored .030 over, oversize : Ford Valves, ported & polished head, : Offy intake with 1" spacer, 650 Carter : & Electric Pump, 6 to 1 Headers, MP Elex : Distributor (Hi Perf Advanced : Curve)#P3690785, MP Blaster Coil, Hughes : Cam,Hughes Solid Tappets & Hughes : springs with dampners, 1.5 Rocker Ratio (No : spacers on shaft), Smith Bros shortened Push : Rods,MP Double Roller Chain, etc. : Cam specs:Lobe Separation 110, Centerline 107, : Lobe Lift .294, Valve Lift .441 (Intake : & Exhaust), Duration @ .050 Tappet Lift : 224 and 265 Advertised, Camshaft Timing @ : .050 Tappet Lift: Intake Opens 6 Degrees BTC : and Closes 38 Degrees ABC; Exhaust Opens 46 : Degrees BBC & Closes -2 Degrees ATC. : Valve Lash Hot is .018 Intake & .020 : Exhaust. Non symmetrical ground cam. : Cam was installed at 105.5+ centerline working : off #1 Intake Lifter. This was close as I : could get it since I was at a 8 Degree : bushing on cam gear (Max) and 2 degree : offset crank key. This may account for some : increase in timing 18-20 degrees and 40-42 : total. The 18-20 degrees is at 1,000-1,200 : rpm since it doesn't want to idle correctly : below 1,000. : Don't know why I not getting vacuum advance but : it appears to be the carb not a pod problem, : but without vac adv I'm at 40-42 total, so : more vac advance would probably too much. : Will have to checkout carb vac ports but : otherwise carb performs fine. Engine seemed : to perform well on street - No pinging, : backfiring, stalling, etc. Each time I try : retarding timing further the engine starts : to get rough and will barely run at less : than 10-12 Degrees BTDC. Should it idle less : than 1,000rpm?? What if anything should I do : with the distributor?? Or is it a case that : she "Runs where she Runs"?? : I've always been a V8er, thus, as I have found : out this /6 world is a totally different : ball game. I don't know how a Hi Pro /6 is : suppose to run or sound. : Lastly the car has a built up 904, GER : Converter and 8 3/4 with 391 posi and 9X15 : Hoosiers (Street/Strip intentions). : Any and all comments and help greatly : appreciated. Your combo doesn't sound a whole bunch different than mine. Only thing I see is that the carb is probably a little big. Also, check for vaccuum leaks, mine wouldn't idle when I put the Offy and Holley on. It was sucking air under the carb mounting plate. You should be able to surprise a few people at the track! Dennis slantzilla@excite.com |
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| Author: | Dart270 [ Mon Dec 24, 2001 12:27 pm ] |
| Post subject: | Re: Doc - Too Much Advance - Cont'd |
Quote:
: Your combo doesn't sound a whole bunch : different than mine. Only thing I see is : that the carb is probably a little big. : Also, check for vaccuum leaks, mine wouldn't : idle when I put the Offy and Holley on. It : was sucking air under the carb mounting : plate. You should be able to surprise a few : people at the track! Dennis Xman, That cam is not big enough to cause a serious idle problem if it's degreed in. I run my 234 @ 0,050 cam and similar combo to yours (although with 10.5 comp) down to 600 RPM idle in gear. Dennis is right, the carb may be a bit big, but should idle fine. I ran a 600 Edelbrock or Holley for a while, and it wasn't too bad, just slightly boggy at low end. With your setup, you want to run about 15-18 deg of initial advance, about 30-34 total mechanical, and 40-50 total with vacuum. Use ported vacuum (no vacuum to Advance pod at idle). I would think it's a vac leak or maybe misadjusted valves. Check the lash and try loosening it up a bit. Hope this helps, Lou |
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