Re: [Chevelle-list] Detonation question
Brian, Did this dentination just start? I assume you hear it? First off, when we talk detination, static compression means very little. You need your cam specs and then you can detirmine your dynamic compression ratio, which is what ultimately detirmines what fuel and timing you can run. The second thing I ask is if this is a newer combo what heads do you have? How far in the hole is you piston at TDC (some call this deck heighth) and what head gasket are you using? This will detirmine your quench distance which is crucial in avoiding detination. Head design makes a big difference. A newer heart shaped chamber can run a bit more compression with out detintation. Also are you running a cast or alum head? Again alum can take much more. If you have this info and send it my way I can do some calculations and get a better feel for what your combo should need. What engine temp does your engine run at when it detinates? For working with what you got... more fuel will help with detination so I would fatten it up. I would also highly recomend running the premium grade and seeing ifthat helps. Your timing isn't much if you are running 10 and 16 for a total of 26 degrees so I doubt that is your problem. I'm not real experienced at running at the altitude you are. I'm sure this plays a role in things as well. Send out a bit more info of when this all started and your specs and I will see what I can do. Mikey From: Brian Zack [EMAIL PROTECTED] Reply-To: The Chevelle Mailing List [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: [Chevelle-list] Detonation question Date: Wed, 26 Nov 2003 08:28:16 -0700 What are the things to look at to avoid detonation? I have a 350 w/ 9:1 compression and a pretty mild cam. I run the med grade fuel. If I am getting some detonation under load, Do I need to look at timing, fuel mixture, jetting? I am at around 5000 to 5500 ft in altitude. I have a hei dist. w/ the pertronix kit and am running 10 degrees initial timing the factory setting on the adjustable vac. advance (I think its 16 degrees) and the lightest springs on the weights (The weights and springs came with the kit). At the strip trying to tune it, I had to use the lighter springs otherwise, my times were around a ½ sec. slower with the heavier springs. The carb is the edlebrock 600 cfm elec. choke and I put the 1 step leaner primary rods in. No actual jet changes. As far as going to the strip, I don't think I can make it out again til next year, (I think it already closed) so tuning there won't be an option. Right now, I do only have the 2.73 gears and 28 tall tires, which is probably contributing to the extra load condition. Any opinions? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] _ Set yourself up for fun at home! Get tips on home entertainment equipment, video game reviews, and more here. http://special.msn.com/home/homeent.armx
RE: [Chevelle-list] Detonation question
This engine has the stock cast 76cc heads with the ports lightly smoothed out and your basic felpro head gaskets. I am running the flat top cast pistons. This engine has just under 20K miles on it. I think it is detonation I'm hearing. I seem to be able to hear it now with my flowmaster exhaust. (It seems I can kinda hear it through the exhaust). I am planning for and trying to save up for some s/r torquers and a bigger cam for hopefully next spring. I'm planning on the comp cams xe262. The cam I have now is the crane energizer cam w/ .440 lift and I think its 260 duration I'm not sure of the @ .050 dur. When I built the engine, I didn't measure how far down the bore the pistons are. At that time, I didn't know anything about the DCR and I asked for 9:1 pistons and don't know if these pistons were manufactured a little further down than desirable or not. I can only guess at my measurements. Right now, What I can figure from my guesses is my DCR is around 7.4:1 to 7.5:1.When I was considering heads for the future, it was either the vortecs or the world s/r torquers, but, I think the vortecs would make me have to run a lot more expensive fuel because of going to a DCR of around 8.5:1. The total advance of 26 you have doesn't include how much advandce the weights and springs add. I'll have to check how much those add, but from memory, I think total was around 48 degrees. Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] -Original Message- From: Capt Crunch [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 9:02 AM To: [EMAIL PROTECTED] Subject: Re: [Chevelle-list] Detonation question Brian, Did this dentination just start? I assume you hear it? First off, when we talk detination, static compression means very little. You need your cam specs and then you can detirmine your dynamic compression ratio, which is what ultimately detirmines what fuel and timing you can run. The second thing I ask is if this is a newer combo what heads do you have? How far in the hole is you piston at TDC (some call this deck heighth) and what head gasket are you using? This will detirmine your quench distance which is crucial in avoiding detination. Head design makes a big difference. A newer heart shaped chamber can run a bit more compression with out detintation. Also are you running a cast or alum head? Again alum can take much more. If you have this info and send it my way I can do some calculations and get a better feel for what your combo should need. What engine temp does your engine run at when it detinates? For working with what you got... more fuel will help with detination so I would fatten it up. I would also highly recomend running the premium grade and seeing ifthat helps. Your timing isn't much if you are running 10 and 16 for a total of 26 degrees so I doubt that is your problem. I'm not real experienced at running at the altitude you are. I'm sure this plays a role in things as well. Send out a bit more info of when this all started and your specs and I will see what I can do. Mikey From: Brian Zack [EMAIL PROTECTED] Reply-To: The Chevelle Mailing List [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: [Chevelle-list] Detonation question Date: Wed, 26 Nov 2003 08:28:16 -0700 What are the things to look at to avoid detonation? I have a 350 w/ 9:1 compression and a pretty mild cam. I run the med grade fuel. If I am getting some detonation under load, Do I need to look at timing, fuel mixture, jetting? I am at around 5000 to 5500 ft in altitude. I have a hei dist. w/ the pertronix kit and am running 10 degrees initial timing the factory setting on the adjustable vac. advance (I think its 16 degrees) and the lightest springs on the weights (The weights and springs came with the kit). At the strip trying to tune it, I had to use the lighter springs otherwise, my times were around a ½ sec. slower with the heavier springs. The carb is the edlebrock 600 cfm elec. choke and I put the 1 step leaner primary rods in. No actual jet changes. As far as going to the strip, I don't think I can make it out again til next year, (I think it already closed) so tuning there won't be an option. Right now, I do only have the 2.73 gears and 28 tall tires, which is probably contributing to the extra load condition. Any opinions? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] _ Set yourself up for fun at home! Get tips on home entertainment equipment, video game reviews, and more here. http://special.msn.com/home/homeent.armx
Re: [Chevelle-list] Detonation question
If you're trying to run 48 degrees of advance in that engine,there's your problem right there. Try to pull it back to somewhere around 36-38,total. Clint Hooper HH Custom,owner LT5 Registry Director http://www.LT5Registry.net/ ACES #1650 http://dalesplace.com/misc/friends/clint_hooper.htm - Original Message - From: Brian Zack [EMAIL PROTECTED] This engine has the stock cast 76cc heads with the ports lightly smoothed out and your basic felpro head gaskets. I am running the flat top cast pistons. This engine has just under 20K miles on it. I think it is detonation I'm hearing. I seem to be able to hear it now with my flowmaster exhaust. (It seems I can kinda hear it through the exhaust). I am planning for and trying to save up for some s/r torquers and a bigger cam for hopefully next spring. I'm planning on the comp cams xe262. The cam I have now is the crane energizer cam w/ .440 lift and I think its 260 duration I'm not sure of the @ .050 dur. When I built the engine, I didn't measure how far down the bore the pistons are. At that time, I didn't know anything about the DCR and I asked for 9:1 pistons and don't know if these pistons were manufactured a little further down than desirable or not. I can only guess at my measurements. Right now, What I can figure from my guesses is my DCR is around 7.4:1 to 7.5:1.When I was considering heads for the future, it was either the vortecs or the world s/r torquers, but, I think the vortecs would make me have to run a lot more expensive fuel because of going to a DCR of around 8.5:1. The total advance of 26 you have doesn't include how much advandce the weights and springs add. I'll have to check how much those add, but from memory, I think total was around 48 degrees. Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED]
RE: [Chevelle-list] Detonation question
Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] -Original Message- From: Clint Hooper [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 11:05 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Detonation question If you're trying to run 48 degrees of advance in that engine,there's your problem right there. Try to pull it back to somewhere around 36-38,total. Clint Hooper HH Custom,owner LT5 Registry Director http://www.LT5Registry.net/ ACES #1650 http://dalesplace.com/misc/friends/clint_hooper.htm - Original Message - From: Brian Zack [EMAIL PROTECTED] This engine has the stock cast 76cc heads with the ports lightly smoothed out and your basic felpro head gaskets. I am running the flat top cast pistons. This engine has just under 20K miles on it. I think it is detonation I'm hearing. I seem to be able to hear it now with my flowmaster exhaust. (It seems I can kinda hear it through the exhaust). I am planning for and trying to save up for some s/r torquers and a bigger cam for hopefully next spring. I'm planning on the comp cams xe262. The cam I have now is the crane energizer cam w/ .440 lift and I think its 260 duration I'm not sure of the @ .050 dur. When I built the engine, I didn't measure how far down the bore the pistons are. At that time, I didn't know anything about the DCR and I asked for 9:1 pistons and don't know if these pistons were manufactured a little further down than desirable or not. I can only guess at my measurements. Right now, What I can figure from my guesses is my DCR is around 7.4:1 to 7.5:1.When I was considering heads for the future, it was either the vortecs or the world s/r torquers, but, I think the vortecs would make me have to run a lot more expensive fuel because of going to a DCR of around 8.5:1. The total advance of 26 you have doesn't include how much advandce the weights and springs add. I'll have to check how much those add, but from memory, I think total was around 48 degrees. Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED]
Re: [Chevelle-list] Detonation question
How much initial advance did you say the engine has? Clint Hooper HH Custom,owner LT5 Registry Director http://www.LT5Registry.net/ ACES #1650 http://dalesplace.com/misc/friends/clint_hooper.htm - Original Message - From: Brian Zack [EMAIL PROTECTED] Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED]
RE: [Chevelle-list] Detonation question
At 12:18 PM 11/26/2003, you wrote: Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] Vacuum don't count as total advance. When I read your post I thought you were adding vacuum advance to the mix because 48 is way to much. If it pings at light throttle take some out of vacuum . On my vortex head 383 max is 32 degs, 10 ini with 22 degs distributor, vacuum I use 10 deg pod. If you add it all up = 42. You need to ck the advance at 3500-4000 rpm with the vacuum plugged.
RE: [Chevelle-list] Detonation question
10 degrees at damper + 22 at weights and springs (I think) + 16 vacuum advance. That is where I got 48. Is that not correct? Is total not including vacuum too? Brian Zack Structural Technician mailto:[EMAIL PROTECTED] Dekker/Perich/Sabatini architecture interiors planning engineering 505.761.9700 fax 505.761.4222. Visit our Website at www.dpsabq.com -Original Message- From: Clint Hooper [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 11:51 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Detonation question How much initial advance did you say the engine has? Clint Hooper HH Custom,owner LT5 Registry Director http://www.LT5Registry.net/ ACES #1650 http://dalesplace.com/misc/friends/clint_hooper.htm - Original Message - From: Brian Zack [EMAIL PROTECTED] Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED]
RE: [Chevelle-list] Detonation question
Ok. Maybe I can try taking some out of the vacuum. Brian Zack '70 Chevelle Malibu mailto:brianz@dpsabq.com -Original Message- From: Dave Corgill [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 11:49 AM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question At 12:18 PM 11/26/2003, you wrote: Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] Vacuum don't count as total advance. When I read your post I thought you were adding vacuum advance to the mix because 48 is way to much. If it pings at light throttle take some out of vacuum . On my vortex head 383 max is 32 degs, 10 ini with 22 degs distributor, vacuum I use 10 deg pod. If you add it all up = 42. You need to ck the advance at 3500-4000 rpm with the vacuum plugged.
RE: [Chevelle-list] Detonation question
Your original post said the detonation occurred under load. If this is the case, changing the vacuum advance may not help since it will not be kicked-in under load. In that case, you need to change the initial (damper) advance, and/or total advance by the springs and weights (or the advance curve). Tom Tomlinson -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Brian Zack Sent: Wednesday, November 26, 2003 2:11 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question 10 degrees at damper + 22 at weights and springs (I think) + 16 vacuum advance. That is where I got 48. Is that not correct? Is total not including vacuum too? Brian Zack Structural Technician mailto:[EMAIL PROTECTED] Dekker/Perich/Sabatini architecture interiors planning engineering 505.761.9700 fax 505.761.4222. Visit our Website at www.dpsabq.com -Original Message- From: Clint Hooper [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 11:51 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Detonation question How much initial advance did you say the engine has? Clint Hooper HH Custom,owner LT5 Registry Director http://www.LT5Registry.net/ ACES #1650 http://dalesplace.com/misc/friends/clint_hooper.htm - Original Message - From: Brian Zack [EMAIL PROTECTED] Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED]
RE: [Chevelle-list] Detonation question
Yes, it seems to do it taking off from a start up hill a little heavy footed and when accelerating without downshifting. OK, Dumb question. Do I need more or less timing? It's been a long, short week. Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] -Original Message- From: Tom and Sue Tomlinson [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 1:05 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question Your original post said the detonation occurred under load. If this is the case, changing the vacuum advance may not help since it will not be kicked-in under load. In that case, you need to change the initial (damper) advance, and/or total advance by the springs and weights (or the advance curve). Tom Tomlinson -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Brian Zack Sent: Wednesday, November 26, 2003 2:11 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question 10 degrees at damper + 22 at weights and springs (I think) + 16 vacuum advance. That is where I got 48. Is that not correct? Is total not including vacuum too? Brian Zack Structural Technician mailto:[EMAIL PROTECTED] Dekker/Perich/Sabatini architecture interiors planning engineering 505.761.9700 fax 505.761.4222. Visit our Website at www.dpsabq.com -Original Message- From: Clint Hooper [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 11:51 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Detonation question How much initial advance did you say the engine has? Clint Hooper HH Custom,owner LT5 Registry Director http://www.LT5Registry.net/ ACES #1650 http://dalesplace.com/misc/friends/clint_hooper.htm - Original Message - From: Brian Zack [EMAIL PROTECTED] Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED]
RE: [Chevelle-list] Detonation question
You need less advance. An easy check would be to change the initial timing at the damper to 5-6 deg instead of 10 deg. One of the other posts suggested upgrading the gas. I would try that too. Tom -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Brian Zack Sent: Wednesday, November 26, 2003 3:28 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question Yes, it seems to do it taking off from a start up hill a little heavy footed and when accelerating without downshifting. OK, Dumb question. Do I need more or less timing? It's been a long, short week. Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] -Original Message- From: Tom and Sue Tomlinson [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 1:05 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question Your original post said the detonation occurred under load. If this is the case, changing the vacuum advance may not help since it will not be kicked-in under load. In that case, you need to change the initial (damper) advance, and/or total advance by the springs and weights (or the advance curve). Tom Tomlinson -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Brian Zack Sent: Wednesday, November 26, 2003 2:11 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question 10 degrees at damper + 22 at weights and springs (I think) + 16 vacuum advance. That is where I got 48. Is that not correct? Is total not including vacuum too? Brian Zack Structural Technician mailto:[EMAIL PROTECTED] Dekker/Perich/Sabatini architecture interiors planning engineering 505.761.9700 fax 505.761.4222. Visit our Website at www.dpsabq.com -Original Message- From: Clint Hooper [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 11:51 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Detonation question How much initial advance did you say the engine has? Clint Hooper HH Custom,owner LT5 Registry Director http://www.LT5Registry.net/ ACES #1650 http://dalesplace.com/misc/friends/clint_hooper.htm - Original Message - From: Brian Zack [EMAIL PROTECTED] Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED]
Re: [Chevelle-list] Detonation question
Too much advance Brian... like Clint said pull the total back to the 32-36 degree area. I would say more like 32 if you want to run your current fuel. First thing first brian disconnect the vac advance for now cause it will make no difference at WOT or for total advance. I assume your engine is liking 10 degrees inital timing more then 6 or 8 degrees? If that is the case leave it at ten. Then change yourcentrifugal to get you total advance (initial+ centrifugal) to equal 32 degrees. Hope this helps Mikey - Original Message From: Brian Zack Sent: Wednesday, November 26, 2003 2:24 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question Yes, it seems to do it taking off from a start up hill a little heavy footed and when accelerating without downshifting. OK, Dumb question. Do I need more or less timing? It's been a long, short week.Brian Zack'70 Chevelle Malibumailto:[EMAIL PROTECTED] -Original Message-From: Tom and Sue Tomlinson [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 1:05 PMTo: The Chevelle Mailing ListSubject: RE: [Chevelle-list] Detonation questionYour original post said the detonation occurred under load. If this is thecase, changing the vacuum advance may not help since it will not bekicked-in under load. In that case, you need to change the initial (damper)advance, and/or total advance by the springs and weights (or the advancecurve).Tom Tomlinson-Original Message-From: [EMAIL PROTECTED][mailto:[EMAIL PROTECTED] Behalf Of Brian ZackSent: Wednesday, November 26, 2003 2:11 PMTo: The Chevelle Mailing ListSubject: RE: [Chevelle-list] Detonation question10 degrees at damper + 22 at weights and springs (I think) + 16 vacuumadvance. That is where I got 48. Is that not correct? Is total not includingvacuum too?Brian ZackStructural Technicianmailto:[EMAIL PROTECTED]Dekker/Perich/Sabatiniarchitecture interiors planning engineering505.761.9700 fax 505.761.4222.Visit our Website at www.dpsabq.com-Original Message-From: Clint Hooper [mailto:[EMAIL PROTECTED]Sent: Wednesday, November 26, 2003 11:51 AMTo: The Chevelle Mailing ListSubject: Re: [Chevelle-list] Detonation questionHow much initial advance did you say the engine has?Clint HooperHH Custom,ownerLT5 Registry Directorhttp://www.LT5Registry.net/ACES #1650http://dalesplace.com/misc/friends/clint_hooper.htm- Original Message -From: "Brian Zack" [EMAIL PROTECTED]Where would you suggest taking it out of? Weights and springs? Vacuumadvance? Or initial? Or a little out of each?Brian Zack'70 Chevelle Malibumailto:[EMAIL PROTECTED]
RE: [Chevelle-list] Detonation question
It is already at 32 degrees. 10 initial + 22 centrifugal. Doesnt the vacuum advance help with gas mileage? It does sound like maybe the vacuum advance is too much. Is that why you said to disconnect it for now? I have tried premium and it didnt make much difference. I think Ill try a few of the things mentioned here both separately and together and see what happens. Thanks all for the knowledge and help on this There is a really great knowledge base here. Hope everyone has a great Thanksgiving and GOD Bless! Brian Zack '70 Chevelle Malibu mailto:brianz@dpsabq.com -Original Message- From: Capt Crunch [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 1:59 PM To: Chevelle List Subject: Re: [Chevelle-list] Detonation question Too much advance Brian... like Clint said pull the total back to the 32-36 degree area. I would say more like 32 if you want to run your current fuel. First thing first brian disconnect the vac advance for now cause it will make no difference at WOT or for total advance. I assume your engine is liking 10 degrees inital timing more then 6 or 8 degrees? If that is the case leave it at ten. Then change yourcentrifugal to get you total advance (initial+ centrifugal) to equal 32 degrees. Hope this helps Mikey - Original Message From: Brian Zack Sent: Wednesday, November 26, 2003 2:24 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question Yes, it seems to do it taking off from a start up hill a little heavy footed and when accelerating without downshifting. OK, Dumb question. Do I need more or less timing? It's been a long, short week. Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] -Original Message- From: Tom and Sue Tomlinson [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 1:05 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question Your original post said the detonation occurred under load. If this is the case, changing the vacuum advance may not help since it will not be kicked-in under load. In that case, you need to change the initial (damper) advance, and/or total advance by the springs and weights (or the advance curve). Tom Tomlinson -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Brian Zack Sent: Wednesday, November 26, 2003 2:11 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question 10 degrees at damper + 22 at weights and springs (I think) + 16 vacuum advance. That is where I got 48. Is that not correct? Is total not including vacuum too? Brian Zack Structural Technician mailto:[EMAIL PROTECTED] Dekker/Perich/Sabatini architecture interiors planning engineering 505.761.9700 fax 505.761.4222. Visit our Website at www.dpsabq.com -Original Message- From: Clint Hooper [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 11:51 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Detonation question How much initial advance did you say the engine has? Clint Hooper HH Custom,owner LT5 Registry Director http://www.LT5Registry.net/ ACES #1650 http://dalesplace.com/misc/friends/clint_hooper.htm - Original Message - From: Brian Zack [EMAIL PROTECTED] Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED]
Re: [Chevelle-list] Detonation question
What temp. is engine running at? Do you have an accuate temp guage? Do you notice a difference when air temp is high vs low? - Original Message - From: Brian Zack To: The Chevelle Mailing List Sent: Wednesday, November 26, 2003 5:08 PM Subject: RE: [Chevelle-list] Detonation question It is already at 32 degrees. 10 initial + 22 centrifugal. Doesnt the vacuum advance help with gas mileage? It does sound like maybe the vacuum advance is too much. Is that why you said to disconnect it for now? I have tried premium and it didnt make much difference. I think Ill try a few of the things mentioned here both separately and together and see what happens. Thanks all for the knowledge and help on this There is a really great knowledge base here. Hope everyone has a great Thanksgiving and GOD Bless! Brian Zack '70 Chevelle Malibu mailto:brianz@dpsabq.com -Original Message-From: Capt Crunch [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 1:59 PMTo: Chevelle ListSubject: Re: [Chevelle-list] Detonation question Too much advance Brian... like Clint said pull the total back to the 32-36 degree area. I would say more like 32 if you want to run your current fuel. First thing first brian disconnect the vac advance for now cause it will make no difference at WOT or for total advance. I assume your engine is liking 10 degrees inital timing more then 6 or 8 degrees? If that is the case leave it at ten. Then change yourcentrifugal to get you total advance (initial+ centrifugal) to equal 32 degrees. Hope this helps Mikey - Original Message From: Brian Zack Sent: Wednesday, November 26, 2003 2:24 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question Yes, it seems to do it taking off from a start up hill a little heavy footed and when accelerating without downshifting. OK, Dumb question. Do I need more or less timing? It's been a long, short week.Brian Zack'70 Chevelle Malibumailto:[EMAIL PROTECTED] -Original Message-From: Tom and Sue Tomlinson [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 1:05 PMTo: The Chevelle Mailing ListSubject: RE: [Chevelle-list] Detonation questionYour original post said the detonation occurred under load. If this is thecase, changing the vacuum advance may not help since it will not bekicked-in under load. In that case, you need to change the initial (damper)advance, and/or total advance by the springs and weights (or the advancecurve).Tom Tomlinson-Original Message-From: [EMAIL PROTECTED][mailto:[EMAIL PROTECTED] Behalf Of Brian ZackSent: Wednesday, November 26, 2003 2:11 PMTo: The Chevelle Mailing ListSubject: RE: [Chevelle-list] Detonation question10 degrees at damper + 22 at weights and springs (I think) + 16 vacuumadvance. That is where I got 48. Is that not correct? Is total not includingvacuum too?Brian ZackStructural Technicianmailto:[EMAIL PROTECTED]Dekker/Perich/Sabatiniarchitecture interiors planning engineering505.761.9700 fax 505.761.4222.Visit our Website at www.dpsabq.com-Original Message-From: Clint Hooper [mailto:[EMAIL PROTECTED]Sent: Wednesday, November 26, 2003 11:51 AMTo: The Chevelle Mailing ListSubject: Re: [Chevelle-list] Detonation questionHow much initial advance did you say the engine has?Clint HooperHH Custom,ownerLT5 Registry Directorhttp://www.LT5Registry.net/ACES #1650http://dalesplace.com/misc/friends/clint_hooper.htm- Original Message -From: "Brian Zack" [EMAIL PROTECTED]Where would you suggest taking it out of? Weights and springs? Vacuumadvance? Or initial? Or a little out of each?Brian Zack'70 Chevelle Malibumailto:[EMAIL PROTECTED]
RE: [Chevelle-list] Detonation question
I hadnt really started listening that closely till lately, so I didnt notice if it was worse at high temp or not. Right now, my temps arent getting over 180. But, during the summer with the air on and sitting in traffic, it climbs to about 215-220. When I change the heads and cam this spring, Im going to put on a high flow water pump and reduce the ratio for the summer along with water wetter. I wont have acces to my e-mail again till Monday, So Happy Thanksgiving. Brian Zack '70 Chevelle Malibu mailto:brianz@dpsabq.com -Original Message- From: yenkochevelle [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 4:48 PM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Detonation question What temp. is engine running at? Do you have an accuate temp guage? Do you notice a difference when air temp is high vs low? - Original Message - From: Brian Zack To: The Chevelle Mailing List Sent: Wednesday, November 26, 2003 5:08 PM Subject: RE: [Chevelle-list] Detonation question It is already at 32 degrees. 10 initial + 22 centrifugal. Doesnt the vacuum advance help with gas mileage? It does sound like maybe the vacuum advance is too much. Is that why you said to disconnect it for now? I have tried premium and it didnt make much difference. I think Ill try a few of the things mentioned here both separately and together and see what happens. Thanks all for the knowledge and help on this There is a really great knowledge base here. Hope everyone has a great Thanksgiving and GOD Bless! Brian Zack '70 Chevelle Malibu mailto:brianz@dpsabq.com -Original Message- From: Capt Crunch [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 1:59 PM To: Chevelle List Subject: Re: [Chevelle-list] Detonation question Too much advance Brian... like Clint said pull the total back to the 32-36 degree area. I would say more like 32 if you want to run your current fuel. First thing first brian disconnect the vac advance for now cause it will make no difference at WOT or for total advance. I assume your engine is liking 10 degrees inital timing more then 6 or 8 degrees? If that is the case leave it at ten. Then change yourcentrifugal to get you total advance (initial+ centrifugal) to equal 32 degrees. Hope this helps Mikey - Original Message From: Brian Zack Sent: Wednesday, November 26, 2003 2:24 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question Yes, it seems to do it taking off from a start up hill a little heavy footed and when accelerating without downshifting. OK, Dumb question. Do I need more or less timing? It's been a long, short week. Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED] -Original Message- From: Tom and Sue Tomlinson [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 1:05 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question Your original post said the detonation occurred under load. If this is the case, changing the vacuum advance may not help since it will not be kicked-in under load. In that case, you need to change the initial (damper) advance, and/or total advance by the springs and weights (or the advance curve). Tom Tomlinson -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Brian Zack Sent: Wednesday, November 26, 2003 2:11 PM To: The Chevelle Mailing List Subject: RE: [Chevelle-list] Detonation question 10 degrees at damper + 22 at weights and springs (I think) + 16 vacuum advance. That is where I got 48. Is that not correct? Is total not including vacuum too? Brian Zack Structural Technician mailto:[EMAIL PROTECTED] Dekker/Perich/Sabatini architecture interiors planning engineering 505.761.9700 fax 505.761.4222. Visit our Website at www.dpsabq.com -Original Message- From: Clint Hooper [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 11:51 AM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] Detonation question How much initial advance did you say the engine has? Clint Hooper HH Custom,owner LT5 Registry Director http://www.LT5Registry.net/ ACES #1650 http://dalesplace.com/misc/friends/clint_hooper.htm - Original Message - From: Brian Zack [EMAIL PROTECTED] Where would you suggest taking it out of? Weights and springs? Vacuum advance? Or initial? Or a little out of each? Brian Zack '70 Chevelle Malibu mailto:[EMAIL PROTECTED]
Re: [Chevelle-list] Detonation question
I think the vacuum advance does come on under load because the off idle (ported) vacuum is strong at part throttle.
Re: [Chevelle-list] Detonation question
Maybe try 10 initial + 15 centrifugal and leave the vacuum advance connected and see what happens. You said you have the lightest springs in the kit? Keep experimenting. I like 10 deg initial because of the snappy throttle response I get around town, but you gotta fix that detonation at WOT cause thats hell on pistons and valves. Keep tweakin it!
