This is a good example of a pinging / detonation / preignition sound, which is really hard to find on youtube amongst all the garbage search results. So thank you for that. Plus that engine really sings. Lovely.
Finally I got to hear what it sounds like in reality. I was beginning to think that I had some sort of selective hearing because I could never hear it on any other video that said I should have! You made it clear, thank you.
You should really check the timing on that thing and possibly recurve the distributor. Putting in a bigger cam lowers cylinder pressure. Make sure your total timing is no higher than 36° but with Vortec heads, optimal is usually 32° to 34° with it's fast burn chamber design.
It, depends on the how aggressive the opening ramps on the lobes are. Aggressive ramps, will definitely cause higher cylinder pressure and detonation, even with milder compression ratios. It's, also harder on Valve train components. I do agree, a timing adjustment could have gotten rid of the detonation. But, who wants to detune?😀
@@strokermaverick It's not detuning if it's wrong. Also I am going to have to disagree with your "aggressive ramp opening rates" theory, how fast the valve opens has nothing to do with detonation. Now if that was an engine with a high static compression ratio and he put a smaller cam (less degrees of duration @ .050") in it the detonation would make sense. So either it's running way to hot or the distributor timing isn't optimized.
Good tips on the vortec heads.. Timing is set at 33 degrees. My afr was in the safe zone 12.5 to 13.0. It is junk yard engine that is not fresh. It didn't smoke. It ran good on a mixture of 87 and 93. I plan on reducing quench and freshing it up in the future. The bigger cam raised the peak cylinder pressure and combustion chamber tempature at high rpm's traping more fuel and air in the combustion chamber. More power. Yes at lower rpm it would have less pressure because of bleed off.
@@itseithergonnaworkoritaint7852 There's more to it than just adding a "bigger" cam, it's all about valve overlap. If you put a more aggressive cam in that has very little overlap, you are most certainly going to get higher cylinder pressures. If a cam has a lot of overlap, then your dynamic cylinder pressure will be lower.
A stock cam has a wide Lobe Separation Angle (LCA). A performance cam is going to have a narrower LCA. Stock cams maybe installed in a retarded position in relationship to the crankshaft. Performance cams are often ground 3 degrees advance. Closing up the LCA and advancing the cam is going to cause the intake valve to close quicker most of the time. Which if it does, will cause a rise in cylinder pressure. In general, I am speaking of milder performance cams.
I have the same detonation problem as you 062 vortec heads on a sbc. 400 bored out 40 over I had the heads milled 0.10 they didn't debur the edges around the combustion chamber. I did it myself maybe I skipped some . but I have found out if you don't round off the edges after Milling it will cause detonation. Right now I have a Howard 231/ 235 @0.50 .I just ordered a Isky 292 Mega. I'm taking off the heads changing the head gasket from 0.41 least 0.20 to 0.27 to get right quench. My rattle goes away if I run 110 octane. I have 146 to 153 cranking compression. Speed Pro pistons 10.7
Having a burr makes sense. When I was finding TDC im sure I nicked a valve creating a burr. I forgot to loosen the valves while checking for tdc, hitting a valve. I removed the heads and checked for nicks and did not see any. The lowest cranking compression i have seen on my gauge was 165. That was on a 9.7 to 1 355 with a large cam. I have ran several sets vortec heads with different quenches and compression ratios. This was the first and only time I have seen detonation. Good luck. Let me know if the changes worked.
The cam is probably small enough that it makes more cylinder pressure with less compression. It is smack dab in the zone only requiring 93 mix in 2:1 with 87. Therefore job well done. However you could do carb tuning further if notrich enough or maybe one size richer . Well whatever it wants to be the best. Usually up one size from dyno i have been told. Also check out that holley part throttle circuit addition modification if not have.. forgive my sleepy ramblings.
Funny, I will be using a Melling 22280 duration 220/224 110 ls 495/502. Exact cam except for the LSA changed from 114 to 110. Guess that I will have to use 91 octane. This is going in a 66 Chevelle.
Nice, you should be fine. This was a junkyard engine. I think it would of been fine if it was freshened. As is the motor ran good and didn't smoke. It just required higher octane then I thought.
May I ask what new camshaft was put in this stock engine? Did you run a steel shim head gasket also? I will be building something like this myself this winter. Thanks
It is a cam from a blueprint engines 390 Hp 355ci crate engine 220/224 114 l.s. .495/.502. Engine is a junkyard vortec 350 that i just added a cam to. Im going to freshing it up and add a new cam to make it run quicker 1/4 mile times in the future.
This is a 300.00 junk yard engine that is not fresh. I did have to replace the crank. The crank snout was bent maybe from a accident. I paid 200.00 for the intake,cam and lifters. It ran fine on a mixture of 87 and 93. With the stock cam it was fine on 87 octane.
@@nylegreen261 Hope I don't sound critical of what you are doing as I totally enjoy and appreciate exactly what you are doing. Around 2000 I built a 383 with Edelbrock E-200 vortec heads so I have a history being a vortec head fan.
It's all about cam choice! I'm running a 427 BBC with a static compression ratio of 12.2:1, but with my cam's valve overlap, my dynamic compression is only 7.63:1, so I can run cheap fuel and get away with it. I run higher octane at the strip, but I can run low budget fuel all day on the streets.
Out of curiosity. Is the sound of detonation coming from the motor or do you listen to it coming out of the exhaust? Currently trying to figure out if my engine is detonating but not sure if I need to listen to the exhaust or the engine itself lol
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This is a good example of a pinging / detonation / preignition sound, which is really hard to find on youtube amongst all the garbage search results. So thank you for that. Plus that engine really sings. Lovely.
Thank you . It surprised me how noticeable it was in the car. I stayed in the throttle longer then I should of.
Finally I got to hear what it sounds like in reality. I was beginning to think that I had some sort of selective hearing because I could never hear it on any other video that said I should have! You made it clear, thank you.
@@65283impala Nice, thank you.
That cam is packing the cylinders good!
You should really check the timing on that thing and possibly recurve the distributor. Putting in a bigger cam lowers cylinder pressure. Make sure your total timing is no higher than 36° but with Vortec heads, optimal is usually 32° to 34° with it's fast burn chamber design.
It, depends on the how aggressive the opening ramps on the lobes are. Aggressive ramps, will definitely cause higher cylinder pressure and detonation, even with milder compression ratios. It's, also harder on Valve train components. I do agree, a timing adjustment could have gotten rid of the detonation. But, who wants to detune?😀
@@strokermaverick
It's not detuning if it's wrong. Also I am going to have to disagree with your "aggressive ramp opening rates" theory, how fast the valve opens has nothing to do with detonation.
Now if that was an engine with a high static compression ratio and he put a smaller cam (less degrees of duration @ .050") in it the detonation would make sense. So either it's running way to hot or the distributor timing isn't optimized.
Good tips on the vortec heads.. Timing is set at 33 degrees. My afr was in the safe zone 12.5 to 13.0. It is junk yard engine that is not fresh. It didn't smoke. It ran good on a mixture of 87 and 93. I plan on reducing quench and freshing it up in the future. The bigger cam raised the peak cylinder pressure and combustion chamber tempature at high rpm's traping more fuel and air in the combustion chamber. More power. Yes at lower rpm it would have less pressure because of bleed off.
@@itseithergonnaworkoritaint7852 There's more to it than just adding a "bigger" cam, it's all about valve overlap. If you put a more aggressive cam in that has very little overlap, you are most certainly going to get higher cylinder pressures. If a cam has a lot of overlap, then your dynamic cylinder pressure will be lower.
A stock cam has a wide Lobe Separation Angle (LCA). A performance cam is going to have a narrower LCA. Stock cams maybe installed in a retarded position in relationship to the crankshaft. Performance cams are often ground 3 degrees advance. Closing up the LCA and advancing the cam is going to cause the intake valve to close quicker most of the time. Which if it does, will cause a rise in cylinder pressure. In general, I am speaking of milder performance cams.
I have the same detonation problem as you 062 vortec heads on a sbc. 400 bored out 40 over I had the heads milled 0.10 they didn't debur the edges around the combustion chamber. I did it myself maybe I skipped some . but I have found out if you don't round off the edges after Milling it will cause detonation. Right now I have a Howard 231/ 235 @0.50 .I just ordered a Isky 292 Mega. I'm taking off the heads changing the head gasket from 0.41 least 0.20 to 0.27 to get right quench. My rattle goes away if I run 110 octane. I have 146 to 153 cranking compression. Speed Pro pistons 10.7
Having a burr makes sense. When I was finding TDC im sure I nicked a valve creating a burr. I forgot to loosen the valves while checking for tdc, hitting a valve. I removed the heads and checked for nicks and did not see any. The lowest cranking compression i have seen on my gauge was 165. That was on a 9.7 to 1 355 with a large cam. I have ran several sets vortec heads with different quenches and compression ratios. This was the first and only time I have seen detonation. Good luck. Let me know if the changes worked.
I would double check your timing. Thats a very mild setup, theres no reason you should have to run 93 octane on that engine
Not a bad idea thank you.
The cam is probably small enough that it makes more cylinder pressure with less compression. It is smack dab in the zone only requiring 93 mix in 2:1 with 87. Therefore job well done. However you could do carb tuning further if notrich enough or maybe one size richer . Well whatever it wants to be the best. Usually up one size from dyno i have been told. Also check out that holley part throttle circuit addition modification if not have.. forgive my sleepy ramblings.
What’s the temp outside
Wow this is deep
Funny, I will be using a Melling 22280 duration 220/224 110 ls 495/502. Exact cam except for the LSA changed from 114 to 110. Guess that I will have to use 91 octane. This is going in a 66 Chevelle.
Nice, you should be fine. This was a junkyard engine. I think it would of been fine if it was freshened. As is the motor ran good and didn't smoke. It just required higher octane then I thought.
Going from a 114 to a 110 LSA should soften up your dynamic compression a lot, so you probably won't have any trouble.
May I ask what new camshaft was put in this stock engine? Did you run a steel shim head gasket also? I will be building something like this myself this winter.
Thanks
It is a cam from a blueprint engines 390 Hp 355ci crate engine 220/224 114 l.s. .495/.502. Engine is a junkyard vortec 350 that i just added a cam to. Im going to freshing it up and add a new cam to make it run quicker 1/4 mile times in the future.
My friend who built my engine must have gone to cam school to make my 10.7 to 1 1st gen like 89 pump.
This is a 300.00 junk yard engine that is not fresh. I did have to replace the crank. The crank snout was bent maybe from a accident. I paid 200.00 for the intake,cam and lifters. It ran fine on a mixture of 87 and 93. With the stock cam it was fine on 87 octane.
@@nylegreen261 Hope I don't sound critical of what you are doing as I totally enjoy and appreciate exactly what you are doing. Around 2000 I built a 383 with Edelbrock E-200 vortec heads so I have a history being a vortec head fan.
No problem. I enjoy the comment section.
It's all about cam choice! I'm running a 427 BBC with a static compression ratio of 12.2:1, but with my cam's valve overlap, my dynamic compression is only 7.63:1, so I can run cheap fuel and get away with it. I run higher octane at the strip, but I can run low budget fuel all day on the streets.
Out of curiosity. Is the sound of detonation coming from the motor or do you listen to it coming out of the exhaust? Currently trying to figure out if my engine is detonating but not sure if I need to listen to the exhaust or the engine itself lol
This is coming from the combustion chamber. I knew their was something wrong and had to get out of the throttle.
set otal timing to about 20-25. The vortec chamber does not need regular sbc timing.
I'm on it thank you.
That's way too low, 32 is what GM recommends.
@@nylegreen261 I would spin the distributor in a clockwise rotation about 4 times to really bring in the good spark levels!!
Dynamic compression?