650 AVS 2 lag for a half Second if I kick him hard

[Moparjack 489]

Lower rpm ping under load that clears up as rpm goes up might be tuned out. Look into the plugs.

Ok, thanks . But I still wonder why I need to be open the transfer slot of the AVS2 so much with the idle set screw that I measure vacuum on the time portet vacuum port . Again, if I try to get zero vacuum on this port in idle I have to advance the Initial timming of about 24 degree to get 700 rpm idle .
Actually I still have 10 in hg vacuum on manifold port and on portet vacuum port on the carb . And my Initial timing is about 12 degree

 

[Moparjack 489]

Lower rpm ping under load that clears up as rpm goes up might be tuned out. Look into the plugs.

Make it sense to try this 73 racing plugs ? normal I still run the 85

 

[Slap Stick]

Are you running a stock cam?
With the low vacuum I would say not. Maybe the cam is closing the valves early, raising compression. That won't tune out.
Just thinking out loud.

 

[Moparjack 489]

Are you running a stock cam?
With the low vacuum I would say not. Maybe the cam is closing the valves early, raising compression. That won't tune out.
Just thinking out loud.

actually is this cam inside to try to reduce the compression

 

[Moparjack 489]

Before I had these cam inside

 

[Moparjack 489]

The engine had a pinging problem since it build in a special shop, with stock manifold and the 268 cam with a 10,5:1 compression on iron heads .
After I get a bearing failure , we change to the 274 cam , change the stock manifold to a Indy dual plane and put thicker head gasket to get a 10.0:1 compression , but engine still pinging, mostly just for a Second under load when the transmission shift from 2 to 3 gear and the rpms drops unter 3000 rpm . The fire core distributor has already the two black stiffest springs inside , if I change it to the blue ones it will pinging very quickly also in a 2000-2500 rpm range , . With the black springs mostly the pinging I will recognize in about 2600-2800 by shift up . If you accelerate in Drive in 3 gear from 2000 rpm to 3500 rpm it normally will not pinging .
other main thing when I regonize pinging much more and often is as my water temperature goes over 180 degree , if it raise to 200 degree water temp , you must very carefully with the gas pedal for not pinging .

 

[Moparjack 489]

Sorry for my bad English

 

[Nate S]

The engine had a pinging problem since it build in a special shop, with stock manifold and the 268 cam with a 10,5:1 compression on iron heads .
After I get a bearing failure , we change to the 274 cam , change the stock manifold to a Indy dual plane and put thicker head gasket to get a 10.0:1 compression , but engine still pinging, mostly just for a Second under load when the transmission shift from 2 to 3 gear and the rpms drops unter 3000 rpm . The fire core distributor has already the two black stiffest springs inside , if I change it to the blue ones it will pinging very quickly also in a 2000-2500 rpm range , . With the black springs mostly the pinging I will recognize in about 2600-2800 by shift up . If you accelerate in Drive in 3 gear from 2000 rpm to 3500 rpm it normally will not pinging .
other main thing when I regonize pinging much more and often is as my water temperature goes over 180 degree , if it raise to 200 degree water temp , you must very carefully with the gas pedal for not pinging .

I think you need to back up a step and evaluate a bunch of things. My thoughts:
- The distributor advance plates are in -distributor degrees- , multiply by 2 for crankshaft advance
- Make sure your max advance is 34-38°. If you're knocking like mad, 34 will be better. Put a mark 2.125" clockwise from the TDC mark on the balancer. That's 34 when lined up with the TDC mark on the cover. It should line up there when the distributor is done advancing (4000 rpm?)
- Use one of those spark plug hole piston stops and confirm that the TDC mark on your harmonic balancer is actually at TDC
- While you're in there having fun, throw a dial indicator on your #1 intake rocker and check the cam ICL. If your timing set is advanced a bunch it would make both old and new cams knock.
- A 650 CFM AVS should give instantaneous response. Problem probably isn't the carb if it's new.
- Are the idle mixture screws responding properly? -Make it stumble when they get turned in?
- How did you arrive at 10.5 or 10:1. Did you buy those pistons or did you measure deck height, head CCs and calculate? 10:1 with that cam shouldn't be knocking.
- If it wasn't calculated based on actual measurements, what pressure does a compression test give?

 

[Moparjack 489]

I think you need to back up a step and evaluate a bunch of things. My thoughts:
- The distributor advance plates are in -distributor degrees- , multiply by 2 for crankshaft advance
- Make sure your max advance is 34-38°. If you're knocking like mad, 34 will be better. Put a mark 2.125" clockwise from the TDC mark on the balancer. That's 34 when lined up with the TDC mark on the cover. It should line up there when the distributor is done advancing (4000 rpm?)
- Use one of those spark plug hole piston stops and confirm that the TDC mark on your harmonic balancer is actually at TDC
- While you're in there having fun, throw a dial indicator on your #1 intake rocker and check the cam ICL. If your timing set is advanced a bunch it would make both old and new cams knock.
- A 650 CFM AVS should give instantaneous response. Problem probably isn't the carb if it's new.
- Are the idle mixture screws responding properly? -Make it stumble when they get turned in?
- How did you arrive at 10.5 or 10:1. Did you buy those pistons or did you measure deck height, head CCs and calculate? 10:1 with that cam shouldn't be knocking.
- If it wasn't calculated based on actual measurements, what pressure does a compression test give?

I will give the most answer in a few days because from tomorrow I outside around .
But yes the compression was measured deck hight, head cc and calculated . Before with 10,5 and now with 10.0

the compression test I make in years ago with the first set up and was very a little to high I remember , must look for this data‘s I write it down . but if I found time on weekend I will make a compression test again with the new actual set up ,
What you mean with the idle screw‘s ? The carburater AVS2 is new .

 

[Nate S]

I will give the most answer in a few days because from tomorrow I outside around .
But yes the compression was measured deck hight, head cc and calculated . Before with 10,5 and now with 10.0

the compression test I make in years ago with the first set up and was very a little to high I remember , must look for this data‘s I write it down . but if I found time on weekend I will make a compression test again with the new actual set up ,
What you mean with the idle screw‘s ? The carburater AVS2 is new .

Yes I meant the idle screws, sorry if that wasn't clear. Just to get an idea if the stumble was related to an initial lean or rich condition. What sort of fuel do you have available? 10% ethanol? Straight gas? Octane? I don't have any idea what comes out of the pump in Germany.

Being that the compression is a REAL 10:1 the knock sounds excessive. Ignition timing is a likely culprit. If I were to guess, it would seem like you are expecting 14° of advance from the 14° plate and setting initial timing to 24 or near, but that's distributor degrees so it's really advancing 28 for an insane total of 52°. Another high probability is a slipped harmonic balancer so everything is offset but looks just fine. Now I get that wouldn't explain the stumble but I think you really need to understand the knock first. If you wreck the engine there isn't much point in fixing the stumble.

 

[Moparjack 489]

Yes I meant the idle screws, sorry if that wasn't clear. Just to get an idea if the stumble was related to an initial lean or rich condition. What sort of fuel do you have available? 10% ethanol? Straight gas? Octane? I don't have any idea what comes out of the pump in Germany.

Being that the compression is a REAL 10:1 the knock sounds excessive. Ignition timing is a likely culprit. If I were to guess, it would seem like you are expecting 14° of advance from the 14° plate and setting initial timing to 24 or near, but that's distributor degrees so it's really advancing 28 for an insane total of 52°. Another high probability is a slipped harmonic balancer so everything is offset but looks just fine. Now I get that wouldn't explain the stumble but I think you really need to understand the knock first. If you wreck the engine there isn't much point in fixing the stumble.

thanks you for you’re fast reply !
Ok understand it with the idle screws , no that’s fine , I also have an A/F ratio in my car . Stumble also nearly gone with make the secondary air valve a half turn stiffer and get from a 31 to a 35 nozzle . Now the engine not lean up on quick full throttle and it’s much bette r.
Back to the timming !
You right that’s the important thing , I believe you !
Ok , I think tdc and harmonic Balancer are be ok and set correctly .
What I really not understand is this Plastik key for Adjust the advance plate slot , yes they give me keys from 14 to 28 degree adjustment . But if I adjust the slot with the 14 degree Plastik key , the advance in realty like more than 22 degree or more . actually I adjust by the 14 degree Plastik key and my initial timming in idle is about 10-12 degree , full advance by 3600 about 34-35 degree .
if I want a real advance of about 14 degree I need like to open this slot s just the half thickness of the 14 degree Plastik key .....

Why fire core make so vague Plastik keys.?
i mean they make a set from 14,16,18,20,22,24,26 and 28 degree . If I must calculate the keys like 14x2 , or 16x2 makes no sense , because who need a key With 56 degree advance if I take the 28 key x2 = 56

 

[Moparjack 489]

Fuel in Germany or this what I get on the car is 100 octane or 102 octane . Very good fuel

 

[BSB67]

I still run the 85

That's too hot.

Retard cam 2° if the plugs don't help enough.

 

[Moparjack 489]

That's too hot.

Retard cam 2° if the plugs don't help enough.

i will try plugs first , thanks

 

[Nate S]

thanks you for you’re fast reply !
Ok understand it with the idle screws , no that’s fine , I also have an A/F ratio in my car . Stumble also nearly gone with make the secondary air valve a half turn stiffer and get from a 31 to a 35 nozzle . Now the engine not lean up on quick full throttle and it’s much bette r.
Back to the timming !
You right that’s the important thing , I believe you !
Ok , I think tdc and harmonic Balancer are be ok and set correctly .
What I really not understand is this Plastik key for Adjust the advance plate slot , yes they give me keys from 14 to 28 degree adjustment . But if I adjust the slot with the 14 degree Plastik key , the advance in realty like more than 22 degree or more . actually I adjust by the 14 degree Plastik key and my initial timming in idle is about 10-12 degree , full advance by 3600 about 34-35 degree .
if I want a real advance of about 14 degree I need like to open this slot s just the half thickness of the 14 degree Plastik key .....

Why fire core make so vague Plastik keys.?
i mean they make a set from 14,16,18,20,22,24,26 and 28 degree . If I must calculate the keys like 14x2 , or 16x2 makes no sense , because who need a key With 56 degree advance if I take the 28 key x2 = 56

You’re right, that makes no sense. If it’s crankshaft degrees that’s unusual for the industry and obviously they didn’t get it right either way. Seems like you have the ignition timing under control. I’d really go after cam timing and balancer slippage just to be sure. It does happen.

 

[Moparjack 489]

You’re right, that makes no sense. If it’s crankshaft degrees that’s unusual for the industry and obviously they didn’t get it right either way. Seems like you have the ignition timing under control. I’d really go after cam timing and balancer slippage just to be sure. It does happen.[/

Ok, anywhere but I sure it’s right because my friend make the repair ( rebuild ) after the damage . but anywhere how I can check Balancer slippage and cam timming check ?

 

[Nate S]

For balancer slippage. You can get an adjustable metal plug that threads into spark plug holes. You'll want to turn the engine (wrench not starter) so the timing mark on the balancer is maybe an inch or so before TDC. Then thread in the stop and adjust inward until it stops (it hits the piston). Back up the engine and rotate into the stop. Mark the harmonic balancer where the 0° mark is on the timing cover. Then back up the engine a full turn until it hits the stop again. Mark the balancer again where the 0° mark is on the timing cover. Take out the plug and turn the engine where you can see the Timing mark on the balancer and both marks you just put on. If all is correct the timing mark on the balancer will be exactly between the other two. You should measure it with a tape measure to be sure. If it's not, make a new mark right between the two. That's your new balancer timing mark. Use it for timing etc.

For cam timing (basic check). Get the engine at TDC, check the distributor rotor, if it's pointing at #1, turn the engine over 1 revolution, if it's on #6, you're good to start. Take off the driver side valve cover and rig up a dial indicator so it's contacting the intake rocker right over the pushrod. Rotate the engine clockwise until the indicator is as far up as it will go (full lift). Zero the indicator. Rotate the engine (clockwise) until the indicator is back down .050", mark the harmonic balancer at the 0° line on the timing cover. Now back up the engine (counterclockwise) until the indicator goes back up to max and back down to .060". Go clockwise again until .050" and put another mark on the balancer at 0°. If you're doing this in a fully assembled car the rest is easiest to do from the bottom.

Get those last two marks in view on the balancer. Measure the distance between and add a new mark exactly halfway between. Now measure around the balancer from your last mark to the Timing mark you made in part 1 (or the factory groove if it was in the right place). Write down this number. The circumference of a stock balancer is ~22.78". divide your last number by 22.78 ... should be like 6.7/22.78 = .2944 . Multiply that number by 360... like .2944*360=106. That's your cam intake centerline after TDC. For your cam that should be 106°. If it's more than 2° less than that (advanced) the cylinder pressures will be higher and make it knock more.

A note on accuracy. ~each 1/16" of an inch is 1°. Keep that in mind. Sloppy measurements will mess up your answer.

 

[Moparjack 489]

For balancer slippage. You can get an adjustable metal plug that threads into spark plug holes. You'll want to turn the engine (wrench not starter) so the timing mark on the balancer is maybe an inch or so before TDC. Then thread in the stop and adjust inward until it stops (it hits the piston). Back up the engine and rotate into the stop. Mark the harmonic balancer where the 0° mark is on the timing cover. Then back up the engine a full turn until it hits the stop again. Mark the balancer again where the 0° mark is on the timing cover. Take out the plug and turn the engine where you can see the Timing mark on the balancer and both marks you just put on. If all is correct the timing mark on the balancer will be exactly between the other two. You should measure it with a tape measure to be sure. If it's not, make a new mark right between the two. That's your new balancer timing mark. Use it for timing etc.

For cam timing (basic check). Get the engine at TDC, check the distributor rotor, if it's pointing at #1, turn the engine over 1 revolution, if it's on #6, you're good to start. Take off the driver side valve cover and rig up a dial indicator so it's contacting the intake rocker right over the pushrod. Rotate the engine clockwise until the indicator is as far up as it will go (full lift). Zero the indicator. Rotate the engine (clockwise) until the indicator is back down .050", mark the harmonic balancer at the 0° line on the timing cover. Now back up the engine (counterclockwise) until the indicator goes back up to max and back down to .060". Go clockwise again until .050" and put another mark on the balancer at 0°. If you're doing this in a fully assembled car the rest is easiest to do from the bottom.

Get those last two marks in view on the balancer. Measure the distance between and add a new mark exactly halfway between. Now measure around the balancer from your last mark to the Timing mark you made in part 1 (or the factory groove if it was in the right place). Write down this number. The circumference of a stock balancer is ~22.78". divide your last number by 22.78 ... should be like 6.7/22.78 = .2944 . Multiply that number by 360... like .2944*360=106. That's your cam intake centerline after TDC. For your cam that should be 106°. If it's more than 2° less than that (advanced) the cylinder pressures will be higher and make it knock more.

A note on accuracy. ~each 1/16" of an inch is 1°. Keep that in mind. Sloppy measurements will mess up your answer.

Thank‘s so much for you’re very nice instruction s !!!
I will start to check the balancer first !