sled_dog
1 ton status
Yeah its gonna need to be a head change for you.
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
Cranking Compression vs. Octane
- Thread starter bigburban383
- Start date
Beast388
1/2 ton status
[ QUOTE ]
[ QUOTE ]
You probably did not square deck the block for good quench which will lower the comp ratio, but make the engine more prone to detonation.
[/ QUOTE ]
Decking the block into a good quench zone does the exact opposite. It will INCREASE compression ratio, and make the engine LESS prone to detonation.
Even with perfect quench distance in a 383 with a torquey cam and 305 heads and 10:1 static CR, it's going to be VERY knock prone.
[/ QUOTE ]
Read what I wrote. I said he probably did not square deck the block....meaning the piston is further down in the bore, which will result in a LOWER compresion ratio!! With improper quench, the engine is more prone to detonation.
Pay attention Timmy. /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif
[ QUOTE ]
You probably did not square deck the block for good quench which will lower the comp ratio, but make the engine more prone to detonation.
[/ QUOTE ]
Decking the block into a good quench zone does the exact opposite. It will INCREASE compression ratio, and make the engine LESS prone to detonation.
Even with perfect quench distance in a 383 with a torquey cam and 305 heads and 10:1 static CR, it's going to be VERY knock prone.
[/ QUOTE ]
Read what I wrote. I said he probably did not square deck the block....meaning the piston is further down in the bore, which will result in a LOWER compresion ratio!! With improper quench, the engine is more prone to detonation.
Pay attention Timmy. /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif
alaskanbowtie
1/2 ton status
My 358 with KB flat tops , 67cc chamber heads "cast iron" and a quench hieght of 38 thousands is 10.3.1 and thats a measurement by the machine shop , OH and 6.00" rods .I run 92 and have to turn the timing back a bit, when I mix half n half with 101 octane av gas I can turn up the timing considerably and it runs like a raped ape!!! But thats only every once in a while /forums/images/graemlins/rotfl.gif I would run 93 if I had access to it but all we have is 92 so I will be buying Aluminum heads next go around, they deal with the hot spots and heat better to help eliminate the easy detonation problems associated with the cast heads and higher compression ratio's. Your compression is a bit high for 93 with cast heads, unless you turn back the timing . Good luck and if you buy new heads consider Aluminum for the money, hands down a better investment! /forums/images/graemlins/waytogo.gif
84_Chevy_K10
Banned
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
You probably did not square deck the block for good quench which will lower the comp ratio, but make the engine more prone to detonation.
[/ QUOTE ]
Decking the block into a good quench zone does the exact opposite. It will INCREASE compression ratio, and make the engine LESS prone to detonation.
Even with perfect quench distance in a 383 with a torquey cam and 305 heads and 10:1 static CR, it's going to be VERY knock prone.
[/ QUOTE ]
Read what I wrote. I said he probably did not square deck the block....meaning the piston is further down in the bore, which will result in a LOWER compresion ratio!! With improper quench, the engine is more prone to detonation.
Pay attention Timmy. /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif
[/ QUOTE ]
I am sorry. Took three re-reads of the sentence to clarify that one. It does make sense, just the first few times, it is very unclear what you meant.
Sorry, didn't mean to come down on you so hard, but at first glance, that sentence isn't very clear at all.
[ QUOTE ]
[ QUOTE ]
You probably did not square deck the block for good quench which will lower the comp ratio, but make the engine more prone to detonation.
[/ QUOTE ]
Decking the block into a good quench zone does the exact opposite. It will INCREASE compression ratio, and make the engine LESS prone to detonation.
Even with perfect quench distance in a 383 with a torquey cam and 305 heads and 10:1 static CR, it's going to be VERY knock prone.
[/ QUOTE ]
Read what I wrote. I said he probably did not square deck the block....meaning the piston is further down in the bore, which will result in a LOWER compresion ratio!! With improper quench, the engine is more prone to detonation.
Pay attention Timmy. /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif
[/ QUOTE ]
I am sorry. Took three re-reads of the sentence to clarify that one. It does make sense, just the first few times, it is very unclear what you meant.
Sorry, didn't mean to come down on you so hard, but at first glance, that sentence isn't very clear at all.
bigburban383
1/2 ton status
This blows, I filled my tank yesterday before hooking up the scanner and put 20 gallons of 87 octane in on top of about 8 gallons. I put in some 104 octane booster in, but it only treats upto 20 gallonc, that stuff is $7.00 a bottle!
Beast388
1/2 ton status
[ QUOTE ]
This blows, I filled my tank yesterday before hooking up the scanner and put 20 gallons of 87 octane in on top of about 8 gallons. I put in some 104 octane booster in, but it only treats upto 20 gallonc, that stuff is $7.00 a bottle!
[/ QUOTE ]
You definately need to make some engine changes. After a few months of buying the high $$ gas and octane "booster" you could pay for a good set of rebuilt heads.
If you list the specs on your motor, I bet we (CK5) can make some good recommendations on what to change. You want all aspects of your engine to work together. Right now the number one thing you need to change is the heads.....unshrouded or not, those 305 heads don't belong on a 388. /forums/images/graemlins/deal.gif /forums/images/graemlins/waytogo.gif
This blows, I filled my tank yesterday before hooking up the scanner and put 20 gallons of 87 octane in on top of about 8 gallons. I put in some 104 octane booster in, but it only treats upto 20 gallonc, that stuff is $7.00 a bottle!
[/ QUOTE ]
You definately need to make some engine changes. After a few months of buying the high $$ gas and octane "booster" you could pay for a good set of rebuilt heads.
If you list the specs on your motor, I bet we (CK5) can make some good recommendations on what to change. You want all aspects of your engine to work together. Right now the number one thing you need to change is the heads.....unshrouded or not, those 305 heads don't belong on a 388. /forums/images/graemlins/deal.gif /forums/images/graemlins/waytogo.gif
alaskanbowtie
1/2 ton status
ok, now you know what really will resolve the problem but mean time don't buy the 104 [darn] it's not as good as it sounds and doesn't do anything for a motor that you can see on the dyno...... I know I have done this and NO change. But you can run a half gallon of toulene with every tank and it will help with detonation until you get something done or decide to just drive it that way.... remember compression makes horsepower /forums/images/graemlins/eek.gif and if you "can" get it to run that way safely you will have more balls!!! Toulene is 8 to 10 dollars a gallon at the hardware store in the paint section and it DOES actually help a little, I run a gallon with every tank. So either way your getting a better deal cash wise and detonation wise. 104 is made of toulene...... and a few other things but the majority of it is toulene. /forums/images/graemlins/waytogo.gif
bigburban383
1/2 ton status
[ QUOTE ]
ok, now you know what really will resolve the problem but mean time don't buy the 104 [darn] it's not as good as it sounds and doesn't do anything for a motor that you can see on the dyno...... I know I have done this and NO change. But you can run a half gallon of toulene with every tank and it will help with detonation until you get something done or decide to just drive it that way.... remember compression makes horsepower /forums/images/graemlins/eek.gif and if you "can" get it to run that way safely you will have more balls!!! Toulene is 8 to 10 dollars a gallon at the hardware store in the paint section and it DOES actually help a little, I run a gallon with every tank. So either way your getting a better deal cash wise and detonation wise. 104 is made of toulene...... and a few other things but the majority of it is toulene. /forums/images/graemlins/waytogo.gif
[/ QUOTE ]
Is that stuff bad for your fuel system, toulene?
ok, now you know what really will resolve the problem but mean time don't buy the 104 [darn] it's not as good as it sounds and doesn't do anything for a motor that you can see on the dyno...... I know I have done this and NO change. But you can run a half gallon of toulene with every tank and it will help with detonation until you get something done or decide to just drive it that way.... remember compression makes horsepower /forums/images/graemlins/eek.gif and if you "can" get it to run that way safely you will have more balls!!! Toulene is 8 to 10 dollars a gallon at the hardware store in the paint section and it DOES actually help a little, I run a gallon with every tank. So either way your getting a better deal cash wise and detonation wise. 104 is made of toulene...... and a few other things but the majority of it is toulene. /forums/images/graemlins/waytogo.gif
[/ QUOTE ]
Is that stuff bad for your fuel system, toulene?
bigburban383
1/2 ton status
[ QUOTE ]
[ QUOTE ]
This blows, I filled my tank yesterday before hooking up the scanner and put 20 gallons of 87 octane in on top of about 8 gallons. I put in some 104 octane booster in, but it only treats upto 20 gallonc, that stuff is $7.00 a bottle!
[/ QUOTE ]
You definately need to make some engine changes. After a few months of buying the high $$ gas and octane "booster" you could pay for a good set of rebuilt heads.
If you list the specs on your motor, I bet we (CK5) can make some good recommendations on what to change. You want all aspects of your engine to work together. Right now the number one thing you need to change is the heads.....unshrouded or not, those 305 heads don't belong on a 388. /forums/images/graemlins/deal.gif /forums/images/graemlins/waytogo.gif
[/ QUOTE ]
I know the 305 heads shouldnt be on it, buts its all I had availible. I want to get those SR Torquers but I have no money right now, I don't have a job ether /forums/images/graemlins/1zhelp.gif
[ QUOTE ]
This blows, I filled my tank yesterday before hooking up the scanner and put 20 gallons of 87 octane in on top of about 8 gallons. I put in some 104 octane booster in, but it only treats upto 20 gallonc, that stuff is $7.00 a bottle!
[/ QUOTE ]
You definately need to make some engine changes. After a few months of buying the high $$ gas and octane "booster" you could pay for a good set of rebuilt heads.
If you list the specs on your motor, I bet we (CK5) can make some good recommendations on what to change. You want all aspects of your engine to work together. Right now the number one thing you need to change is the heads.....unshrouded or not, those 305 heads don't belong on a 388. /forums/images/graemlins/deal.gif /forums/images/graemlins/waytogo.gif
[/ QUOTE ]
I know the 305 heads shouldnt be on it, buts its all I had availible. I want to get those SR Torquers but I have no money right now, I don't have a job ether /forums/images/graemlins/1zhelp.gif
SUBFAN
1/2 ton status
Pay attention to what Beast388 is saying....Talk with the machine shops around you. They might be willing to swap you pretty reasonably for the heads you have on there right now. The S/R Torquers would be a decent choice, but getting that 'ping' under control is the first thing you need to do.
Remember, every time that thing pings, it is eating your rod/main bearings and taking that much more life away from your new powerplant.
I will check the basement tonight, there may be a set of heads I would let go to help solve the problem, since I don't like the way things are sounding. /forums/images/graemlins/waytogo.gif
Remember, every time that thing pings, it is eating your rod/main bearings and taking that much more life away from your new powerplant.
I will check the basement tonight, there may be a set of heads I would let go to help solve the problem, since I don't like the way things are sounding. /forums/images/graemlins/waytogo.gif
84_Chevy_K10
Banned
Toulene is already in your gasoline and won't hurt a thing. It should give you a pretty good boost in octane too, much better than that crap in the bottle.
bigburban383
1/2 ton status
[ QUOTE ]
Pay attention to what Beast388 is saying....Talk with the machine shops around you. They might be willing to swap you pretty reasonably for the heads you have on there right now. The S/R Torquers would be a decent choice, but getting that 'ping' under control is the first thing you need to do.
Remember, every time that thing pings, it is eating your rod/main bearings and taking that much more life away from your new powerplant.
I will check the basement tonight, there may be a set of heads I would let go to help solve the problem, since I don't like the way things are sounding. /forums/images/graemlins/waytogo.gif
[/ QUOTE ]
I supposed I can redo my old stock 350 heads. I just hope that I don't have to buy another set of $100 custom pushrods. The stock pushrod length for an 84' 305 and a 90' 350 are the same right?
Pay attention to what Beast388 is saying....Talk with the machine shops around you. They might be willing to swap you pretty reasonably for the heads you have on there right now. The S/R Torquers would be a decent choice, but getting that 'ping' under control is the first thing you need to do.
Remember, every time that thing pings, it is eating your rod/main bearings and taking that much more life away from your new powerplant.
I will check the basement tonight, there may be a set of heads I would let go to help solve the problem, since I don't like the way things are sounding. /forums/images/graemlins/waytogo.gif
[/ QUOTE ]
I supposed I can redo my old stock 350 heads. I just hope that I don't have to buy another set of $100 custom pushrods. The stock pushrod length for an 84' 305 and a 90' 350 are the same right?
84_Chevy_K10
Banned
You need to verify where the rocker is riding on the valve tip. You can't just bolt an engine together and go. If your engine has been machined, there is no way for someone over the internet to guess what pushrod length you need.
Beast388
1/2 ton status
[ QUOTE ]
The stock pushrod length for an 84' 305 and a 90' 350 are the same right?
[/ QUOTE ]
The only way to determine your required pushrod length is to use the correct tool. When I switched from my stock 350 heads to my S/R Torquers, I needed a pushrod that was 0.080" longer. /forums/images/graemlins/deal.gif
Here is what the tool looks like:
Jegs Link
The stock pushrod length for an 84' 305 and a 90' 350 are the same right?
[/ QUOTE ]
The only way to determine your required pushrod length is to use the correct tool. When I switched from my stock 350 heads to my S/R Torquers, I needed a pushrod that was 0.080" longer. /forums/images/graemlins/deal.gif
Here is what the tool looks like:
Jegs Link
