asked for a cam spec and wound up totally confused
09-21-2013, 12:19 PM
#41
10 Second Club
Some can and some pistons let go....I'd run on the fat side and give up a little power.
I was talking to a buddy about this and he told me about a BBC he had where the fly-cuts you could see the ring...Machinist said it was like gas porting and it would be fine. Lasted a long time and on 2 stages
Agreed 
I was talking to a buddy about this and he told me about a BBC he had where the fly-cuts you could see the ring...Machinist said it was like gas porting and it would be fine. Lasted a long time and on 2 stages
Last edited by Doug G; 09-21-2013 at 01:18 PM. Reason: spellin'
09-21-2013, 05:37 PM
#48
going off of memory, I had to cut .090 off of the intake to get .070 clearance. had .099 exhaust clearance. this was using stock gaskets.
a smaller intake valve and non milled heads should clear better. remember I am running milled heads to get 59cc along with the 2.055 intake valves. I also think the angle of the valves are different on TFS heads in comparison to a stock casting. all things that could change PTV clearance...just not sure if it would give more or less.
lindy tool. it works great. just do your part on prep and making sure every piston is at perfect tdc before cutting is the key. after doing it on a stand (for the 2nd motor) I wouldn't do it in the car. it would be a major PITA.
a smaller intake valve and non milled heads should clear better. remember I am running milled heads to get 59cc along with the 2.055 intake valves. I also think the angle of the valves are different on TFS heads in comparison to a stock casting. all things that could change PTV clearance...just not sure if it would give more or less.
lindy tool. it works great. just do your part on prep and making sure every piston is at perfect tdc before cutting is the key. after doing it on a stand (for the 2nd motor) I wouldn't do it in the car. it would be a major PITA.
09-21-2013, 06:14 PM
#51
remember I am running milled heads to get 59cc along with the 2.055 intake valves. I also think the angle of the valves are different on TFS heads in comparison to a stock casting. all things that could change PTV clearance...just not sure if it would give more or less.
09-21-2013, 09:45 PM
#53
Teching In
Thread Starter
Join Date: Aug 2013
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
For years on this board and others, the myth that a single plane short runner intake manifold makes less torque than a dual plane or Fast intake has been told. That the torque lost from a longer runner cannot in any way shape or form be made up when switched to a short runner single plane intake.
This is false.
This is said because cam timing events are not proper for the combination. There is a thread in the Gen 3 section right now where I just did a cam for a gentleman. He switched from a Fast 102 on his TFS 225 combo and EPS cam to a Super Victor and one of my custom cams. My custom cam is larger than his old EPS cam, and we were still able to match the torque curve pound ft. tq. for lb. ft. of torque up to 5000rpm where the single plane started to pull away. Uncorrected the gains were 32-33rwhp. SAE corrected for weather conditions on both days they were much, much more.
Some will say, but it's a big lazy port with no velocity. Au contraire mon frere'. The main reason the LS3 heads don't perform on par in regards to torque values down low is once again cam timing. The port is very large, it has a large intake valve. We do not need to hold the intake valve open nearly as long to fill the cylinder at higher rpm's fully. This improves low speed torque greatly. As valve lift is increased, air speed in the runner increases as well. ICL is a measure of how many crank degrees it takes the intake lobe to reach peak valve lift after TDC. If we can reach that peak valve lift sooner after TDC, we're reaching peak air speed in the intake port sooner. This will help build port speed at lower piston speeds(engine rpm) and close the intake valve earlier from the further advanced ICL.
With a single plane, we need the signal from overlap to help accelerate the intake charge into the port until the downward motion of the piston and the negative pressure left behind the piston can help aid in pulling that charge into the cylinder.
Only problem with overlap is it can create P to V issues when the piston nears or is at TDC. This problem is exasperated by the large LS3 intake valve.
This is why I recommended fly-cutting for the OP so he could have the most powerful set-up possible. With great bottom end and top end.
I can grind a cam that will not require fly-cutting, but I've found that these LS3 combo's really like compression as well. While you're fly-cutting, you may as well fly-cut enough to mill the heads some too. Milling is cheap and easy to find a machine shop to do it.
Hope this helps.
This is false.
This is said because cam timing events are not proper for the combination. There is a thread in the Gen 3 section right now where I just did a cam for a gentleman. He switched from a Fast 102 on his TFS 225 combo and EPS cam to a Super Victor and one of my custom cams. My custom cam is larger than his old EPS cam, and we were still able to match the torque curve pound ft. tq. for lb. ft. of torque up to 5000rpm where the single plane started to pull away. Uncorrected the gains were 32-33rwhp. SAE corrected for weather conditions on both days they were much, much more.
Some will say, but it's a big lazy port with no velocity. Au contraire mon frere'. The main reason the LS3 heads don't perform on par in regards to torque values down low is once again cam timing. The port is very large, it has a large intake valve. We do not need to hold the intake valve open nearly as long to fill the cylinder at higher rpm's fully. This improves low speed torque greatly. As valve lift is increased, air speed in the runner increases as well. ICL is a measure of how many crank degrees it takes the intake lobe to reach peak valve lift after TDC. If we can reach that peak valve lift sooner after TDC, we're reaching peak air speed in the intake port sooner. This will help build port speed at lower piston speeds(engine rpm) and close the intake valve earlier from the further advanced ICL.
With a single plane, we need the signal from overlap to help accelerate the intake charge into the port until the downward motion of the piston and the negative pressure left behind the piston can help aid in pulling that charge into the cylinder.
Only problem with overlap is it can create P to V issues when the piston nears or is at TDC. This problem is exasperated by the large LS3 intake valve.
This is why I recommended fly-cutting for the OP so he could have the most powerful set-up possible. With great bottom end and top end.
I can grind a cam that will not require fly-cutting, but I've found that these LS3 combo's really like compression as well. While you're fly-cutting, you may as well fly-cut enough to mill the heads some too. Milling is cheap and easy to find a machine shop to do it.
Hope this helps.
If I went dual plane instead of single with the ls3 heads I have, and a very small LSA cam (say 106-110) . Instead of the normal 112 and above. Would I have to do any flycutting of the pistons? Or have piston to valve clearance issues still? This is the turning point/pause I have encountered with deciding the motor. The cam,single or dual plane intake, and a converter to match.
If the Andy fellow made all tht trq and horsepower under 6500 rpm. Me having a 3.42 gear and th350 trans, kinda makes me think I may not be spinning it wayyyyy up to 6500+ going thru the traps. .Right or wrong?
09-21-2013, 10:29 PM
#54
lsa doesn't determine p2v. it's all in the valve events. if you want max effort without flycutting you may need to step back to a cathedral. there are a lot of people who don't buy into the ls3/l92 head hype including me. the stock ls6/317 heads with a Trex have been proven to be strong performers with single plane carb setups. ported unmilled 243 heads with the t-rex could be a monster without having to flycut...or martin could have more flexibility to spec a good cam without having to flycut. that monster intake valve in the LS3/L92 head is unnecessary and kills your options IMO.
or just take martin's professional advice and flycut your pistons to get an optimal setup.
or just take martin's professional advice and flycut your pistons to get an optimal setup.
09-22-2013, 06:31 AM
#56
10 Second Club
LS3/L92 head/valve combo isn't what requires the fly-cut ...it's the cam events as said above.
Even IF I would have kept the 317's and did the same .050 shave with the same cam, fly-cuts would be needed. (just a smaller diameter)
IF you use the LS3 heads, you want a cam that's going make good use of them.
Heads and cam are where the power is made......or lost.
Even IF I would have kept the 317's and did the same .050 shave with the same cam, fly-cuts would be needed. (just a smaller diameter)
IF you use the LS3 heads, you want a cam that's going make good use of them.
Heads and cam are where the power is made......or lost.
09-23-2013, 07:19 AM
#57
To the OP, I think that if you can make all the usable power you want and can keep the engine from spinning to the moon, You are ahead of the game . Why spin the engine to 7K when you can save parts failure by shifting at 6200-6400 ?
Martin is a wizard at getting max effort out of an engine, I just wish that Martin or any of the other good cam grinders around would grab one of those GMPP dual planes and do some work with cam design and see what it has to offer. Andy and family at D&A machine did a lot of research and played with multiple intakes and found the GMPP dual to make the best power across the board on the big port heads. The Engine Masters Challenge is all about average power, not peak HP dyno glory. D&A is the only outfit that I know of that has done true comparisons on the intake.
I completely understand it takes a lot of research and development to test something new and a lot of research has gone into making the single plane work with the big heads. But what if , like Tigger said, the GMPP dual is the best setup for a dual purpose street car and the whole LS community missed it ? Looks to me like the cam grinder that pushes that combo would be the go to guy, till the other gurus caught up to the learning curve ,if it is the best combo .
Martin is a wizard at getting max effort out of an engine, I just wish that Martin or any of the other good cam grinders around would grab one of those GMPP dual planes and do some work with cam design and see what it has to offer. Andy and family at D&A machine did a lot of research and played with multiple intakes and found the GMPP dual to make the best power across the board on the big port heads. The Engine Masters Challenge is all about average power, not peak HP dyno glory. D&A is the only outfit that I know of that has done true comparisons on the intake.
I completely understand it takes a lot of research and development to test something new and a lot of research has gone into making the single plane work with the big heads. But what if , like Tigger said, the GMPP dual is the best setup for a dual purpose street car and the whole LS community missed it ? Looks to me like the cam grinder that pushes that combo would be the go to guy, till the other gurus caught up to the learning curve ,if it is the best combo .
09-23-2013, 10:12 AM
#58
Teching In
Thread Starter
Join Date: Aug 2013
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
[QUOTE=newschool72;17703787]To the OP, I think that if you can make all the usable power you want and can keep the engine from spinning to the moon, You are ahead of the game . Why spin the engine to 7K when you can save parts failure by shifting at 6200-6400 ?
Martin is a wizard at getting max effort out of an engine, I just wish that Martin or any of the other good cam grinders around would grab one of those GMPP dual planes and do some work with cam design and see what it has to offer. Andy and family at D&A machine did a lot of research and played with multiple intakes and found the GMPP dual to make the best power across the board on the big port heads. The Engine Masters Challenge is all about average power, not peak HP dyno glory. D&A is the only outfit that I know of that has done true comparisons on the intake.
I completely understand it takes a lot of research and development to test something new and a lot of research has gone into making the single plane work with the big heads. But what if , like Tigger said, the GMPP dual is the best setup for a dual purpose street car and the whole LS community missed it ? Looks to me like the cam grinder that pushes that combo would be the go to guy, till the other gurus caught up to the learning curve ,if it is the best comb
THANKYOU TO EVERYONE WHO GAVE SOME SORT OF INSIGHT. I APPRECIATE IT!!!!
Martin is a wizard at getting max effort out of an engine, I just wish that Martin or any of the other good cam grinders around would grab one of those GMPP dual planes and do some work with cam design and see what it has to offer. Andy and family at D&A machine did a lot of research and played with multiple intakes and found the GMPP dual to make the best power across the board on the big port heads. The Engine Masters Challenge is all about average power, not peak HP dyno glory. D&A is the only outfit that I know of that has done true comparisons on the intake.
I completely understand it takes a lot of research and development to test something new and a lot of research has gone into making the single plane work with the big heads. But what if , like Tigger said, the GMPP dual is the best setup for a dual purpose street car and the whole LS community missed it ? Looks to me like the cam grinder that pushes that combo would be the go to guy, till the other gurus caught up to the learning curve ,if it is the best comb
THANKYOU TO EVERYONE WHO GAVE SOME SORT OF INSIGHT. I APPRECIATE IT!!!!
Last edited by savage9scorpio; 06-10-2014 at 06:46 PM.
09-23-2013, 10:36 AM
#59
I think I need to clarify something for the record because I always push baby cams and average power. My references are always geared towards street first/track second, because that is what I have been working on for the last couple years. I agree with all above for a track first/street second car. If a man is running a 4K stall, deep gears, max effort cam and supporting mods, then a single plane is the way to go, no doubt. I just see a lot of people go big then wind up slower than a much milder combo because they give up all that good meat in the 3500-5000rpm range to shoot for the HP glory up top. They wind up with a car that wont hook because they are blasting their mild suspension with that monster torque given by the high stall converter. Look at all the times in peoples sigs ....11.31 at 129, 11.20 at 132, 11.80 at 126, etc, etc... A well sorted mild setup will run those times minus the big MPH and actually hook up in the process, be much friendlier to the engine and drive train and be much more fun to drive more than 10-15 miles. That is my point for street first/track second. Purpose built drag cars will shine with the big parts because the suspension will hold it.
I had a 65 Chevelle many years ago that I raced on the street just for fun. It had a 337 SBC and would hook dead on street tires. I never lost a race and regularly beat BBC cars. By the time they got moving, I had them by 7-8 cars. Of course this was many years ago, before good tires were out there for street cars, but I think it is still valid because as tires got better ,so did engine tech. Tires hook better, but it is still pretty easy to build enough power to blow them off.
I believe a well sorted mild combo will beat a poorly sorted radical setup w the street tires being the fusible link in the combo. All of this is IMO, of course, feel free to think about it however you want, LOL.
I had a 65 Chevelle many years ago that I raced on the street just for fun. It had a 337 SBC and would hook dead on street tires. I never lost a race and regularly beat BBC cars. By the time they got moving, I had them by 7-8 cars. Of course this was many years ago, before good tires were out there for street cars, but I think it is still valid because as tires got better ,so did engine tech. Tires hook better, but it is still pretty easy to build enough power to blow them off.
I believe a well sorted mild combo will beat a poorly sorted radical setup w the street tires being the fusible link in the combo. All of this is IMO, of course, feel free to think about it however you want, LOL.
09-23-2013, 10:52 AM
#60
I think I need to clarify something for the record because I always push baby cams and average power. My references are always geared towards street first/track second, because that is what I have been working on for the last couple years. I agree with all above for a track first/street second car. If a man is running a 4K stall, deep gears, max effort cam and supporting mods, then a single plane is the way to go, no doubt. I just see a lot of people go big then wind up slower than a much milder combo because they give up all that good meat in the 3500-5000rpm range to shoot for the HP glory up top. They wind up with a car that wont hook because they are blasting their mild suspension with that monster torque given by the high stall converter. Look at all the times in peoples sigs ....11.31 at 129, 11.20 at 132, 11.80 at 126, etc, etc... A well sorted mild setup will run those times minus the big MPH and actually hook up in the process, be much friendlier to the engine and drive train and be much more fun to drive more than 10-15 miles. That is my point for street first/track second. Purpose built drag cars will shine with the big parts because the suspension will hold it.
I had a 65 Chevelle many years ago that I raced on the street just for fun. It had a 337 SBC and would hook dead on street tires. I never lost a race and regularly beat BBC cars. By the time they got moving, I had them by 7-8 cars. Of course this was many years ago, before good tires were out there for street cars, but I think it is still valid because as tires got better ,so did engine tech. Tires hook better, but it is still pretty easy to build enough power to blow them off.
I believe a well sorted mild combo will beat a poorly sorted radical setup w the street tires being the fusible link in the combo. All of this is IMO, of course, feel free to think about it however you want, LOL.
I had a 65 Chevelle many years ago that I raced on the street just for fun. It had a 337 SBC and would hook dead on street tires. I never lost a race and regularly beat BBC cars. By the time they got moving, I had them by 7-8 cars. Of course this was many years ago, before good tires were out there for street cars, but I think it is still valid because as tires got better ,so did engine tech. Tires hook better, but it is still pretty easy to build enough power to blow them off.
I believe a well sorted mild combo will beat a poorly sorted radical setup w the street tires being the fusible link in the combo. All of this is IMO, of course, feel free to think about it however you want, LOL.