For Those Wanting To Port Your Heads!!!

Wow, looks like I posted in the middle of a brewing storm. I just hope none of that was aimed my way. I guess not, since no names were named.. and it would be kinda silly to talk to me about racing engines when I don't like racing anyway..

Originally Posted by PaulS1950

BHAM,
Where does your engine get it's peak torque? Mine gets it at 3200 RPM according to the cam spec sheet. I can accelerate to 6000 RPM because the amount of torque per minute is high enough to allow me to do so. That is what the HP is - torque per minute. One HP is 33000 ft lbs of torque per minute. HP is a measurement of the work done. Torque is a measurement of potential.
If I have a car with 200 pounds of drag measured at a 12 inch radius from the axle center (besides throwing it away) and I have an engine with 200 ft lbs of torque it won't go anywhere. The potential and the load are the same. In that case the horsepower being delivered is the same as being consumed so the net HP is zero.
Like I said you have to have both.

true, both are very important.. i think we have gotten off the true subject here, porting out heads in the garage... there is an ongoing battle between tq and hp..and which is better. personally i think tq is better, but i drive my car mainly on the street and 1/4. i again think personally tq is better on the 1/4 and hp would be better for the circle track where rpm are genarally higher. i donot want to get in a tug o war on this subject, first because hp and tq all depend on what application you are running-1/4 drag- round e round-street racing.i prefer street/ drag therefore i port my heads for the best all around tq curve.

Originally Posted by Inline6Lover

Wow, looks like I posted in the middle of a brewing storm. I just hope none of that was aimed my way. I guess not, since no names were named.. and it would be kinda silly to talk to me about racing engines when I don't like racing anyway..

no pointing at all, and this is a friendly conversation... we are all after a common goal..[faster cars] we all just have a different idea how to make them faster...

BHAM, about the comment on overly big heads and valves, and using a small cam.

There is an advantage to this. Valvetrain stress being the most important.

I have such a set-up and I am very happy with the results.

My 200 CC 2.05 heads, with a small .5 inch lift and 226 duration, has a lot less valve train stress then a 1.94 185 cc head, with a .550 lift and 240 durration cam. I can spin this motor up to 7000 RPM's and must limit it there, because the connecting rods I used will not take the stress. Put pulls hard in every gear to that RPM, though I choose to shift near 6400 RPM's for best results.

The advantage of large heads and small cam are: a lot less spring seat and opening pressure, (saves HP loss) less lift means less dynamic momentum pressure, less effort on the pushrods to open the valves, resulting in less pushrod deflection, (means the valves actually open to spec)and my engine is more efficent (loosing less HP) the lifters track the cam lobes better, since the dynamics actions are reduced. Less chance of valve float. The cam grind is also fatter on the sides of the lobes, since the lift is less. This means more average flow then just a really good peak flow on a higher lift cam. Big 200 CC runners take advantage of this effect.

One very important cam spec that no one talks about, is the rate of valve opening. On flat tappet cams, the rate is always faster then a roller cam, but the roller cam has better peak opening then a flat tappet. This is one reason why the cams are not interchangable.

A faster rate of opening, establishes a better partial lift air flow throughout the valve opening/closing operation. Higher lift Flat tappet cams will have a lesser opening/closing rate, since the lobes are much taller.

I port matched my heads to my manifold, took some ridges out from the casting mistakes, my cam was custom ground by a good friend to match the heads I am using.

Just the fact that you removed the valve guide bosses tells me a lot. That is a great way to build short life heads. You can not get the heat out of the valve without those bosses, especially the exhaust valve, you will burn those valves really quick. The valve guide is short enough as it is, taking another 3/8 off of them is bad news. The valves will also start to deflect at high RPM's reducing HP and seating of the valves at high RPM's. Polish does very little, except eye-candy.

Looks like you are a little mixed up too. The ONLY place a flat tappet cam has faster valve motion is off the seat, up to about 050 lift. THEN the roller takes over very fast. By 200 lift, the roller setuo is far ahead of the flat tappet setup.With the same duration aat 050. the flat tappet never had a chance.

JOE SHERMAN RACING ENGINES

Ya, I think I got them backwards.....

The flat tappet can dwell longer at full opening, but with a slower rate....I think the roller does not dwell as long at the top.... been a while since I thought about this.

But the higher the lift for the lobes for a flat tappet cam, the less the opening rate can be.

(I think...smiles)

Just the fact that you removed the valve guide bosses tells me a lot. That is a great way to build short life heads.


AS YOU CAN SEE IN THE PICS THE BOSS ISNT REMOVED ITS JUST WORKED ON ..I NEVER SAID TO REMOVE THE BOSS COMPLETELY.

Wow.. I can't believe you guys are trying to argue or tell Joe Sherman how things should be done. It makes no difference WHERE (Home or some huge business) the heads are ported, if someone that does them knows what they are doing.



I just hope you people don't piss established professionals like Joe off and they decided not to share any knowledge with us.

Originally Posted by Boss50

I just hope you people don't piss established professionals like Joe off and they decided not to share any knowledge with us.

I was kinda thinking the same thing. There is nothign wrong with a reasoned disagreement. there is more than one way to skin a cat and from what ive seen joe has no problem with somebody disagreeing with him, but there is a big difference between a disagreement over technique and telling a pro with a ton of experience that he has no idea what he is talking about. I hope everybody keeps common sense here and doesnt chase anybody away from this site.

BHAM, joe is a very respected member of this site, and his opinion is very respected, hes not some goofball that thinks he knows better than everybody else. you will get no support for attacking him here, and may even find yourself kicked off the site. This site is very understanding that everybody has an opinion, but the admins do not tolerate personal attacks on others, all it does is turn the site into a drama pissing match. Right now its a great resource with a lot of knowlegable people.

Originally Posted by sharpshot71

I was kinda thinking the same thing. There is nothign wrong with a reasoned disagreement. there is more than one way to skin a cat and from what ive seen joe has no problem with somebody disagreeing with him, but there is a big difference between a disagreement over technique and telling a pro with a ton of experience that he has no idea what he is talking about. I hope everybody keeps common sense here and doesnt chase anybody away from this site.

BHAM, joe is a very respected member of this site, and his opinion is very respected, hes not some goofball that thinks he knows better than everybody else. you will get no support for attacking him here, and may even find yourself kicked off the site. This site is very understanding that everybody has an opinion, but the admins do not tolerate personal attacks on others, all it does is turn the site into a drama pissing match. Right now its a great resource with a lot of knowlegable people.

PLEASE TAKE NOTE THAT I STATED THAT I DIDNT WANT THIS TO TURN INTO A PISSING MATCH...THIS IS JUST PEOPLE EXPRESSING THEIR IDEAS ON HOW ALL THINGS WORK.....