unshrouding valves on bbc
#2
Senior Member
DYNO OPERATOR
Join Date: Feb 2006
Location: VA Hospital, Dallas, Tx (214 302 1924) cell-972-464-7400
Posts: 540
To answer all your questions about this;
Yes.
If block is bare, put blue on the area surrounding the chambers and bolt heads to block. Use a scribe and reach inside and scribe the heads all around the cylinder.
Remove head. Place head gasket to be used on head. Place bolts in the head gasket larger than necessary. Stick some 1/2 bolts in the gasket holding it in place so it can not move.
Now mark with scribe around the valve relieved sections of the head gasket. That is the maximum you will go when doing valve unshrouding.
Where the valve relief Extends past the cylinder wall where valve relief is it won';t do any good to cut head any farther back at that location. Unless you place head gasket on the block and also mark it where the valve reliefs are and grind those relief notches in the block. If you do be very careful and do not grind the notch too deep. If you do decide to grind notches in block only cut it for intake vlaves and not very deep. You will then need to debur where you cut the block in the cylinder wall area. Haven't done this in many years.
Esay way to cut the valve unshrouding reliefs is to get a flap wheel for sanding that is a little larger in outside diameter than the valve that cuts only on the outside diameter of the flap wheel. I say this because there are also flap wheels used on a disc style sanding disc that cut on the falt surface.; You want the type that cuts on the outside diameter.
As you sand with it at only the valve relief position, move it continously up and down and slightlyu side to side. Usually anytime I am sanding or grinding on a head i am constantly keeping the stone, sanding surface, cutter or grinding surface moving, usually in small circles. I keep better control by keeping the tool continously moving.
Possibly someone else will come by and tell you an easier or better way.
Ed
Yes.
If block is bare, put blue on the area surrounding the chambers and bolt heads to block. Use a scribe and reach inside and scribe the heads all around the cylinder.
Remove head. Place head gasket to be used on head. Place bolts in the head gasket larger than necessary. Stick some 1/2 bolts in the gasket holding it in place so it can not move.
Now mark with scribe around the valve relieved sections of the head gasket. That is the maximum you will go when doing valve unshrouding.
Where the valve relief Extends past the cylinder wall where valve relief is it won';t do any good to cut head any farther back at that location. Unless you place head gasket on the block and also mark it where the valve reliefs are and grind those relief notches in the block. If you do be very careful and do not grind the notch too deep. If you do decide to grind notches in block only cut it for intake vlaves and not very deep. You will then need to debur where you cut the block in the cylinder wall area. Haven't done this in many years.
Esay way to cut the valve unshrouding reliefs is to get a flap wheel for sanding that is a little larger in outside diameter than the valve that cuts only on the outside diameter of the flap wheel. I say this because there are also flap wheels used on a disc style sanding disc that cut on the falt surface.; You want the type that cuts on the outside diameter.
As you sand with it at only the valve relief position, move it continously up and down and slightlyu side to side. Usually anytime I am sanding or grinding on a head i am constantly keeping the stone, sanding surface, cutter or grinding surface moving, usually in small circles. I keep better control by keeping the tool continously moving.
Possibly someone else will come by and tell you an easier or better way.
Ed
#3
Senior Member
RACING JUNKIE
Join Date: Jan 2006
Location: La.
Posts: 2,890
I would think they are already done but unshrouding the valves is a process that opens up the combustion chamber in the heads on the short side of the valves to the head gasket or bore size of the motor. It definately helps if they are not done already. Also valve pocket porting to 85% of the valve dia. is a good thing.
just my opinion.
Zip.
just my opinion.
Zip.
#5
Senior Member
RACING JUNKIE
Join Date: Jan 2006
Location: La.
Posts: 2,890
Originally Posted by edvancedengines
Zip,
I have seen a lot of your opinions here.
Thank you for trying to be helpful for others.
I like your opinions.
Ed
I have seen a lot of your opinions here.
Thank you for trying to be helpful for others.
I like your opinions.
Ed
Just a day in history that i will never forget, and i will never know everything and will never stop learning until the day i die.
Zip.
#6
Senior Member
DYNO OPERATOR
Join Date: Feb 2006
Location: VA Hospital, Dallas, Tx (214 302 1924) cell-972-464-7400
Posts: 540
Zip,
What is your name?
What part of Louisiana are you from?
I am Ed Wilson.
I arrived in Louisiana in the Lake Charles/Sulphur/Carlyss/DeQuency area in 1977. I raced in that area on the street/highways. and the tracks until 1979. That car was wrecked in a non racing traffic accident. In 1981 I brought out a different sort of Chevy Nova that got featured in a few magazines. I raced that car from 1981 till 1985. In 1985 We took my engine out and installed it into Doug Mead's old Top Fueler and ran it a year.
Before the Louisiana tour I was in Houston racing from 1970 until 1977. lol. Prior to Houston I was in Ft.Worth Texas doing a little racing but mostly working. Before that I was in the APOSF area in S.Vietnam.
Is there any chance you know me, or I know you?
Ed
What is your name?
What part of Louisiana are you from?
I am Ed Wilson.
I arrived in Louisiana in the Lake Charles/Sulphur/Carlyss/DeQuency area in 1977. I raced in that area on the street/highways. and the tracks until 1979. That car was wrecked in a non racing traffic accident. In 1981 I brought out a different sort of Chevy Nova that got featured in a few magazines. I raced that car from 1981 till 1985. In 1985 We took my engine out and installed it into Doug Mead's old Top Fueler and ran it a year.
Before the Louisiana tour I was in Houston racing from 1970 until 1977. lol. Prior to Houston I was in Ft.Worth Texas doing a little racing but mostly working. Before that I was in the APOSF area in S.Vietnam.
Is there any chance you know me, or I know you?
Ed
#7
Member
CRAFTSMAN
Join Date: Dec 2006
Posts: 52
sorry if you get ofended but de dee deee don't spend over 3000 on a set of cnc heads and do any porting by hand or on any cnc heads for that reason if you want to really see if the valves need unshouding before you kill you combustion chamber send the to joe mondello have the wet flow tested and he'll tell you if you'll see any flow gain at all. theres no point in cutting the combustion chambers if they don't need cut are they cnc chambers if so don't worry about it just bolt them on either way you'll have to have them cc each chamber to be sure each cylinder has the same compression. i meantioned joe mondello don't get confussed with his site he doesn't just do oldsmobile he will work on anything but "BE WARNED" he is expensive but you'll never find a better porter in you life time if i had to pick between a set of cnc's from some other guy and a set of hand ported heads by him i'd take his hands down.
#8
Member
CRAFTSMAN
Join Date: Dec 2006
Posts: 52
but for a much shorter version if the valve is big enough and its a small chamber size then yes you'll definitly see more horsepower from unsrouding the valves call and ask joe he'll tell you all about it ask him about when he took .060 out of the chamber and picked up 24cfm
#9
Senior Member
RACING JUNKIE
Join Date: Jan 2006
Location: La.
Posts: 2,890
Originally Posted by edvancedengines
Zip,
What is your name?
What part of Louisiana are you from?
I am Ed Wilson.
I arrived in Louisiana in the Lake Charles/Sulphur/Carlyss/DeQuency area in 1977. I raced in that area on the street/highways. and the tracks until 1979. That car was wrecked in a non racing traffic accident. In 1981 I brought out a different sort of Chevy Nova that got featured in a few magazines. I raced that car from 1981 till 1985. In 1985 We took my engine out and installed it into Doug Mead's old Top Fueler and ran it a year.
Before the Louisiana tour I was in Houston racing from 1970 until 1977. lol. Prior to Houston I was in Ft.Worth Texas doing a little racing but mostly working. Before that I was in the APOSF area in S.Vietnam.
Is there any chance you know me, or I know you?
Ed
What is your name?
What part of Louisiana are you from?
I am Ed Wilson.
I arrived in Louisiana in the Lake Charles/Sulphur/Carlyss/DeQuency area in 1977. I raced in that area on the street/highways. and the tracks until 1979. That car was wrecked in a non racing traffic accident. In 1981 I brought out a different sort of Chevy Nova that got featured in a few magazines. I raced that car from 1981 till 1985. In 1985 We took my engine out and installed it into Doug Mead's old Top Fueler and ran it a year.
Before the Louisiana tour I was in Houston racing from 1970 until 1977. lol. Prior to Houston I was in Ft.Worth Texas doing a little racing but mostly working. Before that I was in the APOSF area in S.Vietnam.
Is there any chance you know me, or I know you?
Ed
Zip.
#10
Senior Member
DYNO OPERATOR
Join Date: Feb 2006
Location: VA Hospital, Dallas, Tx (214 302 1924) cell-972-464-7400
Posts: 540
TIMMYBOY,
hOW DID YOU GET ALL THE INFO FOR YOUR RESPONSE OUT OF THE ORIGINAL QUESTION? i DIDN'T. (caps by accident)
Maybe you know the situation better than we do, because we don't know zilch except what was written as a question. That question was amply answered along with methods to do it if needed.
Understand that on all of these forums there are many people who see questions and the reponses to them besides the original poster of the question. Many of them do not own porting tools and a few who do are not sure how to do the work. My explantions should be clear and to the point and easy for anyone with some mechanical abilities who are not used to working with cylinder heads. If each valve is done exactly the same the chamber cc of all chambers will remain the same. It takes quite a bit of sanding to make a one cc difference. Also this modification can in no way harm runner flow as measured on a bench. It might help some but can not hurt any. There is no such thing as a valve unshrouded too much in any engine.
I will agree with you 1000% that Joe Mondello is very sharp. Joe Mondello is not on this forum answering questions though and if the original poster had acess to him, that question should not have been asked here at all. Last I heard Mr. Mondello is very ill and is living in Tennessee. He is a member on SpeedTalk with us, but has not posted in a very long time. As a kid I greww up with Mondello Heads. I know very well who he is and his contributions and innovations.
Ed
hOW DID YOU GET ALL THE INFO FOR YOUR RESPONSE OUT OF THE ORIGINAL QUESTION? i DIDN'T. (caps by accident)
What is actually done when check and unshroud the valve? I have a set of dart 355 cnc's and was wanting to check to see if they need it. Is this worth any real horsepower?
Understand that on all of these forums there are many people who see questions and the reponses to them besides the original poster of the question. Many of them do not own porting tools and a few who do are not sure how to do the work. My explantions should be clear and to the point and easy for anyone with some mechanical abilities who are not used to working with cylinder heads. If each valve is done exactly the same the chamber cc of all chambers will remain the same. It takes quite a bit of sanding to make a one cc difference. Also this modification can in no way harm runner flow as measured on a bench. It might help some but can not hurt any. There is no such thing as a valve unshrouded too much in any engine.
I will agree with you 1000% that Joe Mondello is very sharp. Joe Mondello is not on this forum answering questions though and if the original poster had acess to him, that question should not have been asked here at all. Last I heard Mr. Mondello is very ill and is living in Tennessee. He is a member on SpeedTalk with us, but has not posted in a very long time. As a kid I greww up with Mondello Heads. I know very well who he is and his contributions and innovations.
Ed