Piston To Valve Clerance, Confusing?
01-21-2008, 08:01 PM
#12
3rd Gear Member
Join Date: Mar 2007
Location:
Posts: 636
RE: Piston To Valve Clerance, Confusing?
im thinking if you go with this came and use 1.6 the lift will change
its {.513 I/529 e} right with 1.7 so using a 1.6 is going to knock it down to about .483I .499E
the only thing I would change on my HCI would have to be the cam I would have went with something that would make it idle better!! I used the tfs stage 1 cam and I have idle issues I would have went with one of those steeda cams!
the gt40p heads flow numbers are pretty much the same after .500 lift so .500 is the magic number anything over this lift is not going to help you much. I went with the tfs 1 its .499I .511E right around .500 lift
I havent given my car a decent N/A tune the best I have run is 13.99 N/A with this setup gt40p ,tfs 1 ,rpm intake. 3.73 gear
Hope that helps you some?
its {.513 I/529 e} right with 1.7 so using a 1.6 is going to knock it down to about .483I .499E
the only thing I would change on my HCI would have to be the cam I would have went with something that would make it idle better!! I used the tfs stage 1 cam and I have idle issues I would have went with one of those steeda cams!
the gt40p heads flow numbers are pretty much the same after .500 lift so .500 is the magic number anything over this lift is not going to help you much. I went with the tfs 1 its .499I .511E right around .500 lift
I havent given my car a decent N/A tune the best I have run is 13.99 N/A with this setup gt40p ,tfs 1 ,rpm intake. 3.73 gear
Hope that helps you some?
01-21-2008, 08:55 PM
#14
6th Gear Member
Join Date: May 2006
Location: earleville md
Posts: 10,357
RE: Piston To Valve Clerance, Confusing?
stud mount? you converted your gt40s to that? good job dude, that was a good move... or do you mean the stockers? or do you have aftermarket heads?
as for your cam... relax... its gonna be ok lol
call up some cam companys and see what they suggest
as for your cam... relax... its gonna be ok lol
call up some cam companys and see what they suggest
01-22-2008, 08:57 PM
#16
5th Gear Member
Join Date: Jan 2006
Location: Puerto Rico
Posts: 3,926
RE: Piston To Valve Clerance, Confusing?
Why is it that we continue with the valve lift = PtV problems?........
LIFT is NOT THE ISSUE...... it's the overlap you have to check for. BUT, you need to check!
01-22-2008, 09:01 PM
#17
6th Gear Member
Join Date: Nov 2005
Location: Rochester, NY
Posts: 8,467
RE: Piston To Valve Clerance, Confusing?
If lift has nothing to do with it then why do companies always tell you not to run a cam with over certain amount of lift? Depending on duration/overlap the valve is quite possibly going to be all the way open when the piston is close to the top.
01-22-2008, 09:26 PM
#18
3rd Gear Member
Join Date: Nov 2007
Location: Orange County, CA
Posts: 614
RE: Piston To Valve Clerance, Confusing?
WHATEVER YOU DO DONT PUSS OUT check your p to v clearance. go to the hobby store or the craft store get some of that modeling clay that doesnt dry out. I have had mine for about 5 years. just check before you button it up, that way you will know if you are really close or if you have some room. piece of mind, buddy
01-23-2008, 08:24 AM
#19
5th Gear Member
Join Date: Jan 2006
Location: Puerto Rico
Posts: 3,926
RE: Piston To Valve Clerance, Confusing?
ORIGINAL: OnyxCobra
If lift has nothing to do with it then why do companies always tell you not to run a cam with over certain amount of lift? Depending on duration/overlap the valve is quite possibly going to be all the way open when the piston is close to the top.
If lift has nothing to do with it then why do companies always tell you not to run a cam with over certain amount of lift? Depending on duration/overlap the valve is quite possibly going to be all the way open when the piston is close to the top.
BTW.... during overlap the intake valve is starting to open and the exhaust finishing its closing cycle, so neither will be at total valve lift......
01-23-2008, 01:02 PM
#20
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
RE: Piston To Valve Clerance, Confusing?
ORIGINAL: Joel5.0
In error...... that would be something for them to answer however, it is wrong associating total valve lift with PtV problems. If you look at any cam card, total valve lift happens at the Int. Center Line (ICL) or ECL for the exhaust. Their values are given in degrees of crankshaft rotation from TDC, and they are in the 100°+ values. At 100° from TDC (to take the smaller value)..... the piston is down the cylinder >60% of the total stroke.... or >1.8" from the deck...... how would a valve lift of .600" (as an example) cause PtV issues if the piston is >1.8" away from the block deck? You may want to check a better explanation at Piston to valve clearance checking methods
BTW.... during overlap the intake valve is starting to open and the exhaust finishing its closing cycle, so neither will be at total valve lift......
ORIGINAL: OnyxCobra
If lift has nothing to do with it then why do companies always tell you not to run a cam with over certain amount of lift? Depending on duration/overlap the valve is quite possibly going to be all the way open when the piston is close to the top.
If lift has nothing to do with it then why do companies always tell you not to run a cam with over certain amount of lift? Depending on duration/overlap the valve is quite possibly going to be all the way open when the piston is close to the top.
BTW.... during overlap the intake valve is starting to open and the exhaust finishing its closing cycle, so neither will be at total valve lift......
That's why in interference engines if the timing jumps you can smash the valves. Lift is the same, but the timing has been altered, and you get PTV interference(hence the term interference engine).