Factory Retarded Cam Timing
- Thread starter Turbo Performance
- Start date
He's not correct. It just changes the open and close times per crank degree. It doesn't effect any duration time. I'm actually suprised he posted something so dumb
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I'm not in any way sticking up for him...but I assume what he meant was retarding it moves it later in the cycle and closer to the piston coming up...
Of course degreeing/timing of cam doesn't affect duration
Of course degreeing/timing of cam doesn't affect duration
Umm did you. Miss the part where he rannit like this?!?
I pulled mine apart had 0.0" protrusion and Bs gaskets making roughly 0.038" worth of quench definitely room there
Kind of what I thought, just wanted him to clarify. Regardless of the holes he seems to dig on the forums. FWIW Greg has been nothing but helpful in all my conversations and dealings with him.
Edit: As far as there being room or not, it was definitely ran this way for a season without any interference issue.
Had it cached in Tapatalk I guess. Still comes up for me.
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I've ground dots off cams for people like you , if the cam was truly off by two teeth it would not run, I have more real experience fitting cams in and knowing what fits and doesn't fit then anyone on this forum. Something was amiss , where was the cam installed in the motor. the factory cam usually is in at 98 to 101 . Put your new cam in at 100 to 102 Factory cams are 107.8 LSA being that tight of a LSA does not give it much room. Your new cam is on a 112 LSA
To give you an Example of factory variance's. G.M. Performance gave me 5 new engine kits when I started this program. The installed ILC { intake lobe centerline } varied by as much as 4 degrees .
taking the same cam and installing it in retarded meaning the ILC is bigger IE 106 VS 100 means the intake valve closes 6 degrees later. The total duration remains the same , but the critical spot when the intake closure event happens determining the amount of air captured changes the way the motor runs . At zero lash the Duramax typical has .035 to .045 intake clearance and .045 to .55 exhaust. Retard the cams a exhaust clearance closes up at around .007 per degree and the intake opens up around .0035 .
here I am pulling one of these brand new motors apart about 6 years ago
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To the people that like to dog pile, I have talked to someone every day off these forums helping them figure something out , of pointing then in the direction. or giving them a contact I have a book of contacts that include most every one in the racing world.
I have very close ties with G.M. Racing and get the little parts and info that is useful ..
I have very close ties with G.M. Racing and get the little parts and info that is useful ..
are you on drugs.you best reread your small engines repair manuals again.:roflmao:
and I feel bad for the nimrods your helping to go slower.:thumb:
what part of it do you not understand. Intake closure event is far more significant in rpm band and air capture. The total event is the same , I have been doing cam design on competitive race engines programs for 30 years, and diesels for 10 , I send out 3 or 4 Dmax cams every week. Brett Williams truck has my cam in it.
I think Bret is running my cam!
:roflmao: Greg or Dave C who's cam? What's the verdict Wade? Oops Dave C. Greg is your car going to be in Ohio this weekend or did you get everything you could and now your done with them? I'm running my own special regrind of a cam I will be selling as the Double Humper bump stick. I'm getting pretty good with a Dremel and cordless Snap On grinder. Who all wants to get in line for the Double Humper Bumper? $195 with your core of course. P.S. If you want the FULL BILLIT FILLET Double Humper Bumper then you looking at three easy payments of $129.99 plus SH.
:roflmao: Greg or Dave C who's cam? What's the verdict Wade? Oops Dave C. Greg is your car going to be in Ohio this weekend or did you get everything you could and now your done with them? I'm running my own special regrind of a cam I will be selling as the Double Humper bump stick. I'm getting pretty good with a Dremel and cordless Snap On grinder. Who all wants to get in line for the Double Humper Bumper? $195 with your core of course. P.S. If you want the FULL BILLIT FILLET Double Humper Bumper then you looking at three easy payments of $129.99 plus SH.
Cool..
You elude to knowing mulitple OEM camshaft specs yet give nothing.. Along with piston to valve clearances yet give nothing..
Have you clayed said clearances? What protrusion, if any? What gaskets? What crank ° and at what lift of the valve was it closest?
.045" is a lot of room to work with when talking the first/last .005-.010" lift at zero lash.. Add .010-.012" lash and one has moved valve piston clearance in relation to crank °
Advance/retarding crank/cam timing to move power band up/down the rpm swing, has been around for a very long time.. 4-8° advance/retard crank/camshaft timing will not cause an engine not to run. Only way for an engine to not run is to have the piston and valves make contact.
You elude to knowing mulitple OEM camshaft specs yet give nothing.. Along with piston to valve clearances yet give nothing..
Have you clayed said clearances? What protrusion, if any? What gaskets? What crank ° and at what lift of the valve was it closest?
.045" is a lot of room to work with when talking the first/last .005-.010" lift at zero lash.. Add .010-.012" lash and one has moved valve piston clearance in relation to crank °
Advance/retarding crank/cam timing to move power band up/down the rpm swing, has been around for a very long time.. 4-8° advance/retard crank/camshaft timing will not cause an engine not to run. Only way for an engine to not run is to have the piston and valves make contact.
I've ground dots off cams for people like you , if the cam was truly off by two teeth it would not run, I have more real experience fitting cams in and knowing what fits and doesn't fit then anyone on this forum. Something was amiss , where was the cam installed in the motor. the factory cam usually is in at 98 to 101 . Put your new cam in at 100 to 102 Factory cams are 107.8 LSA being that tight of a LSA does not give it much room. Your new cam is on a 112 LSA
To give you an Example of factory variance's. G.M. Performance gave me 5 new engine kits when I started this program. The installed ILC { intake lobe centerline } varied by as much as 4 degrees .
taking the same cam and installing it in retarded meaning the ILC is bigger IE 106 VS 100 means the intake valve closes 6 degrees later. The total duration remains the same , but the critical spot when the intake closure event happens determining the amount of air captured changes the way the motor runs . At zero lash the Duramax typical has .035 to .045 intake clearance and .045 to .55 exhaust. Retard the cams a exhaust clearance closes up at around .007 per degree and the intake opens up around .0035 .
here I am pulling one of these brand new motors apart about 6 years ago
I disagree, Comp Cams Stage 1 or SoCal's both clear in a factory short block.... The stocker I've checked degreed at 99.5* ICL, one tooth retarded is 8.4*.... That makes it installed at 107* ICL....I'd have to check Comps specs, but that cam is ground at a 110 ICL and it clears straight up with a few more degrees of duration and a few more thousand's of lift....
Greg
Am I missing something or is there not a pointer for reference? It looks like to me he was just acting like he was doing something for a picture like always! lmao
Am I missing something or is there not a pointer for reference? It looks like to me he was just acting like he was doing something for a picture like always! lmao
You can use most anything as a reference pointer for the degree wheel. My guess is the stud hanging out of the block around the zero mark in the picture.
As far as clearances. The stock cam is very, very forgiving on clearance. I can see it being two teeth off, but man, it must have been a pig down low. Not recommended.
I recall someone here or on DP going advanced and retarded one tooth on the cam timing to see if it made a difference. But I don't recall all the details. Maybe someone else can dig up the thread.
As far as clearances. The stock cam is very, very forgiving on clearance. I can see it being two teeth off, but man, it must have been a pig down low. Not recommended.
I recall someone here or on DP going advanced and retarded one tooth on the cam timing to see if it made a difference. But I don't recall all the details. Maybe someone else can dig up the thread.
Advancing the timing is something I'd be interested in.. Engine falls on its face under 1800.. Been looking at option to move power left 300rpm or gearing right 300rpm... Its none turbo/tuning related
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I have never "clayed" any engine as you say. Buy i can check clearance without taking the motor apart. I would not like to run tighter then .030 intake but i have . Levi Where did the new car degree in at and what was thw piston to valve .
For a diesel installed ICL of 98-102 is good for bottom end power....you would have to find that old thread and see what advancing the stock cam did....I don't believe advancing more than that would help...
Definitely something I could've built/planned on while it was out getting pistons fixed.. Right now its roughly cheap parts/down time to swap ring n pinions than to pull the top off the engine to advance the cam X°
Right now its in stock setting
Yeah, removing engine to remove rockers and pushrods to roll engine upside down to slide cam out and advance it would take some time... Heads don't have to come off:thumb: