timing chain alingment question
August 4th, 2014, 04:56 PM
#121
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Location: Central Fl
Posts: 7,824
True but you also have to take into account that some cam manufacturers still grind their cams off Berco profiles. That will make them grow or shrink from the original spec depending on the master profile used.
August 4th, 2014, 04:59 PM
#122
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Join Date: Apr 2012
Location: New Mexico
Posts: 2,972
Not trying to start an argument, but this is not correct. You have to find the highest point of lift on the lobe (Smitty explained this a couple of pages back), you can't go by the numbers at the lowest part of the lobe. Pardon me if this is not what you mean, but it sounds like you are saying to start at the bottom, check at .050, then rotate through and check again at .050, this will NOT give the the IC. Here is from Lunatis site,
Rotate the engine clockwise until maximum lift is reached. Zero the dial indicator and continue in
clockwise rotation until a .050 reading is reached. Mark the degree wheel at this time. Rotate the
engine counterclockwise until maximum lift is reached again. Continue counter clockwise rotation
until a reading of .070 is indicated. Now rotate the engine clockwise until the .050 is indicated on
the dial indicator. This operation will take up any slack that exist in the timing chain and gears.
Halfway between these two marks is the center on the intake lobe. An example of this might be
153" on one side of the approximate centerline and 63 deg. on the other side. By adding these two
figures you get a sum of 216 deg. This number halved gives 108 deg. This is your lobe center.
Rotate the engine clockwise until maximum lift is reached. Zero the dial indicator and continue in
clockwise rotation until a .050 reading is reached. Mark the degree wheel at this time. Rotate the
engine counterclockwise until maximum lift is reached again. Continue counter clockwise rotation
until a reading of .070 is indicated. Now rotate the engine clockwise until the .050 is indicated on
the dial indicator. This operation will take up any slack that exist in the timing chain and gears.
Halfway between these two marks is the center on the intake lobe. An example of this might be
153" on one side of the approximate centerline and 63 deg. on the other side. By adding these two
figures you get a sum of 216 deg. This number halved gives 108 deg. This is your lobe center.
Good luck, I'm out.
Last edited by RandyS; August 4th, 2014 at 05:02 PM.
August 4th, 2014, 05:03 PM
#123
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Join Date: Aug 2007
Posts: 2,250
August 4th, 2014, 05:32 PM
#124
Ok so per the lunati spec card here goes
IN. opening @.050 is 10.5
IN. closing @.050 is 42.5
Ex opening @ .050 is 54.5
Ex closing @.050 is 6.5
duration is 233/241 @ .050
centerline is 106
I got on the number one
in. opening 10
in closing 40
ex. opening 54
ex. closing 6.5
#6 I got
In. opening10.5
in. closing 40
ex. opening 54.5
ex. closing 3.5 ( I had a weird spot for the indicator due to mu stand being a standard issue one)
All figures where @ .050
My lift @ 1.6 is 560 1.5 is 520
My centerline came out to 115
Duration is 230 on the intake and 240 on the ex.
what do you guys think.
I want to thank you guys a lot. Smitty nailed it on the head about the centerline that comment alone made me realize what I was doing wrong. All my figures where @ .050 now I know how its done lol. BIG THANKS GUYS
IN. opening @.050 is 10.5
IN. closing @.050 is 42.5
Ex opening @ .050 is 54.5
Ex closing @.050 is 6.5
duration is 233/241 @ .050
centerline is 106
I got on the number one
in. opening 10
in closing 40
ex. opening 54
ex. closing 6.5
#6 I got
In. opening10.5
in. closing 40
ex. opening 54.5
ex. closing 3.5 ( I had a weird spot for the indicator due to mu stand being a standard issue one)
All figures where @ .050
My lift @ 1.6 is 560 1.5 is 520
My centerline came out to 115
Duration is 230 on the intake and 240 on the ex.
what do you guys think.
I want to thank you guys a lot. Smitty nailed it on the head about the centerline that comment alone made me realize what I was doing wrong. All my figures where @ .050 now I know how its done lol. BIG THANKS GUYS
August 4th, 2014, 05:37 PM
#125
Registered User
Join Date: Aug 2007
Posts: 2,250
Ok so per the lunati spec card here goes
IN. opening @.050 is 10.5
IN. closing @.050 is 42.5
Ex opening @ .050 is 54.5
Ex closing @.050 is 6.5
duration is 233/241 @ .050
centerline is 106
I got on the number one
in. opening 10
in closing 40
ex. opening 54
ex. closing 6.5
#6 I got
In. opening10.5
in. closing 40
ex. opening 54.5
ex. closing 3.5 ( I had a weird spot for the indicator due to mu stand being a standard issue one)
All figures where @ .050
My lift @ 1.6 is 560 1.5 is 520
My centerline came out to 115
Duration is 230 on the intake and 240 on the ex.
what do you guys think.
I want to thank you guys a lot. Smitty nailed it on the head about the centerline that comment alone made me realize what I was doing wrong. All my figures where @ .050 now I know how its done lol. BIG THANKS GUYS
IN. opening @.050 is 10.5
IN. closing @.050 is 42.5
Ex opening @ .050 is 54.5
Ex closing @.050 is 6.5
duration is 233/241 @ .050
centerline is 106
I got on the number one
in. opening 10
in closing 40
ex. opening 54
ex. closing 6.5
#6 I got
In. opening10.5
in. closing 40
ex. opening 54.5
ex. closing 3.5 ( I had a weird spot for the indicator due to mu stand being a standard issue one)
All figures where @ .050
My lift @ 1.6 is 560 1.5 is 520
My centerline came out to 115
Duration is 230 on the intake and 240 on the ex.
what do you guys think.
I want to thank you guys a lot. Smitty nailed it on the head about the centerline that comment alone made me realize what I was doing wrong. All my figures where @ .050 now I know how its done lol. BIG THANKS GUYS
Last edited by captjim; August 4th, 2014 at 05:39 PM.
August 4th, 2014, 05:47 PM
#126
40 @ the intake opening is 220 plus 10 is 230 devide by 2 and that 115 . I went with the higher number because 40 plus 10 is 50 and that would not be right. that is with me checking the opening right @ .050 and then .050 before it closes.
August 4th, 2014, 05:52 PM
#127
Registered User
Join Date: Aug 2007
Posts: 2,250
None of that makes any sense to me, but I can assure you that 115 is not correct.
August 4th, 2014, 06:02 PM
#128
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Join Date: Nov 2008
Location: Central Fl
Posts: 7,824
Apparently I posted for nothing, you didn't follow my formula.
230 duration divided by 2 = 115. Opening is occurring at 10btdc. 115-10 is? 105, that's your intake centerline. You all made this way too difficult.
And .560 lift with a 1.6 rocker is .350 lobe lift, the intake lobe is off that much? Really? How much do the lifters rise from dead zero to max lift? Lift on intake and exhaust is different correct?
Last edited by cutlassefi; August 4th, 2014 at 06:08 PM.
August 4th, 2014, 06:10 PM
#130
Registered User
Join Date: Nov 2008
Location: Central Fl
Posts: 7,824
August 4th, 2014, 06:11 PM
#131
Same place eric dot to dot but I Learned a lot and Mark efi im sorry I forgot about your formula. thank you for correcting that . I apologize for that. Yes I now know how and I will know now.
yes the lift is different on intake and exhaust.
mark my question is if you multiply 350 by 1.5 it comes out to 525 . So I think what you said about the sbc journal may be right.
It may have been made difficult but I learned there is a few different techniques and I now know my mistake too much info lol.
yes the lift is different on intake and exhaust.
mark my question is if you multiply 350 by 1.5 it comes out to 525 . So I think what you said about the sbc journal may be right.
It may have been made difficult but I learned there is a few different techniques and I now know my mistake too much info lol.
Last edited by coppercutlass; August 4th, 2014 at 06:13 PM.
August 4th, 2014, 06:34 PM
#132
Registered User
Join Date: Dec 2011
Location: Houston
Posts: 51
That's sort of what I mean. If the .050 numbers are good, screw the ICL. It's meaningless at that point.
August 4th, 2014, 07:11 PM
#134
not really that simple sampson . I understand what these guys are talking about as far as checking things out. This isn't a stock rebuild. Im going to be beating the tar out of it. It is important I know these things.
August 5th, 2014, 12:26 AM
#135
'87 Delta 88 Royale
Join Date: Dec 2010
Location: Margate, England
Posts: 2,513
I'm glad you finally got it right, let us know how far out (if any) the timing dots are please.
And here is an example of an exasperated OP getting conflicting advice, and if you'll forgive me, not understanding some of it properly at first.
But nobody lost the plot and started venting at other posters, maybe a few posts were a bit testy, but despite the frustrations and misunderstandings of coppercutlass and everyone who offerd help and advice this thread has hopefully had a happy ending.
Brownie points all round I say
.
Roger.
And here is an example of an exasperated OP getting conflicting advice, and if you'll forgive me, not understanding some of it properly at first.
But nobody lost the plot and started venting at other posters, maybe a few posts were a bit testy, but despite the frustrations and misunderstandings of coppercutlass and everyone who offerd help and advice this thread has hopefully had a happy ending.
Brownie points all round I say
.Roger.
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