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> What rocker arm ratios do people see?
stugray
post Dec 17 2012, 10:26 PM
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I am adjusting the valve geometry while putting in a Raby 9700 cam and I am seeing .38 on the exhaust cam lift and .496 at the valve (an exh rocker ratio of 1.3) and I have a .39 on the intake with a .546 at the valve ( an int rocker ratio of 1.4) is this what everyone else gets for rocker ratios:

Intake rocker ratio = 1.4
Exhaust rocker ratio = 1.3

These are the 1.7 (1.8?) rockers that accept the 911 swivel feet.
I am using the swivel feet, have modified the rocker faces, adjustable push rod, and zero lash to do the meaurements.

Do those rocker ratios look like stock?

I want to take 50 thousandths off the Combustion chambers to increase the CR, but my measurements say I wont have enough clearance on the Intake valve once I shave off 50 thousandths.

I only have ~0.075 clearance now from the piston to the Int valve as it is with a deck of 0.030 and everything else (crank & rods) stock - flat top 96mm pistons.

That Intake valve travel of ~0.55 looks huge to me. Anyone else care to comment?

Stu


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stugray   What rocker arm ratios do people see?   Dec 17 2012, 10:26 PM
Dave_Darling   The stock ratios range from 1.3 to 1.4, so you...   Dec 17 2012, 11:29 PM
edwin   Call European machine works? They've helped in...   Dec 17 2012, 11:38 PM
stugray   Dave - So is it possible to find an intake rocker ...   Dec 18 2012, 12:08 PM
Dave_Darling   Dave - So is it possible to find an intake rocker...   Dec 18 2012, 06:02 PM
monkeyboy   I believe WebCam actually makes them, but they are...   Dec 18 2012, 12:32 PM
brant   I too believe they are built to order... custom o...   Dec 18 2012, 12:41 PM
Mark Henry   I too believe they are built to order... custom ...   Dec 18 2012, 12:45 PM
bobhasissues   When you say "at the valve" are you actu...   Dec 18 2012, 06:23 PM
stugray   bob - Yes - and simultaneously at the pushrod t...   Dec 18 2012, 07:22 PM
bobhasissues   Stu, Nobody will try to help you if you continue ...   Dec 18 2012, 09:40 PM
stugray   Stu, Nobody will try to help you if you continue...   Feb 10 2013, 11:07 PM
bobhasissues   Bob, now that we have established that these rocke...   Feb 11 2013, 08:15 PM
stugray   bob- I see nowhere in the previous post that co...   Dec 18 2012, 11:01 PM
Racer Chris   I'll gladly trade you a set of 1.3 ratio, 1.7L...   Dec 18 2012, 11:44 PM
Mark Henry   Dude the reason I don't help you is simple.......   Dec 18 2012, 11:50 PM
stugray   That's funny because it says Type IV store r...   Dec 19 2012, 08:27 AM
Racer Chris   I am also reading on Jakes cam instructions that ...   Dec 19 2012, 10:10 AM
Jeff Hail   I am also reading on Jakes cam instructions that...   Feb 4 2015, 11:39 PM
Mark Henry   [quote name='Racer Chris' post='1786713' date='De...   Feb 5 2015, 06:27 AM
r_towle   post a picture of the cam card. It will possibly g...   Dec 19 2012, 09:13 AM
stugray   rich, Thanks. I will scan the card & post it ...   Dec 19 2012, 09:33 AM
stugray   I will take pictures tonight. I measure .388 Cam...   Dec 19 2012, 11:42 AM
nathansnathan   "Valve lift" is taking the ratio of the ...   Dec 19 2012, 11:50 AM
stugray   I will get pics of the test rig after dinner, but ...   Dec 19 2012, 07:04 PM
Todd Enlund   And BTW - I fully profiled the cam myself, and th...   Dec 27 2012, 02:22 AM
Racer Chris   And BTW - I fully profiled the cam myself, and t...   Dec 27 2012, 05:55 AM
r_towle   I am confused. You have not milled out your heads ...   Dec 19 2012, 07:41 PM
stugray   Not exactly - I am measuring how much clearance ...   Dec 19 2012, 08:43 PM
stugray   Some pics: Pics of setup to measure deck height: ...   Dec 19 2012, 09:02 PM
nathansnathan   My experience with it was that it was easy to get ...   Dec 19 2012, 11:42 PM
stugray   I have taken ~.060 off the rocker faces and coun...   Dec 20 2012, 12:02 AM
nathansnathan   I have taken ~.060 off the rocker faces and cou...   Dec 20 2012, 08:36 AM
Racer Chris   Stu, Is it possible the ratio was altered by remac...   Dec 20 2012, 10:02 AM
stugray   Racer Chris, I measured all 4 of them, Valve lift...   Dec 22 2012, 04:09 PM
stugray   Ok, so after some measurements, I get the whole ...   Dec 23 2012, 06:29 PM
stugray   Two more questions: 1 - When some of you have had...   Dec 24 2012, 04:51 PM
nathansnathan   And nathansnathan How is that possible? Regard...   Dec 30 2012, 06:02 PM
wndsrfr   2 - Who has a good selection of rocker shims? ...   Dec 30 2012, 07:26 PM
stugray   Quick bump so racer chris doesnt forget about me ;...   Dec 26 2012, 05:17 PM
Racer Chris   Quick bump so racer chris doesnt forget about me ...   Dec 26 2012, 07:10 PM
tscrihfield   stu, if i could lend some advice. I would not adv...   Dec 26 2012, 07:17 PM
nathansnathan   I've given it more thought their and edited ab...   Dec 30 2012, 10:02 PM
stugray   So I had the engine case "decked", the r...   Feb 10 2013, 05:11 PM
nathansnathan   It sounds to me like you are doing something wrong...   Feb 10 2013, 06:44 PM
stugray   :confused:   Feb 10 2013, 10:54 PM
Racer Chris   It is not possible that you are the first to disco...   Feb 10 2013, 11:05 PM
stugray   Chris - I had three reputable machine heads sit ...   Feb 10 2013, 11:13 PM
barefoot   Chris - I had three reputable machine heads sit...   Dec 7 2015, 04:34 PM
stugray   Chris - I had three reputable machine heads si...   Dec 7 2015, 07:31 PM
barefoot   [quote name='stugray' post='1818427...   Dec 7 2015, 08:50 PM
Racer Chris   The cam card says the valve lift is .368". Yo...   Feb 11 2013, 12:03 AM
stugray   Chris, That's right. I need to remeasure the ...   Feb 11 2013, 07:51 AM
worn   Chris, That's right. I need to remeasure the...   Feb 11 2013, 10:30 AM
stugray   I just spoke with one of the Type-IV experts at Fa...   Feb 11 2013, 02:11 PM
stugray   Bob I " will build a grenade, that's why ...   Feb 12 2013, 02:40 PM
stugray   Ok, so I decided to go with a webcam 86b instead o...   Mar 26 2013, 08:25 PM
worn   Ok, so I decided to go with a webcam 86b instead ...   Mar 27 2013, 09:38 AM
nathansnathan   So apparently Webcam knows that these rockers are...   Mar 27 2013, 11:09 AM
stugray   My plan is to set the intake right at the "ad...   Mar 27 2013, 12:13 PM
worn   My plan is to set the intake right at the "a...   Mar 27 2013, 02:09 PM
stugray   I have found (after testing 8 sets of rockers) tha...   Mar 27 2013, 03:29 PM
stugray   So I put in the new webcam 86b. Advertised lift i...   Mar 31 2013, 03:14 PM
stugray   Just finished the "Clay on the Piston" t...   Mar 31 2013, 03:26 PM
stugray   One observation that I made: When measuring the w...   Apr 1 2013, 09:55 AM
stugray   Important lesson learned! I cut the pushrods ...   Apr 3 2013, 12:20 PM
worn   Important lesson learned! I cut the pushrods...   Apr 3 2013, 03:22 PM
Jake Raby   So much for us just repackaging things and selli...   Apr 3 2013, 06:43 PM
worn   Not even Web Cam knows what we do to camshafts...   Apr 4 2013, 10:35 AM
stugray   Jake I have promoted your hardware often, even a...   Apr 3 2013, 09:39 PM
Jake Raby   Jake I have promoted your hardware often, even ...   Apr 4 2013, 05:45 PM
stugray   Jake, the above quote was merely an exact comment ...   Apr 4 2013, 09:21 PM
stugray   After going through all of this measuring and havi...   Apr 29 2013, 01:31 PM
stugray   Bump the above question for rdauenhauer. Jake? Ty...   Feb 4 2015, 02:21 PM
rdauenhauer   I missed this. Good read.   Feb 4 2015, 03:19 PM
Dave_Darling   The ratio of all of the stock rockers "should...   Dec 7 2015, 05:30 PM
Steve Pratel   :rotfl: Really? come on guys let it go already.   Dec 7 2015, 08:54 PM
stugray   :rotfl: Really? come on guys let it go already. ...   Dec 7 2015, 09:43 PM
Superhawk996   :rotfl: Really? come on guys let it go already. ...   Jan 9 2022, 08:18 AM
930cabman   What is the consensus from this dramatic post? can...   Jan 8 2022, 06:14 PM
iankarr   I used Jake's method as the basis for my video...   Jan 9 2022, 09:52 AM
930cabman   I used Jake's method as the basis for my vide...   Jan 9 2022, 10:34 AM
iankarr   Please don’t do THAT lol. Jake’s method, yesâ€...   Jan 9 2022, 10:43 AM
Mark Henry   There's always going to be variants of small d...   Jan 9 2022, 11:50 AM
930cabman   Exactly, overthinking can be problematic. Part of ...   Jan 9 2022, 04:01 PM


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