dialing in scat c35 cam

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got problems
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Joined: Mon May 05, 2003 7:28 pm

dialing in scat c35 cam

Postby got problems » Sun May 23, 2004 11:29 pm

hi guys, i'm trying to dial in the scat c35 cam for my new 1776 for my bug, but seem to be hgaving some problems. i am using the october and november 2001 issues of vw trends as a guide since none of my other shop mauals cover it.

my cam card is a little hard to read, but i think these are the numbers;
IO 34BT IC 70AB
EO 70BB EC 34BT

this is vastly different from what i got on just the intake:
peak: 76AB
max lift: .378" @75AB

IO (@.050") 19AT
(@.004") 74AT

IC (@.050") 35BB
(@.004") 71AT

half lift: (@.050") .1655 @25BT
(@.004") .1885 @19BT


the vw trends article says to use .050" as clearance, but the cam card says "Running clearance .004"-intake .006" exhaust" at the top oif the card. this seems like a pretty big difference.
can anyone tell me what i'm doing wrong or point me to a website with a better guide to dialing in the cam. i don't really like this article, but its the only guide i can find. thanks guys.

-andrew
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volksmann
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Re: dialing in scat c35 cam

Postby volksmann » Sun May 30, 2004 6:57 am

got problems wrote:...............
the vw trends article says to use .050" as clearance, but the cam card says "Running clearance .004"-intake .006" exhaust"
-andrew


Don't know if you solved your problem. The .050 is the amount lift at the cam, not valve clearance.
Set your valve clearance to 0.004, turn the engine over till you have 0.050 of valve lift, then you take your reading.

Ken
Last edited by volksmann on Sun May 30, 2004 9:58 pm, edited 1 time in total.
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got problems
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Postby got problems » Sun May 30, 2004 8:03 pm

the article calls .050 the "checking clearance point" and makes no mention of the "running clearance" or the valve lift or valve clearance. how would i set the valve clearance to .004? better yet, do you know of an online article on cam timing? i've looked and can't find one.

thanks

-ah
Guest

Postby Guest » Sun May 30, 2004 9:51 pm

I found a few web site on degreeing a camshaft, not specifically for vw, but should give you the general ideal. If you want to do a search use these key words: degreeing, camshaft or cam

Ken

Check these out and if you have some questions just ask. :wink:
http://www.webcaminc.net/degreeing.html

http://www.newcovenant.com/speedcrafter/tech/tech.asp

http://www.ridgecrest.ca.us/~biesiade/camdegree.htm

http://www.thedirtforum.com/degree.htm

http://home.hiwaay.net/~langford/corvai ... e_cam.html
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volksmann
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Postby volksmann » Sun May 30, 2004 9:54 pm

I was log in, really. :oops:

Ken
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got problems
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Postby got problems » Sun May 30, 2004 10:18 pm

thanks for the articles. i went back and did the whole process all over again and came back with much beter results, but not near. for IO i got 20BT and 47AB for IC, but that is way off from the IO34BT IC70AB on the cam card. i made sure the gear was installed correctly and the dots line up w/ the crank. is this cam just bad? its a scat and i recently had a scat crank off center by 12 grams (the most jake raby had ever seen). should i try another one?

thanks

-ah
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volksmann
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Postby volksmann » Sun May 30, 2004 11:40 pm

If those numbers are taken when the cam is at 0.050 lift. they should be right, Cam manufactures use two set of numbers, Advertised duration and duration @ 0.050 lift, To get the duration number you add valve opening, and closing numbers plus 180. Take your numbers on your card, IO34BT and IC70AB then add 180 and you get a 284 duration, The cam is actually advertised as a 286 duration.

Now add what you did, 20BT + 47BT + 180 = 247 duration. That is the correct duration at 0.050 lift. according to these guys.

http://www.phnet.fi/public/hefor1/vwinfoca.htm

The 180 number is the crank swing in degrees, from tdc to bdc. This is some of the basic cam info.

Ken
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got problems
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Postby got problems » Sat Jun 05, 2004 8:37 pm

ok, i've gone back over all my factors in dialing this in and still have trouble. the crank and cam gears are ibnstalled right and are matched w/ the dots. i found tdc and set up the dial gauge on the intaek of the #1 cylidner. i am using a bugpack aluminum degreed flywheel.

now, i can get the 34bt and 70AB readings, but only when i spin the crank to the left. on the engine in my bug, it spins to the right. when i try getting the reading rotating right, i get 70 AB for the intake opening and 34BT for the intake close. am i just stupid or is something put on backwards? are you suppose to dial it in while rotating left or right?

thanks again

-ah
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volksmann
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Joined: Fri Feb 28, 2003 3:01 am

Postby volksmann » Sat Jun 05, 2004 8:59 pm

The engine should be turned in the direction of running rotation.
If you are looking at the pulley end turn it to the right, if looking at the flywheel then turn it to the left.

Ken
csa000

Postby csa000 » Mon Jul 12, 2004 2:29 am

May help, may not but are you sure your cam gear is lined up right on the cam? The dot will line up with the slot for the oil pump. I found this out the hard way :oops:
camilo13
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Joined: Fri Apr 29, 2011 7:05 am

Re: dialing in scat c35 cam

Postby camilo13 » Fri Apr 29, 2011 7:15 am

Telling my age here, but way back in 78 I bought a Scat Cam. I took it home and tried to set it up and no matter what I did the cam did not work....its almost like the cam was ground backwards. I took it and my case to Butch Harris Racing and they tired everything and the cam was just ground wrong. I bought an Engle Cam after talking to the Engle Cam owner (before email) and he shipped me his cam. I dropped it into the case and dialed it in and it matched the card using the clearances specified. I never bought another Scat Cam after that.
ridenrace6
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Joined: Wed Aug 26, 2009 10:00 pm
Location: moulton, al.

Re:

Postby ridenrace6 » Tue Oct 30, 2012 10:07 pm

i have always just "bolted on" the gear but am looking in to degreeing after all the post ive been reading of late about cams not bring "right" from the factory, these appear to be the only 2 valid links anymore out this previous post

Guest wrote:I found a few web site on degreeing a camshaft, not specifically for vw, but should give you the general ideal. If you want to do a search use these key words: degreeing, camshaft or cam

Ken

Check these out and if you have some questions just ask. :wink:
http://www.webcaminc.net/degreeing.html

http://www.thedirtforum.com/degree.htm
Mr572u
Posts: 1
Joined: Sun May 19, 2013 6:11 pm

Re: dialing in scat c35 cam

Postby Mr572u » Sun May 19, 2013 6:32 pm

I just stumbled on this site, reading up about the C35. There is a guy with a C35 on the Facebook page, Vintage Fiberglass Dune buggys and his runs great with a little lope to the idle. He posted a video you can view. Anyway, reading some of your specs on this cam, one of you told another about .050 lift at the cam. Think about that a minute.-- .050 is about the same as the gap on some spark plugs. As for setting the rockers, .004 and .006 is pretty close. Usually if you hear the rockers tick a little, they are about right. If they don't tick, they are too tight. Sometimes if you don't use a quality cam lube for initial start up, the cam can go flat and be ruined in a matter of minutes. If you fire the engine and run it around 2000 rpm for 20 minutes without stopping, it will break in and be fine. Anyway, good luck with your specs. As for me. I'm looking for much more than 5/100" or fifty thousandths of lift, even on a worn out stocker. :)

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