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Camshaft Question


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#1 Rbrracing32 OFFLINE  

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Posted August 14, 2014 - 05:21 PM

Guys I had my cam reground for a stock 4000 rpm class.the point lobe was worn and the guy rather than just welding up the grove he reground the lobe by cutting the base circle and making a new lobe.now my problem is it want run it's dieting in the exhaust. So I put a degree wheel on and it's firing right at tdc can the points lobe be welded up and reground or is my cam junk now.

#2 DougT OFFLINE  

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Posted August 14, 2014 - 05:34 PM

Are your valves opening and closing at the right time with the reground cam or do you need to change the timing marks? Maybe if you advance the cam one tooth?



#3 Rbrracing32 OFFLINE  

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Posted August 14, 2014 - 05:53 PM

Don't know Doug how do I check for that.

#4 Rbrracing32 OFFLINE  

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Posted August 14, 2014 - 05:57 PM

I asked the grinder about doing that and he said that if I done that it would change my valve timming. I don't know at what degree the valves should open and start closing or I could roll the numbers.

#5 LilysDad OFFLINE  

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Posted August 14, 2014 - 05:57 PM

Can you run electronic ignition?



#6 LilysDad OFFLINE  

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Posted August 14, 2014 - 06:00 PM

 it want run it's dieting in the exhaust.

I don't understand 'dieting in the exhaust'.



#7 Rbrracing32 OFFLINE  

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Posted August 14, 2014 - 06:03 PM

Firing in the exhaust. Fat fingered it😳

#8 Chris11 OFFLINE  

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Posted August 14, 2014 - 08:55 PM

Have you done valve lash? do you mean detonation? did you get a sheet on the cam?

#9 Texas Deere and Horse OFFLINE  

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Posted August 14, 2014 - 09:03 PM

Whoever ground your Cam should have given you a grind sheet telling you all the info on the lobe timing. He should have also told you how to time it back in time for your engine. I would contact him and see if he has the info you need to install properly or give you a good cam to replace this one.



#10 Rbrracing32 OFFLINE  

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Posted August 14, 2014 - 10:06 PM

I called him and he is like duh I'll have to talk to my dad in the am I pulled it back out put degree wheel on it before removing and the points plunger is opening right at tdc that's not gona work I also made sure tbe timming marks was aligned that I didn't mess up I know I'm not perfect but they was aligned. Even rotated to make sure. So when he tried to regrind that points love he must have gotten of about 20 degrees before tdc that's normally where the points on the kohlers start to open.

#11 Rbrracing32 OFFLINE  

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Posted August 14, 2014 - 10:08 PM

When I mean firing in the exhaust it is getting tbe exhaust really hot. It's firing on tdc so when it fires it's coming up on exhaust rather than the compresion coming up. To tdc.

#12 Bruce Dorsi OFFLINE  

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Posted August 15, 2014 - 07:06 AM

Did you install a longer point plunger after the cam was reground?

 

I'm thinking that if the base circle of the lobe was reduced, a longer plunger may be needed to get the points to open sooner because the adjustment slot of the points may not be long enough.

 

Think of it this way - The point plunger can be part way up the lobe of the cam before the points move.  ....Once the plunger gets near the tip of the lobe, the points open. 

 

Are the points opening to the full amount of the correct point gap?  .....Point gap affects ignition timing.



#13 Rbrracing32 OFFLINE  

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Posted August 15, 2014 - 10:46 AM

Yea they are opening up I have Chevy points on it. I put a degree wheel on it last night and it is opening my point at tdc. That's 20 degrees off of where it should be. I talk to the grinder today he said his master didn't exactly match the ignition lobe on my cams. I was like why the hell did you go ahead and grind it then. Duh.

#14 Bruce Dorsi OFFLINE  

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Posted August 15, 2014 - 04:18 PM

What happens if you set the crankshaft at the 20* advance that you want, then set the points to open there?

 

Is there enough adjustment at the points?  

 

At what reading on your degree wheel are the points at their maximum opening?



#15 LilysDad OFFLINE  

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Posted August 15, 2014 - 04:49 PM

Are you going to tell us who the rocket surgeon is who did your work? I've got a Briggs engine he can neuter for me.


Edited by LilysDad, August 15, 2014 - 04:50 PM.





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