Is cam in right?

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Aug 19, 2017 | 07:20 PM

#21

keithl1967

Racer

Joined: Feb 2012

Posts: 421

Likes: 27

From: Harrisburg PA

Is the vacuum steady, but low, or is it low and erratic? The needle should not vary very much. If it is "bouncing", along with everything else you are describing, you wither have wiped a cam lobe or two, or the lifters are broken...might also explain why the one keeps loosening on you...

I had a motor with a mechanical cam...two exploded lifters, but I could still get it to run with a very rich mixture, but would backfire through the carb from time to time, and the idle was always rough...
didn't realize the lifter issue until I finally got frustrated and tore the motor down...

Aug 19, 2017 | 11:07 PM

#22

lionelhutz

Race Director

Joined: Apr 2007

Posts: 11,152

Likes: 890

From: South Western Ontario

Quote:

Originally Posted by pigfarmer

Also, the thread was started by someone else and this has since hijacked it.

I think you are quite mistaken in why I posted. I had no intention of helping you with your issue because this isn't your thread. I posted the response to ensure everyone else knew what you posted was wrong, to the point it shouldn't even be debated. I hope one day the 180* out cam myth dies instead of being perpetuated.

The OP needs to fix the rocker issue, and then confirm TDC. After that, he can move on to the timing and carburetor tuning to get his engine running right.

Last edited by lionelhutz; Aug 19, 2017 at 11:08 PM.

Aug 20, 2017 | 02:50 PM

#23

techinspector1

Intermediate

Joined: Aug 2017

Posts: 32

Likes: 1

From: Zephyrhills Florida

I'm sure that most fellows and gals on here know how to find top dead center, but maybe there are a few that don't, so I will post a tutorial that I wrote many years ago to fill the gap for those few......
http://www.crankshaftcoalition.com/w...op_dead_center

Aug 21, 2017 | 11:40 AM

#24

Duke94

Thread Starter

Le Mans Master

Joined: Mar 2001

Posts: 6,640

Likes: 287

From: Ann Arbor Michigan

Quote:

Originally Posted by keithl1967

The vacuum is low but steady. We pulled the manifold and lifters last night but didn't have a chance to check any yet.

Thanks

Aug 21, 2017 | 07:55 PM

#25

HeadsU.P.

Le Mans Master

Joined: Aug 2017

Posts: 8,336

Likes: 2,810

From: Cool Northern Michigan

Theres always the possibility the cam was installed wrong. Not 180 out but another way. Most timing chain sets come with the option of changing the timing of the cam. There are three markings and three slots or keyways on the crank sprocket. Of the three, I believe one is straight up, one is 4* advanced and lastly 4* retarded. Which mark did someone use and not double check?