Compression issue after mods. Think I broke my hand.

R

Railroad Bulls

New Member
#1
#1
So, my 212 Predator Hemi had the following: (this is in a Monster Moto btw... and in case it matters, which it probably doesn't, it's running a 13t clutch.)

18 lb valve springs
Header
ARC flywheel
Pod filter
36 jet and E-tube.

Ran great, but the chain kept popping off cause I couldn't get the fitment right.... too long or too short. Soooo I had to order an offset link for it. So, while I was waiting, I did the following, after draining the oil:

Governor removal
ARC connecting rod
CS Clone Core Cam

Put everything back together... and while I was at it I drilled out my engine mounts and put on a mocked up chain tensioner, and wala.... my chain fit!

So, I loaded it up in the car and drove out to the school for its first proper run.

Put oil in it... pulled the cord... and my hand is literally swollen now. This thing is IMPOSSIBLE to pull. I'm a 6'2" 200lb active guy who can hold my own, so believe me when I say... it's not HARD to start... it is IMPOSSIBLE to start. I would have to be the Hulk to come anywhere near being able to turn this thing over in any kind of way that has a chance of starting it. Eventually I CAN force it through a stroke... but, if I try to just pull the cord, it stops abruptly and snaps back.

Thinking maybe I had left more oil than I had noticed in it when I put it on its side to work on it, I pulled the spark plug, pulled the cord a few times.... no oil came out... so I put the plug back in, and BAM. Right back against that brick wall. This is my first engine build... so i'm stumped. I read about a compression release or something on a cam, but none of the paperwork on the CS cam mentions that... so i'm not sure what the hell to do. I REALLY don't want to crack this thing open again. Any ideas?
 
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M

mckutzy

Member
#3
#3
This is the stock cam with comp release... If it doesnt have this, its probably meant to be started by, an outside electric starter...
 
R

Railroad Bulls

New Member
#4
#4
Actually... no i didnt check valve lash. My buddys a mechanicand said that on the 212 i shouldnt have to worry. He said if the valve lash wasnt right id hear it. Could that literally keep the motor from even turning over?
 
ole4

ole4

#5
#5
Yes if exhaust lash is loose compression release will not work and it will yank the cord out of your hand and hurt you.
 
danford1

danford1

#7
#7
Set your lash to 0.003" with piston at TDC and both valves closed. You can even go smaller like 0.001" if doing it on a "cold" engine (ambient temp as if it sat all night).
Exactly as mentioned above about the exhaust lash being loose. It Will fire when you pull it and yank the cord from your hand. I had a 5 hp Briggs I put a non compression release cam in. My God that was tough. I could start it if I rolled it over slow and got it on the compression stroke TDC kind of thing, then pulled fast and hard. After having the pull rope ripped out of my hand a few times, I took out the cam and went back to stock.
Try setting the lash first. If this is the cam you bought, it should have the compression release.
https://www.dynocams.com/item/cl-cs/
 
TheDullCarbide

TheDullCarbide

Active Member
#8
#8
Yes check your lash especially because the CS/CM series cams have reground base circles. This means that to gain the lift, instead of adding material to the top of the lobe, they grind it away from the bottom. Now you have to tighten up your lash to compensate and use the decompressor lobe.
 
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