420 CC question

If you did the head bots to 44 ft lbs then back then off carefully and retorque between 20 & 25 ftlbs.
If you run the engine with that amount of tension on the bolts they will most likely strip the threads when the alloy gets hot.
 
Did you check the valves on the inside of the head to see if they seated properly while you had the head off? An unseated exaust valve would cause a no compression issue.
 
dfbroxy said:
Did you check the valves on the inside of the head to see if they seated properly while you had the head off? An unseated exaust valve would cause a no compression issue.
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No sir, I didn't. There was a lot of carbon build up. I scraped almost all of it out the a spoon (for the rounded edges). Then wiped what I could with a rag. (I need a new wire wheel for my drill). But, it was getting about 150 before I removed the head. Which is excessive, from what I've read. But still compression.
Now, I can hold my thumb over the plug hole while trying to crank it. I can feel it pushing and sucking. But it's not hardly any.
 
Boudreaux In Eunice La. said:
Is that MM or thousands ?
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Thousandths. I think the MM was 10 & 15. Being that there's a 3 thousandths tolerance on these, makes me think it's not real critical. But where I set them was within tolerance. Unless something came loose when I tried to start it.
They were snugged up. I double checked that before I put the valve cover back on. Triple checked the gap.
 
hrdman2luv said:
Thousandths. I think the MM was 10 & 15. Being that there's a 3 thousandths tolerance on these, makes me think it's not real critical. But where I set them was within tolerance. Unless something came loose when I tried to start it.
They were snugged up. I double checked that before I put the valve cover back on. Triple checked the gap.
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That has the be a translation error.
No one runs 50 thou or 80 thou on the valve lash unless you got a blower and are using nitro.

0,5 & 0,8 mm is aboyt right or even 0.005" & 0.008" could also be right.
 
bertsmobile1 said:
That has the be a translation error.
No one runs 50 thou or 80 thou on the valve lash unless you got a blower and are using nitro.

0,5 & 0,8 mm is aboyt right or even 0.005" & 0.008" could also be right.
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Yes, translation error. .005 and .008. Could be I got the int. and exh mixed up. But I don't think so. Even if, I'd still get more compression than I'm getting. I hope the head gasket is reusable. I'm thinking I'm gonna have to take the head off again.


What causes low compression?
Valves not seating properly. Possible, but not probable.
Not adjusted properly. Almost impossible because I checked them several times.
Head gasket bad. It's new
Rings gone. Impossible, because I was getting plenty of compression before removing the head.

I did loosen the PCV cover. Because there was two bolts under the fly wheel, I wasn't able to take the plate all the way off. Just loosened it to get a look at the screen under the plate. With the gasket still in position (and looking good) I snugged all the bolts back down.
 
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