I found my Cranking Cylinder Pressure (CCP) problem

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512Stroker

512Stroker

We are all here because we are not all there.
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After a long conversation with a great Cam Tech at Howards - Kirk - we determined that something was not right with my current Comp XR274HR-10 cam setup and before I start swapping cams it would be best to run a compression test again using a different compression tester to verify the low CCP (115-120psi) numbers I got 2 years ago using a off brand chinese made tester that I got from a friend.
So today using a old KD Tool compression stamped made in the USA I re ran all 8 cylinders and low and behold I averaged 190 psi across the board. Great news
So here I am have been running around like a 3 legged chicken for the past 2 years screaming low CCP! low CCP! blaming the camshaft - Sorry Comp Cams.
The morel to this story is - NEVER EVER trust cheap *** crap for quality chinese made tools they will only get you in trouble.
I knew better, I feel like a Dam Fool!
 
I have a mix of all kinds of stuff, thrift stores, garage sales, etc, AND MY OLD PROTO compression tester I bought new in the early SEVENTIES. And it LOOKS like it LOLOL. It is still as accurate as any of them after all these years.
 
I think I will check my compression checker with a couple of gauges in my shop to see if they all read the same.
 
DUDE! CCP, Chinese tools, 3 legged chicken?

What did you expect? Plus 2 YEARS it took you to verify and fix! :rofl:
 
Syleng1 said:
DUDE! CCP, Chinese tools, 3 legged chicken?

What did you expect? Plus 2 YEARS it took you to verify and fix! :rofl:
Click to expand...
Thanks
Now I really feel like crap.
Job well done.
When you are old and disabled you move slow.
Plus it will run like a scalded cat so I never dug deep until recent, no excuse just the truth.
 
Then you should be having trouble running off pump premium without spark knock. Are you?
 
512Stroker said:
After a long conversation with a great Cam Tech at Howards - Kirk - we determined that something was not right with my current Comp XR274HR-10 cam setup and before I start swapping cams it would be best to run a compression test again using a different compression tester to verify the low CCP (115-120psi) numbers I got 2 years ago using a off brand chinese made tester that I got from a friend.
So today using a old KD Tool compression stamped made in the USA I re ran all 8 cylinders and low and behold I averaged 190 psi across the board. Great news
So here I am have been running around like a 3 legged chicken for the past 2 years screaming low CCP! low CCP! blaming the camshaft - Sorry Comp Cams.
The morel to this story is - NEVER EVER trust cheap *** crap for quality chinese made tools they will only get you in trouble.
I knew better, I feel like a Dam Fool!
Click to expand...

Amen - anything from China is junk [PERIOD] case closed.
 
Best to have back up tools for your own piece of mind. I have a few compression tester. One is a Niehoff as old as I am.
 
What was the original reason you were checking your ccp ? If it ran really well why would you need that info, other than a newly built engine to have a number to go by down the road ? Which would be a good idea !! Just wondering ! Glad it was your tool set rather than your engine !!
 
Rmoore said:
What was the original reason you were checking your ccp ? If it ran really well why would you need that info, other than a newly built engine to have a number to go by down the road ? Which would be a good idea !! Just wondering ! Glad it was your tool set rather than your engine !!
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This is the fist SBM I have had, always had BBM's lot's of torque.
After the build of this 340 I always felt it was low on torque, I was wrong, this is only so much you can do with 340 cid.
There is no replacement for displacement!
Lesson learned - Go big or go home.
 
512Stroker said:
This is the fist SBM I have had, always had BBM's lot's of torque.
After the build of this 340 I always felt it was low on torque, I was wrong, this is only so much you can do with 340 cid.
There is no replacement for displacement!
Lesson learned - Go big or go home.
Click to expand...

cool ! I’ve never messed with small block stuff either ! But , I will say there are some small blocks on this form and at the track that are really impressive ! In fact I’ll just say it , there are some bad to the bone small block Mopars out there ! For some reason I’ve never paid them no mind !! My eyes have been opened !
 
RustyRatRod said:
Then you should be having trouble running off pump premium without spark knock. Are you?
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Rusty that is strange
I have had the same thoughts
I am currently running 34* all in at around 2800 rpm with vacuum advance that adds 10* at cruz speed, all FBO ignition.
91 octane pump fuel, no ethanol.
No detonation, not even one ping.
Explain that for an iron head 340.
Perhaps the 9.5 CR is the answer?
 
512Stroker said:
Rusty that is strange
I have had the same thoughts
I am currently running 34* all in at around 2800 rpm with vacuum advance that adds 10* at cruz speed, all FBO ignition.
91 octane pump fuel, no ethanol.
No detonation, not even one ping.
Explain that for an iron head 340.
Perhaps the 9.5 CR is the answer?
Click to expand...

No, cylinder pressure has a much more dramatic affect on detonation than static compression. You should be having trouble on 91 with that much cylinder pressure. I'm questioning the new gauge.
 
RustyRatRod said:
No, cylinder pressure has a much more dramatic affect on detonation than static compression. You should be having trouble on 91 with that much cylinder pressure. I'm questioning the new gauge.
Click to expand...
I am with you I dont trust the results.
I have made the decision to DRIVE THE CRAP out of it and no longer worry about it. If it fails I deal with it then.
This engine has approx 5000 miles on it in its current configuration.
 
I don’t get it. With 190psi and 340 inches you should have a pretty nasty little small block. Torque (or lack there of) should not be a problem. What are the cam specs? And I agree with RRR that’s a lot of cranking cylinder pressure for 91 octane and cast iron heads. With 115psi it wouldn’t get out of its own way. Something seems odd.
 
Detonation.
This thread is a great example of an engine that you would expect to ping....but doesn't. And then there is the engine that you would not expect to ping...but does.
To me, it shows that are a lot variables at work & at the end of the day, you just have to try it.....
 
512Stroker said:
After a long conversation with a great Cam Tech at Howards - Kirk - we determined that something was not right with my current Comp XR274HR-10 cam setup and before I start swapping cams it would be best to run a compression test again using a different compression tester to verify the low CCP (115-120psi) numbers I got 2 years ago using a off brand chinese made tester that I got from a friend.
So today using a old KD Tool compression stamped made in the USA I re ran all 8 cylinders and low and behold I averaged 190 psi across the board. Great news
So here I am have been running around like a 3 legged chicken for the past 2 years screaming low CCP! low CCP! blaming the camshaft - Sorry Comp Cams.
The morel to this story is - NEVER EVER trust cheap *** crap for quality chinese made tools they will only get you in trouble.
I knew better, I feel like a Dam Fool!
Click to expand...
You should
 
TT5.9mag said:
I don’t get it. With 190psi and 340 inches you should have a pretty nasty little small block. Torque (or lack there of) should not be a problem. What are the cam specs? And I agree with RRR that’s a lot of cranking cylinder pressure for 91 octane and cast iron heads. With 115psi it wouldn’t get out of its own way. Something seems odd.
Click to expand...
It is a nasty little SBM just does not produce torque like a BBM that I am more familiar with. 417 lb/ft @ 4500 rpm uncorrected the air was really bad that day.
Cam is a Comp XR274HR-10
Int/Exh
224/230 @ .050
.538/.534 lift
110 LSA installed @ 105

You are right something is odd but I am not taking it apart to find out.
Every time I dig deep I just end up at the bottom of a barrel of snakes.
 
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