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Re: Stock 1970 340 T/A Block Compression Test [Re: f2502011] #2411989
12/01/17 09:58 PM
12/01/17 09:58 PM
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Porter67 Offline
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Not that id say do it, but every time I see a chevy guy float his valves, his carbon goes out the tail pipes as well.

Robert, most the time we would run them hard to blow the carbon out a good part of that was to clean the carboned up plugs as well.

Id check the plugs and see if they are burnt back and replace if needed.

Heck, you guys already got his rebuild done for him.

Re: Stock 1970 340 T/A Block Compression Test [Re: Porter67] #2412032
12/02/17 12:01 AM
12/02/17 12:01 AM
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Lincoln Nebraska
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RapidRobert Offline
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Quote:
Heck, you guys already got his rebuild done for him.
Hey we're here to help!


live every 24 hour block of time like it's your last day on earth
Re: Stock 1970 340 T/A Block Compression Test [Re: RapidRobert] #2412033
12/02/17 12:05 AM
12/02/17 12:05 AM
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Posts: 96,649
On The Boat, On The Lake, Wa. ...
amxautox Offline
Still Retired. Still Posting on Moparts. A Lot.
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On The Boat, On The Lake, Wa. ...
We don't mind spending HIS money. biggrin


Tom

"Everyone should believe in something; I believe I'll go fishing."

-Henry David Thoreau

Men and fish are alike. They both get into trouble when they open their mouths

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Re: Stock 1970 340 T/A Block Compression Test [Re: dogdays] #2412075
12/02/17 02:16 AM
12/02/17 02:16 AM
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Originally Posted By dogdays
Wow, next they'll be telling you to get a borescope!

Those compression numbers from your first legitimate test are low. They are lower than low.

You said there is a lot of carbon in the engine. Last year Hot Rod magazine in one of their "we fix a problem car" articles worked on a mustang and it had low compression in some holes. The mechanic said lets take it out and "blow the carbon out." I always thought that was just a myth. He told the writer that sometimes engines get carbon deposits holding the valve a little open and losing compression.
Go out and get the car warmed up[, do a bunch of hard acceleration runs and some high speed runs. That may help. Get back home and aim the exhaust system away from buildings, people, etc. Remove air filter and with engine running about 2500rpm, trickle some water into one side of the carb. You should get a blast of white steam, maybe carrying with it little chunks of carbon. It's pretty dramatic and will stain a wall or fence. Repeat for the other side. Take it out and run it back up to operating temp and do it again. This may help.

It sure sounds to me like rings aren't working. Try to seat the rings with some sharp acceleration blasts followed by letting the engine pull the car down to speed with throttle closed.

Leakdown tests can tell you the condition of things. If you pressurize a cylinder and air leaks out past the piston the next step is surgery.

R.


The initial and second set of compression results were done with a rental gauge with unknown history from a local auto parts store. The results were questionable. The latest ones were done with the new gauge and were in within spec of > or = 110.

Can rings become unseated? If so how and why?

If I do the leakdown on a warm engine and get good results vs bad results on a cold engine what would that mean?


1970 EK2 T/A 727
Re: Stock 1970 340 T/A Block Compression Test [Re: f2502011] #2413783
12/05/17 08:03 PM
12/05/17 08:03 PM
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Did cold leak down today new leak down gauges and got 13.5-14.3% loss at 90PSI. First had to fix my compressor it wouldn’t build pressure and fix a few air hose leaks.


1970 EK2 T/A 727
Re: Stock 1970 340 T/A Block Compression Test [Re: f2502011] #2413907
12/05/17 11:22 PM
12/05/17 11:22 PM
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Bend,OR USA
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Cab_Burge Offline
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Are you going to do a warm or hot test? If not maybe do one cylinder and let us know what you find thumbs
I'm thinking your motor is good based on these results thumbs twocents


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Stock 1970 340 T/A Block Compression Test [Re: Cab_Burge] #2413921
12/05/17 11:39 PM
12/05/17 11:39 PM
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f2502011 Offline OP
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Originally Posted By Cab_Burge
Are you going to do a warm or hot test? If not maybe do one cylinder and let us know what you find thumbs
I'm thinking your motor is good based on these results thumbs twocents


Probably not based on the latest results.


1970 EK2 T/A 727
Re: Stock 1970 340 T/A Block Compression Test [Re: f2502011] #2413928
12/05/17 11:48 PM
12/05/17 11:48 PM
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northwest USA
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NANKET Offline
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What is the problem with this car? What are you trying to solve? Does it run correctly?

Re: Stock 1970 340 T/A Block Compression Test [Re: NANKET] #2413950
12/06/17 12:17 AM
12/06/17 12:17 AM
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Originally Posted By NANKET
What is the problem with this car? What are you trying to solve? Does it run correctly?


Not sure there is one just trying to figure that out by testing.


1970 EK2 T/A 727
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