Page 4 of 4 < 1 2 3 4
Topic Options
#2411989 - 12/01/17 06:58 PM Re: Stock 1970 340 T/A Block Compression Test [Re: f2502011]
EV2Bird Offline
On Vacation

Registered: 06/23/14
Posts: 3114
Loc: Kansas Roads Between 0 and 140...
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.

Top
#2412032 - 12/01/17 09:01 PM Re: Stock 1970 340 T/A Block Compression Test [Re: EV2Bird]
RapidRobert Online   content
Circle Track

Registered: 11/20/03
Posts: 33019
Loc: Lincoln Nebraska
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

Top
#2412033 - 12/01/17 09:05 PM Re: Stock 1970 340 T/A Block Compression Test [Re: RapidRobert]
amxautox Online   content
Still Retired. Still Posting on Moparts. A Lot.

Registered: 05/13/03
Posts: 96109
Loc: 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

author unknown


Top
#2412075 - 12/01/17 11:16 PM Re: Stock 1970 340 T/A Block Compression Test [Re: dogdays]
f2502011 Offline
enthusiast

Registered: 04/19/12
Posts: 274
Loc: US
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

Top
#2413783 - 12/05/17 05:03 PM Re: Stock 1970 340 T/A Block Compression Test [Re: f2502011]
f2502011 Offline
enthusiast

Registered: 04/19/12
Posts: 274
Loc: US
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

Top
#2413907 - 12/05/17 08:22 PM Re: Stock 1970 340 T/A Block Compression Test [Re: f2502011]
Cab_Burge Offline
Too Many Posts

Registered: 08/23/03
Posts: 29970
Loc: Bend,OR USA
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)

Top
#2413921 - 12/05/17 08:39 PM Re: Stock 1970 340 T/A Block Compression Test [Re: Cab_Burge]
f2502011 Offline
enthusiast

Registered: 04/19/12
Posts: 274
Loc: US
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

Top
#2413928 - 12/05/17 08:48 PM Re: Stock 1970 340 T/A Block Compression Test [Re: f2502011]
NANKET Offline
master

Registered: 12/13/03
Posts: 3768
Loc: northwest USA
What is the problem with this car? What are you trying to solve? Does it run correctly?

Top
#2413950 - 12/05/17 09:17 PM Re: Stock 1970 340 T/A Block Compression Test [Re: NANKET]
f2502011 Offline
enthusiast

Registered: 04/19/12
Posts: 274
Loc: US
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

Top
Page 4 of 4 < 1 2 3 4

Advertisement
Sponsored Link
Forum Stats
25,078 Registered Members
32 Forums
185,694 Topics
2,158,838 Posts

Most users ever online: 882 @ 03/05/17 10:15 PM
Moparts Newest Topics
Big block solid roller lifter advice
by formula S
01/21/18 12:54 PM
Russo
by BH27G1B
01/21/18 12:24 PM
Hemi Power Steering Valve
by Davtona
01/21/18 12:10 PM
71 B body w/Hemi and a/c
by Handygun
01/21/18 11:26 AM