| From | Message |
kota on 20s
GenIII
 
6/01/2002
18:04:12
|
 Subject: compression test results.. help!
IP: Logged
Message:
here is the results:
8=170........7=180
6=170........5=180
4=190........3=190
2=190........1=180
on the #6 cylender i tested it about 3 times. it ranged from 20# on the 1st crank to 90#'s... and the final # went from 155 to 165, then i put a small amout of oil into the cylender and i got 170.
the oil and water have not mixed, so could the head be a little warped, or cracked, or is it within the limits??
i think its odd that all are over 180#'s except 2 cylenders that are together.
what are your opinions?
Eric, 98 5.2 5speed, K&N gen II, 50mm TB, 2bbl M-1, 1.7RR's, JBA ciramic headers, carsound cat, dumped gibson, and a lot more
|
moparjoe20
Dodge Dakota
JOIN HERE
6/02/2002
01:09:16
| RE: compression test results.. help!
IP: Logged
Message:
If oil caused the cranking pressure to jump up almost 20psi you have ring problems , do a leak down test on it to find out whats going on.
|
IntenseDak39
*GenIII*
6/02/2002
07:00:18
| RE: compression test results.. help!
IP: Logged
Message:
i believe that those numbers are with in limits...
now when i did a compression check on my shelby i had:
1= 175
2= 170
3= 95
4= 130
i will look it up and see what i can find about the standard compression for your engine
intensedak39
|
CW
GenIII
6/02/2002
10:44:19
|  RE: compression test results.. help!
IP: Logged
Message:
Well within limits if not a little high. Every engine in the world will come up in compression with oil in the cylinders. I think you are allowed 15% varience and you are well within that. You are at sea level but at 3000 feet I see only about 140-150 from new engines. Dodge says anything over a 100 is good. :-/
2001 4.7HO RC 5sp 3.92 LSD
Click on thumbnail for mods.
|
kota on 20s
GenIII
6/02/2002
12:05:11
| RE: compression test results.. help!
IP: Logged
Message:
moparjoe, on cly #6, i got 155, then 165, then i put oil into the cylender and got 170. so with the oil i got another 5#'s
Eric, 98 5.2 5speed, K&N gen II, 50mm TB, 2bbl M-1, 1.7RR's, JBA ciramic headers, carsound cat, dumped gibson, and a lot more
|
smart ass
Dodge Dakota
JOIN HERE
6/03/2002
21:00:06
| RE: compression test results.. help!
IP: Logged
Message:
Eric, dude,, you again are only testing the 6 banger, not an 8..
|
kota on 20s
GenIII
6/04/2002
00:43:40
| RE: compression test results.. help!
IP: Logged
Message:
didnt you read my responce in the other thread?
Eric, 98 5.2 5speed, K&N gen II, 50mm TB, 2bbl M-1, 1.7RR's, JBA ciramic headers, carsound cat, dumped gibson, and a lot more
|
joel
Dodge Dakota
JOIN HERE
6/04/2002
15:33:30
| RE: compression test results.. help!
IP: Logged
Message:
Find the percentage of the variance from 165 to 190. Figuring in the pressure result using oil will mess up the results.
If 15% is ok and my math is right then your at 11.5% variance.
Joel
|
1Flamed92Dak
GenII
6/04/2002
17:27:01
| RE: compression test results.. help!
IP: Logged
Message:
He as long as your within 20% of each cylinder i think your fine and by your post you are within Tolerances less than 20lbs per Cylinder
|
Dr.Dakota
Dodge Dakota
JOIN HERE
6/04/2002
19:51:34
| RE: compression test results.. help!
IP: Logged
Message:
A brand new engine should have a maximum of a 10% Variance. If my math is right (and as a pHd in Biochemistry it better be) you have a 11% variance. That extra 1% could be from the compression gauge (is it a screw in or a rubber tipped type that you press on while someone else cranks) Anyways I wouldn't be upset over 11% variance, especially with psi that high. if you had a 15% variance on a screw in gauge and the highest was only, lets say, 120 psi then I would be looking for some worn rings, grooved cylinder walls, worn or burned valves. History of that engine would also play a part in deciding on its condition too.
|
Swany
Dodge Dakota
JOIN HERE
8/03/2004
14:07:24
|  RE: compression test results.. help!
IP: Logged
Message:
Help!
Have a ford 2300 racecar engine breaks down above 4000 rpm . have change everthing electrical and electronic ,distribeutor , aux shaft , seated valves , all gaskets ,leak down test , valve springs , changed timing ,advanced cam , reset valves . Compression test is low on all cylinders 60 up 100 pounds after advancing cam . cam is now way out of specs for setup do to advancing it. problem started all of a sudden, engine did get hot at that time but only about 230 degrees. WHATS WRONG, TIERD OF CKRANTCHING MY HEAD. THANKS
|
uh actually
Dodge Dakota
JOIN HERE
8/04/2004
16:35:30
| RE: compression test results.. help!
IP: Logged
Message:
contrary to what some of you have implied, the correct way to test engine compression is AFTER
spraying a small amount of oil in each cylinder.
"If oil caused the cranking pressure to jump up almost 20psi you have ring problems , do a leak down test on it to find out whats going on."
What's going on is Moparjoe20 has no idea how to test properly.
One thing that no-one has yet to mention is that burned exhaust valves/seats can cause low readings in compresion tests.
|
Bob Lincoln
Dodge Dakota
JOIN HERE
8/04/2004
18:51:32
| RE: compression test results.. help!
IP: Logged
Message:
Uh, actually, actually...
You're wrong. Compression is tested before AND after adding oil to the cylinders. If compression increases significantly, ring wear is indicated; if no or little difference, valves/valve seal/guide wear is likely the issue.
Moparjoe does know how to test properly.
|
Wal
Dodge Dakota
JOIN HERE
8/05/2004
02:15:04
| RE: compression test results.. help!
IP: Logged
Message:
how about running a leakdown now ;-)
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
