Compression readings
Thread Starter
|
Senior User
Joined: May 2010
Posts: 223
Likes: 0
From: Florida
Compression readings
I have a 74 390, it runs fair with RV cam. I have never seen any blue smoke out the exhaust and the plugs are clean. I am not sure what has been done to the engine as far as total rebuild, the pistons are 30 over. My compression test when hot, all the plugs out, and wide open throttle ranges with one cylinder 95, two at 105, and five at 110. Adding some oil to each cylinder test got me one cylinder 1% increase, four cylinders 4% increase, two cylinders 7% increase, and one cylinder 8% increase. What does this mean?
Thread Starter
|
Senior User
Joined: May 2010
Posts: 223
Likes: 0
From: Florida
It has a slight miss on occasion around 1500 rpm almost like its not getting enough fuel, espically if you are going slow and the transmission stays in third without down shifting. If you get on it there is no miss. I almost think i have a carb issue and it has been this way since the carb was new. I am going to increase the pump nozzle shooter size and see what happens. I have done this one time before and it seemed to make a small difference. I just watched a video on how to perform a leak down test i may do this after the pump nozzle change.
Thread Starter
|
Senior User
Joined: May 2010
Posts: 223
Likes: 0
From: Florida
Started back tracking my upgrade to find what has caused my problem. Timing gears were lined up correctly. Took the heads off and all but two exhaust valves were up in the head past the flush point. Dropping them off tommorrow to get reworked.
Down in the cylinders on the cylinder walls i see a tint of copper within the hone marks, is this normal or a wear sign?
Down in the cylinders on the cylinder walls i see a tint of copper within the hone marks, is this normal or a wear sign?
Thread
Thread Starter
Forum
Replies
Last Post
nickydobbs
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
3
Sep 17, 2014 11:58 PM
91Bronc300
1973 - 1979 F-100 & Larger F-Series Trucks
7
Sep 22, 2011 06:57 PM
Boltgunner
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
17
Feb 6, 2006 10:58 PM
Katmandu2
Ford Inline Six, 200, 250, 4.9L / 300
7
Aug 30, 2003 02:27 PM
