engine probs!!

Hello,

I have been having problems with getting my engine started.I have got a spark and there is fuel going to plugs but it is turning over slowly. Even with a new
battery and starter. I pulled all the plugs and when I went to turn it over again it turned over alot faster. I then went and bought a compression tester and hooked it up to a cylinder and got only about 50psi. I then put some oil down the cylinder and retested for compression and got the 120psi I was lookiing for?? they were all like this. What does this mean? The heads all have new gaskets and sealen where needed and I am sure I torqued the bolts to spec. The engine is a rebuild
Please Help Thanks DAve

Quote:

Hello, I have been having problems with getting my engine started.I have got a spark and there is fuel going to plugs but it is turning over slowly. Even with a new battery and starter. I pulled all the plugs and when I went to turn it over again it turned over alot faster. I then went and bought a compression tester and hooked it up to a cylinder and got only about 50psi. I then put some oil down the cylinder and retested for compression and got the 120psi I was lookiing for?? they were all like this. What does this mean? The heads all have new gaskets and sealen where needed and I am sure I torqued the bolts to spec. The engine is a rebuild Please Help Thanks DAve

Hi Dave,
Who rebuilt the motor ?.

HEy there,

I bought it off someone and I didn't meet him the engine came by mail. HE has helped me throught the install process of the engine and seems like he rebuilt it properly??
DAve

Quote:

HEy there, I bought it off someone and I didn't meet him the engine came by mail. HE has helped me throught the install process of the engine and seems like he rebuilt it properly?? DAve

Something is wrong with this rebuild !!!!.

Well there are a lot of question to the orginal post.

First you can have a Low Compresstion Ratio if you use the wrong heads, What CC Heads?, Was a Turbo or Supercharger going to be use on the motor?, Did he rebuild with the wrong Piston Rings?.

Second was there a differance between each of the cylinder PSI readings or was they all they same 50 PSI?.

Third (If it was me) I would rebuild this motor again and do it right.

Take, Block & Heads to a machine shop, Have them cleaned up & Magna Fluxed both (checking for cracks in the block & head), Also I would have them check for trueness of the deck of the block & Heads and if needed (Mill them True), also have them check the alignment of the Mains and Align Hone if needed too, Get a 3 angle valve job done on the heads at the sametime.

Now you should have a Good Foundation to work from - A Good block & Heads - You will also know all your spec's on the motor (Cylinder Bore Size, Main Bearing Size, Cam Bearing Size, Both the Mains & the Cam will be aligned for sure, The Block Deck & Heads will be true), it would be a good idea to let them install the Cam Bearing too.

Purchase a gasket set with Main Bearings also get a new set of Piston Rings to the Spec's that you was given (hope you do not have to over bore cylinders) - if so you will need new Pistons too.

Now you are ready to rebuild - turque everything back to spec's, Motor should turn freely and your compresstion should be good in all cylinders, Now reinstall motor in vehicle and have fun.

Note :
If you rebuild the above motor it can cost from $800 - up, depends.

If this is a stock motor you can purchase a New Full Block from a Ford Dealer for $800 - $1500 and you can get them from Discount Auto Parts or other Auto Parts Stores from $650 - $1200 Rebuilt already or you can go to a Junk Yard and purchase a motor out of a wreaked in the rear end vehicle from about $350 - $650.

Hope this helps you.

Hello,

J Get some info from this person who built the motor, such as purpose it was built for, expected compression ratio, cam specs,ask them about the low compression pressure, anything else will not hurt. Can you turn the motor over by hand? If so does it spin evenly, no stiff spots? The oil test that you did indicates that the rings are the culprit, since you said the compression came up with the oil in the cyl. Therefore the heads should be sealing just fine. By the way, at what rpm did you do the compression test at? If the engine isn't turned over fast enough then the test isn't a valid test. After all you said it was turning over slow. How wany miles if any are on the motor? Have the rings seated yet? Are you shure the timing itn't too far advanced, this will cause the engine turn over slow. The compression test results, are they within 10% of each other, if so chances are that either the ring gaps are in allignment, the rings are upside down, or the the rings are the wrong size. These are just some low $ things to check before dumping a lot of $$$$ in a fresh rebuild.