Running on 7 cyl in NJ!

[broncojoe90]

Hey everyone, i picked up my 90' bronco xlt from the shop today and was told #8 cylinder has "low" compression and is pretty much dead. The receipt says 20psi "dry" & 30psi "wet"... I dont have the money right now to put in a new motor , but maybe someone has an idea for a "cheap" rebuild. I just need this truck to last another year until i get something newer. any ideas??? all are welcome

thanx

I already have changed: plugs, wires, cap, rotor,ignition coil, air filter, fuel filter, idle air control valve and run 20w50 oil..

 

[miesk5]

yo!

Low compression in one cylinder usually indicates a bad exhaust valve; after the "wet"... test (If compression is low in one or more cylinders, you can isolate the problem to the valves or rings by squirting a little 30 weight motor oil into the cylinder through the spark plug hole and repeating the compression test. The oil temporarily seals the rings.)

If the compression readings are higher the second time around, it means the rings and/or cylinder is worn. No change in the compression readings would tell you the cylinder has a bad valve.

by Larry C

so, a cheap valve job o #8 can help you get along for awhile

 

[miesk5]

wrong Link, but that Link is for this;

A leakage test can also be used in conjunction with a compression test to diagnose other kinds of problems.

.

A cylinder that has poor compression but minimal leakage usually has a valvetrain problem such as a worn cam lobe, broken valve spring, collapsed lifter, bent push rod, etc

.so, a few items there to ck...not a big $ issue for most, exc for the cam lobe

did the mechanic bother to lift the rocker arm cover to ck for a bad spring....or pull push rod/lifter?..or did you just ask for a compr. test?

Sorry, am away on a mission & this lap top has a **** poor fan and shuts down every few mins, so maybe someone else can chime in here and give you info on checking all above and diy replacement.

will be away for a few days....GL!

 

[miesk5]

http://www.aa1car.com/library/compression.htm Link for Engine Compression Testing

By Larry

have to add quickie additions to this reply in case fan stops on laptop

 

[broncojoe90]

hey thanx for the info... i only asked to check truck due to rough running and turned out to be low comp in #8 cyl... just going to think about where i want to spend my money.. thanx again