Gt restoration 4efte compression test results

[Harry1994gt]

1994 gt starlet 4efte, so ive compression tested my motor which i bought with the car as a non runner, the car had a tdo4 turbo kit and was parked 4 years ago with a motor than apparently ran but had a knock, results were cylinders 1-3 read 100psi and cylinder 4 read 90psi, i then added a teaspoon of oil to each cylinder and retested, results were cylinder 1-2 150psi cylinder 3 135psi and cylinder 4 95psi

I am trying to decide what route to go with this engine and am learning as i go so i am asking for any guidance as to what these readings mean and could tell us about this motor and what happened when it went bang/started knocking, thanks in advance for all your input

 

[gorganl2000]

typical stock 4efte cylinder compression is around 150psi for a healthy engine...cylinders should be within 5.0% or so of each other
i'd suggest you pull the engine down completely if it is knocked and see just how much damage is there----then decide what to do,,, rebuild or replace

 

[davehart]

Very low compression there.

Mine which is broken has around 105 accross each 4. They should be in the 150's for a healthy unit.

Rebuild time I would say for that engine.

 

[Jay]

As above, haul it out and strip it down. The rings, bores, pistons and valves should all be inspected before you make a call on the engine.

If you can get a cylinder leakage test done beforehand it should give an indication of where the air is going/what to expect.

 

[Harry1994gt]

Thanks Jay, thats what im going to do

 

[Harry1994gt]

In the end after tearing it down i found cylinder 3 had a spun rod bearing and the walls of cylinder 4 were badly warped. This may or may not help someone diagnosing in future just thought id mention it