Replacement Engine - Cold Compression Test Results Worry Me
01-05-2016, 06:33 PM
#1
Instructor
Thread Starter
Replacement Engine - Cold Compression Test Results Worry Me
Hello guys,
So my engine (JDM - Type S) came in yesterday and before I install it I wanted to change timing belt, seals, etc... everything that needs to be done while it's easy to access.
So the first thing I did was a compression test to see the results on each cylinder.
I know that you are supposed to do a compression test after the engine is warm but I wanted to get an idea before I really started putting all my time into and getting it installed and then have an issue.
So here are my results:
I'm not sure of the cylinder numbers so I'm going to state it like this.
Firewall side of the engine: (Left to Right) I did (2) tests
190/175 240/230 180/185
Front Side of the engine (Left to Right)
130/130 100/110 155/150 *(NOTE: I could get the pressures to come up higher on this side but had to turn over the engine a lot more revolutions)*
Now I only let the engine turn over 5 revolutions each test and I'm sure the battery is weakened after each test as well but I did have a battery charge with start assist on the battery for each test.
I was concerned so I went and talked to a Master Mechanic who works at Honda here in my town that is a friend of a friend and he said I really wouldn't be able to tell until the car has been running for a while and that I should be ok. He asked me how many miles and I told him it was a JDM and he said he's never had any issues with JDM engines.
However I'm still concerned because I've seen videos of compression tests being done on JDM motors and they were all pretty close across the cylinders.
What do you guys think, am I overthinking this? Should I go on with the install or not? I have 90 day warranty on the engine I think it was it was.
Thoughts or advice???
So my engine (JDM - Type S) came in yesterday and before I install it I wanted to change timing belt, seals, etc... everything that needs to be done while it's easy to access.
So the first thing I did was a compression test to see the results on each cylinder.
I know that you are supposed to do a compression test after the engine is warm but I wanted to get an idea before I really started putting all my time into and getting it installed and then have an issue.
So here are my results:
I'm not sure of the cylinder numbers so I'm going to state it like this.
Firewall side of the engine: (Left to Right) I did (2) tests
190/175 240/230 180/185
Front Side of the engine (Left to Right)
130/130 100/110 155/150 *(NOTE: I could get the pressures to come up higher on this side but had to turn over the engine a lot more revolutions)*
Now I only let the engine turn over 5 revolutions each test and I'm sure the battery is weakened after each test as well but I did have a battery charge with start assist on the battery for each test.
I was concerned so I went and talked to a Master Mechanic who works at Honda here in my town that is a friend of a friend and he said I really wouldn't be able to tell until the car has been running for a while and that I should be ok. He asked me how many miles and I told him it was a JDM and he said he's never had any issues with JDM engines.
However I'm still concerned because I've seen videos of compression tests being done on JDM motors and they were all pretty close across the cylinders.
What do you guys think, am I overthinking this? Should I go on with the install or not? I have 90 day warranty on the engine I think it was it was.
Thoughts or advice???
01-05-2016, 10:18 PM
#2
Instructor
Thread Starter
Well I tried again with a "Full" charge on the battery and got much better results than the initial try.
I'm sure battery strength came into play on the readings.
I'm not going to worry about it anymore and start installing it.
I'm sure battery strength came into play on the readings.
I'm not going to worry about it anymore and start installing it.
01-06-2016, 11:57 AM
#4
Instructor
Thread Starter
It's used (JDM Engine from Japan) and yeah it has oil in it. I think the weak battery was the culprit. I waited until my charger had a full charge and tried it again and the compression was much higher. I suppose the engine wasn't cranking fast enough to make good compression.