Compression Interpretation

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thspeller

Active Member
Posts
118
Location
London
Hi All - there is a lot of noise out there about compressions but wanted some straight up advice on my engine health. I have a 2.25 (2.3) petrol from early ninety 8:1 non gas flowed.

I’m about to undertake a rebuild but before I open the money taps, want some advice on the engine condition. Compressions done (no plugs, full battery, warm engine, throttle open) were 125/135/135/135 (dry) and 135/145/142/142 (wet). Not huge increase on wet and all within the 10% limits. No obvious colour to exhaust, no obvious bubbling in coolant. Runs sweet as anything (bar a kickback on starting - but think this is ignition related unless it’s timing chain). Might be a little down on power (too end especially).

The spec 8:1 compression is 165 and I was hoping for more than 150 dry.

What would you read of these figures and how would you suggest I move forward?

Thanks for your time.

Tom
 
Are you using the correct figures
The shot below shows the 2.25 petrol from early defender with 8:1has a cylinder pressure of 11.2 Kgf/cm2
Which is 159psi
So not quite as bad as it seems although drop between 1 and 2 annoying
Is the compression tester reading accurate
As the wet test improved all readings it’s probably not a valve seating problem
So if you’re planning a full engine rebuild anyway, you will find any issues as you go
If it’s running ok are you sure you want to rebuild
Performance wise have you done a road test 0-60 and video it and compare with standard
I did a thread comparing different motors
Not sure if a petrol was tested
https://www.landyzone.co.uk/land-rover/slow-diesel-road-test.339938/
 

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Just an opinion; It being a fairly old ran in engine with pretty close pressures I’d be quite pleased with that as a starter. If your rebuilding it anyway check the bore measurements and go from there wether it’s new rings or rebore.
 
Was this for 0-60 time lol? Couple of failed attempts but I think I’ve solved my running issues recently and the roads are a bit quieter currently for a clean run.

A few years ago my engine was so bad it was bleeding oil and would roll backwards on a hill in gear, but still managed 70. I just went straight for re-bore. Found a couple of surprises in the strip down.
 
Thanks guys - id lovely dearly not to rebuild. Can’t afford. Just wanted to know whether, if I rebuild the car around THIS engine, it’s not a waste of time if these reading suggest the engine is at the end of its life? From what you’re saying, those readings aren’t too bad which is brilliant.

If wet test increases by less than 10% and only to the mid 140s, does that mean a turner reconditioned has flowed head might given some improvement?

cheers

Tom
 
Was this for 0-60 time lol? Couple of failed attempts but I think I’ve solved my running issues recently and the roads are a bit quieter currently for a clean run.

A few years ago my engine was so bad it was bleeding oil and would roll backwards on a hill in gear, but still managed 70. I just went straight for re-bore. Found a couple of surprises in the strip down.

yes , just make sure it’s on the way to the supermarket
I’ve since put a 200di in mine so needs a retest
 
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