1.9 Compression

[treesimon 0]

Ive just done a compression test on my 1.9 at running temp. Mileage is 177k, Head was recondition a year ago and there is no evidence that the bottom end ever been touched.

 

What id like to know is are these healthy results for a typical 1.9?

 

No.1 = 13.6 bar - 197 psi

 

No.2 = 14 bar - 203 psi

 

No.3 = 13.6 bar - 197 psi

 

No.4 = 13.3 bar - 192 psi

 

 

Also at some point i was thinking reconditioning the whole engine, what results would i be likely to see if i did?

[Tom Fenton 1,525]

Sounds in pretty healthy fettle to me. The actual magnitude is not so important. The variation between cylinders is important, and in your case they are all close enough to suggest its as healthy as can be expected for 177k.

[welshpug 1,622]

that sounds very healthy, I think an Mi16 is around the 220 mark when healthy due to the higher compression ratio, like Tom said they are pretty even, well within 10%

 

did you do it cold or hot?

Edited January 22, 2010 by welshpug

[treesimon 0]

that sounds very healthy, I think an Mi16 is around the 220 mark when healthy due to the higher compression ratio, like Tom said they are pretty even, well within 10%

 

did you do it cold or hot?

 

 

That was done at running temp.

 

would expected to see more or less cold?

[pug309twin40s 1]

those results are very good. all very close and near 200psi which shows you have a very good engine even though its done high mileage.

[richsmells 2]

Echoing above, looks healthy and consistent. Did you do a leakdown test?

[treesimon 0]

Echoing above, looks healthy and consistent. Did you do a leakdown test?

 

what's a leakdown test?

[DamirGTI 323]

= http://www.motorcycleproject.com/motorcycl...t/leakdown.html

 

Damir

[treesimon 0]

= http://www.motorcycleproject.com/motorcycl...t/leakdown.html

 

Damir

 

 

Cheers, think i'll be making one of those thursday night when im at work, got all those part in the stores.

[davey205 7 1 Cars]

oh dear just done one on my 1.6 83,000 no work done to engine except cambelt change and she only read 11 - 11.5 bar , can someone suggest acceptable values for a 1.6

Edited January 24, 2010 by davey205

[davey205 7 1 Cars]

oh dear just done one on my 1.6 83,000 no work done to engine except cambelt change and she only read 11 - 11.5 bar , can someone suggest acceptable values for a 1.6

ill go and shoot myself ..... i didn't realize that you had to do full throttle or any throttle at all when you did the compression test

[treesimon 0]

ill go and shoot myself ..... i didn't realize that you had to do full throttle or any throttle at all when you did the compression test

 

when I did mine it was with the throttle fully open and the engine at running temp.

 

From what Tom said I think that the quantity of pressure is not as important as see that all cylinders are within a bar of each other, the closer the better.

If one cylinder is down compared to the others you can try putting a little oil into that cylinder then retest, if the Reading goes up then it could indicate that a ring is worn.

on My car the next step will be to do a leakdown test once I've made the kit up to do it. People say it more reliable test and if you had just a head and block without manifolds on you'd know where the leak was coming from very easily.

 

I'd think that a 1.6 would be slight less than a 1.9 due to the stroke being shorter?

[jengis 0]

I'd think that a 1.6 would be slight less than a 1.9 due to the stroke being shorter?

 

compression ratio and camshaft specifications/timing are the main factors that would determine the compression pressures a healthy engine should produce. I'd expect 1.6's and 1.9's to be pretty similar in this respect.

[rodionski 3 1 Cars]

that sounds very healthy, I think an Mi16 is around the 220 mark when healthy due to the higher compression ratio, like Tom said they are pretty even, well within 10%

 

did you do it cold or hot?

 

Are you sure about that? Because that number is veeeery high! This makes for about 15.1 bar compression.....

What's the source for your information?

 

Thanks.

[Anthony 1,000]

*looks at the thread date"

 

Generally I'd expect to see something in the order of about 18-20 times the compression ratio for a typical road-going engine in healthy condition.

 

So say something in the region of 185-210psi for an 1.9 Mi16 (10.4:1) and 170-195psi for a 1.9 8v (9.6:1)

 

Obviously there's lots of factors that would change those readings, not least the accuracy of the compression tester itself! Camshaft duration/timing and cranking speed will change things, as will whether the engine is hot or cold, plus of course the condition of the rings, valves/seats and headgasket.

 

Main thing to look out for really is that all the figures are fairly high and within about 5-10% or so of each other

[rodionski 3 1 Cars]

The difference between the cylinders is clear, so no questions about that part.

The actual reference figure for a new stock engine is what I am searching for. I need to know the average benchmark, preferably from Peugeot literature :-)