compression - help

[Mike_G]

I have got information that engine I want to buy have compression 148

What the hell id this?? How many Bar is this??

It is XR2 from 1997. Is it good compression for that engine??

Please help

[jw.]

It's about 10bar. A bit high, I would have thought. But what do I know?

[Toffy]

Originally Posted by Mike_G

I have got information that engine I want to buy have compression 148

What the hell id this?? How many Bar is this??

It is XR2 from 1997. Is it good compression for that engine??

Please help

"148" is most likely the compression value in psi-units. (pound per square inch)
psi values are most commom in compression measurement
1 psi = 0,0689475729 bar (btw, you can google this : type in "psi -> bar" in the search field and press enter)
148 psi = about 10,2 bar

I' don't know XR2's that good. 148psi sounds high and therefore good to me.
But you have only 1 value ! Having equal measurements on all cilinders is also very important. When one measurement is 'down', this means you have a problem cilinder, that needs to be fixed...

The other guys here on the site can confirm if the 148psi rating sounds OK.
They probably are able to predict which cilinder is usually a 'problem' cilinder on this engine type...

Hope this helps, T.

[Burty]

i think xr2 run around 160 psi. as long as all clyinders are within 5 psi of each other it should be ok

[RossM]

yep will second burty's 160, went to pick up a rebuilt xr2 with 10 hours onit and they were all just over 160

[Mike_G]

But do you think I can ride on this engine on 148 or will I have to rebuild it??
Offcours if difference between cylinders will be less than 5 psi??

[Cookee]

It all depends on the age of the engine - the earlier ones were only 175 hp not 200 and might have lower compression?

[FabFour]

The actual compression number is so unimportant vs the fact that the compression between each cylender needs to be the same or within about 5.

The guages you buy from Halfords are quite often 20% out, and age, poor handling etc makes them very inaccurate, so looking for a specific figure is almost irellevant.

What is critical is that they all read the same ( or near the same )

Finally a very high compression could indicate skimming, and a tendancy to detonate - which is bad, but you should see this affecting the cylenders, due to one side getting leaner air and one side getting richer air, so they should be out of the pressure range differential if this did occur.

[PHANTOM EVOLUTION]

just to add more fun to the compression of this XR2 ,you could have the left/right hand banks different by more than 5 psi and from mercurys point of view theres nothing wrong with the engine,and the compression may differ depending on port height.

[Mike_G]

Thanks for your answers

Mike