1991 240 Cylinder Compression-OEM merge

I apologize for posting this question but I am unable to locate the answer on Google

I have a 1991 Volvo 240 2.4L non-turbo. Auto

What were the cylinder compression value at stock? What do you consider a low psi?

Mine are 160-161-167-169

Thank you

Rlover

gonna roast ya a bit but be better at google...

So lemme give you 2 important tools for your future volvo escapades

1. Post in the right sub forum - maintenance & non performance
2. Your engine is a B230F, search that + "compression specs" and your world will be a better place

Tfest said:

gonna roast ya a bit but be better at google...

Click to expand...

I don?t mind I like learning. I searched for about 20 minutes on google. I searched variants of ?->B230F cylinder compression specifications. The search provided plenty of entries of others posting stats from motors but no hard data links from a definitive site. Just observations from others. 7 links back to this forum but yet again no hard links.

B230F What is stock Cylinder Compression

Google is not very helpful on searches. Plenty of people posting values over the past 20yrs here and elsewhere but just opinions back with no definitive links provided

Does anyone have definitive links for stock cylinder compression?

Thank you

Rlover

Tfest said:

So lemme give you 2 important tools for your future volvo escapades

1. Post in the right sub forum - maintenance & non performance
2. Your engine is a B230F, search that + "compression specs" and your world will be a better place

Click to expand...

Nothing definitive in searches prior to posting this here. Opinions only found. Looking for opinions with supporting hard links. I reposted here as you said to do. I will report this post and ask to be deleted or combined with the below link

https://forums.turbobricks.com/showthread.php?p=6278015#post6278015

Your numbers are great, someone will eventually move this to maintenance and you'll get 900 different opinions. There used to be a link to the greenbook on here somewhere but I cannot find it. It's been years since I messed with the redblock.

128 to 170 and 15% of each other

/end thread

I have never seen a definitive published value for compression values on a new engine. There are minimum values in the Bentley manual and other sources. I would not be the slightest bit concerned with the readings you got. I?ve seen B230s with readings as low as 125 psi that ran fine. The highest I have seen is 185 psi on all 4 cylinders of a B230FD with 284,000 miles on it.

2manyturbos said:

I have never seen a definitive published value for compression values on a new engine. There are minimum values in the Bentley manual and other sources. I would not be the slightest bit concerned with the readings you got. I?ve seen B230s with readings as low as 125 psi that ran fine. The highest I have seen is 185 psi on all 4 cylinders of a B230FD with 284,000 miles on it.

Click to expand...

This ^^

My last redblock I assembled while mostly drink and ran 18psi through it all day long with 0 issues. These motors are pretty bulletproof, just keep some kind of oil in the crank case and go on with your day.

The published figure is .9 MPa (130 psi) with a maximum deviation of .2 MPa (30 psi).

https://www.volvoclub.org.uk/tech/data/200DataSheetSection2c.pdf

^^

That makes sense. Most of the B230FTs I?ve tested had 130-135 psi readings on all 4. The NA B230s were consistently at 150 psi. I have no idea how accurate my 2 different gages are.

Compression numbers vary by compression ratio and volume.
Those numbers are good for 8.5-9:1.

^^

And camshaft.

Don't focus on the numbers but the difference across all of the cylinders

2manyturbos said:

^^

That makes sense. Most of the B230FTs I?ve tested had 130-135 psi readings on all 4. The NA B230s were consistently at 150 psi. I have no idea how accurate my 2 different gages are.

Click to expand...

Which is why it's always better to focus on the difference across all cylinders. There's just enough variables out there.

doucheNozzle said:

Don't focus on the numbers but the difference across all of the cylinders

Click to expand...

Sort of this and leak down and quantity of blowby is more important to examine, does it have a lot of air wheezing around leaky valves or can the leak be isolated on the leak down test as to where the majority of it is going?

Does it shutoff quick from idle/one or two punches of compression watching the crank pulley and even kick backwards a little like a diesel or spin down loosely/hooptily like an old worn out tractor/lawnmower with a heavy flywheel w/tons of blowby &/or if the head is off & bottom end on the engine stand does it ?lose atf overnight? in the bores?
Does it get to max compression or within 5-10psi the same on all holes on the first 1-3 hits?

Without disassembly idk what else to say?
Actual # is just that & there are lots of variables that can change the number considerably such as:
-carbon buildup on the pistons
-valve lash / clearance setting
-starter heath / cranking speed
-battery &/or cable terminal health/ internal resistance/conductivity
-camshaft selection
-factory variation in how far the pistons are above or below deck vs. quoted compression.
-throttle open or shut?
Etc etc.

These ^ are all variables even if the engine is brand new factory perfect w/rings seated on the factory breakin dyno new w/~0 miles?

That said, B230F cars I observe ~190 even on a healthy battery and starter/same compression gauge (however accurate it is or isn?t over the years FWIW?).
Healthy high compression M cam B23F 220psi is common enough?

B230s suck/don?t tolerate neglect as well or running around low on oil or with a couple quarts of watery roofing tar for oil with their short little pistons pre oil squirters and those short little pistons in the shed larger bore motor then a 1961 clean slate design redblock B18 are much more blowby prone than B21/23, but much lighter pistons & rods w/less reciprocating weight on B230 as well / trade-off?

The piston oil squirter B230s cool/oil those short horribly tippy pistons a little better, but tooling drift and raw materials is questionable on the last/later B2xx ?93+ in some cases as are raw materials IMO, but easier to find a healthier used squirter B230, oftentimes?

2manyturbos said:

^^

And camshaft.

Click to expand...

Thanks for adding that. My dad ran leftover race pistons in a 510 with a stock cam on the street. Knocked like crazy. I never had the nerve to check compression for fear of hurting my gauge.

The last healthy B230F I checked had 200psi in all cylinders. That was a 375k mile engine that was well cared for with M1 from the first owner. That said the main thing is that balance between the cylinders being close.