biggingers87

Sure mate, here's whats written on the description:

CARRIED OUT COMPRESSION TEST. CARRIED OUT CHECKS
FROM ENGINE HOT AND COLD
FRONT CHAMBER COLD 720 KPA HOT 660 KPA
REAR CHAMBER COLD 750 KPA HOT 680 KPA
CHECKS INDICATE BOTH FRONT AND REAR CHAMBER BELOW MIN WHEN HOT

How far away are those figures mentioned?

Thanks

RIWWP

iTrader: (2)

There is data missing, but assuming that is normalized and they were only posting the low numbers, then the rear just barely fails, the front fails slightly more. A 690 is the failing mark when the RPMs are normalized to 250rpm. If those are not normalized and are at a higher RPM then you are failing quite a bit more. If those are not normalized and are at a lower RPM, then you are probably actually passing.


Usually compression checks give 7 numbers:
Front rotor: Face1, Face2, Face3
Rear rotor: Face1, Face2, Face3
Crank speed: RPM

biggingers87

After reading up on compression tests on here, it was the first thing I noticed that there was no RPM speed given.

So we've established it's just failed...is it a case of "a fails a fail" regardless of the readings or is there anything worth trying to try improve this?

Is Seafoam cleaning worth a shot?

shadycrew31

iTrader: (6)

No seafoam does nothing, you can try premixing.

RIWWP

iTrader: (2)

The problem with answering that clearly is that it entirely depends on WHY it failed compression. As in, 'what seal or seals are now beyond tolerance, and what is causing that tolerance gap?'

Seafoaming has been shown to improve engine compression (it did on mine), but we suspect that this is ONLY IF the compression loss is due to soft carbon buildup on the housing that is offsetting the seal unevenly or carbon buildup in the seal track itself upsetting the seal's seating angle. Seafoaming can clear out this carbon (to some degree) that can help the seals seat better. My engine had 3 compression tests in 2.5 months, and the first one was failing, 2nd one was barely passing, the 3rd was comfortably passing. Presumably due to the decarb treatment.


However, that is all largely theory (see Shady's post above mine for an example of people that don't agree with it)


If the compression loss is due to seal wear or seal deformation, then no, seafoaming will not do anything at all.



It's cheap, and won't hurt anything (unless you have a cat connected, then we recommend disconnecting the cat when you do it), and if it helps, well, that's hardly a bad thing.

zoom44

id like to see the numbers from each chamber first. it could be a sticky seal that could be fixed up by a decarb/steam clean. could be the starter wasnt cranking fast enough. etcetc

biggingers87

Thanks guys.

I will phone the garage tomorrow and ask them for more specific details.

Just to confirm, and further to RIWWP's post above, I should be asking them for the following readings:

Front rotor: Face1, Face2, Face3
Rear rotor: Face1, Face2, Face3
Crank speed: RPM

I'm wondering if they would actually know what is causing the poor compression?

I'm a complete n00b when it comes to items under the bonnet I'm afraid

RIWWP

iTrader: (2)

No, you can't really know what the compression loss is caused by for any particular motor unless it's taken apart. Perhaps it could be something obvious if you get in there with a borescope, but usually it's tolerance changes in the tenth of an inch or less, and that is hard to see, even if it's in the apex seals. If it's in the side seals, you have zero chance.

Old Rotor

My compression was all so improved from decarbon cleaning with Seafoam. Then premix after that.

nycgps

iTrader: (1)

if it's just 1 chamber low, it's most likely side seals. if it's 2. then it's most likely Apex. if it's 3. it could be both + worn out housing.

but yea, u gotta open it up to know for sure.