Piston rings shot :(

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Feb 04, 2014 12:27 pm

Just curious... Am I remembering right that it's an A8 that's gone in @106pete's mates lude? And was that with similar symptoms?

Rv_t · Post by **Rv_t** » Tue Feb 04, 2014 12:52 pm

Mine is smoking and loosing oil at high revs

Supercharged 無限MUGEN BB1 Profile · Post by **nucleustylzlude** » Tue Feb 04, 2014 1:31 pm

I wouldn't be scared into replacing an engine just because some guy in a garage has said your piston rings have gone because you told him you're losing oil. Seems an extreme option before actually diagnosing what / if at all the problem is.

VTEC engines, especially older ones like our H22's like to burn oil, especially in VTEC. Doesn't mean you need to replace the engine in a rush.

As suggested, if you're concerned take it to another trusted garage and get them to perform a compression test and leakdown test. They'll tell you how healthy the engine is then.

Rv_t · Post by **Rv_t** » Tue Feb 04, 2014 1:56 pm

I mean the guy I've known for a long time and he did do a compression test...don't know if he did leak down though...he said he can do piston rings but there is a hood chance they will go again because of worn bearings ....? Sorry I'm nit great with engines

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Feb 04, 2014 2:04 pm

No worries about not being great with engines - no need to appologise.

Bearings have nothing to do with rings though.
If the bores were worn/scored, that could wear new rings out again fairly quickly.

I seem to recall the way you can definitively test if it's piston rings (as opposed to something else) is do the compression test on the engine 'as is', note the readings for each cylinder, pour a bit of fairly thick oil into the cylinder, then re-test. If the compression has significantly improved, then it's rings. If no change, then it wasn't rings causing low compression.

Did he say all cylinders were down on compression, or just some?
There are different levels of compression on H22 engines, depending on what exact model of engine yours is. Was it definitely checked against the correct standard?

What's the service history like on the car? Any history of oil change intervals being over-run?

Rv_t · Post by **Rv_t** » Tue Feb 04, 2014 4:04 pm

Hi mate the device history is great and the compression was down on only some pistons is what he said. And I think it was the bores he thought could be scored that would cause the rings.to go again

Supercharged 無限MUGEN BB1 Profile · Post by **nucleustylzlude** » Tue Feb 04, 2014 4:31 pm

Right...what were the compression test results - can you ask him?

Numbers can vary depending on the test equipment, the way you do the procedure and what engine it is. Plus there is a Honda service limit in the variation between cylinders, so there is scope to be out a little on some cylinders. I've yet to see someone with consistent pressure across all four cylinders.

When you find a cylinder (or more) down on pressure its finding out where that pressure is going. Up into the head of the engine through the valves or down into the main block past the piston rings. Or worse...headgasket - but that would be more obvious in other ways (don't freak out!

). The wet test by adding the oil into the chambers is to help seal the piston rings, redo the test and see if the compression improves = rings. If it doesn't improve = valves/seats,etc.

But all that to one side, a leak down test will show a better picture of a loss of pressure and is the test he needs to do to back up the thought of a new engine. A leak down test requires more specialist equipment and measures the pressure of each cylinder over time. It will let you know how badly the loss is compared to a compression test.

Hope that helps you out. And please don't apologise for lack of engine knowledge - we're here to help bud.

106pete · Post by **106pete** » Tue Feb 04, 2014 5:29 pm

My friends was drinking a lot of oil at hi rpm, and left huge clouds of smoke and a constant taste of oil to the driver behind!

We did a compression test ages ago and found it to be quite good and tiny but better with oil in the bores, but compression rest doesn't check the scraper ring as that's what should be stopping the oil! Most seize in position and stop doin there job and start to smoke.

We finally decided to do the rings as it suddenly got a lot worse and found one cylinder is scored.

If this guy is just a general mechanic he may not know abit the frm liners and possibly used the wrong honing stones/strokes, this could put the cylinders over tolorance and smoke. Did he fit genuine honda rings? Aftermarket items are not recommended.

If new rings have failed so soon then there's obviously more of a problem, either a new block or complete engine will be your cheapest option from the sounds of it.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Feb 04, 2014 5:38 pm

nucleustylzlude wrote:The wet test by adding the oil into the chambers is to help seal the piston rings, redo the test and see if the compression improves = rings.

I was sure I was right on that one, but having not actually done it myself (only done compression tests) there was that little bit of doubt...

nucleustylzlude wrote:a leak down test will show a better picture of a loss of pressure and is the test he needs to do

Don't know why, but I hadn't heard of a leak down test before today

so had a look at good ol' eric the car guy

Obvious really, dunno why I didn't know it before

(BTW my guess as to why he didn't hear air rushing out with the leak down tester attached to cylinder 6 in comparison to having the air line straight on it, is because the leak down gauge restricts the flow rate and with no back pressure from the cylinder, the flow is so low that you can't notice it

)

Rv_t · Post by **Rv_t** » Tue Feb 04, 2014 6:35 pm

Ok I've asked for results of compression test and will post - out of interest which engines will fit straight swap with no hassle??