How to check my Piston Rings?
Turbo Mini Forums

Hi all,

I just have a quick question, I bought 1330cc engine complete and was told it is in working condition, but I should of checked the condition of it before putting it in my car.

Now put in my car and I am getting a lot of white smoke on revving the engine. So I have now taken my head off to do the head gasket.

My question is I do not want to rebuild my head and put a new gasket on, and then get the same issue with white smoke? So before doing this is there a way of checking the bottom end, i.e. piston rings with the head off or will I have to take the engine out and just do a full strip down and rebuild on it? Which I wish this is not the case, as I do not have the time to do it.

I have checked my compression before taking the head off, it was reading 12.1psi on cylinder 4, 12.1psi on cylinder 3, 13.2psi on cylinder 2 and 13.2psi on cylinder 1.

All help is really appreciated.

Thanks

Bobby

Id say you have two options, strip and inspect or refit the head and redo the comp test. First dry and the with some oil in the bores, if the pressure reading is signifiantly higher with the oil, then rings are goosed. If not the problem was in the head some where.

What is the condition of the head at the moment ? Guides, valves, seats ?

"So wat we gonna do tonight Brain?"
"Same thing we do evernight Pinky!"
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Unfortunately have not opened the head up yet to check the condition of the head, i.e. guides valve and seats, I found alot of oil on the valves 3 & 4 though

inlets or exhausts

Looks like the exhaust

Bobby, Those compression. Figures are insanley low, are you sure the figures are in PSI ? If so strip the engine you may find a whole host of problems!

Ie, piston ring lands goosed! Before you just fit the engine its very wise! To strip the engine, and see if thing are what the Guy who you bought it off is correct, same goes for the head.

You may have bought an engine which has done more miles than captain. Janeways startreck voyeger, hope this is not the case but the advice I have given, is sound IMO

I would suspect a decimal point error - 120 to 130 psi is more like it !

Metric is for people who can't do fractions.

sorry just had a look at my compression tool and it is 12.1 bar (which is 185ish psi) and 13.2 bar (which is 190ish psi)

White smoke is usually water....so be clear about that.

Blue smoke is oil, and can usually be smelt as such.

What do the bores actually look like ? What did the chambers and piston crowns look like ? and the ports ?
Can you take a decent photo ?

Compression test sounds fine really, although perhaps not a particularly low compression engine ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Here are some pics of the pistons and it is defiantly white smoke not blue.

I cannot upload pics how do I do it?

http://s1308.beta.photobucket.com/user/kappa81/library/

Bad pictures and too much water

If you cannot see the cross hatch on the bore from honing, then it is quite possible the rings are not sealing correctly as far as oil usage goes. Although it isnt quite as simple as that

On the other hand....white smoke could be as simple as a lot of water lying in the exhaust and gradually turning to steam as the exhaust gets warm. This can happen if the car has sat for a while, if it was parked downhill so water could run into the silencer, if a previous HG failure dumped water into the exhaust etc etc

But white and relatively odourless ( or sweet, ie antifreeze ) is water smoke.
Oil smoke is a blue colour and usually stinks.

Fuel smoke from excessively rich is darker and again stinks and can hurt the eyes

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

bores look a bit shiney

White smoke can also be brake fluid when master is weeping and diaphragm in servo is shot and it gets sucked down servo hose. is it actually using oil and water?

I'd say not rings based on the results and colour of smoke.

For the cost of a head gasket, I'd stick the head back on. and take it for a drive.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

That is exactly what I am thinking of doing, head is going for a skim and then going to put it back together, hopefully will rectify the problem

Why are you skimming it? You can check it for flatness with a metal ruler.

I'm with Andy here, Everyone who thinks they know about engines always says 'skim the head' rarely is this needed. Head's take a lot of effort to warp.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I always skim my head when redoing the head gasket, just to get good seating to the block

no point, just clean it.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Well what I might do is give it a sand down, clean it up and put it back on then, but will check it with a metal ruler first though for warpness

Its not likely to be warped unless you have let it get seriously over heated for a good period of time.

Well I did not not, as I only have just dropped the engine in, but maybe the owner before did, but will double check it tonight though, just for my own satisfaction

also forgot to mention, cheers for the help guys