[Mk2] [Turbo] Oil seals keep failling... HELP

[Tubster]

Hi all

So I recently bought my first MR2 Turbo... good!



But it keeps getting oil leaks... bad!

When I bought the car there was a small leak coming from the sump, which I had replaced. A week later it decided to dump all of its oil in a 40 mile trip, which turned out to be a turbo pipe, which I also had replaced (it was split down the entire length!). At this point I was hoping all was well.

Not to be. Yesterday I took the car up the road to get some nice photos (pointless exercise anyway since it started raining!), and then went to move the car and noticed a pool of oil under it. I cursed my way back to the garage and it seems it's coming from possibly the cam seals now. I bought the car knowing that it was a replacement engine that had been installed and initially I felt that, particularly the turbo feed, was a used part.

However, now I'm starting to wonder if there's something pressurising the engine causing it to blow seals?

Anyone got any suggestions?

[Ryan S]

sounds just like bad luck mate, mind the car's over 20 year old now, replacement engine or not, things are gonna start to go, you could always check the oil pressure but the sump and especially rocker covers are very prone to leaking on these, sounds like it's all just hit you at once!!

[Peter Gidden]

Pressure in the lubrication system, i.e. developed by the oil pump is totally different and not linked in any way to pressure in the crankcase.

Either:

the engine is producing excessive blow-by gasses through worn bores/rings. Does it smoke? Is the cam cover breather hose connected to the inlet pipe correctly?

or

the engine has been badly rebuilt

or

as Sheppy says, the engine is old and the seals are tired naturally

[Tubster]

Pressure in the lubrication system, i.e. developed by the oil pump is totally different and not linked in any way to pressure in the crankcase.

Either:

the engine is producing excessive blow-by gasses through worn bores/rings. Does it smoke? Is the cam cover breather hose connected to the inlet pipe correctly?

or

the engine has been badly rebuilt

or

as Sheppy says, the engine is old and the seals are tired naturally

I'm hoping it's been badly installed! It does smoke a little, but nothing that would seem unusually bad (and it smokes less once warmed, again, nothing unusual). I've checked all the breathers and they seem okay (ie not blocked) and appeared to all be connected okay.

If it's piston rings...

But from what you've said the sump seal is independent and can be discounted. What about the turbo feed pipe going? Could that be as a result of pressurisation due to the piston rings? And how does that actually manifest itself, surely you'd just get a bit of a loss of power if the piston rings aren't properly sealing in the bores? I'm more used to messing about with 2-stroke motorcross engines than car engines in all fairness...

[Peter Gidden]

What about the turbo feed pipe going? Could that be as a result of pressurisation due to the piston rings? And how does that actually manifest itself, surely you'd just get a bit of a loss of power if the piston rings aren't properly sealing in the bores? ...

The turbo oil pipe is fragile compared to many engine components and needs to be handled with care if removed. I've known a couple fail naturally over the years, but it's demise could have been assisted by an unknowing, hamfisted mechanic.

As i said, oil pressure has nothing to do with crankcase pressure. You will get a small loss of power, but where are the gases that are getting past the rings going to go? They are escaping past the rings at about 800psi so soon fill the crankcase...

[Tubster]

Thanks for your help Peter! And fair enough, is there a pressure test that can be done with the piston rings or is it a case of get the head off and inspect them by eye?

[Peter Gidden]

is there a pressure test that can be done with the piston rings or is it a case of get the head off and inspect them by eye?

A compression test will give you a good indication. A leak down test would be better.

[Ryan S]

Thanks for your help Peter! And fair enough, is there a pressure test that can be done with the piston rings or is it a case of get the head off and inspect them by eye?

you can compression test using a er..........compression tester, very easy to do. shold only take half an hour tops too.

[Ryan S]

snap!!

[Tubster]

Thank you all! If I tried to pressure test the cylinder in my Honda motorcross 2-stroker, I'd end up cracking the plating since the tolerances are so tight and the piston is basically seized in the cylinder unless you warm it up first... hence the (noob) question. Will report back.

[Ryan S]

Thank you all! If I tried to pressure test the cylinder in my Honda motorcross 2-stroker, I'd end up cracking the plating... hence the (noob) question. Will report back.

take off all the HT leads (obviously don't mix them up) take out spark plug of the cylinder you want to test, screw in the tester, then crank over, you can't really go long unless you cross thread a plug or the tester


post back your results, these engines are solid mate, if it's a problem with the rings i;d be surprised, having said that, nobody knows the history or what a previous owner could have done (ran 2 bar of boost etc).


good luck

[Tubster]

Thank you all! If I tried to pressure test the cylinder in my Honda motorcross 2-stroker, I'd end up cracking the plating... hence the (noob) question. Will report back.

take off all the HT leads (obviously don't mix them up) take out spark plug of the cylinder you want to test, screw in the tester, then crank over, you can't really go long unless you cross thread a plug or the tester


post back your results, these engines are solid mate, if it's a problem with the rings i;d be surprised, having said that, nobody knows the history or what a previous owner could have done (ran 2 bar of boost etc).


good luck

The joys of having people in the know Just got to acquire said tester. Will report back.

If normal, is it just a case that I've been unlucky and the seals are all going at the same time?

Incidentally, what would be an abnormal reading? Less than 100psi?

[Peter Gidden]

Corrected for you.

take off all the HT leads (obviously don't mix them up) and take out all the spark plugs. Also take out the EFI fuse so you're not injecting neat fuel into the bores.

Crank engine with WOT each time you test.

[Tubster]

Corrected for you.

take off all the HT leads (obviously don't mix them up) and take out all the spark plugs. Also take out the EFI fuse so you're not injecting neat fuel into the bores.

Crank engine with WOT each time you test.

Thanks! Didn't even consider flooring the throttle.

[Ryan S]

Corrected for you.

take off all the HT leads (obviously don't mix them up) and take out all the spark plugs. Also take out the EFI fuse so you're not injecting neat fuel into the bores.

Crank engine with WOT each time you test.

whoops!!! yeah sorry mate, take out the EFI fuse and WOT

[Tubster]

Final question on this, would it be wise to run the engine with EFI taken out until it stalls to get rid of any residual fuel or is that not how it works?

[Peter Gidden]

Final question on this, would it be wise to run the engine with EFI taken out until it stalls to get rid of any residual fuel or is that not how it works?

No need.

[Ryan S]

you won't have any risidual fuel mate, if that was the case, your car would be flooded everytime you turned the ignition of, what you;re thinking of is carbs with a solid state fuel pump, you must be old school

[Tubster]

As stated previously, I play with motorcross engines as that's what's in my Superkart with accompanying carb and mechanical fuel pump But obviously the fuel pump here is electrical and the disconnection of the EFI fuse will prevent any and all fuel being pumped into the cylinders I guess?

(learning here guys bear with if I sound stupid! This is only my 3rd car and as a 22 year old I've never had to play with car engines before... I didn't really want to start now but there you go!)

[Peter Gidden]

But obviously the fuel pump here is electrical and the disconnection of the EFI fuse will prevent any and all fuel being pumped into the cylinders I guess?