Attention 18r-g gurus!

[iTz InSaNiTy]

Hi everyone,

My 18R-G engine in my RT104 is spitting oil out the cam cover breather and the crank case breather as well. It's amking a really good mess of my engine bay and a warm surprise for Mr Piggy!

Any ideas on how to stop this?

I understand that fumes are supposed to come out these breathers and I have uni filters on them, but I'm talking about so much oil coming out them that it fills up the top of the cam cover with oil and dribbles oil down the back of the engine and onto the road! Not to mention the crank case breather getting oil sprayed everywhere by the radiator fan.

Thanks,
Stephen

[Silly Rabbit]

Run pipes into a big catch can in the mean time......and then possibly rebuild cos it sounds terminal.....what's the compression like and how old / flogged out is the engine?....has it only now started doing it or has it got progressively worse over time?

I know when my 3T was blowing a lot of oil it was cos the engine was shagged and the ring lands had broken on a couple of the pistons and was pushing oil out.

[iTz InSaNiTy]

Thanks for your quick reply =D

Hmmm more money... so sick of spending money on this engine... 182, 195, 180 and 185 were the compression test results 3 months ago. It made 102RWHP on the dyno... still goes just as hard. It's been progressively been spitting more and more oil. The head had a full rebuild one year ago, we never touched the block. At $1000 for a set of pistons... I may as well just buy another engine...

Any other ideas why it might be doing this?

[Silly Rabbit]

Well the compression figures seem good........mine had nil compression on 1 cylinder and low on 2 others so was pretty easy to see why it was blowing oil

Blow by or pushing oil out the breathers etc is usually caused by low compression so seems strange that yours has reasonably good readings. You may not need to buy new pistons if the cylinders only need a light hone and a new set of rings. Did that to my engine and she is back to putting out 80rwkw so doesn't need to be mega expensive.

[airfireman1]

Check that the PCV valve is not blocked as that can cause the sump to pressurise and push oil out of the breather

[roadkill]

seconded for the pcv valve. It should let excess air out of the crank - crank case breather. If your unsure it's working just take it off all together and direct the air to the inlet manifold as it should be.

bEn

[o_man_ra23]

Mine did very similar when I tried ripping the top off two pistons. Didn't have the side breather, just the cam cover item, and it filled a catch can and sprayed the engine bay in half an hour's driving...

From memory the 18R_G PCV is an external item though. I've never seen one in the flesh, and only ever had the hose plumbed straight into the intake for any of my good engines, and never had a problem with oil until broken pistons...

Re-check your compression. Very simple test, and a gauge from Superthief will be accurate enough.

[roadkill]

pcv valve sits on the inlet cam cover. factory at least anyway. But yes - most people just have a hose going from the breather to the inlet.

bEn

[Rodger]

I also suggest the PCV valve is a cause. If it is blocked then air pulses in and out of the breather pipe on the cam cover. I thought the PCV sat inline with a pipe from a fitting/plate on the inlet side of the 18R blocks?

If you have no PCV in place then you can not stop the breather pipe having oil and fuel fumes come from it. Even a good motor has blow-by and air pulses from the crank and rods swinging around.

The PCV is designed to extract oil and fuel fumes from the engine block and send it into the intake to be burnt. The cam cover pipe is there to let fresh filtered air into the block to be drawn through picking up the oil/fuel fumes and out the PCV.

Regards
Rodger

[iTz InSaNiTy]

Thanks for all the replies... I didn't notice a PCV valve last time I was tinkering with the engine? Are you sure that the 210 head (earliest 18R-G) has one? I didn't like the idea of running hoses back into the intake, hence the uni filters...

[o_man_ra23]

Unifilter is illegal. By law you must run it back into the intake, however the amount of oil you are describing is more than it should give out.

[ian]

a new pcv valve is not expensive
run it from the connection to the inlet manifold
if you have a close look at the inlet manifold you will find a few points where it can be connected
some people buy the little filters and fit them on the valve covers just coz they look racy
not knowing that it can cause problems with pressure build up

[supra2]

It does sound like a broken piston or ring.
I have had one 18rg pop the welch plug out the back of a cam shaft, flooding the head faster than it could drain giving same problem youve decribed.

[iTz InSaNiTy]

We ran the two breathers into a catch can and drove it hard for 5 minutes and then opened the bonnet... About 500mL of oil was in the catch can and looks like even more was sprayed over the firewall and steering box where the hose fell off the crank case breather... Looks like it's REALLY screwed now . I think that supra2 is the correct one. Only thing is the car still pulls hard. What compression test results is a 9.7:1 compression 18R-G supposed to have? I would have thought 200+psi across all four? Maybe it's never had good compression and that's why it feels like it always has? Is 102RWHP is a bit sad from an engine that has had a recent full head rebuild, with oversized valves, and reground cams that are really really lumpy and only wakes up at 5000 rpm? Looks like I'll need to rebuild the bottom end? I'ts currently an 18R-C block with high comp pistons in it... the timing case at the front is all cracked from where the engine was in an accident.

If I was going to rebuild a block, I would want a genuine 18R-G with no front damage. Anyone have one to suit rebuild in NSW?

[supra2]

It only takes a small crack in a ring land to create enough crankcase presure to hold the oil in the head, even worse if its running high revs.
If its still only a crack, it will hold good compression so the performance may still be good, but not for much longer.
If you pull it apart now, it may save the block from a rebore if its not scored.