Can I Save the Old Girl?

[67rway]

I am having issues with my A4, which I picked up a few years ago from a guys shop floor where it presumable sat for several years. I did many of the key upgrades after firing it on the a roll around dolly, including plugs, a carb rebuild, elect fuel pump, resealing valve cover plate, elec ignition, polishing filter, and a general cleaning/painting.

She fires up 100% reliably, runs up as high as 2200 rpms(if only when needed), idles well, and pulls strong. The issues I'm having are:
- excessive blowby smoke via crankcase vent, so much so that I've routed the breather hose into the full time blower intake (no Indigo PCV... yet)
- fouls the #4 spark plug after ~20 hours; enough for a slight miss
which is solved by a plug cleaning or replacement
- slight undiagnosed oil leakage (which I believe is from my improvised fuel pump block plate
- oil pressure which drops from 40+ to below 10 after 1.5 hours of constant 1800 rpm
- Comp of #1 - 140, #2 - 130, #3 - 130, #4 115. Number #4 went to 160 wet.

I have gone through a few different episodes of MMO in all cylinders over the last couple years, and am doing another now.

My gut says she may still have stuck rings in cyl #4 which may be the entire cause of the blowby, and may still be freed up with MMO. But can't come up with any answer other than bad bearings for the reliable oil pressure drop over time.

Am I missing something?

I figure one more go at this one before I pull her.

Thanks,

[sastanley]

Those compression numbers seem a little bit out of whack.. (i.e., too high).
If it runs like you say, of course you can save her..if the rings are inexplicably stuck it might mean a ring replacement. I've had a bit of trouble with oil pressure too in the past. It could mean oil passing thru the oil rings.

Is the #4 fouling with oil?? I had a #4 that didn't want to fire, but mine was a valve issue..lots of MMO for lots of hours freed it up eventually..I toss a bit of MMO in the gas too...although Dave Neptune likes a good high quality 2-cycle motorcycle oil..if I run out of MMO, I may try his suggestion just to see if it is better or worse, but I've had good luck with MMO and I still have at least 2 quarts in my bottle.

[HalcyonS]

seafoam time?

Did you try a seafoam treatment?
I don't hear about it much on this forum but others rave about it - for unsticking valves and rings etc.
I ran it in to my fuel line via a T right before the carb.
I metered it in - as much in the gas as possible - just keeping from stalling.
Do this right before an oil change - you've got to get rid of the crud it dislodges

[marthur]

Dave Neptune likes a good high quality 2-cycle motorcycle oil

And I have used my 2 stroke outboard oil very successfully. In fact, for many years I have dumped the last of the dinghy gas into the tank at the end of the season for exactly that reason.

[Marian Claire]

What steps have you taken to help the oil pressure? Have you adjusted when it drops to 10 psi, removed and cleaned the adjustment unit, tried a higher viscosity oil, tried the old "cone" style pressure adjustment?
Dan S/V Marian Claire

[romantic comedy]

BTw, if you want to try a PCV, no need for a kit. Just use the vacuum from the tap in the manifold. Screw in a hose barb and get a PCV valve from auto supply.

[sastanley]

Halcyon...I love to fog my motors with the spray Seafoam! They smoke a bit in the spring, but it is my favorite 'fogging oil'.

I just finally did the oil change and winterization this past weekend...in a few weeks, I'll go down to the boat with a oil can and squirt some MMO in the cylinders and then spin it around. I try to do this once or twice over the winter to keep things loosened up and avoid sticking.

[Dave Neptune]

Very Important

romantic comedy, absolutely not all PCV valves are the same!!!!!!!! Bleed and volume quantities as well as the vacuum settings of the valve itself are very different!!!!!!!!!!!!!!!!!!!!!!!

DO NOT JUST GRAB NY PCV as you will likely not get the right match!!! Go to Indigo to get the proper valve for the A-4 or match the Indigo part numbers up if you have one!!!!!!

Dave Neptune

[JDK]

Crusty old motors with sticky valves and stuck rings and blowby have a friend.....

[romantic comedy]

romantic comedy, absolutely not all PCV valves are the same!!!!!!!! Bleed and volume quantities as well as the vacuum settings of the valve itself are very different!!!!!!!!!!!!!!!!!!!!!!!

DO NOT JUST GRAB NY PCV as you will likely not get the right match!!! Go to Indigo to get the proper valve for the A-4 or match the Indigo part numbers up if you have one!!!!!!

Dave Neptune

I agree Dave. I was just focused on the vacuum take off.
Thanks for the follow up.

[67rway]

Great Feedback

Many thanks to all for the great input.

The plug #4 symptoms show up feeling like an imbalance issue after a 8-10 short trips out/back, and the plug is darker/wetter than the other three. The easy fix is to clean/swap it perdiodically, no big deal.

The comp test figures do seem a bit high, perhaps due to my method (warm, throttle wide open, crank 5 times) perhaps my tester, or maybe carbon build-up. I don't know. The only thing which worries me about it is the variation, and fact that I get such a lift in #4 wet.

I have been running 40w diesel oil in her for the last couple oil changes, but no 2-stroke or Seafoam. Things to try...

I should really try the Indigo pcv system to process the blowby fumes, but still can't come up with a rationale for how it might contribute to my biggest issue; oil pressure dropping on a cruise-type trip. Yes, I have replaced the oil pressure valve, and still find I need to bump it up a couple of times on a long 7-8 hour trip. By the way, she does tend to run progressively warmer as this occurs. Any chance combustion gasses are causing oil pressure drop and a 15-20 degree increase in op temp?

[romantic comedy]

That is the way you are supposed to do a compression test. You just crank until the gauge stops going up. (yes, warmed and full throttle)

[sastanley]

67, I found that multi-weight oil helps a lot with dropping oil pressure on long trips.

I am running Rotella 5w-40 synthetic HD turbo diesel truck oil presently. I am hoping that this oil will give me slightly lower start up pressure than the Rotella 15w-40 did, which a lot of us here also run.

Don Moyer feels that as long as you have 1 PSI of oil pressure per 100 RPM, (i.e., you can maintain 20 PSI at 2,000 RPM), you are safe..I was getting close to that, so I started experimenting with oils and I also got the Indigo Oil filter kit with 'remote' pressure regulator..There tend to be issues with the late model ball style Atomic 4 oil pressure regulator, so I gave the the Indigo kit a try and it's worked well.

Also, I have had good luck with the Indigo PCV system, but readily admit it is a stop-gap measure to re-route crankcase oil fumes from probably old worn out rings out the exhaust instead of into the cabin via the crankcase vent/slash tube. One day I'll have to break down and rebuild the motor.

[Marian Claire]

" I have replaced the oil pressure valve, and still find I need to bump it up a couple of times on a long 7-8 hour trip."
Can you give more info on this. Are you adjusting on the fly and seeing a temporary increase in pressure? Do you make any adjustments between trips? Do you have the ball/spring or the cone type? Did you dress the seat when you replaced the adjustment parts?
Dan S/V Marian Claire

[67rway]

Yes, the diesel oil I've been running is 15w-40, not the 40w previously mentioned (winter air travel to blame!). I could see going thicker, but not sure how a 5w-40 would help.

As for the oil pressure adjustment questions:
- I am running the cone type adjuster, but did not see any apparent deflection in the seat, so I did not perform the dress procedure. Is popular wisdom that it might account for oil pressure dropping over time?
- our last extended trips required anchoring (we're river sailors) when we started bumping up against the fuel pump cut-off, and dialing up the oil pressure to a reasonable level(40 psi for a buffer) twice, and opening up the engine bay inside the boat to increase air flow and seemingly decrease temps. One of the two times in these longer 7-8 hour upstream trips I have to swap/clean the #4 plug.

The 'admiral' thinks I'm nuts...