Spark Plug Oiling Up 1937 Terraplane 6 Cyl

broughsup

I had an issue some  time ago with No 6 Plug oiling up. I had 3 ring pistons at that time and have now fitted 4 ring pistons (now bored out to +.040). I still have the same problem with No 6 plug - after about 200 miles. There is an excess  of oil in that cylinder compared to the others but as all cylinders were bored exactly the same and new, old stock pistons, used there should be no difference.  Has anyone out there got any ideas as to what may be causing this problem??

I also have an issue with the valve faces becoming pitted. I have new old stock valves and hardened inserts.

broughsup

Thanks Ken for the help.

I have not yet removed the sump but had thoughts along that line. Would there be some way of detecting an overfull dipper tray and some means of rectifying the problem?  The valve guides were replaced some time ago and are in good condition. The engine has done about 4000 miles now but the plug oils up very quickly.

I will check the tappet clearance, which I will have to do when cold at this time. I do have suspicions regarding the carburettor. At present I am using a Rochester and have previously used a Stromberg and am looking for the correct Carter. The engine is running hotter than I would expect and I am getting 16 - 17 mpg. The other spark plugs are all white.  I have had popping out the exhaust but cannot find any air leaks and a vacuum test seems to show reasonable results.

The valve pitting is only on the exhaust valves

Glowplug

There are some tests that are simple to complete and will provide vital information. The following link is to
my Hudson website.
http://hudsonrestoration1948-54.com/
Go to the page and select Engine on the left side of front page. On that page go to the link at the bottom of the page that is entitled ... Vacuum testing.

Good luck

Frankvintagefullflowcom

The drain tube at the rear main provides a path for oil to return to the reservoir after it has passed through the rear main bearing. Oil from the front of that bearing simply runs into the dipper tray but, to the rear, it must have a drain hole. If it isn't open, it will become immediately evident in the form of a puddle on the floor.

Splashers have no rear main seal so it doesn't take much accumulation to fill the slinger cavity behind the bearing and escape out the annular space betwixt the crank and block/main-cap. In any case, that hole, plugged or not, has no influence on the level of oil in the dipper tray.

Which is to say, that's not your issue here. What is, is still a mystery but I doubt the dipper tray oil level is it.

F

Frankvintagefullflowcom

Bingo.

Frankvintagefullflowcom

"The valve guides were replaced some time ago and are in good condition."

Is this something you actually witnessed?

At the risk of insulting anyone (when has that ever stopped me) Are you certain that it's running on all 6? Is the "popping" in the exhaust a regular tempo or intermittent? Did you personally install all of the components you've mentioned?  Even a worn guide in a side-valve engine won't inhale much oil. Any chance the #6 bottom oil ring got broken upon installation?

F

broughsup

Thanks for all the comments.

The oil control rings are cast iron  -  They are NOS "Ramco" brand with a inner band behind the ring and a narrow steel ring below the cast iron ring. 

I will remove the sump and draw out the No 6 piston and check the rings and bore and try to determine the oil level in the dipper tray.

The engine is firing on all cylinders and I'm certain there are no cracks in the block. I will remove the rest of the valves and clean up the faces on the Exhaust Valves and refit.

I will then address the carburettor issue  -  Is the Carter WA 1 carb a good option or would a somewhat more modern Stromberg be a better option.?

Thanks Ken - I am in contact with Chief Guru Geoff quite regularly.

broughsup

Yes it is a single barrel

Trevor J

Hi there.  I live in NewZealand and have a 37 Terraplane coupe.  I had issues with my Carby and have replaced the original with a Tillotson carby which was a generic after market one available for many 30s cars.

I was able to by a New old stock carby for $10.00  + postage.  They bolt straight on with no alteration.  The model you want is a YR2.  you see them ranging from $10.00 to $120 US on ebay.  The beauty of them is that the main jet is adjustable which makes tuning a breeze.  I am sure that many will say get the original however it has worked for me and is very cost effective.  I have done the same conversion on one of my Nash cars with equally good results.  Worth a try.  Trevor

broughsup

I will keep an eye on Ebay. The NOS ones are US $100-00 at the moment.  Many Thanks

Trevor J

To be fair that is still cheap.

Trevor

KTRON

As others have mentioned, your engine simply might not be broken in yet. Do you know what type of rings you used? If the compression rings are chrome your engine may be smoking for a good while before they wear into the cylinders sufficiently. Carbon rings wear in almost immediately after initial startup. Put about 500 loaded highway miles on the engine. If the engine quits smoking, the rings have started to break in and wear to the cylinder. If smoking continues, you still have a problem!

Do you have a scope that you can put through a plug hole to see the condition of the cylinders?
I'd pull all 6 plugs on a cold engine and turn the engine over a number of times with the starter to compare the amount of oil present on the top edge of the piston(s), and on the cylinder wall(s). Typically a cold engine will not push oil past a valve guide, before past a broken or bad oil control ring. Alternatively you can test the valve guides simply by running the engine. If you hold the engine at medium to high throttle for a minute, (allowing the valves to get nice and hot - swelling in the guides) and then decelerate, the valve stems will cool rapidly. If the exhaust becomes blue or hazy on deceleration the engine is burning oil from worn valve guides. If the exhaust is hazy on acceleration the engine is burning oil from bad rings.

My guess is that the oil control ring on #6 is bad, or that cylinder is more out of round than the others (poor ring seating) Do you happen to know if the engine was bored over with a boring bar, or enlarged with a rigid body hone?  I seriously doubt that the engine has pressurized wrist pins, but if it does i'd check them, they are a common problem with the two-cycle diesels I play with.

As a hobby I rebuild and restore old gasoline/diesel engines - air cooled, condenser cooled and liquid cooled. I havent worked on a Hudson engine as of yet, but have worked on other flathead and overhead valve gas engines of that period. The above should hold true for your Hudson engine,

Chris

broughsup

Update - I have not yet taken No 6 piston out. I have measured the amount that the engine slants from front (high end) to back. The angle is 3 degrees with the vehicle on flat surface. this gives a fall of 30mm (1 1/4 inches) front to back.

I set the sump up on the bench at the same angle and poured oil into the dipper tray. I note two issues  -  1, using cold oil, the oil level builds up in the dipper tray and is very slow to dissipate through the screen on the centre hole back into the bottom of the sump.   2, When the oil does drain back to the sump  the remaining oil level in No 6 dipper trough is approx 6mm (1/4 inch) higher than No 5 and same again for No 4. As a result I have measured that No 6 bearing cap and the bottom of the crankshaft would be splashing into the oil at least by 6mm and  probably more as oil is feeding into that dipper tray from the oil pump. This no doubt would slosh a whole lot more oil around that region of the engine.

Should the engine be sitting level.?

Should I remove the strainer from the centre drain hole of the dipper tray?

I should mention that the car is a Brough Superior  -  An English built body on Terraplane chassis and mechanicals with some changes to lower the suspension

Geoff

Under normal running conditions the oil level will regulate itself due to the action of the scoops.  The oil is fed in  the front and rear of the motor, and  runs back  via the cut-out in the centre of the tray assembly.   I doubt that the angle would make any difference, although it may pay to check your rear engine mount.  

broughsup

Further Update

Thanks Geoff. I am tempted to remove the screen in the oil return hole in the centre of the dipper tray.  -  I want to stop this digging but how else do I get to the bottom of this?

I have taken out No 6 piston and find all rings and bore are in good condition.