Jump to content
Sign in to follow this  
sanyantho

74 620 L18 burning oil

Recommended Posts

Hi Guys,

      Once again Im in need of help. My 620 has been burning a lot of oil lately, I did some research on this forum, but havent came up with a solution. Here is what know so far. The cylinder is not leaking, there isnt any white or blue smoke coming out the tail pipe, the vent from the crankshaft to the pvc value is connected, the hose from the value cover to the air filter is clean and opened. Is there anything else I should check? I am not a mechanic, but I have manage to get my little truck running from the help of members of this website. So any help is greatly appreciated.

 

Thanks in advance

Sanyantho

Share this post


Link to post

Exactly what is a lot?  A quart every couple of thousand miles? More? less??

 

Lets assume that it isn't burning any oil. What's left?..... Leaking. Get a sheet of cardboard and slide under the engine for the weekend. Check Monday. Got any drips? front? one side? rear near the transmission?

  • Like 1

Share this post


Link to post
24 minutes ago, datzenmike said:

Exactly what is a lot?  A quart every couple of thousand miles? More? less??

 

Lets assume that it isn't burning any oil. What's left?..... Leaking. Get a sheet of cardboard and slide under the engine for the weekend. Check Monday. Got any drips? front? one side? rear near the transmission?

Losing a quart every 100 miles or so. I will get a cardboard and slide it under the engine for the weekend.

 

Thanks

Share this post


Link to post

A qt every 100 you should be able to see the underside of the car wet with oil. The cardboard will give you a starting place to start looking on the engine.

  • Like 1

Share this post


Link to post

If it was burning it, that would be about a 16:1 ratio, like a 1960 Homelite chainsaw.  You'd notice it for sure.

  • Like 1

Share this post


Link to post

leaks oil or it don't. look under after parking. I alwasy pick a clean parking spot then ck later on for leaks. I had a water leak and was lazy to actually ck where it was coming from blaming the Chinese 3 core radiator. But radiator is far fwd and leak was more aft. notice water pump area. I tighten the bolts down and now no leak

 

smokes a lot or it don't ck the pipe for excessive oil.

 

I had a leaky motr and it was the oil sender diaphram dripping out out then running to the back making it look like a rear seal

  • Like 1

Share this post


Link to post
2 hours ago, bilzbobaggins said:

Does the oil seem like it is has a lot of fuel in it?

The oil does smell like fuel.

 

Upon further inspection, there is a fair amount of white smoke coming out the tail pipe during acceleration. The cardboard is clean, no oil leak from the engine. I will check the tail pipe for excessive oil.

 

Thanks guys!

Share this post


Link to post
13 minutes ago, sanyantho said:

The oil does smell like fuel.

 

Upon further inspection, there is a fair amount of white smoke coming out the tail pipe during acceleration. The cardboard is clean, no oil leak from the engine. I will check the tail pipe for excessive oil.

 

Thanks guys!

 

Is it really thin?  Watery almost?  Could be a bad fuel pump leaking fuel into the oil.  I know you have a weber.  Not sure what could come loose in one and leak fuel into the oil.  I had a jet roll loose on my b210 with a stock carb.

  • Like 1

Share this post


Link to post
6 hours ago, bilzbobaggins said:

 

Is it really thin?  Watery almost?  Could be a bad fuel pump leaking fuel into the oil.  I know you have a weber.  Not sure what could come loose in one and leak fuel into the oil.  I had a jet roll loose on my b210 with a stock carb.

A bad fuel pump leaking fuel into the oil, would not cause a loss of oil, would it?

 

Thanks

Share this post


Link to post

 Any chance it's over filled with oil? Is it the correct dip stick? The crank will splash oil all over the rings or whip it into a fog of droplets that will find their way out the vent to the PCV and into the intake.

 

A quart every 100 miles is a phenomenal amount and will smoke like crazy....

 

Broken piston/rings?

Bad valve guide seals?

Bad blow-by?

 

Pull all four spark plugs. Are they all oily? or just one?

  • Like 1

Share this post


Link to post
12 minutes ago, datzenmike said:

 Any chance it's over filled with oil? Is it the correct dip stick? The crank will splash oil all over the rings or whip it into a fog of droplets that will find their way out the vent to the PCV and into the intake.

 

A quart every 100 miles is a phenomenal amount and will smoke like crazy....

 

Broken piston/rings?

Bad valve guide seals?

Bad blow-by?

 

Pull all four spark plugs. Are they all oily? or just one?

Seem to be the correct dipstick. It came with the truck when i bought it a few years ago. My oil pressure gauge light would come on when I am low on oil.

 

Piston/rings was good when I checked before I installed the cylinder heads.

How do I check for bad valve guide seals? and bad blow-by?

 

I will pull the spark plugs tomorrow to see if they are oily.

 

 

Thanks

Share this post


Link to post

Check the oil more often than letting the light tell you you are low. The warning light is to tell you you are out of oil and the pressure below about 8 PSI who knows maybe zero pressure!!!!. 

 

Remove the oil fill cap on the valve cover with the warm engine running. Hold a strip of paper over the opening. A good engine with little blow by will not move the paper.

 

 

  • Like 2

Share this post


Link to post
1 hour ago, sanyantho said:

A bad fuel pump leaking fuel into the oil, would not cause a loss of oil, would it?

 

Thanks

 

It thins out the oil into oblivion.  The more I think about it and remember, I think you would have problems with the plugs getting fouled out and it not running.  This happened to me around 22 years ago.  lol 

 

1 hour ago, datzenmike said:

Check the oil more often than letting the light tell you you are low. The warning light is to tell you you are out of oil and the pressure below about 8 PSI who knows maybe zero pressure!!!!. 

 

Remove the oil fill cap on the valve cover with the warm engine running. Hold a strip of paper over the opening. A good engine with little blow by will not move the paper.

 

 

 

 

That is close to how I check the cummings diesel motors when I am at the auction.  I back the cap off and let it set.  Then start the motor and work the throttle.  Watch for the cap trying to get blown off.

  • Like 2

Share this post


Link to post

if you waited till the oil light comes on its pretty much almost too late already.

Its going to be a oil burner after that.

 

I had a 510 that I got for 100$ and I let the oil get low and ran it out where it almost locked up. I was close to home and pushed it.

After that it was a 1 quart every 2 or 3 days

  • Sad 1

Share this post


Link to post

I call it the 'chuck engine' light.

  • Haha 1

Share this post


Link to post
15 hours ago, datzenmike said:

Check the oil more often than letting the light tell you you are low. The warning light is to tell you you are out of oil and the pressure below about 8 PSI who knows maybe zero pressure!!!!. 

 

Remove the oil fill cap on the valve cover with the warm engine running. Hold a strip of paper over the opening. A good engine with little blow by will not move the paper.

 

 

Hi Mike, It appears that I have extreme blow by. The sheet of paper over the value cover hole is flapping like crazy! What does this mean? Can I fix it or do I need a new engine?

Thanks

Share this post


Link to post
5 hours ago, banzai510(hainz) said:

if you waited till the oil light comes on its pretty much almost too late already.

Its going to be a oil burner after that.

 

I had a 510 that I got for 100$ and I let the oil get low and ran it out where it almost locked up. I was close to home and pushed it.

After that it was a 1 quart every 2 or 3 days

Hi Hainz, how long did the oil burner lasted? with a quart every 2 or 3 days? Asking for a friend! haha

Share this post


Link to post

It means worn rings at minimum.

Doesn't mean you need a new engine, just a rebuild.

If you are not going to rebuild, but going to buy a fresh engine, sell me the L18, I could use a spare one.

 

  • Like 1

Share this post


Link to post

Air out the valve cover is typical.

 

oil burner is a oil burner(still will run for years just one goes broke, I eventually pulled the motor when I stripped the car for parts. But just to let you know the main bearing was installed wrong where the bearing with the oil hole was on the cap side thus bearing not really getting oil and the motor I put 20k miles on it. So WTF you think it would have killed it from the beginning. But if your buddy works at the junkyard Im sure you can use a strainer(fuck that) get oil from  junked  cars for free. Better yet steal it from a recycle place that has 55gal cans of it and dump it in. and drive in front of a Tesla

 

One way I use to catch blow by is at IDLE pull the crank case vent.  One can just smell how bad it is or at night while the vent is open one can shine a flashlight across the area and the smoke will be more easlily seen(against the black ness).

 

One you start to increase speed the crank case vent will suck inwards.

 

If motor is new and has blow by ? then maybe the oil rings werent gapped right and they butted up causeing them to break or a gouge in the cylinder wall.

I had a rebuilt in Thailand L18 and every cyl had a line in there and was a oil burner but not as much as yours. How I caught it was I had siderafts on the with open crank case vent. at idle at Mc Donarlds in the drive thru I would smeal stink and I could see a light blue smoke against my head lights at nite coming from the hood

Edited by banzai510(hainz)
  • Haha 2

Share this post


Link to post

Peak pressure inside the combustion chamber is 300-1,000 PSI depending on throttle setting. The rings have to seal between the piston and the cylinder walls... a big job. Once worn out or damaged that's it. Pressure leaks into the crankcase and some blows out the PCV hose into the intake and is burnt, but the majority blows out the valve cover hose and into the carburetor throat and is burned. However inside the crankcase is a fog of fine oil droplets flung off and spun around by the crankshaft. Normally they eventually stick to a surface and gravity tugs in back into the oil pan. With a large blow by this mist is pulled along and ends up escaping and into the carburetor.

 

There is no cure but to rebuild or replace the engine.   

  • Sad 1

Share this post


Link to post

It would be if there are parts and machine shop receipts. Basic re-build (rebuilt head, over bore, new pistons, rings, bearings and gaskets etc.) will run $1,200- $1,500.  Lot of money for something you can't take for a test drive. Then you have to come up with a carburetor.

  • Like 1

Share this post


Link to post

If the head is in good shape, it could be very valuable. The ad makes no mention of who built the engine, and that would be important information. If it were home built, I might ask a lot more questions than if it were Rebello built. Rebello doesn't paint their engines blue though, so it's probably not one of their 2300s.

  • Like 1

Share this post


Link to post

offer 1 k   that's it.

 

plus since its a 6bolt crank you need a flywheels and a clutch package for that  t/o bearing and correct sleeve.

 

 

find a cheap L18 for a few hundred and that will bolt in with least mods

L16 even cheaper to FREE

Edited by banzai510(hainz)
  • Like 1

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.