Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

AJK

B&S 326431-0190-01 16hp smoking

Recommended Posts

AJK

rebuilt this engine, cyl. bored, new piston, new rings, new breather, new hose from breather to carb. idles good, but at more than 1/2 throttle blows lots of smoke and fouls the plug. Took head off and it's soaked with oil from intake to center of piston. Rings are good. could it be sucking oil past intake valve? if so now what? Thanks for any and all help.

Share this post


Link to post
Share on other sites
MikeES

As Chris727 stated if ring gaps are lined up, and or too big a ring gap.

Even with bad intake valve guides, there would need to be excess pressure in the crankcase to push a lot of oil out the guide, especially at 1/2 throttle (carb open, which has less vacuum at the intake valve).

Synthetic oil? If so may have prevented the rings from seating, more blow-by into crankcase.

Breather working/assembled correctly? Could also create excess crankcase pressure.

Share this post


Link to post
Share on other sites
Mike_H

Kinda...You can get a service replacement valve guide, but if I remember correctly, you have to ream the block, then press the new ones in. I did it to mine, but its been a couple years, and the memory is a little foggy.

Share this post


Link to post
Share on other sites
powerking_one

Art,

Your "new" crankcase breather/disk check valve could be defective letting oil fill up in the valve spring cavity and the carb sucking it in through the breather tube and carb. Also on some engines it's possible to install the breather upside down where the oil drain holes are NOT facing down.

Tom (PK)

Share this post


Link to post
Share on other sites
AJK

Sounds like I would have to have someone redo the guides not a DIY for me. Piston ( .020 over ) and rings was from B&S. Breather could only be on one way so the hose will go to carb. Had it apart again rings in right, none broken, gap good, piston and rod in the right way, waiting for a head gasket. been fooling around on and off for 16 mo. about ready to give up and put it on the block cheap^

Mike it may be the same as your 1977 It's a 7016H 16900006 engine 326431-0190-01

Share this post


Link to post
Share on other sites
theniteowl

I am not familiar with this engine. Does it have variable valve timing?

If you run at half throttle does it still leak oil into the cylinder and foul the plug?

If the oil is pulling in through the valves then the chamber there should have a significant amount of oil in it. If it is pulling past the rings only then there should not be much oil around the valves right? I could be wrong, only beginning in rebuilding these engines.

If I am correct then that can give you a clue as to where the oil is getting through.

How does oil get past the rings? Doesnt it require excessive crank case pressure due to leaky valves or would leaky rings on the compression stroke be enough to push oil through on the down stroke?

One thought and anyone who thinks this is a bad idea please speak up.

If you took the cover over the valves off the side and cranked the engine there would not be enough suction for it to pull any oil out of the crank case through the valve guides.

Just thinking up tests that might give more clues if my assumptions on how the engine works are correct.

Share this post


Link to post
Share on other sites
AJK

it's all splash oiled by the time you get the breather off to see the valves all the oil has run down the 5/8" hole to the sump.

I'm thinking of making a clear cover for the breather so I can see what's going on.

Share this post


Link to post
Share on other sites
Mike_H

Art, my date code is 011177. I remember cuz it's the same as my wife birthday. When you measured your bore, did you take multiple measurements? Maybe it's out of round, and your forcing oil past the rings that way?

Share this post


Link to post
Share on other sites
BLT

Do you have a dipstick oil fill and if so is it tight fitting. I had a similar problem last year with a 10 HP vertical. The long and short of it was the dipstick fill cap bobbing up and down disrupting the balance and letting the oil pour out the breather. I held the original stick down running , no problem , released the pressure on the stick and the oil would eventually find it's way out the engine. I purchased a new stick and fill tube, installed it and now no problem. And it really drove me nuts for couple of weeks and it just by chance I saw the dipstick doing its thing as I was ready to scrap the engine.

Share this post


Link to post
Share on other sites
BLT
quote:Originally posted by AJK

it's all splash oiled by the time you get the breather off to see the valves all the oil has run down the 5/8" hole to the sump.I'm thinking of making a clear cover for the breather so I can see what's going on.


id="quote">
id="quote">I got this strange feeling that if you block off the breather flow, you'll blow oil out the crank seals.

Share this post


Link to post
Share on other sites
TimJr

Are the rings on the right way? Some ring sets have a top or up side marked on them. I know some 16hp iron Briggs are that way. About 5 years ago I helped friend with some of his rebuild. Bored, all OEM parts etc. He put the rings on upside down. He knew better, so I never checked his work. The tractor doesn't get used much, but after 2 summers, we couldn't chalk the oil use up to just not being broken in yet. So, we yanked the engine and pulled out the slug to find the rings on wrong. Ordered up a set of rings, put it together and it was like magic - smoke was gone.

Share this post


Link to post
Share on other sites
Hudco

make sure the breather is right it has to drain, and also has to work like a check valve , also a single cylinder engine crankcase is like a air pump it has to suck air in and push air out every time that piston goes up and down the bore but it happens so fast not much happens unless your rings are leaking compression causing blow by then you really notice it without vac. pres. gauges on the breather tube

Share this post


Link to post
Share on other sites
AJK

Rings are in with inside chamfer up, no chamfer on the OD of them.

If I am getting blowby then the breather tube should be very wet with oil, correct?

will put it together Monday, could I run it with out the breather tube and see what comes out the breather?

By the way,, Thanks for all the replies.

Share this post


Link to post
Share on other sites
BLT
quote:Originally posted by AJK

Rings are in with inside chamfer up, no chamfer on the OD of them.If I am getting blowby then the breather tube should be very wet with oil, correct?will put it together Monday, could I run it with out the breather tube and see what comes out the breather?By the way,, Thanks for all the replies.


id="quote">
id="quote">Venting beyond the breather to the atmosphere won't hurt anything. I just put some masking tape on carb tube to keep the dirt out.

Share this post


Link to post
Share on other sites
MrSteele

Engines used to vent to atmosphere with a hose off the breather extending to under the cover. Pollution controls demanded that the breather vented into the carb. That also gives positive ventilation as the vent is now in the suction path of the carb/air system. I would check the breather, even though it is new, might never have worked in the first place. When you have the breather in your hand, can you hear it rattle if you shake it? If not, it is stuck, and you are sucking oil into the carb

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Who's Online (See full list)

    There are no registered users currently online

  • Today's Birthdays

    1. Ole Settler
      Ole Settler
      (72 years old)
  • Recent Status Updates

    • Dean McFadden

      Dean McFadden

      Good morning peeps! I’m always searching for helpful information with my AC collection. Hope to find out new information and pass on my own experience in restoration. Here are some pics of my babies. I’m still looking for front rims for the 410 so yesterday I put the 310 wheels on took it for a drive. Working pretty good but still needs some carb work. Gotta get the 310 running next. Have a great day!😁
       

      · 1 reply
    • thedaddycat

      thedaddycat  »  SmilinSam

      It's in pretty sad shape, but yes I have a yellow plastic cap that I'm fairly certain is what you need. PM me your details and I'll get it out to you.
      · 0 replies
  • Adverts

×