Post an engine model and type#. Why are you rebuilding it?

It's a Briggs Model 28M707 Type 014001

It's my Dad's motor of a Dixon riding mower. He said he needs to add something like a couple quarts of oil every 3 hours. I assumed it was bad rings or valves as it smokes a lot. After pulling off the cover, I noticed the oil leak that looks like it's not coming from a gasket area.

Unfortunately, I don't believe the short blocks for these are available anymore. Maybe there is an odd one out there.(496606) Rebuilds on these to be done right are costly w/ the machine shop thrown in. The engine replacement is an OHV.(21B907-0026-G1) Bolts on but needs new exhaust hook up if a chassis type. Are you ready for this?

I have rebuilt a couple of auto engines before, so I have some micrometers and other tools. If the block is cracked, that might be a deal breaker. I'm just wondering if anyone has seen a block crack like this. Maybe the oil is seeping from some other place, but I can't see where.

"If the block is cracked, that might be a deal breaker. I'm just wondering if anyone has seen a block crack like this. Maybe the oil is seeping from some other place, but I can't see where."

I guess the only way to find out is tear the engine down. NO, I have not heard of a block cracking in this area, I would suspect the crankcase breather gasket but that amount of oil does indicate likely badly worn rings at least.

In the mean time, we need the model and type number of the engine.

There is a whole array of engines that will readily fit the Dixon. I am a former Dixon certified Tech and have several new and used Dixon parts as I bought the remaining inventory of a dealer.

Walt Conner
wconner5 at verizon dot net (put in proper format)

It's a Briggs Model 28M707 Type 014001

If, after tearing it down, you do not SEE a crack......you might want to use a method I learned from an old motorcycle mechanic years ago. Clean the surfaces of the block just as clean as you can get them using a mineral spirits type solvent. After cleaning with the mineral spirits, spray the surfaces of the block with aerosol carb cleaner or aerosol brake parts cleaner (the idea is to remove the solvent from the surface of the block). Allow the block to dry completely. Next, spray the entire area where you suspect a crack might exist with a "talcum powder based" aerosol deodorant. You want to get a good coat of talcum powder stuck onto the surface of the block. Next, use a heat gun, hair dryer, or a heat lamp to warm the block. What will occur (if a crack exists) is the solvent and old oil will be expelled anong the crack as the block warms and the crack will be revealed as a dark line against the white backdrop of the talcum powder.

Sure it's the area around the exhaust valve and NOT the intake valve?
On an old engine, the valve guides can get quite worn and oil will be sucked past the intake valve from vacuum.

With the intake valve wide open, is there a lot of side play when pushing on the valve head?

I think I would have to agree with walt I think you should look at the breather gasket or the breater tube which goes to the air cleaner assembly ( I've never seen a cracked block in that area but I havent seen everything yet)as you nearest source of oil emissions.
I would also do a vacuum test on the block as well as a leak down test, a pressurized crankcase can be an oil pissin nightmare.
The shortblocks for these 496606 are history but you can still grab a cylinder Pt#496413 for $260.00 list if its crackt or you dont want to hone or bore.
Good Luck Jim

Thanks for all the input. I will tear it down and try the talcum powder procedure mentioned in this post.