Thoughts on this Briggs twin.

[enamel 35]

Picked yo a work horse with a bad starter. 

So eas removing tins and notice a spark plug was missing. So I took the head off and seen this. Whays your thoughts? I assimeit will smoke decently if put back together like it is. 

Engine is a briggs twin number 402437 0694 01 

 

 

 

[enamel 35]

Also i have a new starter gear on way so I can do compression test. 

[Achto 27,584]

A lot of piston wash there.  Cylinder looks pretty glossy, with not much cross hatch left. Would guess that the rings are about shot.

[ri702bill 8,326]

I see a distinct straight line between the two headbolts on the upper right... where the exhaust valve lines. Looks to me to be a blown head gasket...

 

[enamel 35]

I'll get pics of gasket in a bit. 

Edited September 18, 2023 by enamel

[enamel 35]

[Bill D 1,922]

I say clean it up see how it runs.  Plane the head flat and put some new head bolts and head gaskets on it.  It will be tough to get an accurate compression reading on the Briggs due to the easy spin camshaft design.  Mine tops out at 60 psi per cylinder, but it runs fine. It might surprise you.

[enamel 35]

Alright thanks. This is my forst twin briggs so don't know much about them lol 

[lynnmor 7,307]

Lap the head flat and then set it on the block with bluing applied to see if the surfaces mate.  Your head gasket was leaking and there is no blowout leading me to believe that either the head or block isn't flat.  The carbon probably came from worn rings, how was the air filter maintained?

[enamel 35]

The green foam for filter was dirty. The filter was clean. But this part is filthy 

You can see how dirty by where I wiped a section clean. 

[Bill D 1,922]

7 minutes ago, enamel said:

The green foam for filter was dirty. The filter was clean. But this part is filthy 

You can see how dirty by where I wiped a section clean. 

Not good.  It probably sucked in a lot of dirt in it's life.

[Jon Paulsen 290]

Welcome here, fella Hoosier. 

[bds1984 1,429]

These engines are so simple and crude I would clean everything real good, tear it down to hone the cylinders, new rings, gaskets, filters, and reassemble it.  Run her and a few oil changes at a few hours at a time, and never look back.  I've brought back worse and they still run great.

[lynnmor 7,307]

13 hours ago, enamel said:

The green foam for filter was dirty. The filter was clean. But this part is filthy 

You can see how dirty by where I wiped a section clean. 

 

It is obvious that the air filter wasn't installed correctly or the wrong filter was used.  Dirty air is a major cause of ring wear.

[ri702bill 8,326]

3 hours ago, lynnmor said:

It is obvious that the air filter wasn't installed correctly or the wrong filter was used.  Dirty air is a major cause of ring wear.

Becomes a Mini-sandblaster and accelerates wear.....

[RED-Z06 2,221]

She will definitely use some oil, thats alot of grit that engine has eaten.  The nylon starter gears were an ongoing problem,  as were barely adequate starters.  It was pretty common to have to pull the heads and scrape carbon every 250-300 hours or it would build up enough to cause the pistons to hit the heads

[enamel 35]

Sorry i havent replied. Been busy with a Grasshopper lol. 

 

But got the new gear and 2 new plugs. Might try and get it back together this weekend. 

[horseman with no horse 26]

2 hours ago, enamel said:

Sorry i havent replied. Been busy with a Grasshopper lol. 

 

But got the new gear and 2 new plugs. Might try and get it back together this weekend. 

We Would love to hear another update!

[kpinnc 12,065]

On 9/23/2023 at 2:20 PM, enamel said:

But got the new gear and 2 new plugs. Might try and get it back together this weekend. 

 

After your first oil change, you might try 10W-40. Of course that is if she smokes at start up or burns any oil. 

 

Thicker oil isn't a fix for engine wear, but it might buy you a little time until you have to rebuild. Again this is only if she seems to have more wear.

 

Rotella oils have zinc and other additives that you won't find in standard motor oils. They can go along way over time as well for reducing wear.

[enamel 35]

Well im hoping since it's sat for some years 5 I think or so the rings might be stuck and oil is from me hand turning it over.  I was told the engine didn't smoke and judging from the starter and time to change it that's why it was parked lol. 

[kpinnc 12,065]

7 hours ago, enamel said:

I was told the engine didn't smoke and judging from the starter and time to change it that's why it was parked lol. 

 

The plastic starter gear I think was pretty ingenious. They never damaged a flywheel gear, and were simple and cheap to replace. 

[RED-Z06 2,221]

4 minutes ago, kpinnc said:

 

The plastic starter gear I think was pretty ingenious. They never damaged a flywheel gear, and were simple and cheap to replace. 

Not always so simple.  On the Opposed twins the starter is under the flywheel, on horizontal models its down low at the frame and requires usually pulling the engine...on vertical models you either pull the flywheel or use a thin 1/2 wrench to loosen the rear bolt under the flywheel then slip it out the side.  Replacing rhe gear involved either removing a roll pin through the assembly or a hog ring type clip.

 

I was overjoyed when briggs went to the metal gear...problem was the used a nylon ring gear for a few years...but finally they saw the light and i have never had to touch their metal on metal gears.

[Fordiesel69 263]

The twin briggs do have a little bit of issues with the valve seats coming out, but other than that they literally run forever.  Even if they burn oil, just top them off regularly.