18HP Briggs v-twin Vanguard engine guru needed

Hello all I hope someone can help me out here. I have a B&S 18 HP v-twin model number 350447 type 1331-E1 code 04051311. I bought this on a piece of equipment last May with 2674 Hrs. This machine had sit idle for 5 years. The carb was shot and needed replacement when I purchased it. I cleaned all the mice nests from the cooling fins as well as servicing it. At that time I adjusted the valves according to the service manual and did a compression test. Looking at the engine the right side was 170 psi and the front was 160. The engine ran well for abut 200 hrs with routine maintenance. The engine started having problems first with smoking and it smelled like oil if it was not run every day. First it was a little then a lot. Then after sitting for a while the engine would not start. The battery had a full charge and the starter was checked good according to the service manual. I drained the oil and it was slightly overfilled and came out a grey color and seemed as though it had gas in it. The oil had about 50 hrs on it straight 30wt. I checked the fuel shutoff valve on the carb and it was operational. I checked the compression and the right side of the motor now had 120 psi and the left side had 145. There seemed to be leakage around the head gasket on the right side (low compression side). The air filter was also covered in oil. I removed the heads and installed all new gaskets and torqued all to factory specs. There was also a lot of carbon buildup on the top of the piston on both sides and in the head which I cleaned off with carb cleaner and a fine scrub pad. I checked the sealing of the valves by putting carb cleaner in the head on top of a paper towel. No leakage over night. Torqued everything to factory specs and installed back into machine. Engine fired right up this time no problem and ran good however it still smoked. After checking the compression on both cylinders the right side now had 90psi and the left side now had 150psi. I also checked the head and top of the cylinder mounting service for distortion (.004" or less)

My question to you all is how many hrs is a Briggs vanguard 18hp engine made to run if all factory maintenance schedules are performed?

Has anyone on here rebuilt one of these engines or is it not worth the time. I can buy a replacement B&S engine for $1100.

I have a factory service manual. How do I know what piston I would need to rebuild it? I see there is different sizes available.

Could my engine be repowered by just doing a light hone and rings if there was no scoring on the piston or cylinder skirts?

Is it best to have a briggs dealer do the honing and piston resizing if needed and how much would that cost? Would they even do that anymore?

I see the hone is available (#19205) but not the tool to check the cylinder size anymore (#19404). Does anyone know a replacement to check the cylinder size? The FSM says to measure the cylinder with telescoping tool #19404 and dial caliper #19199 at six points to see if within spec.

Also I do not understand why my right side cylinder compression test went down that much after my disassemble. Did the excess carbon make it raise that much?

Thanks for your help
Sean

https://www.briggsandstratton.com/n...ManualSearch.html?searchrequested=350447-1331

see page 7 in operators manual

i use 5w-30w full synthetic in my 2010 20h.p. Vanguard with filter change it takes 48oz. i adjust valves with engine cold to .005., also check air filter & prefilter.

mechanic mark said:

https://www.briggsandstratton.com/n...ManualSearch.html?searchrequested=350447-1331

see page 7 in operators manual

i use 5w-30w full synthetic in my 2010 20h.p. Vanguard with filter change it takes 48oz. i adjust valves with engine cold to .005., also check air filter & prefilter.

Click to expand...

Are you suggesting that straight 30 wt oil was the culprit of engine or ring damage? This is Napa brand 30wt that I change about every 50 hrs as suggested in my book (FSM manual covers engine 290000-380000) with filter change at 100 hrs. Interesting my book is different than the one you referenced in that it references 5w-30 synthetic oil under 40 degrees and straight 30 over 40 degrees. This mower does not get used under 40 degrees. In my equipment that I run under 40 degrees or all year I do run synthetic 5w-30.

How often do you change oil and filter on your 5w-30 synthetic Briggs engine?

That Vanguard is pretty much a commercial built engine, does have sleeved cylinders if I remember right. Something I have seen before is cylinder wear at the head bolt areas. I guess the cylinder gets distorted due to bolt torque downs? But I'd suspect basic wear of rings and cylinder, valve guides, blow by into the air inlet and loss of compression due to wear. But first thing I'd do is recheck the valve adjustment.

Allmost impossible to give you a meaninful answer.

No oil ever causes excessive wear
However fuel contaminated oil will.
The fuel solenoid in the carb DOES NOT CUT OFF THE FUEL SUPPLY to the carb is simply blocks off the main jet.
If the float valve does not cut off the fuel supply properly the bowl will overfill and dribble down into the engine via the bowl vent.
Twenty years ago these were outside the engine so you could see the drips and know the carb was flooding.
EPA regulations force the companies to put the vent inside so the fuel tank just empties into the engine.
Lots of oi in the breather tube ( seen around the filter housing ) is a good indication this is happening.
An oil level that despite smoke remains the same or actually goes up confirms this is happening.

A high compression reading means that the compression rings are sealing ( the top 2 sings ) but it means diddly squat for the oil scraper ring , on the bottom.
Excessive carbon on the piston crown indicates that way too much oil is getting into the cylinder.
Oil gets into the cylinder 4 ways
1) off the cylinder walls cause the scrapers are gone
2) via the inlet guide because the head is over oiled &/or the valve guide oil seal is gone
3) via the carb because the compression rings are gone and you are getting blow by through the crank case breather.
4) via the head gasket

Sean2202 said:

Are you suggesting that straight 30 wt oil was the culprit of engine or ring damage? This is Napa brand 30wt that I change about every 50 hrs as suggested in my book (FSM manual covers engine 290000-380000) with filter change at 100 hrs. Interesting my book is different than the one you referenced in that it references 5w-30 synthetic oil under 40 degrees and straight 30 over 40 degrees. This mower does not get used under 40 degrees. In my equipment that I run under 40 degrees or all year I do run synthetic 5w-30.

How often do you change oil and filter on your 5w-30 synthetic Briggs engine?

Click to expand...

i check oil level on dipstick before each use & color of oil also, change oil & filter every 100 hrs. if not sooner depending on color of oil, i also check air filter & prefilter very often, i wash prefilter with dishwashing liquid ajax as needed let air dry & replace cartridge filter as needed after visual inspection. i use pennzoil or valvoline 5w-30 full synthetic oil.

With the lower compression now on the one side and burning of oil, it sounds as if the rings for that side are worn.

To check those W/O major disassembly, you need to do a "leak down test". On that cylinder, get it to TDC on the compression stroke. Lock up the engine so it does NOT rotate.

Insert your tool, pressurize it to 100PSI and listen/feel for leaks. You'll likely feel much of the air come out of the oil filler neck (air pushed past the compression rings into the crankcase). You shouldn't be dropping more than roughly 15%.

(if air comes out the carb-bad intake valve, exhaust-exhaust valve- yours will very likely come out the oil filler opening)


Compared to the other cylinder, it sounds like your closer to loosing 50%, not good ….

I suspect the fuel that seeped into the oil allowed for some extra wear on that one cylinder for some reason.

I would pull the head again on the low compression side, and put up some pics of things.
Including the cylinder wall, the head/gasket areas before any gasket removing, etc....

Thank you all for your replies. I rechecked the valve clearance again according to the FSM. My FSM states 1/4 past TDC on compression stroke. My clearances where all on target set at .005. (FSM states .004-.006 intake and exhaust cold). I have found some discrepancies with my FSM as I believe there has been updates so are the valves still checked this way?

Thanks for the tip on the fuel solenoid. In my fleet of B&S engines (10 or So) What is the best way to make sure the float valve is not stuck? I have been turning the gas off if the machine is not used often. Should we stick to 50 hr oil changes to keep an eye on things better? On my new engine it recommends oil change at 100 now. How many hours or time would it take for a leaking carb float to add enough gas contamination to oil to damage an engine? Does the fuel always flow into the same cylinder, the side with the starter. The reason why I am asking is I have another engine of the same vintage that the compression on the RH (starter side) is about 15 psi off of the right side. This machine only gets used about 100 hrs a year. I did not find oil in the air cleaner, overfilled, or discolored oil when I drained it.

Also I have read to wash the prefilter, then lightly oil it and squeeze out the excess. The new book I have does not say anything about this. What is the preferred method?

I have purchased a new engine for this piece of equipment and will play with this old engine when I have time. I will definitely try that leak down tester method. Thanks for sharing.

Here are some original pictures that I took before and after. The first is the RH side with the starter that shows the oil around the head gasket area and piston. The head gasket did have a leaking spot here. Next pictures are of after I cleaned the whole engine. Not sure if you can tell from the second picture but the piston seemed like it was closer to the cylinder wall on the side with lower compression than the side that had normal compression. Although this engine ran could it be as simple as replacing the rings and a simple hone? Unfortunately I did not take any photos of the underside of the valves and heads. They had carbon deposits but did not seem extremely excessive.

Sean

Sean2202 said:

Thank you all for your replies. I rechecked the valve clearance again according to the FSM. My FSM states 1/4 past TDC on compression stroke. My clearances where all on target set at .005. (FSM states .004-.006 intake and exhaust cold). I have found some discrepancies with my FSM as I believe there has been updates so are the valves still checked this way?

Thanks for the tip on the fuel solenoid. In my fleet of B&S engines (10 or So) What is the best way to make sure the float valve is not stuck? I have been turning the gas off if the machine is not used often. Should we stick to 50 hr oil changes to keep an eye on things better? On my new engine it recommends oil change at 100 now. How many hours or time would it take for a leaking carb float to add enough gas contamination to oil to damage an engine? Does the fuel always flow into the same cylinder, the side with the starter. The reason why I am asking is I have another engine of the same vintage that the compression on the RH (starter side) is about 15 psi off of the right side. This machine only gets used about 100 hrs a year. I did not find oil in the air cleaner, overfilled, or discolored oil when I drained it.

Also I have read to wash the prefilter, then lightly oil it and squeeze out the excess. The new book I have does not say anything about this. What is the preferred method?

I have purchased a new engine for this piece of equipment and will play with this old engine when I have time. I will definitely try that leak down tester method. Thanks for sharing.

Here are some original pictures that I took before and after. The first is the RH side with the starter that shows the oil around the head gasket area and piston. The head gasket did have a leaking spot here. Next pictures are of after I cleaned the whole engine. Not sure if you can tell from the second picture but the piston seemed like it was closer to the cylinder wall on the side with lower compression than the side that had normal compression. Although this engine ran could it be as simple as replacing the rings and a simple hone? Unfortunately I did not take any photos of the underside of the valves and heads. They had carbon deposits but did not seem extremely excessive.

Sean

Click to expand...

15 psi off could be a big thing if you have 100 psi on the good cylinder or nothing to worry about if the good cylinder is 160 psi. The latest information is to not oil the precleaner on a paper cartridge type filter. the problem is most people over oil them. Lightly oil according to Briggs is 1 tsp for the whole surround filter. So the current recommendation is to oil a foam only type filter(push mower filters) and not oil the foam over paper filter.

50 hour oil changes is fine, The gas in the oil by itself won't damage the engine, The problem is running it with the gas in the oil which will damage the engine. A leaking float valve on a fuel pump engine will quickly overwhelm the engine in most cases. A leaking float valve on a gravity feed engine if leaking bad will cause the engine to run rich and normally blow black smoke as it floods the engine, or if let to set will fill the crankcase in just a few minutes in some cases.