31P777-0237-G5 Engine Build and Install

Resumed work on this head because I need the tractor to collect leaves and the high lift blades newly installed on the mower deck, along with the new spindle, use more power than the standard blades.  This is just to hard on the existing worn out engine.

Polished the non seating valve surfaces a bit.   Lapped the valves and added the springs and rockers.  Used gas to do a leak test.  The images below are about 2 hours apart.

The flywheel is on but there is not alternator coil under it.  I plan to finish that and add the ignition coil prior to bolting on the head.  Thinking about leaving the head until after the engine is bolted to the tractor.  Need to find the safe place I put them.

Friday, October 23, 2015

Installed the alternator and ignition.  But not the kill wire.   I could not find these parts so I took them off another 31P777.

While I was there I filed a timing mark on the flywheel with the piston at 1/4 inch past TDC.  See "Valve Timing Mark for Intek 31"

Thursday, October 29, 2015

DO NOT DO THIS: 31P head torque update

I would stick to the original torque spec unless you see different from B&S!

I obtained a new gasket and was given NEW updated torque and sequence instructions that supposedly B&S issued to combat this problem. The service manual has the torque at 220 inch/lbs for the head bolts. The new recommendation is to use 250 in/lbs in a new torque sequence. This is what I did. I put on the new head gasket and then the cylinder head and screwed in the head bolt finger tight. I then torqued them down in the following sequence:

6 2 4 8 3 7 1 5

at 80 in/lbs, then again at 160 in/lbs and lastly at 250 in/lbs.

The same article say to lube the head bolt threads.  Thinking anti seize will work best.

DYT4000 31P777 0348 E1

Tuesday, March 3, 2015

Today was car wash day.   Was not too bad. 

Cranks too good.  No compression.  It had a RJ17 used in L heads and does not have enough reach to get the spark where it is needed.  Purchased a new sparkle plug.

I expect a valve problem and if not that a busted rod.   I have a spare head if it is a valve problem.  If it is a busted rod lets hope it did not mess up the rest of the engine.    The unit looks like it was well cared for most of its life so maybe the cylinder bore still has some life left in it.

Borrowed a wheel from the LT1000 but the rear end would not turn. Seem odd the both the engine and transaxle would be messed up.  Maybe the transaxle was bad and the valve got stuck while sitting.  Anyway it is now in the insulated but unheated shop so I can look at it in relative comfort. 

Wednesday, March 4, 2015

Went over and pulled the valve cover.  Came off easy.  Valves are moving.  Started pulling the head.  Have to take off muffler and carb which will have to wait till daylight.  It looks like someone has been in this engine but then it is 11 years old.

The head gasket had the typical failure. (so not a busted rod or valve problems) Path from the cylinder to the valve area.

Set the bore gage to zero on the good block and used that to measure this one.  It has .005" of wear in one axis and nearly zero in the other.  The 200 hour block where the owner never changed the filter is nearly uniform .005" on the top.  I do not recall what it was at the bottom but I have read dirty oil should wear more on the bottom but this was dirty oil and I am thinking it did not.

But the cylinder has no scoring and the crank and cam seems to be ok.  The cylinder is very oily but with that bad gasket it will suck oil into the cylinder on the intake stroke.

I am contemplating putting a used head gasket on it and see if I can get some compression.  But first I want to take a look at the valves.

Found a gasket but the metal foil is mostly missing.  Maybe use black RTV (which is what I have) to get a good seal just to test the conditions of the rings with a compression test.....   But amazon is selling the gasket for $6 and I am not going to mess around for that.  I should come in about a week.  It would be nice to find that this thing could run without major work.  Maybe too much to wish for.

Switching over to the rototiller 5.5HP engine assembly.

Friday, March 6, 2015

Gasket will be here on tuesday.

Saturday, March 7, 2015

Need to pull off the seat pan to get at the transaxle.  

Tuesday, March 10, 2015

The head gasket came but was unusable.  Amazon will have another here on Thursday.  Not bad.









Thursday, March 12, 2015

There was a mixup in the replacement gasket.  Not sure what happened but I am told there will be on here tomorrow.

Briggs 31P777-0237-G5 #1 and #2

I scored a 2nd Briggs 31P777.  This engine is from the original owner and friend Jess, He said it was spewing oil out so much it covered the trailer he was pulling.  It has 200 hours on it.















I neglected to take a picture prior to pulling the cylinder head. This is a picture of the plastic shroud.

Need to measure the bore to be sure but the hope is that it is good and that the problem is something like a clogged breather.

My hope is that I am seeing hash marks in this picture? (this turned out to be big time wishful thinking)

The head is oily but not much in the way of deposits.

There is a plan A and a plan B here.  Unless the sale of parts from the first engine is very successful I plan to see if I can get this one running.  On the other hand if the first sells well they both go.

Thursday, January 22, 2015

My initial plan for this engine is to see if I can get it running and maybe stop the oil blowout.  To that end I rearranged the shop so I have a space near the front to work on small engines.  

Sunday, January25, 2015

Will need the following to reassemble.  Maybe

Briggs P/N 19356 (#18)

Oil Seal Protector Kit-Includes Sleeves Shown
Your Price: $13.55
*EMAIL TO ORDER
stoner1@iserve.net

Monday, February 2, 2015

I have the crank out of the block on 31P777 #1.  The the counter weighs are still on and will stay there till I wash parts for reassembly.  Other then that the only parts still together is the head.

Looking for Intek tips on MowBetter mower racing forum.

Tuesday, February 24, 2015

Jess called and said he needed a carb.  So I made one.  Turned out he did not have the fuel shutoff plugged in.  Later he was having governor trouble so I gave him the governor control plate off of #2 which was his engine.

Made 2 carbs into one today.  One had a stuck electric fuel shutoff, another had a too big 0 ring sealing the fuel inlet between the metal body and the plastic bit the float attaches to. Swelled or wrong part?  I came up short a main jet,  Not sure the jet was ever there.

	The brass bit in the center is the main jet  and it will fall out.

Everything cleaned up nice including the gaskets.  It seem the ultrasonic cleaning is a good way to salvage them if possible.

I also brought the major engine parts in to be washed.  Too cold to do it in the shop.  At this point I have washed the block so I can hone to break the glaze.  I got most of the filings left behind by the dremel when I ground off the one cap bolt.  It is going to be washed many more times after honing.   

Friday, March 6, 2015

The block took a lot of washing.  Switching to wiping with AFT did the trick.  Going to give it a final wash with brake cleaner prior to assembly.

New rod cap bolts are on the way.

Measuring the Cylinder and parts value

I set the bore gauge to the cylinder reject size of 3.567 in.  The cylinder was unbelievable consistently 1.5 thou more than this.

As much as I would like to keep this engine I have no need for it and a plastic shroud, muffler, and dip stick will be way more then the $10 I have into it now.   The logical thing to do is to ebay the parts.

The question now is do I just part it out or have some fun making it run first.  Expectations is that parts are worth about the same either way.  It will be interesting to measure the difference between the virgin cylinder bore and the worn area.

There prices based on what similar parts sold for on ebay

• 035 carb  $4.95 Economy Shipping
• 025-$69.99 crank list for more $10.00 Standard Shipping
• 012 stator
• <20 head
• 090 block $18.00 Economy Shipping
• 025 piston and rod $5.95 Expedited Shipping
• 075 flywheel  #698282 mod $12.95 Expedited Shipping
• g50 oil pan $12.65 Expedited Shipping
• 007 Push rods
• 025 cam shaft and gov
• 005 oil filler tube
• 025 pulley $11 shipping
• 010 head bolts $6 shipping
• 010 other bolts $6 shipping
• 020 carb linkage $6 shipping
• 
  

They total to $348.

There may be parts I did not think of and ones that are in bad shape and cannot be sold.

Briggs 31P777-0237-G5

Bought a naked 31ci inch single cylinder BS engine today. 31P777-0237-G5.  I am seeing a lot of different HP figures for this engine so we will call it north of 15 and south of 20.   18 or 18.5 seems to be the the most common numbers.   Rumor has it that it has a cast iron bore.  18.5 is correct.

It is missing the starter and there is dirt in the filler tube which is missing the dip stick.  Need to figure out how to rinse the engine out.  I am not too worried with the pressure lube system. 

To the left is an image of a similar engine on ebay.

I should part it out but am tempted to get it running if possible.  One never knows why a 'found' engine is take out of service.

Starters from the old L-Head engines look like they might work.

The good news is that she is an oil burner and it has a cast iron sleeve!  It is too cold to inspect the bore.  The head gasket looked good.

Learned on the web that one can file the ends of of .010 rings and use them as .003 rings.  If it is out of round or tapered I will bore it out to .010 over and either get a rebuild kit or sell the block and bits on ebay.

Piston with rings is B&S 796173.  $87.52 with shipping from tewarehouse.

Service manual (missing images should be good one in repair books.
276781 Single Cylinder OHV .pdf