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Valve guide moved

#1

Phillybo

Phillybo

Working on a v twin briggs(44t977 -0015g1) with a bent intake push rod. The valve guide is pushed (has a spring,rubber seal on top)out slightly higher than the exhaust guide. Can anyone tell me how much the guides should stick out of the head?
Thinking about readjusting and peening valve guide.


#2

A

Auto Doc's

Helo Phillybo,

Have you compared it to the other head to verify what is going on? Often times a pushrod get bent on these when the valve lash is too far out of spec. The pushrod come to the edge of the rocker cup and it binds up on these.


#3

Tiger Small Engine

Tiger Small Engine

Phillybo said:
Working on a v twin briggs(44t977 -0015g1) with a bent intake push rod. The valve guide is pushed (has a spring,rubber seal on top)out slightly higher than the exhaust guide. Can anyone tell me how much the guides should stick out of the head?
Thinking about readjusting and peening valve guide.
Click to expand...
You posted the same question on Lawnsite (another forum). How could anyone possibly know the exact spec on valve guide on that specific Briggs model cylinder head, without having a good one out on the bench?
If the valve guide actually moved, the only real way to make it right long term is a new cylinder head. Yes there are ways to “bush fix” it, but not recommended.


#4

Phillybo

Phillybo

Auto Doc's said:
Helo Phillybo,

Have you compared it to the other head to verify what is going on? Often times a pushrod get bent on these when the valve lash is too far out of spec. The pushrod come to the edge of the rocker cup and it binds up on these.
Click to expand...
Think that may be the case here. Springs push down same amount on both exhaust and intake. Valve lash was VERY loose so I may have gotten lucky and just bent a push rod. Thanks for the response!


#5

Phillybo

Phillybo

Tiger Small Engine said:
You posted the same question on Lawnsite (another forum). How could anyone possibly know the exact spec on valve guide on that specific Briggs model cylinder head, without having a good one out on the bench?
If the valve guide actually moved, the only real way to make it right long term is a new cylinder head. Yes there are ways to “bush fix” it, but not recommended.
Click to expand...
Thought maybe someone had a manual that would tell.


#6

R

Rivets

This manual may help you out. Valve guides are above the head body. https://www.hunterlomison.com/pdfs/0C8221.pdf


#7

A

Auto Doc's

Phillybo said:
Think that may be the case here. Springs push down same amount on both exhaust and intake. Valve lash was VERY loose so I may have gotten lucky and just bent a push rod. Thanks for the response!
Click to expand...
Hi Phillybo,

The manuals do not give the exact design specification for the installed height of the valve guides.

If this head has a pushrod guide plate mounted below the rocker arm retainer bolts, be sure to check them for excessive wear in the area that pushrod comes through. These are often overlooked.


#8

sgkent

sgkent

manual say replace head if it overheats and damages guides. Ne factory kit per head is $200 - $220. What is your time worth? Or lets say you fix it, it lasts 10 hours, guide moves, a valve sticks open, takes out the piston, valve, connecting rod, scores the cylinder wall ... what then?


#9

R

Rivets

Verify that the guide has moved before replacing the head. As I stated the guide does protrude above the head base. A good repair shop should be able to help you.


#10

Phillybo

Phillybo

Rivets said:
This manual may help you out. Valve guides are above the head body. https://www.hunterlomison.com/pdfs/0C8221.pdf
Click to expand...
Thanks!


#11

Phillybo

Phillybo

sgkent said:
manual say replace head if it overheats and damages guides. Ne factory kit per head is $200 - $220. What is your time worth? Or lets say you fix it, it lasts 10 hours, guide moves, a valve sticks open, takes out the piston, valve, connecting rod, scores the cylinder wall ... what then?
Click to expand...
Guess guides were good. Should have did leakdown first. Bad rings. Massive air from oil dipstick


#12

Phillybo

Phillybo

Auto Doc's said:
Hi Phillybo,

The manuals do not give the exact design specification for the installed height of the valve guides.

If this head has a pushrod guide plate mounted below the rocker arm retainer bolts, be sure to check them for excessive wear in the area that pushrod comes through. These are often overlooked.
Click to expand...
Thanks


#13

A

Auto Doc's

How did you determine bad rings? Are the cylinder scored?


#14

Phillybo

Phillybo

Auto Doc's said:
How did you determine bad rings? Are the cylinder scored?
Click to expand...
Did a leakdown test and massive air from distick


#15

Phillybo

Phillybo

Phillybo said:
Did a leakdown test and massive air from distick
Click to expand...


#16

A

Auto Doc's

What was your leak down test gauge showing? I ask because you cannot always trust what the dip stick fill tube is indicating.

Was this engine a "smoker" before the pushrod incident?

Was the head releveled by sand with fine sandpaper on a true flat surface, and a new head gasket used during reassembly?


#17

Phillybo

Phillybo

Auto Doc's said:
What was your leak down test gauge showing? I ask because you cannot always trust what the dip stick fill tube is indicating.

Was this engine a "smoker" before the pushrod incident?

Was the head releveled by sand with fine sandpaper on a true flat surface, and a new head gasket used during reassembly?
Click to expand...
Test guage was building virtually no pressure with almost 100 psi going in.Not sure about the mowers past. Guy just brought it by and asked me to check it. Put new plugs in and they were getting oily immediately.
Runs perfectly for couple minutes and then starts pouring white smoke.


#18

sgkent

sgkent

if the head has not been off, do a visual inspection with a bore scope on the piston. You may find that the pushrod was bent when the piston and the valve met. That can be because the piston cracked and broke into a top and bottom, or a valve hung open. The leak can be either the hole in the piston, cracked piston or a broken guide and bent valve where air is leaking past the guide. Usually that will also show up in the intake or the exhaust.


#19

A

Auto Doc's

I would suspect head warpage and compression pressure blowing past the head gaskets into the valve pushrod area. (That goes straight into the crankcase) Rings are a seldom failure unless they are smoking badly and have scored cylinders due to excessive dusting and poor oil changes.


#20

sgkent

sgkent

Auto Doc's said:
I would suspect head warpage and compression pressure blowing past the head gaskets into the valve pushrod area. (That goes straight into the crankcase) Rings are a seldom failure unless they are smoking badly and have scored cylinders due to excessive dusting and poor oil changes.
Click to expand...
example of warped head



#21

Phillybo

Phillybo

sgkent said:
if the head has not been off, do a visual inspection with a bore scope on the piston. You may find that the pushrod was bent when the piston and the valve met. That can be because the piston cracked and broke into a top and bottom, or a valve hung open. The leak can be either the hole in the piston, cracked piston or a broken guide and bent valve where air is leaking past the guide. Usually that will also show up in the intake or the exhaust.
Click to expand...
I don’t have a scope.It did sound like some air movement around the valves also But mostly out of the dipstick. The plugs got slightly oil running it just for a couple minutes so I’m guess rings or piston.


#22

S

slomo

Tiger Small Engine said:
the only real way to make it right long term is a new cylinder head.
Click to expand...
Totally agree.
Tiger Small Engine said:
Yes there are ways to “bush fix” it, but not recommended.
Click to expand...
Why, because that Band-Aid repair will not last.

People have $1400.00 cell phones and skimp out on mower repairs. Probably have $150,000 worth of cars "laying" on the driveway......... I don't get it.


#23

S

slomo

sgkent said:
example of warped head

Click to expand...
I have never pulled a head for ANY reason that wasn't in need of a serious lapping job.


#24

S

slomo

Phillybo said:
Valve lash was VERY loose so I may have gotten lucky and just bent a push rod.
Click to expand...
No talk about the cooling fins. All hey let's hammer down the valve guide. What about what caused this to happen in the first place?


#25

sgkent

sgkent

Good workable borescope $20 https://amazon.com/dp/B07PBF6DX5?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_9

nice bore scope $49 https://www.amazon.com/dp/B0928Q3T42?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2&th=1

Really nice bore scope $129 for 5', $10 more for 10' https://www.amazon.com/DEPSTECH-Articulating-Articulated-Industrial-Inspection/dp/B0DT16R78W/ref=sr_1_1_sspa?crid=351YHVQORYEB0&dib=eyJ2IjoiMSJ9.7tY6VTCHYFCqHccEaGzh-KuDrrl5vznyq-QCVVhJGKFNRskDh0B9g7RN668bt2OXlPWIINfCpl1MbUI5YwGXQf6i3vGQGJ2IYGjPM3Dfd0sawDb5GBnbPtp9RyyQKYSlDTYsltmWh_hN8wac663RumVPal3YhleEMxdiPPMR2v0hj8UmPvFVTjn5B5anowEj5fT3nenNJiH3gE0JhUOiAYZSqrq7JlgwcbKixWOE9T1A1yBwUv9ymk0hlaEcs988oUbVbiP4T3vrPB7tWuPA7k5j2uWDYn9HFOb4jUqiXf4.Ykj-Ff3xpkCHmu0R6-k5hmhJk91JXQS_gI0PY4_JsL4&dib_tag=se&keywords=depstech+borescope&qid=1757368424&s=industrial&sprefix=depstech+borescope,industrial,152&sr=1-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1


#26

Phillybo

Phillybo

sgkent said:
Good workable borescope $20 https://amazon.com/dp/B07PBF6DX5?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_9

nice bore scope $49 https://www.amazon.com/dp/B0928Q3T42?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2&th=1

Really nice bore scope $129 for 5', $10 more for 10' https://www.amazon.com/DEPSTECH-Articulating-Articulated-Industrial-Inspection/dp/B0DT16R78W/ref=sr_1_1_sspa?crid=351YHVQORYEB0&dib=eyJ2IjoiMSJ9.7tY6VTCHYFCqHccEaGzh-KuDrrl5vznyq-QCVVhJGKFNRskDh0B9g7RN668bt2OXlPWIINfCpl1MbUI5YwGXQf6i3vGQGJ2IYGjPM3Dfd0sawDb5GBnbPtp9RyyQKYSlDTYsltmWh_hN8wac663RumVPal3YhleEMxdiPPMR2v0hj8UmPvFVTjn5B5anowEj5fT3nenNJiH3gE0JhUOiAYZSqrq7JlgwcbKixWOE9T1A1yBwUv9ymk0hlaEcs988oUbVbiP4T3vrPB7tWuPA7k5j2uWDYn9HFOb4jUqiXf4.Ykj-Ff3xpkCHmu0R6-k5hmhJk91JXQS_gI0PY4_JsL4&dib_tag=se&keywords=depstech+borescope&qid=1757368424&s=industrial&sprefix=depstech+borescope,industrial,152&sr=1-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1
Click to expand...
Thanks I need to get one


#27

C

callwill

Had a similar situation. Per advice on a different site more than 5 years ago, i put red thread locker on the exposed valve guide, tapped it back into place and peened around it. I let it sit over night, reassembled it all the next day, adjust ed the valves with new push rods where needed and i am still mowing with it today. Nothing lost by trying.


#28

Phillybo

Phillybo

callwill said:
Had a similar situation. Per advice on a different site more than 5 years ago, i put red thread locker on the exposed valve guide, tapped it back into place and peened around it. I let it sit over night, reassembled it all the next day, adjust ed the valves with new push rods where needed and i am still mowing with it today. Nothing lost by trying.
Click to expand...


awesome!


#29

R

RevB

Phillybo said:
Working on a v twin briggs(44t977 -0015g1) with a bent intake push rod. The valve guide is pushed (has a spring,rubber seal on top)out slightly higher than the exhaust guide. Can anyone tell me how much the guides should stick out of the head?
Thinking about readjusting and peening valve guide.
Click to expand...
Is that your "problem" ? It's not a problem.


#30

J

Jhon

I peened mine like I saw on you tube. After two mows, I checked on it again and it started comming out so I ended up just getting a new head.
On mine, but the rod snapped off. I was able to pull the broken end out with a magnet through the oil fill. Lucky it was the steel one.
Good luck.


#31

O

outdoorpowermike

ok now. I've repaired many of these heads in the past. Remove head, the guide has about 3/16" at top of head under spring. You can buy a set screw package at harbor fright. Tap guide back into head this amount, Find the thickest place on head between cooling fins and drill a hole until the drill bit touches brass guide. You will use a small drill bit, and the 3/16 set screw. Tap guide out of head and you will see drill mark on guide. Use a file and put a grove at the drill spot. Tape the hole you drilled on head to set screw size. Align mark on guide with drill hole, and put some lock tight in guide hole. tap guide into head until file mark is seen. Lock tight set screw and thread into head until it touches guide but don't tighten hard. the cyl head is not very thick. Just enough to touch the guide file mark. New head gasket and adjust valves. I never had any comebacks at shop doing this.


#32

sgkent

sgkent

be aware that the valve guide is not concentric. Each one is unique, and when the valve seats are ground, that guide angle is used as a pilot. Don't turn the guide if you do the above repair, and do not use something hard like steel to drive it back into position for fear of mushrooming it.


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