Return to the home page...

Go Back   Moyer Marine Atomic 4 Community - Home of the Afourians > Discussion Topics > General Maintenance

Reply
 
Thread Tools Display Modes
  #1   IP: 69.172.163.17
Old 10-27-2020, 12:36 PM
cowlum cowlum is offline
Senior Member
 
Join Date: Aug 2020
Posts: 21
Thanks: 2
Thanked 14 Times in 8 Posts
Piston anomoly

Hi

The attached jpg is a periscope photo taken of my number 4 piston after the engine has been sitting for a day.

Questions:
1: What is the screw head like thing in the center?
2: Do the stamped markings mean anything to anyone?
3: Where does the fluid come from? Its not present in the other cylinders.

Regarding question 3. With the flathead design oil wont seep into the cylinders through gravity while at rest, so my best guess is its unburnt additives I've added to my fuel. Seems a lot though and the engine runs great. Number 4 has the lowest compression of all 4 but only by about 5%.

Thanks
Attached Images
 
Reply With Quote
  #2   IP: 155.186.122.195
Old 10-27-2020, 01:10 PM
Dave Neptune Dave Neptune is offline
Afourian MVP, Professor Emeritus
 
Join Date: Jan 2007
Location: Grove, Oklahoma
Posts: 5,035
Thanks: 711
Thanked 1,289 Times in 839 Posts
#1 That is the "center hole" for machining and grinding the piston, IE just a dimple.

#2 The stamped numbers are part numbers.

#3 The fluid is probably water. Water will break up the carbon deposits during combustion.

Do you shut off the water valve? Could be back-flow from the exhaust or a minor leak in the head gasket which may be the compression loss. Water can also seep in through a crack, has the engine overheated recently?

Dave Neptune
Reply With Quote
  #3   IP: 138.207.177.95
Old 10-27-2020, 04:16 PM
joe_db's Avatar
joe_db joe_db is offline
Afourian MVP
 
Join Date: May 2009
Posts: 4,474
Thanks: 49
Thanked 1,026 Times in 721 Posts
Most A4s slope aft and if any water back up the exhaust, it ends up in #4 first.
Reply With Quote
  #4   IP: 134.41.92.9
Old 10-27-2020, 04:56 PM
Mo's Avatar
Mo Mo is offline
Afourian MVP
 
Join Date: Jun 2007
Location: Halifax NS,
Posts: 4,470
Thanks: 292
Thanked 411 Times in 272 Posts
The engine that I removed from the boat 3 weeks ago had one piston with that mark. It was number 1 cylinder, the high end of the engine on my boat. The other 3 cylinders didn't have anything like that. It did have minor pitting on the other 3 cylinders that I think happened the year prior to me buying the boat. I bought it in 2007 and all the valves were seized, the manifold was broke open from frost etc etc....I looked at that hole with a light and it was almost like it was a machining set.
__________________
Mo

"Odyssey"
1976 C&C 30 MKI

The pessimist complains about the wind.
The optimist expects it to change.
The realist adjusts the sails.
...Sir William Arthur Ward.

Last edited by Mo; 10-27-2020 at 07:02 PM.
Reply With Quote
  #5   IP: 69.172.163.17
Old 10-27-2020, 06:14 PM
cowlum cowlum is offline
Senior Member
 
Join Date: Aug 2020
Posts: 21
Thanks: 2
Thanked 14 Times in 8 Posts
Quote:
Originally Posted by Dave Neptune View Post
#1 That is the "center hole" for machining and grinding the piston, IE just a dimple.

#2 The stamped numbers are part numbers.

#3 The fluid is probably water. Water will break up the carbon deposits during combustion.

Do you shut off the water valve? Could be back-flow from the exhaust or a minor leak in the head gasket which may be the compression loss. Water can also seep in through a crack, has the engine overheated recently?

Dave Neptune
I have a raw water strainer that I unscrew breaking suction to the pump, I then wait for the last big gush of water out the exhaust before shutting the engine down. Usually takes about 30 seconds. Then I shut the water valve.

The valve seat area is always dry as a bone.

Thinking it may be a head gasket leak now.

I should take more pictures overtime and see how it goes.

Last edited by cowlum; 10-27-2020 at 06:26 PM.
Reply With Quote
  #6   IP: 155.186.122.195
Old 10-27-2020, 07:06 PM
Dave Neptune Dave Neptune is offline
Afourian MVP, Professor Emeritus
 
Join Date: Jan 2007
Location: Grove, Oklahoma
Posts: 5,035
Thanks: 711
Thanked 1,289 Times in 839 Posts
It most likely is the head-gasket and perhaps another compression check will expose it.

Another possibility for water incursion and the engine still running could be the intake manifold is rusting through which is an easy check. Both are not uncommon.

Dave Neptune
Reply With Quote
  #7   IP: 69.172.163.17
Old 10-27-2020, 11:16 PM
cowlum cowlum is offline
Senior Member
 
Join Date: Aug 2020
Posts: 21
Thanks: 2
Thanked 14 Times in 8 Posts
I ran the engine for 15 minutes, in gear attached to the doc at 1400 rpm.
The fluid remained in the cylinder. I checked the other cylinders and they too had liquid, though less of it.
Is it possible its marvel oil from the gasoline that isn't being burnt off? Or oil from my compression test a month ago, which would be about 2 hours runtime ago? My engine runs quite cool.
She starts easily and runs perfectly. The spark plugs are a little sooty but clean on the electrode tips.

On another note: I dont suppose theres enough numbers showing on the piston to suggest any history for the engine? Factory originals? rebuild etc?

Last edited by cowlum; 10-27-2020 at 11:38 PM.
Reply With Quote
  #8   IP: 104.174.83.118
Old 10-28-2020, 01:15 AM
ndutton's Avatar
ndutton ndutton is offline
Afourian MVP
 
Join Date: May 2009
Location: Torrance, CA
Posts: 9,619
Thanks: 198
Thanked 2,208 Times in 1,425 Posts
Cooling system pressure test:
https://www.moyermarineforum.com/for...ad.php?t=11111
__________________
Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
Reply With Quote
The Following 3 Users Say Thank You to ndutton For This Useful Post:
chapster5 (10-28-2020), Dave Neptune (10-28-2020), TimBSmith (10-28-2020)
  #9   IP: 100.40.58.241
Old 10-28-2020, 07:45 AM
jcwright jcwright is offline
Afourian MVP
 
Join Date: Jul 2012
Posts: 158
Thanks: 5
Thanked 99 Times in 75 Posts
Cowlum,

The markings that are visible on your piston match those on mine, which are original parts. Here is a link to a photo:

https://drive.google.com/file/d/1zTA...w?usp=drivesdk

This does not rule out a previous overhaul of your engine. For example, the original pistons might have been OK, and only rings replaced.

Jack.
Reply With Quote
  #10   IP: 209.6.133.136
Old 10-28-2020, 09:10 AM
TimBSmith TimBSmith is offline
Afourian MVP
 
Join Date: Aug 2020
Location: Brookline, MA USA
Posts: 162
Thanks: 2,239
Thanked 80 Times in 42 Posts
JC what do the registration markings on your pistons reference?

Do you have a larger album from an overhaul or rebuild would love to see. Thank you. Stay well. Tim
__________________
Tim Smith
Oasis
Pearson 30
1974, Number 572
Boston, MA USA
Reply With Quote
  #11   IP: 165.225.20.171
Old 10-28-2020, 09:17 AM
Surcouf's Avatar
Surcouf Surcouf is offline
Afourian MVP, Professor Emeritus
 
Join Date: May 2018
Posts: 361
Thanks: 328
Thanked 163 Times in 123 Posts
mine
https://www.moyermarineforum.com/for...9&postcount=46
__________________
Surcouf
A nostalgic PO - Previously "Almost There" - Catalina 27 (1979)
Reply With Quote
The Following User Says Thank You to Surcouf For This Useful Post:
TimBSmith (10-28-2020)
  #12   IP: 100.40.58.241
Old 10-28-2020, 09:43 AM
jcwright jcwright is offline
Afourian MVP
 
Join Date: Jul 2012
Posts: 158
Thanks: 5
Thanked 99 Times in 75 Posts
Tim,

Here are my notes on my overhaul:

https://drive.google.com/file/d/0B86...ew?usp=sharing

My notes merely describe what I did, not how it should be done. Some people on another forum were (oddly) upset that I did more work and spent more money than I should have. Somewhere near the end I comment on things I would do differently 'next time'.

Hope this helps some. Good luck with your A4.

Jack.
Reply With Quote
The Following 2 Users Say Thank You to jcwright For This Useful Post:
Surcouf (10-28-2020), TimBSmith (10-28-2020)
  #13   IP: 100.40.58.241
Old 10-28-2020, 10:16 AM
jcwright jcwright is offline
Afourian MVP
 
Join Date: Jul 2012
Posts: 158
Thanks: 5
Thanked 99 Times in 75 Posts
Tim,

I forgot to answer your question about the numbers stamped on the piston:

One of the numbers is "2.56055". My average cylinder bore measurement was 2.563. The standard cylinder bore in the MMI manual is 2.562. So, the stamp on the piston appears to be its diameter.

The large "2" in my photo is the piston number/position, and the "Front" arrow indicates direction of installation (though "Front" is not what I first thought).

I can't explain the remaining number on the piston ("2.60999"). Perhaps others know.

Hope this helps.

Jack.
Reply With Quote
The Following User Says Thank You to jcwright For This Useful Post:
TimBSmith (10-28-2020)
  #14   IP: 209.6.133.136
Old 10-28-2020, 10:21 AM
TimBSmith TimBSmith is offline
Afourian MVP
 
Join Date: Aug 2020
Location: Brookline, MA USA
Posts: 162
Thanks: 2,239
Thanked 80 Times in 42 Posts
Jack, thumbing through notes. Awesome documentation.

Registration notes on markup on piston helpful. Thank you for follow-up.

Favorite note so far in your discussion of rebuild or buy economics..

"An unexpected benefit was appreciating all the tools
I’d inherited from my father, each one of which—right down to the smallest wrench and socket—he’d
engraved with his initials decades ago."

Priceless.

Stay well, Tim
__________________
Tim Smith
Oasis
Pearson 30
1974, Number 572
Boston, MA USA

Last edited by TimBSmith; 10-28-2020 at 10:33 AM. Reason: discovery.
Reply With Quote
  #15   IP: 100.40.58.241
Old 10-28-2020, 10:42 AM
jcwright jcwright is offline
Afourian MVP
 
Join Date: Jul 2012
Posts: 158
Thanks: 5
Thanked 99 Times in 75 Posts
Which reminds me--my dad engraved all of his tools with an engraving tool that I gave him for Christmas, I would guess when I was about 10 or so.
Reply With Quote
The Following User Says Thank You to jcwright For This Useful Post:
TimBSmith (10-28-2020)
  #16   IP: 69.172.163.17
Old 10-28-2020, 11:54 PM
cowlum cowlum is offline
Senior Member
 
Join Date: Aug 2020
Posts: 21
Thanks: 2
Thanked 14 Times in 8 Posts
I just cant seem to change the amount of fluid sitting on top of the piston. If I heat the engine up fully, then remove the spark plug it doesn't boil or evaporate despite the heat. Leads me to believe its oil rather than coolant. So I'm less worried. I'll let it sit a few days with plugs out and see if its evaporates. Another thing I did this afternoon was fill the tank with fresh stuff but I doubt the 10-15 minutes run time was long enough to get fresh stuff through the filter and into the engine. The tank was extremely low.

I'll still pressure test the block and manifold when I collect all the required part. I'm curious to try this anyway and it will completely settle what happens next.

Thanks
Reply With Quote
  #17   IP: 71.215.209.38
Old 10-29-2020, 01:30 AM
romantic comedy's Avatar
romantic comedy romantic comedy is offline
Afourian MVP
 
Join Date: May 2007
Location: florida
Posts: 1,912
Thanks: 13
Thanked 118 Times in 100 Posts
Quote:
Originally Posted by cowlum View Post
I just cant seem to change the amount of fluid sitting on top of the piston. If I heat the engine up fully, then remove the spark plug it doesn't boil or evaporate despite the heat. Leads me to believe its oil rather than coolant. So I'm less worried. I'll let it sit a few days with plugs out and see if its evaporates. Another thing I did this afternoon was fill the tank with fresh stuff but I doubt the 10-15 minutes run time was long enough to get fresh stuff through the filter and into the engine. The tank was extremely low.

I'll still pressure test the block and manifold when I collect all the required part. I'm curious to try this anyway and it will completely settle what happens next.

Thanks
Maybe you could add some oil to the cylinder. If it is water they wont mix and you should be able to tell. Maybe there is something better to add?
Reply With Quote
  #18   IP: 155.186.122.195
Old 10-29-2020, 10:49 AM
Dave Neptune Dave Neptune is offline
Afourian MVP, Professor Emeritus
 
Join Date: Jan 2007
Location: Grove, Oklahoma
Posts: 5,035
Thanks: 711
Thanked 1,289 Times in 839 Posts
The fluid looks like antifreeze. Is the engine raw water or fresh water cooled? The antifreeze will evaporate very slowly. Any running of the engine if it were oil would produce copious amounts of smoke once started, did it?

Dave Neptune
Reply With Quote
  #19   IP: 184.151.230.149
Old 10-29-2020, 09:50 PM
cowlum cowlum is offline
Senior Member
 
Join Date: Aug 2020
Posts: 21
Thanks: 2
Thanked 14 Times in 8 Posts
Quote:
Originally Posted by romantic comedy View Post
Maybe you could add some oil to the cylinder. If it is water they wont mix and you should be able to tell. Maybe there is something better to add?
That’s a good idea, I’ll do that but ultimately aim for a pressure test.
Reply With Quote
  #20   IP: 184.151.230.149
Old 10-29-2020, 09:51 PM
cowlum cowlum is offline
Senior Member
 
Join Date: Aug 2020
Posts: 21
Thanks: 2
Thanked 14 Times in 8 Posts
Quote:
Originally Posted by Dave Neptune View Post
The fluid looks like antifreeze. Is the engine raw water or fresh water cooled? The antifreeze will evaporate very slowly. Any running of the engine if it were oil would produce copious amounts of smoke once started, did it?

Dave Neptune
It does look like that but after 15 minutes of running in gear, too hot to touch it looks exactly the same. Water in the exhaust is steaming the usual amount.
Reply With Quote
  #21   IP: 104.174.83.118
Old 10-29-2020, 10:01 PM
ndutton's Avatar
ndutton ndutton is offline
Afourian MVP
 
Join Date: May 2009
Location: Torrance, CA
Posts: 9,619
Thanks: 198
Thanked 2,208 Times in 1,425 Posts
Please address this question:
Quote:
Originally Posted by Dave Neptune View Post
Is the engine raw water or fresh water cooled?
__________________
Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
Reply With Quote
  #22   IP: 69.172.163.17
Old 10-29-2020, 10:17 PM
cowlum cowlum is offline
Senior Member
 
Join Date: Aug 2020
Posts: 21
Thanks: 2
Thanked 14 Times in 8 Posts
Quote:
Originally Posted by ndutton View Post
Please address this question:
Fresh water cooled. No obvious coolant loss.
I'm not ruling out the idea its water, im just confused as to why it wont turn to steam. I guess my assumption was oils harder to burn than water is to steam. But maybe I assume too much.

My best guess at the moment its just something in the fuel that's not significantly effecting the way it runs... I need to get the pressure test parts and the time to test it.

Last edited by cowlum; 10-29-2020 at 10:22 PM.
Reply With Quote
  #23   IP: 162.219.70.239
Old 10-30-2020, 10:22 AM
Peter's Avatar
Peter Peter is offline
Afourian MVP
 
Join Date: Jul 2016
Location: Nova Scotia, Canada
Posts: 297
Thanks: 162
Thanked 140 Times in 101 Posts
Smile

Quote:
Originally Posted by cowlum View Post
It does look like that but after 15 minutes of running in gear, too hot to touch it looks exactly the same. Water in the exhaust is steaming the usual amount.
And is it possible that the usual amount of steam for your engine is consistent with a cooling leak somewhere?

My engine does not "steam" from the exhaust.

Just a suggestion.

Peter

PS - sort of like when I loaned my car to someone and half-way through explaining that the hockey stick through the hole in the floor is the brakes, I realized that maybe there IS something wrong with the car that should get fixed and that hockey stick brakes, while they were normal for me, are in fact not normal.
Reply With Quote
  #24   IP: 47.142.133.234
Old 10-30-2020, 02:40 PM
JOHN COOKSON JOHN COOKSON is offline
Afourian MVP, Professor Emeritus
 
Join Date: Nov 2008
Posts: 3,500
Thanks: 54
Thanked 855 Times in 629 Posts
Quote:
Originally Posted by Dave Neptune View Post
The fluid looks like antifreeze.
Dave Neptune
Agree, it is antifreeze. Not water. If it were water it would
'burn off" - assuming the engine would start with that much water in the cylinders.
I'm going to go against prevailing opinion and suggest that a compression would give some actionable information. The head gasket may be compromised some how some way.

ex TRUE GRIT
Reply With Quote
  #25   IP: 69.172.163.17
Old 10-30-2020, 04:00 PM
cowlum cowlum is offline
Senior Member
 
Join Date: Aug 2020
Posts: 21
Thanks: 2
Thanked 14 Times in 8 Posts
Thanks guys

First things first. I will preform the pressure test when I get parts and my newborn allows the time, im not using the boat now anyway . Its result will decide what happens next and is all that really matters.

But I'm finding the speculation enjoyable non the less so to continue....

I did a few compression tests about a month ago, 95 on all cylinders and 90 for #4 on my original tester. Its been this every year since I bought the boat in 2013 with 200 hours on the engine since. Slightly higher across all four on the tester that came with the timing light kit a friend loaned me. I poured engine oil in cylinder 4 a month ago to see if it would raise compression in alignment with the others, it did not.

I also used seafaom cleaner about a month ago.

The steam from my exhaust is normal for the PNW at this time of year. All boats here steam. I've blown head gaskets on project cars in the past and a good amount of steam requires a good amount of radiator water. But yes, I agree the headgasket steam may be hidden in the normal PNW steam.

My doubts as it to it being water or antifreeze is even when the engines very hot it remains, not steaming, not bubbling. The exhaust port is peppered in white ash which is inline with heat and burning oil. Oil has a much higher flash point than water or antifreeze ive learnt since yesterday. So im still hopeful its just the oil from the compression test.

On the flip side I doubt oil cleans cylinders and pistions, this piston looks steam cleaned.
So this points to head gasket.

The engine runs perfectly and I would not have even been worried had I not put my borrowscope into the spark plug holes for curiosities sake... Lesson learned... or issue found early

The pressure test will reveal all.,,, hopefully.

thanks
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Piston rod replacement / matching BryanLee Overhaul 13 03-07-2011 09:36 AM
Piston Oil Ring Damage Found - relacement ? Mike Jenkins Overhaul 4 12-09-2008 08:48 PM
Water in piston 4 Herman Boermans Troubleshooting 2 10-01-2007 03:26 PM
Water in piston 4 Herman Boermans Troubleshooting 0 09-27-2007 03:53 PM


All times are GMT -4. The time now is 05:58 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2024 Moyer Marine Inc.

All Rights Reserved