Return to the home page...

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

Reply
 
Thread Tools Display Modes
  #1   IP: 174.125.117.120
Old 04-11-2019, 10:57 PM
overez's Avatar
overez overez is offline
Senior Member
 
Join Date: Aug 2012
Location: Lopez Island, WA
Posts: 17
Thanks: 7
Thanked 0 Times in 0 Posts
Red face #4 sticky valves, again.

OK, I know, I've been here before; some people never learn. Last couple years I was busy remodeling, then two grandsons born 2K mi. & 6K mi. away. So my 40 y.o. A4 reminds me about the true cost of neglect. Picture the corroded valve seats and ex.manifold, and its stud. New valves, keepers, washers and assorted gaskets should arrive from M.M. tomorrow. Question is, should I just 'lap the hell out of it' as my machinist neighbor said last go 'round? Or is it time to face the music, pull the engine, and have the machine shop regrind the seat in 'proper' fashion? And only two studs came free when I pulled the head; the corroded back manifold stud (top) did not. I'm inclined to give the in-the-boat DIY another go, but I'm open to suggestions from wiser folk than I. Thank you.
Attached Images
   
Reply With Quote
  #2   IP: 108.60.227.10
Old 04-12-2019, 11:28 AM
edwardc's Avatar
edwardc edwardc is offline
Afourian MVP
 
Join Date: Aug 2009
Location: Laurel, MD
Posts: 2,167
Thanks: 53
Thanked 244 Times in 170 Posts
Can we see a shot of your exhaust system?

Given the amount of corrosion showing on that exhaust port, I would suspect you are having water or moisture intrusion into the manifold from the exhaust. This is a frequent cause of sticking valves.

A well designed exhaust should have the dry part go as high as possible (mine is 12"), and then inject the water at least 4" below the high point, but more is better.
__________________
@(^.^)@ Ed
1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4


Last edited by edwardc; 04-14-2019 at 04:56 PM. Reason: Typo
Reply With Quote
The Following User Says Thank You to edwardc For This Useful Post:
overez (04-12-2019)
  #3   IP: 174.125.117.120
Old 04-12-2019, 12:20 PM
overez's Avatar
overez overez is offline
Senior Member
 
Join Date: Aug 2012
Location: Lopez Island, WA
Posts: 17
Thanks: 7
Thanked 0 Times in 0 Posts
Red face Exhaust riser

I think the corrosion is both external and internal, due to leaking heat exchanger and salt air via exhaust section.
Attached Images
  
Reply With Quote
  #4   IP: 71.208.55.235
Old 04-12-2019, 01:56 PM
romantic comedy's Avatar
romantic comedy romantic comedy is offline
Afourian MVP
 
Join Date: May 2007
Location: florida
Posts: 1,830
Thanks: 5
Thanked 79 Times in 65 Posts
Those seats sure look like they need to be recut. It could be done in the boat though.
Reply With Quote
The Following User Says Thank You to romantic comedy For This Useful Post:
overez (04-12-2019)
  #5   IP: 97.93.70.7
Old 04-12-2019, 04:36 PM
Dave Neptune Dave Neptune is online now
Afourian MVP
 
Join Date: Jan 2007
Location: Lake Arrowhead Ca.
Posts: 3,987
Thanks: 406
Thanked 353 Times in 244 Posts
That water injection point needs to be at least 3~4 inches further downstream.
You could plug it and add the MMI injection Tee below the end of the elbow.
Also check the manifold to see that it has no internal leaks as well.

Dave Neptune
Reply With Quote
The Following 2 Users Say Thank You to Dave Neptune For This Useful Post:
Administrator (04-13-2019), overez (04-12-2019)
  #6   IP: 108.60.227.10
Old 04-12-2019, 05:56 PM
edwardc's Avatar
edwardc edwardc is offline
Afourian MVP
 
Join Date: Aug 2009
Location: Laurel, MD
Posts: 2,167
Thanks: 53
Thanked 244 Times in 170 Posts
Quote:
Originally Posted by Dave Neptune View Post
That water injection point needs to be at least 3~4 inches further downstream.
You could plug it and add the MMI injection Tee below the end of the elbow.
...
Dave Neptune
I agree. It looks like it's only about 1" below the bottom edge of the top of the loop. This allows splashing and steam to easily get back "over the top" and drip down to the manifold.
__________________
@(^.^)@ Ed
1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4

Reply With Quote
The Following 3 Users Say Thank You to edwardc For This Useful Post:
Administrator (04-13-2019), Dave Neptune (04-12-2019), overez (04-13-2019)
  #7   IP: 107.77.97.34
Old 04-12-2019, 10:50 PM
lat 64's Avatar
lat 64 lat 64 is online now
Afourian MVP
 
Join Date: Oct 2008
Location: Fairbanks, Alaska
Posts: 1,883
Thanks: 26
Thanked 158 Times in 105 Posts
Sorry, but your neighbor is right. Grind or cut the seats. Sometimes this can be done in-situ. It was called "field service" in the old days. It'd be lovely if you found a machinist to come to tbe dock for a moonlight call.

R.
__________________
Whiskeyjack a '68 Columbia 36 rebuilt A-4 with 2:1

"Since when is napping doing nothing?"

Last edited by lat 64; 04-12-2019 at 10:53 PM.
Reply With Quote
The Following User Says Thank You to lat 64 For This Useful Post:
overez (04-13-2019)
  #8   IP: 32.211.28.40
Old 04-13-2019, 04:16 PM
Al Schober's Avatar
Al Schober Al Schober is offline
Afourian MVP
 
Join Date: Jul 2009
Location: Uncasville, CT
Posts: 1,481
Thanks: 9
Thanked 193 Times in 163 Posts
Last engine I did, the exhaust seats weren't as bad as yours, yet the shop installed carbide inserts (no extra charge). The intake seats cleaned up OK.
That corrosion of the manifold is likely due to internal water, but could also be a leak at one of the manifold studs where it goes into the block. Pulling those studs would give you two things: a) make sure they're sealed well, and b) check the wall thickness of the block in that area.
Reply With Quote
The Following User Says Thank You to Al Schober For This Useful Post:
overez (04-13-2019)
  #9   IP: 174.125.117.120
Old 04-13-2019, 05:14 PM
overez's Avatar
overez overez is offline
Senior Member
 
Join Date: Aug 2012
Location: Lopez Island, WA
Posts: 17
Thanks: 7
Thanked 0 Times in 0 Posts
Red face Sticky valves and corrosion, next steps

Thanks to all who have weighed in. My next steps will include reworking the exhaust hot section to reduce the splashback/moisture issues that appear to be the primary cause of internal corrosion of the manifold and #4 valves. I'll replace the third manifold stud and look for internal leaks. And I'll regrind those seats by hand (to avoiding pulling the motor), unless guide wobble indicates a deeper problem. I've also identified and am addressing a leak in the heat exchanger that could be the primary source of external corrosion issues that became apparent earlier. Thanks again.
Reply With Quote
  #10   IP: 107.77.97.34
Old 04-14-2019, 01:43 PM
lat 64's Avatar
lat 64 lat 64 is online now
Afourian MVP
 
Join Date: Oct 2008
Location: Fairbanks, Alaska
Posts: 1,883
Thanks: 26
Thanked 158 Times in 105 Posts
I'll go on record as saying you should have an experienced hand oversee or do the grinding. It is not an academic exercise—there is an art to it. Best to learn on a disposable engine like a Chevy. You can put too much sideways pressure on the stone and get the seat out concentric alignment with the guide. This is not readily apparent until the pre-assembly or checks with Prussian blue.(https://www.motorcycleproject.com/text/vlvjob04.html)

If you choose grinding over cutting, you will make a lot of grit dust. It will go all over the engine. This stuff is ABRASIVE. Clean, clean, clean.

Russ
__________________
Whiskeyjack a '68 Columbia 36 rebuilt A-4 with 2:1

"Since when is napping doing nothing?"

Last edited by lat 64; 04-14-2019 at 01:46 PM.
Reply With Quote
The Following 3 Users Say Thank You to lat 64 For This Useful Post:
Administrator (04-14-2019), Dave Neptune (04-16-2019), overez (04-14-2019)
  #11   IP: 174.125.117.120
Old 04-14-2019, 04:43 PM
overez's Avatar
overez overez is offline
Senior Member
 
Join Date: Aug 2012
Location: Lopez Island, WA
Posts: 17
Thanks: 7
Thanked 0 Times in 0 Posts
Unhappy Cutting valve seats

Many thanks for the caution. I will try to coax one of my experienced neighbors aboard for this task. I can well imagine how the carbide blade treatment can go sidways pretty quickly.
Reply With Quote
  #12   IP: 32.211.28.40
Old 04-15-2019, 10:03 PM
Al Schober's Avatar
Al Schober Al Schober is offline
Afourian MVP
 
Join Date: Jul 2009
Location: Uncasville, CT
Posts: 1,481
Thanks: 9
Thanked 193 Times in 163 Posts
Yeah, best to be careful. Easy to dive into a project like this and make it worse.
Friend had problems with a knee (ACL?) and was working with a surgeon, who was doing multiple tests. Friend couldn't understand all the testing - just get in there and fit the d... thing! Surgeon explained: Before I go in there, I want to feel confident I can make it better, not worse.
Repairs with the engine in the boat are to get you through the season - maybe. Pulling the engine and doing things right are for the next 20 years.
Reply With Quote
Reply

Tags
#4 valves, corrosion, valve replacement

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
cure for sticking valves? add bend/trap in exhaust? CamaroMan Troubleshooting 4 10-31-2017 11:38 PM
sticking intake valves jetmech Troubleshooting 2 09-20-2016 09:58 AM
Believe I have stuck exhaust valves. Still have a question P30_889 Troubleshooting 101 06-11-2009 04:08 PM
Apparently sticky valves JimF Troubleshooting 1 06-29-2007 11:44 AM
Sticky Valves rlindgren Troubleshooting 1 08-01-2006 04:03 PM


All times are GMT -4. The time now is 03:10 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2019, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2019 Moyer Marine Inc.

All Rights Reserved