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: 76.106.7.221
Old 09-27-2007, 06:59 PM
Baltimore Sailor's Avatar
Baltimore Sailor Baltimore Sailor is offline
Afourian MVP
 
Join Date: May 2007
Location: Monrovia, MD
Posts: 640
Thanks: 0
Thanked 6 Times in 6 Posts
valve cover removal/replacement

I've searched the forums and found some information, but I still have a few questions. I have fair-to-middling access on the carb side of my A4, and I'd like to have a look at the valves. Is it just a matter of removing the cover and there they are? Are there hazards to look out for when removing the cover? Does the carb have to be removed to get access, or can it be done without doing so?

I have the A4 manual, but didn't see anything about valve adjustment. However, the picture of the engine makes it look like there's a lot of stuff in the way. This may be something I'll wait for layup to do, but I like to find out as much in advance as I can.

Thanks!
Reply With Quote
  #2   IP: 89.251.61.34
Old 09-28-2007, 04:25 AM
Kelly's Avatar
Kelly Kelly is offline
Afourian MVP
 
Join Date: Oct 2004
Location: Brest, France
Posts: 663
Thanks: 0
Thanked 9 Times in 7 Posts
Here's a picture of the valve cover with the carb and manifold removed to improve access.

I would think that you would have to remove the carb, especially if you are thinking about adjusting the tappets (gaps given in the Moyer manual and the yellow A4 maintenance guide).

As for the manifold, I'm not sure. Without, access is much improved but removal may not be necessary. If my memory serves me, the two bolts holding on the valve access cover are long (3-4 inches ?).

Good luck,
Kelly
Attached Images
 
Reply With Quote
  #3   IP: 65.198.70.130
Old 09-28-2007, 11:58 AM
Tom Alessi Tom Alessi is offline
Senior Member
 
Join Date: Nov 2006
Posts: 30
Thanks: 0
Thanked 0 Times in 0 Posts
I'm doing the same job. Do have the same picture with the valve cover off?
Tom
__________________
Tom A
Reply With Quote
  #4   IP: 75.67.142.48
Old 09-28-2007, 12:20 PM
wlevin wlevin is offline
Senior Member
 
Join Date: Nov 2006
Posts: 120
Thanks: 0
Thanked 0 Times in 0 Posts
What made you want to adjust tappets? Are there specific noises or other indications that this needs to be done?
Bill on Otter
Reply With Quote
  #5   IP: 71.168.72.224
Old 09-28-2007, 02:26 PM
David Masury's Avatar
David Masury David Masury is offline
Senior Member
 
Join Date: Oct 2004
Posts: 265
Thanks: 0
Thanked 5 Times in 5 Posts
You can remove the valve cover and adjust the valve clearances without removing the manifold. Taking the carburator off is easy and should be done first.

Previous posts and Don's manual speak of slightly bending the valve cover to help keep it sealed when you replace it. It is only held in place by two bolts and the extra spring in the cover keeps the ends tight to prevent oil seepage.

David
Reply With Quote
  #6   IP: 74.218.125.206
Old 09-29-2007, 08:16 AM
msmith10's Avatar
msmith10 msmith10 is offline
Afourian MVP
 
Join Date: Jun 2006
Location: Columbus, Ohio
Posts: 474
Thanks: 19
Thanked 62 Times in 46 Posts
David is correct. Just remove carb. As for why to check valves, I checked mine this year because the engine is 30 years old, compression is going down, and it was clear from the unblemished paint on the valve cover edges and bolts that this had never been done. After adjusting clearances, my engine ran much smoother and compression increased. Correct procedure is as follows:
A: VALVE ADJUSTMENT PROCEDURE:

1) Set the engine to number one TDC, just as you would for ignition timing. The TDC
position of the No. 1 cylinder is most easily found by holding a finger over the spark plug
hole in the first cylinder (at the flywheel end), while manually turning the flywheel
counterclockwise. As soon as compression is felt, stop turning and look at the position of
the roll pin in front of the crankshaft. Continue turning until the roll pin is perfectly
vertical. The piston will then be at TDC.

2) Check/set the valve clearances in cylinder number one by loosening or tightening the
top of the adjustable tappets (.010" for intake valves and .012" for exhaust valves). In the
first cylinder, the exhaust valve is at the front, and the intake valve is in the direction of
the reversing gear. The clearance is proper when you can insert the appropriate feeler
gauge between the valve stem and the top of the tappet, feeling a slight resistance - or
drag - on the feeler gauge.

3) After setting the valves in the first cylinder, set the valves in the rest of the cylinders
in the normal firing order (1, 2, 4, and 3), being sure to rotate the engine 180 degrees
between cylinders.

NOTE: The arrangement of valves in each cylinder is as follows: The valve at each end
of the engine is an exhaust valve. Then working in from each end toward the center,
there are two intake valves, and then two exhaust valves (in the center of the engine).
From the flywheel end of the engine, the arrangement of valves works out to be:
exhaust/intake (cyl #1), intake/exhaust (cyl #2), exhaust/intake (cyl #3), and
intake/exhaust (cyl #4).
Reply With Quote
  #7   IP: 76.106.7.221
Old 09-29-2007, 11:15 AM
Baltimore Sailor's Avatar
Baltimore Sailor Baltimore Sailor is offline
Afourian MVP
 
Join Date: May 2007
Location: Monrovia, MD
Posts: 640
Thanks: 0
Thanked 6 Times in 6 Posts
Quote:
3) After setting the valves in the first cylinder, set the valves in the rest of the cylinders in the normal firing order (1, 2, 4, and 3), being sure to rotate the engine 180 degrees between cylinders.
Do you mean that one just rotates the flywheel 180 degrees to the next cylinder, then another 180 for the next, etc? So you'd start with the roll pin vertical for cylinder 1, pointing down for 2, up again for 3, down for 4?
Reply With Quote
  #8   IP: 75.185.39.162
Old 09-30-2007, 09:05 PM
msmith10's Avatar
msmith10 msmith10 is offline
Afourian MVP
 
Join Date: Jun 2006
Location: Columbus, Ohio
Posts: 474
Thanks: 19
Thanked 62 Times in 46 Posts
That's correct. You can put your finger over the spark plug hole (sequentially) as you are rotating the engine (counterclockwise), and feel compression build up as the pin gets about 90 degrees ahead of vertical just to reassure yourself. In other words,you will feel compression build up on cylinder 1 as the roll pin gets to about 90 degrees before vertical. Continue to rotate until the pin is vertical, adjust valves. Move on to cylinder 2, same as before, but crankshaft (and roll pin) rotated 180 degrees, adjust valves, etc.
As long as you have good access, this is an easy job. Be sure to have a new gasket for the valve cover plate. If you don't have one, you can make one (as I did) out of cork gasket sheet.
Also, be sure to have a couple of clean rags available to lay in the bottom of the valve chamber as soon as you take the plate off. There are oil passage holes in there that you don't want dirt, pieces of gasket, etc, falling down.

Last edited by msmith10; 09-30-2007 at 09:12 PM.
Reply With Quote
  #9   IP: 89.251.61.34
Old 10-01-2007, 04:53 AM
Kelly's Avatar
Kelly Kelly is offline
Afourian MVP
 
Join Date: Oct 2004
Location: Brest, France
Posts: 663
Thanks: 0
Thanked 9 Times in 7 Posts
I just wanted to get back to the question, "why adjust the tappets?"

I didn't want to do this going in, it's just that in taking apart and cleaning/painting everything, it was "now or never" to take a look and adjust if necessary.

As it turns out, they needed to be adjusted. In buying a used boat with a used engine, you never know exactly what went on in the previous 10 to 40 years.

Now I know the clearances are as they should be.

(Side note: taking off the manifold allowed me to find the old paper towel ballooning into one of the passages in the block. Nice surprise!)

Kelly
Reply With Quote
  #10   IP: 66.245.133.133
Old 10-01-2007, 02:31 PM
HOTFLASH HOTFLASH is offline
Senior Member
 
Join Date: Oct 2004
Location: Chicago
Posts: 210
Thanks: 29
Thanked 26 Times in 21 Posts
Valve Tappet Adjustment Q's

Quote:
Originally Posted by msmith10 View Post
As soon as compression is felt, stop turning and look at the position of the roll pin in front of the crankshaft. Continue turning until the roll pin is perfectly
vertical. .
I too have my valve cover off, and have reduced compression, so I should do the same.

What and where is the "roll pin"? I have the utility crank. Do I have to take the flywheel cover off to see the roll pin?

Also, looking at the valves, just where is the "top of the adjustable tappets."

What is good way to slightly bend the cover?

Is there anything else to look for in there?

Mary
Reply With Quote
  #11   IP: 66.245.133.133
Old 10-02-2007, 02:31 PM
HOTFLASH HOTFLASH is offline
Senior Member
 
Join Date: Oct 2004
Location: Chicago
Posts: 210
Thanks: 29
Thanked 26 Times in 21 Posts
Red face "Roll Pin"

OK, Silly Me, I figured out what the "roll pin" was. I have been using it to find TDC, but did not know what it was called! I still wonder about the other Q's.
Mary
Reply With Quote
  #12   IP: 76.106.7.221
Old 10-02-2007, 05:36 PM
Baltimore Sailor's Avatar
Baltimore Sailor Baltimore Sailor is offline
Afourian MVP
 
Join Date: May 2007
Location: Monrovia, MD
Posts: 640
Thanks: 0
Thanked 6 Times in 6 Posts
Actually, I don't know what the "roll pin" is either. I'm assuming it's something visible on the front of the engine, but I haven't done any timing or valve work yet, so it would probably be a really good idea to know exactly what I'm looking for there.

Thanks!
Reply With Quote
  #13   IP: 66.245.133.133
Old 10-02-2007, 07:18 PM
HOTFLASH HOTFLASH is offline
Senior Member
 
Join Date: Oct 2004
Location: Chicago
Posts: 210
Thanks: 29
Thanked 26 Times in 21 Posts
Roll Pin Description

I am doing this from memory--so size estimates may be a little off, and are based on my late model A4.

Assuming you do not have fresh water cooling, and you can see the hole in the center of the fly wheel cover, you would be able to see the roll pin. Look in, and you will see the center--like the butt end of an axle--of the fly wheel. I think what I am calling the butt end of an axle is actually the end of the crankshaft--not sure about that. On mine it looks like a circle about the circumference size of a penny, maybe a nickel. Thru the end of the "axle" perpendicularly (is that a word?) is the metal "pin" the size of a fat pencil, sticking out about 1/3 inch on both sides of the axle-end. That "pencil" is the roll pin. Looks a little like an arrow through a head--remember those? If you have a hand crank or utility crank, the crank has a cutout on the business end so it can slide onto the "axle" end, around the roll pin making the crank not slip, but be fixed on the "axle" so the crank may turn the flywheel and crankshaft.

I finally realized that was what they were talking about by looking at the engine overhaul manual. I did not know that protrusion had a name and the name was "Roll Pin".

If you have fresh water cooling, a pulley is attached where you would put the hand crank. I do not know about how to remove that.

Hope this helps.

Mary
Reply With Quote
The Following User Says Thank You to HOTFLASH For This Useful Post:
Theo Lewis (07-09-2021)
  #14   IP: 76.106.7.221
Old 10-02-2007, 07:38 PM
Baltimore Sailor's Avatar
Baltimore Sailor Baltimore Sailor is offline
Afourian MVP
 
Join Date: May 2007
Location: Monrovia, MD
Posts: 640
Thanks: 0
Thanked 6 Times in 6 Posts
Thanks! I have raw water cooling, so all this is visible. I figured that was it, but I've figured some pretty dumb things before!
Reply With Quote
  #15   IP: 71.98.56.159
Old 10-02-2007, 07:52 PM
baileyem baileyem is offline
Senior Member
 
Join Date: Jun 2006
Location: Tomahawk, WI
Posts: 175
Thanks: 0
Thanked 1 Time in 1 Post
Smile Roll Pin

Hey guys,

You are correct in describing where the roll pin is and what it is there to do. A roll pin is simply a pin that is not a solid, single piece but is formed by rolling a piece of metal into the form of a rod (pin). It is intended to be driven into a hole that is slightly smaller than its original diameter. It will compress, due to its compressible, rolled form and hold itself in place by the friction created as it trys to expand to its original diameter. They are very effective and can normally be driven out rather easily. They can be purchased in any good hardware store.
End of lecture.

Mike
Reply With Quote
The Following User Says Thank You to baileyem For This Useful Post:
DDO (03-30-2021)
  #16   IP: 75.185.39.162
Old 10-02-2007, 10:36 PM
msmith10's Avatar
msmith10 msmith10 is offline
Afourian MVP
 
Join Date: Jun 2006
Location: Columbus, Ohio
Posts: 474
Thanks: 19
Thanked 62 Times in 46 Posts
If you have an accessory drive (fresh water cooling), there will be a pulley attached to the forward end of the crankshaft which prevents you from removing the flywheel cover. You need to remove this pulley then you can remove the flywheel cover. You will then see either the roll pin extending thru-and-thru the end of the crankshaft, or you'll see a hole in the crankshaft where the roll pin used to be (this was the case with my engine).
Reply With Quote
  #17   IP: 142.68.99.179
Old 10-11-2008, 08:09 AM
rigspelt's Avatar
rigspelt rigspelt is offline
Afourian MVP
 
Join Date: May 2008
Posts: 1,187
Thanks: 0
Thanked 19 Times in 17 Posts
Is this diagram correct? I made it up to help me check the valve tappet clearances.
Attached Images
 
__________________
1974 C&C 27
Reply With Quote
  #18   IP: 70.211.177.109
Old 10-12-2008, 08:05 AM
Don Moyer's Avatar
Don Moyer Don Moyer is offline
 
Join Date: Oct 2004
Posts: 2,811
Thanks: 0
Thanked 183 Times in 124 Posts
Yes. Good job!

Don
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
Broken Valve Spring redwitch Troubleshooting 9 09-18-2020 11:03 PM
Valve Orientation? Unregistered General Interest 1 12-08-2005 07:29 AM
Broken valve stem stuck in the valve guide Unregistered General Maintenance 1 11-19-2005 08:26 AM
Rubber Hose Extending from oil tap below valve chamber cover 1973 Ericson General Interest 1 11-17-2005 02:32 PM


All times are GMT -4. The time now is 02:14 PM.


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