| Valve covers [message #76524] |
Sat, 13 March 2010 08:11  |
vega7677
Messages: 24
Registered: October 2009
Karma: 0
|
Junior Member |
|
|
A while back I asked about excessive oil consumption . Some one mentioned that the valve covers might be a part of the problem.The PO had the 455 blueprinted & balanced somtime in 1999.It had only been driven about 3500 miles before I purchased it.I found some valve covers of the correct kind ,but just yesterday decided to put them on. This is what I found, valve covers that had only 5 bolt holes in them & also had holes in the baffles .Replaced with 10 bolt valve covers & no holes in baffles.
Now if I can find time to take a trip to see if this change helps the oil consumption.
Sherman
|
|
|
|
| Re: Valve covers [message #76525 is a reply to message #76524] |
Sat, 13 March 2010 08:17  |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
Karma: 0
|
Senior Member |
|
|
i'm not sure what you mean by the bolt holes. that's determined by the head drilling.
i changed mine out for the correct ones with the long baffle and found no change in oil consumption.
someone suggested to me to replace the PCV hose with a clear plastic one and watch it while pulling a grade to see if oil is being sucked to the carb.
Fred V
'77 Royale RB 455
P'cola, Fl
|
|
|
|
| Re: Valve covers [message #76526 is a reply to message #76524] |
Sat, 13 March 2010 08:21 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
| vega7677 wrote on Sat, 13 March 2010 08:11 |
A while back I asked about excessive oil consumption . Some one mentioned that the valve covers might be a part of the problem.The PO had the 455 blueprinted & balanced somtime in 1999.It had only been driven about 3500 miles before I purchased it.I found some valve covers of the correct kind ,but just yesterday decided to put them on. This is what I found, valve covers that had only 5 bolt holes in them & also had holes in the baffles .Replaced with 10 bolt valve covers & no holes in baffles.
Now if I can find time to take a trip to see if this change helps the oil consumption.
Sherman
|
Good luck with the new covers.
If you have high oil consumption, have you also checked the calibration of your oil dipstick?
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
|
|
| Re: [GMCnet] Valve covers [message #76539 is a reply to message #76533] |
Sat, 13 March 2010 12:06 |
 |
ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
|
Senior Member |
|
|
Dan,
As I understand it, if the dipstick is not properly set you will add too much oil getting to the full line. This last quart of oil will ooze out the gaskets, etc., and appear to be burning off. The oil dipstick will constantly look like your are burning 1 quart.
Larry Davick
The Mystery Machine
On Mar 13, 2010, at 9:18 AM, Dan Gregg wrote:
>
>
>
>
> i changed mine out for the correct ones with the long baffle and found no change in oil consumption.
>
> [/quote]
>
>
> Interesting Fred.
>
> Ken, what difference would calibrating the dipstick make on oil consumption?
>
> Dan
> --
> Dan & Teri Gregg
>
> danandteri.blogspot.com
>
>
>
> ///Halon Automatic Fire Extinguishers
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
|
|
|
|
| Re: Valve covers [message #76541 is a reply to message #76524] |
Sat, 13 March 2010 12:36 |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
Karma: 0
|
Senior Member |
|
|
i calibrated my dip stick several years ago; first thing i did. i've driven it for 2 gas fill ups without adding oil just to see. it was over 2 quarts low after that.
i can only assume i have bad oil rings. i'v tried everything else.
Fred V
'77 Royale RB 455
P'cola, Fl
|
|
|
|
|
|
| Re: [GMCnet] Valve covers [message #76553 is a reply to message #76524] |
Sat, 13 March 2010 14:32 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
|
Senior Member |
|
|
Sherman,
Here is a picture of the correct valve covers for a 455 Oldsmobile in a GMC:
Photo A. http://www.gmcmhphotos.com/photos/showphoto.php?photo=26476
Here's another one I have in my photos on the website. I have not edited the
comments, however, since these two covers are the same as the one in Photo A
I believe they ARE the correct valve covers for a 455 Oldsmobile. As you can
see there are 10 valve cover bolts.
http://www.gmcmhphotos.com/photos/showphoto.php?photo=28551
Below is a picture of a 403 Oldsmobile and as you can see it has 5 valve
cover bolts:
http://www.gmcmhphotos.com/photos/showphoto.php?photo=16749&cat=4247
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of SR Wright
Sent: Sunday, 14 March 2010 1:11 AM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] Valve covers
A while back I asked about excessive oil consumption . Some one mentioned
that the valve covers might be a part of the problem.The PO had the 455
blueprinted & balanced somtime in 1999.It had only been driven about 3500
miles before I purchased it.I found some valve covers of the correct kind
,but just yesterday decided to put them on. This is what I found, valve
covers that had only 5 bolt holes in them & also had holes in the baffles
.Replaced with 10 bolt valve covers & no holes in baffles.
Now if I can find time to take a trip to see if this change helps the oil
consumption.
Sherman
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
|
|
|
|
|
|
| Re: [GMCnet] Valve covers [message #76562 is a reply to message #76557] |
Sat, 13 March 2010 16:52 |
|
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
|
Senior Member |
|
|
Sherman,
Did the ones you took off have any hole drilled in the baffles?
If you email pictures to me I'll post them on the GMC photo site.
robmueller@iinet.net.au
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of SR Wright
Sent: Sunday, 14 March 2010 7:58 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Valve covers
Rob,
The ones from the 403 are just like what I took off. The heads had 10 bolt
holes , the ones with the long baffles & 10 bolt holes are what I replaced
them with. Hopefully it will help some.
Thanks ,
Sherman
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
|
|
|
|
| Re: Valve covers [message #76573 is a reply to message #76546] |
Sat, 13 March 2010 22:27 |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
Karma: 0
|
Senior Member |
|
|
| WD0AFQ wrote on Sat, 13 March 2010 13:30 |
Fred, how many miles do you have on that engine? I was thinking you overhauled it.
Miguel put 6 quarts in this engine. When I change oil I always put 5. On old engine the dipstick was right on the money. Will have to see if this one is.
I still have my aluminum valve covers with a short baffle. After we get this engine broke in good I may see what changing back to those covers does to oil consumption. They really will look good with the new alum intake sitting there, looking through the glass engine cover.
Dan
|
the engine was rebuilt by PO and has about 25K miles. there's no telling what was done to it. i replaced the valve seals and found a lot of wear in the rockers and a bad valve stem end so the heads were not rebuilt. i'm looking at building up an engine as a spare for when the time comes.
i too add 5 qts. when changing oil and it gets real black real fast after a change. hard to have much faith in the engine even though it runs great.
Fred V
'77 Royale RB 455
P'cola, Fl
|
|
|
|
|
|
| Re: Valve covers [message #76610 is a reply to message #76575] |
Sun, 14 March 2010 10:23 |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
Karma: 0
|
Senior Member |
|
|
| WD0AFQ wrote on Sat, 13 March 2010 22:47 |
Fred, sounds like mine now. My oil was black in 300 miles. Now we know why. Was that way when I got it and it only had 4k on the engine rebuild. I am starting to think the valve cover baffles don't have to be that long to work properly. Like I said, I may put my Holley covers back on when I get this engine broke in good.
Dan,
ready to roll east real soon as jim is on his way
|
Dan, i'm not saying that valve covers don't matter. there is a picture on the photo site of the auto style with the short baffle and big holes drilled in it. with the way our covers fill up with oil i think the correct covers would make a difference.
i had forgotten that i tested my engine by blocking the PCV on a trip with no change in consumption. i wasted my time and money by putting on the correct covers.
by the way you don't have to remove the AC compressor to change the right side. just remove the iron bracket and leave the comp. hanging on the remaining mounts.
Fred V
'77 Royale RB 455
P'cola, Fl
|
|
|
|
| Re: Valve covers [message #76616 is a reply to message #76610] |
Sun, 14 March 2010 11:43 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
|
Senior Member |
|
|
Fred
My 76 glenbrook came from GM with the auto type valve covers and it doesn't use oil due to these covers.
Roy
Roy Keen
Minden,NV
76 X Glenbrook
|
|
|
|
| Re: Valve covers [message #76620 is a reply to message #76533] |
Sun, 14 March 2010 12:06 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
| WD0AFQ wrote on Sat, 13 March 2010 11:18 |
i changed mine out for the correct ones with the long baffle and found no change in oil consumption.
|
Interesting Fred.
Ken, what difference would calibrating the dipstick make on oil consumption?
Dan[/quote]
We have found that for some reason some GMC dipsticks are mis-calibrated. In my 1976 GMC with a 455 after a filter and oil drain putting in 5 quarts fills it to the full mark on the dipstick. Some other GMCs take 6 quarts to make it to the mark. I think the difference is due to the stick being a different length or the tube being different length. I did compare mine once to a 1974 coach at BS that was burning oil and took 6 quarts to make it to the mark on a change. I found that my stick was slightly longer.
I and other pilots have found that when you over fill a crankcase you burn off the top quart or two very rapidly. I feel that this may also be happening to some GMC owners.
I use 1 quart of oil in 6000 miles. I fill mine with 5 quarts after a filter and oil drain. That brings mine exactly to the full mark. I do not care what year your coach is or where the markings are on the dip stick our engines should all hold the same amount of oil.
I also only use Rotella 15 W 40 Dino oil as did the previous two owners since new. Two other oil related things I have are a 180 degree thermostat and an external oil cooler. All of these were done by the first PO so I'm not about to change anything. Cooler oil is happy oil. I feel all of these contribute to my low oil consumption.
Oil level is not the only thing that can affect oil consumption but it is one of the things that could cause it. Over heated rings that lost tension, broken rings, worn rings, worn valve guides, glazed cylinder walls, and PCV problems are a few more things could also cause it.
Someone posted that their oil turns black in a few hundred miles. That is usually caused by excessive blow by past the rings on one or more cylinders. I saw that once on an an airplane engine where the compression rings worked and it would pass a compression test but the oil rings on one cylinder did not seat correctly. Everything inside the engine was coated with baked on black stuff.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
|
|
| Re: Valve covers [message #76639 is a reply to message #76616] |
Sun, 14 March 2010 17:51 |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
Karma: 0
|
Senior Member |
|
|
| roy1 wrote on Sun, 14 March 2010 11:43 |
Fred
My 76 glenbrook came from GM with the auto type valve covers and it doesn't use oil due to these covers.
Roy
|
that's the mystery Roy. someone reported a decrease in consumption when they changed to the correct covers.
Fred V
'77 Royale RB 455
P'cola, Fl
|
|
|
|
| Re: Valve covers [message #76657 is a reply to message #76632] |
Sun, 14 March 2010 20:09 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
| WD0AFQ wrote on Sun, 14 March 2010 14:56 |
Ok Ken. I have never had a problem with the one qt over thing as I never over fill mine. 5 qts on the old engine dipstick, when I changed it, was full on the stick. HAve not determined yet what this dip stick says at full. Miguel put 6 qts in engine to start and I figure that is correct, 5 on changes.
dan
|
I think you are probably OK.
I just do not understand why some GMC dipsticks are mis-calibrated. There must have been something changed in the production run over the 6 years they were made.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
