Pop Quiz - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 08-21-2002, 06:53 AM
Mertz's Avatar
Member
 
Join Date: Jun 2002
Location: Reardan, WA
Posts: 666
Wiki Edits: 0

Thanks: 1
Thanked 3 Times in 3 Posts
Post Pop Quiz

I think I already know the answer but here goes.

I pulled some plugs out of the 350 last night to see how it was running. (I just drove it 25 miles with water injection, since removed) The first one looked great, a little yellow on the end of the insulator and a clean tip. I pulled another one at random and it was pure white with just a little carbon on the metal base. It looked like it has never fired. I had just enough time to check to see it I was getting power to the plug and it was fine. I checked other plugs and they had the same yellow color.

I tried running it with the plug wire off and it ran the same as with it on. I heard a little tapping noise from that side.

A couple of days before I put the vacuum gauge on it to try to vacuum time it and there was a steady reading of 14. I had the valve cover off to install a pcv valve and noticed that the rocker arms are loose but there was no tappet noise. There is no water or gas in the oil. The engine obviously idles rough. The plugs were all new Autolite 26 with new cap and rotor and wires.

Any opinions?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-21-2002, 10:36 AM
aka Duke of URL
 
Last wiki edit: Finding vacuum leaks Last photo:
Join Date: Oct 2001
Location: Rockville, MD
Posts: 4,821
Wiki Edits: 1

Thanks: 0
Thanked 0 Times in 0 Posts
Question

[quote]I pulled another one at random and it was pure white with just a little carbon on the metal base. It looked like it has never fired. I had just enough time to check to see it I was getting power to the plug and it was fine. I checked other plugs and they had the same yellow color.

I tried running it with the plug wire off and it ran the same as with it on. I heard a little tapping noise from that side.<hr></blockquote>

Had that plug been firing, you would have noticed an RPM decrease. It is obvious that the plug is not firing in that cylinder. As for the noise, it may be an internal defect. The way to check for a bad cylinder (piston slap-cracked rings-piston pin) is to take the power off that cylinder and listen.

Was every rocker arm loose or just a few?

[ August 21, 2002: Message edited by: KULTULZ ]</p>
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-21-2002, 10:42 AM
bullheimer's Avatar
NEVER use credit cards!
 

Last journal entry: car with tt2's, (stockers going back on)
Last photo:
Join Date: Jan 2002
Location: North of Seattle
Posts: 2,530
Wiki Edits: 0

Thanks: 0
Thanked 5 Times in 4 Posts
Post

cant really tell from what you have here -how are your wires? rockers can feel really loose and still have no play so be okay. if you start it and can find the one thats tapping tighten it till it stops then give it another half turn-didn't i just tell somebody else this this morning?
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-21-2002, 02:27 PM
4 Jaw Chuck's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Mar 2002
Location: Manitoba, Canada
Age: 46
Posts: 4,975
Wiki Edits: 0

Thanks: 2
Thanked 89 Times in 72 Posts
Post

Just because the plug just came out of a box does not mean it is any good, I would switch some plugs around and see if it does the same on the other cylinders, better yet throw one of your old plugs in that is known good and try it. Next I would check the compression and see what it is.
__________________
Outlawed tunes from outlawed pipes
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-21-2002, 02:48 PM
Mertz's Avatar
Member
 
Join Date: Jun 2002
Location: Reardan, WA
Posts: 666
Wiki Edits: 0

Thanks: 1
Thanked 3 Times in 3 Posts
Post

My guess is that it is a bad plug. I thought maybe it was a stuck valve but I get a steady reading on the vacuum gauge. I am going to buy a new plug and install it tonight. I will let you know tomorrow who got the right answer to the quiz.

I am also going to pull the plug and see if I get air coming out of the hole. This to me would tell me that the valves are closing. If nothing or its weak I'll pull the valve cover and watch the valves.

The rockers can wiggles but I think they are tight to the push rods. It seems like to many of them were loose at the same time that is what got me thinking about stuck valves.

If it is the plug it the first time I have ever had a bad Autolite plug in my 20 years of using them.

BTW there was absolutely no change in engine speed or idle smoothness with the wire disconnceted. Again bad plug.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-22-2002, 06:42 AM
Mertz's Avatar
Member
 
Join Date: Jun 2002
Location: Reardan, WA
Posts: 666
Wiki Edits: 0

Thanks: 1
Thanked 3 Times in 3 Posts
Thumbs down

There is no winner, including me.

Put in a new plug and did not notice any change in idle with or without the wire connected. Was really hoping everything would smooth out. Checked the old plug and it was firing. (Guess the Autolites are still OK).

Checked the compression and got a 115 in that cylinder, #6. I checked #1 and got 130 but the engine was a little warmer. Not good but not bad.

I pulled the rocker cover and the rockers can slide sideways but seem to be tight on the pushrods. This is an Olds 350. It has little plastic plugs on the rockers. What are these for? How do you adjust the valves? There are no screws on the rockers. I couldn't adjust them if I wanted to. I started the engine with the cover off and the valves are working just fine.

I put everything back together. I fine tuned the idle screws and got my vacuum up from 14 to 18. I timed it by ear and had the vacuum at 18. I tried timing for max vacuum and backing it off 1", took it for a test drive and got a lot of knock and ping. Kept backing it off until I had no more ping. Set if for best performance. Went back and reset it by ear, test drive, and it ran better. Didn't check it with the timing light.

I plan on running it for awhile and rechecking the plug. You don't suppose the water injection cleaned all the deposits off the plug do you? JUST KIDDING 4 JAW!!!!!!!.

I still don't like the way it idles. The vacuum is fairly steady with only less than 1/2" change but it still seems to run with a miss. I have a 40 Packard and I can put a quarter on edge when it idles and it won't fall. I like my engines to purr. Even my 428 has been tuned to run reall smooth at idle. Is this just inherent in the 350?

I pulled the wire off the #1 plug and didn't really notice any change. I did hear the slight ticking sound that came from #6 when the wire was disconnected. It must have something to do with no explosion in the cylinder and you can hear the valves.

Long and short of it is that the tuning helped. I still think it should idle smoother. And I am not sure why that plug was so clean.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 08-27-2002, 10:13 AM
Member
 
Last photo:
Join Date: Dec 2001
Location: Deerfield Beach, FL
Posts: 51
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

What is the condition of that plug wire? Do a resitance check on that wire and compare it to the suspect one. Or just switch wires and try your on/off test on that cylinder. You are assuming mechanical, but it may be ignition. Good luck.

Walt in SoFlo
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 08-27-2002, 11:45 AM
Mertz's Avatar
Member
 
Join Date: Jun 2002
Location: Reardan, WA
Posts: 666
Wiki Edits: 0

Thanks: 1
Thanked 3 Times in 3 Posts
Post

I checked the wire by using a plug and grounding it and it got spark to the plug. They are all new wires (doesn't always mean much). I still think it might be an ignition problem but what?

I am going to check some of the other back plugs and see how clean they are. You never know it might be the water. The plug in question however doesn't even show signs of getting hot on the outside of the plug.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 06:35 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.