400 Pontiac Engine Trouble - 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 08-29-2003, 06:10 PM
starabby's Avatar
New Member
 
Last photo:
Join Date: Aug 2003
Location: Port Huron, Mich
Age: 57
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
400 Pontiac Engine Trouble(Posted wrong spot)

I am looking for someone who can give me some ideas of what could be wrong with my motor.
It is a 70 Pontiac 400....totally rebuilt....After i got the engine back from being rebuilt, I put Magnum rocker rollers on. I didnt seem to have a problem till i went down to the Woodward Dream Cruise. The next day the car was a little hard to start. When it did start...there was lifter noise. I tried adjusting them and cant get them to quiet. I took off the intake and checked the lifters and found some were collapsed. I replaced them and changed the oil....and still cant get them to quiet down.....I have factor studs in the heads.....not the screw-in studs. I am wondering if that would make a difference. I would appreciate any help anyone can give me. The place that rebuilt the engine is closed till Tuesday....and I kind of wanted to drive my car this weekend. This has got me puzzeled. Thank you......Bob Castell

Last edited by starabby; 08-29-2003 at 07:16 PM.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-30-2003, 05:49 AM
BOBCRMAN@aol.com's Avatar
Member
 
Last photo:
Join Date: May 2002
Location: Holly, michigan
Posts: 7,951
Wiki Edits: 0

Thanks: 13
Thanked 218 Times in 207 Posts
I have seen some problems with roller rockers binding on the stock studs on pontiacs, check to see if the rocker has clearence at the pivot at full lift, if they bind you will need to clearence with grinder or use different length pushrods, be aware that this bind will wipe a cam lobe or at minimum collapse a lifter or break the rocker. Pontiacs in general use a short valve spring, if you use too much lift or too much rocker ratio you will also coil bind or hit the retainers and guide-seal area.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-30-2003, 06:34 AM
Member
 
Join Date: Feb 2003
Location: North Carolina
Posts: 454
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
It sounds like you have the factory bottleneck type of studs. Are you usine the roller tip magnum rockers or a full roller. If your using the roller tips you should be able to adjust as per factory specs (18 ft lbs of torque) if your using a full roller you will have to change over to screw in studs. For now your best bet may be install the factory rockers and adjust as per above and this can be done with the evgine off. Also what is the casting number on the heads and what did the engine come out of? Also what cam are you running? Once I know I may be able to give you more information.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-30-2003, 11:50 AM
starabby's Avatar
New Member
 
Last photo:
Join Date: Aug 2003
Location: Port Huron, Mich
Age: 57
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thank you for your responses, I have tried to readjust them all by moving the rods till they are just tight and then turning the bolt a half a turn. All seems snug,....then i started it again and still very chattery. I am now wondering about if there is enough oil getting to the top of the engine. As ,,,when i was adjusting them yesterday while running....i did not have oil squirting...like i am used to in the small block chevy. It is getting some oil...but not alot. And it took along time to prime the engine in the beginning. I am in the process of taking apart the front of the engine to check the oil plug. If anyone has any helpful information i this process...please let me know.....Thanks again.....Bob
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-30-2003, 12:07 PM
6567GTO's Avatar
Tire Fryer
 
Last photo:
Join Date: Apr 2003
Location: Shelton, CT
Age: 53
Posts: 311
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Do you have an oil gauge or a light on the dash? What is your oil pressure?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-30-2003, 12:09 PM
starabby's Avatar
New Member
 
Last photo:
Join Date: Aug 2003
Location: Port Huron, Mich
Age: 57
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
the oil pressure is 50 when cold ...and goes to around 35 when warm......
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 08-30-2003, 12:53 PM
1BAD80's Avatar
The Smell of Nitro in the morn
 
Last wiki edit: How to adjust valves Last photo:
Join Date: Jun 2001
Location: Mich
Posts: 2,423
Wiki Edits: 2

Thanks: 0
Thanked 2 Times in 2 Posts
I just noticed, you have to post on the same subject and giving different answer's.
I posted instead of sending a PM, SORRY.
__________________
Luv the smell of NITRO in the morning.

Last edited by 1BAD80; 08-30-2003 at 04:30 PM.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 08-30-2003, 01:03 PM
starabby's Avatar
New Member
 
Last photo:
Join Date: Aug 2003
Location: Port Huron, Mich
Age: 57
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Hi, I first posted in the wrong place....first time i posted....and i posted in the interiors. I didnt know how to place it in the engine part...so i posted again in the engine part. Somehow the first post got put in the engine part also....So there are two posts. I am sorry if i got things mixed up. If you are confused please let me know what your confused on. Im am the wife just trying to find some answeres for my husband who is in the garage working on the car. I try to relay what he is telling me. So Please let me know what the different answeres are so i can clear it up and maybe someone else is confused also....Thank you, Bob's wife
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 08-30-2003, 08:09 PM
Member
 
Join Date: Feb 2003
Location: North Carolina
Posts: 454
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Starabby what kind of machine work did you have done as far as the crank? Sound similar to what I got into on a customers engine about a year ago. The person that built the engine put standard bearings on a .010 under crank. When cold the engine had good oil pressure on the gauge and then when it warmed up the pressure dropped to 15 lbs. and below, and hence no sufficient oil pressure to the top of the engine. If you have the paper work on the machine work post it here so I can see if it's the same situation.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 08-30-2003, 08:18 PM
starabby's Avatar
New Member
 
Last photo:
Join Date: Aug 2003
Location: Port Huron, Mich
Age: 57
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Grusome Goat,

Cleaned Block and parts
Regrind Large Crankshaft M 010 R 010
Rebore 8 cylinders .040
Recondition 8 rods
install and align 8 pistons
Remove and instal 5 cam bearings
assemble short blk
Rod bearings are 010
Main Bearings are 010
Moly rings 040
Cam bearings
core plugs
comp cam.477 intake and .480 exhaust

I hope this is what you wanted to know. If there is anyting else please let us know. We are trying to find a diagram of the oil flow to the top of the motor. Thanks......Bob and Carol
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 08-31-2003, 06:32 AM
Member
 
Join Date: Feb 2003
Location: North Carolina
Posts: 454
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Starabbey, thanks, yes this is what I wanted to know but now a couple more questions if I may. What type of oil pump did they install and what was the clearance on the bearings? Also pertaining to valve adjustment what type of rockers are you running and what is the casting number on the center ports of the heads? I'm just wondering if the oil pump was primed prior to installation. Sometimes if the pump itself is not primed prior to installation it will pick up the oil but not suffienicently. In other words if the pump is installed dry it will develop an air pocket and not pump enough oil to the top of the engine. I'm not saying this is the case but it is a possiblity. And what make of pump did they install? And do you know if the pump may have been disassembled to have any clearance work done i.e. check to make sure the bottom plate of the pump is flat or the rotors or vains have the proper clearance.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 09-01-2003, 08:43 AM
Kevin45's Avatar
Just one of the guys
 

Last journal entry: Garage Toys
Last photo:
Join Date: Jul 2002
Location: Urbana, Ohio
Age: 57
Posts: 3,055
Wiki Edits: 0

Thanks: 1
Thanked 12 Times in 12 Posts
Just a wild guess but the rockers and springs aren't pulling the studs out of the head are they? If everything is too tight this can happen and start to loosen up the rockers.

Kevin
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 09-01-2003, 05:42 PM
1BAD80's Avatar
The Smell of Nitro in the morn
 
Last wiki edit: How to adjust valves Last photo:
Join Date: Jun 2001
Location: Mich
Posts: 2,423
Wiki Edits: 2

Thanks: 0
Thanked 2 Times in 2 Posts
Sounds like someone put in Chevy lifters instead of Pontiac.
__________________
Luv the smell of NITRO in the morning.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 09-01-2003, 07:46 PM
Member
 
Join Date: Feb 2003
Location: North Carolina
Posts: 454
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
80, I didn't think of that but you may have hit the nail on the head. Kevin I have run as much as a .474 lift cam on Pontiacs with the pressed in studs but used stock springs and rockers. If the spring pressure and rocker ratio is excessive then the studs will pull out, such as 120 lbs of seat pressure and 1.65 ratio rockers, then the studs will pull out. But 80 as I said before that sounds like what may have happened, Chevy lifters in a Pontiac. And since Chevy lifters are shorter than the Pontiacs the valve won't stay adjusted and the rockers will bottom out whenever 0 lash is obtained.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 09-01-2003, 07:58 PM
6567GTO's Avatar
Tire Fryer
 
Last photo:
Join Date: Apr 2003
Location: Shelton, CT
Age: 53
Posts: 311
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Good point on the lifters. Just might be what happened.
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 09:59 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.