LD8 non-interference motor?
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 16
Northstar Engines and System Technical Discussion Discussion, LD8 non-interference motor? in Cadillac Engine Technical Discussion; Hello My name is Danny this is my first time posting anything. I have been looking at this site for ...
  1. #1
    GXPN* is offline Cadillac Owners Member
    Automobile(s): 2004 Bonneville GXP LD8 Northstar Engine
    Join Date
    Jan 2013
    Posts
    7

    Camshaft chain tensioner HELP!!!

    Hello My name is Danny this is my first time posting anything. I have been looking at this site for 2 days and all of you seem really knowledgeable. I have a 2004 Bonneville GXP. I have looked at bonneville sites but no one knows northstars there. So here is the issue. I started the car after leaving the store and when i went to drive away it made a loud noise and started to rattle like some one put marbles in the front valve cover. I shut it off and had the car towed home. I pulled the valve cover off and found all the cam followers on the intake cam could be pulled out with no effort (the followers on the exhaust cam are all tight) . in fact i touched one and it fell out. I also found a long thin piece of nylon like material laying down in a channel next to the timing chain. it seems to me that all the lash adjusters on the intake side are stuck i pulled them out and they don't move at all. the top side of the timing chain has a aluminum guide that is just flopping against the chain when i crank it over and makes a horrible noise. So that is where i am at. I Say all this because i have no clue if any of this is wrong or right i am not familiar with these motors. I know old chevy engines not north stars but i want to fix this issue. I know I am not very knowledgeable with this , actually pretty dumb, but that's why i am asking for help. By the way all this is on the head at the front of the car not back at the firewall.Thanks to anyone wanting to comment here I appreciate it.

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    44,003

    Re: Camshaft chain tensioner HELP!!!

    With that much mechanical damage my guess is that you're in for an engine overhaul - just too much broken and moving around, in addition to the real possibility of metal shavings throughout the oil system. If the cam followers did actually leave the face of the cam and lash adjusters then you also have cam problems. A simple (???) left head pull won't fix this one................

  4. #3
    basscatt's Avatar
    basscatt is offline Cadillac Owners Master
    Automobile(s): 89 Coupe DeVille, 95 Sedan DeVille, 03 SLS, two 02 DHS's
    Join Date
    Feb 2004
    Location
    Minnesota
    Age
    63
    Posts
    9,613

    Re: Camshaft chain tensioner HELP!!!

    that really sounds strange unless the car has hundreds of thousands of miles on it -

  5. #4
    GXPN* is offline Cadillac Owners Member
    Automobile(s): 2004 Bonneville GXP LD8 Northstar Engine
    Join Date
    Jan 2013
    Posts
    7

    Re: Camshaft chain tensioner HELP!!!

    Yes the car has 198000 miles on it. The sad thing is it was running great and the head looks awesome no gunk or build up at all. So what your saying is that I have to get a new motor or rebuild this one. the followers never left there place until i moved them the cam looks good but there are metal shavings in the oil.

  6. #5
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    44,003

    Re: Camshaft chain tensioner HELP!!!

    Quote Originally Posted by GXPN* View Post
    Yes the car has 198000 miles on it. The sad thing is it was running great and the head looks awesome no gunk or build up at all. So what your saying is that I have to get a new motor or rebuild this one. the followers never left there place until i moved them the cam looks good but there are metal shavings in the oil.

    Overhaul time
    with some very dedicated cleaning of every oil passage in the engine. Many parts stores and online sources sell kits of various length/various size bristle brushes for just this job.

  7. #6
    basscatt's Avatar
    basscatt is offline Cadillac Owners Master
    Automobile(s): 89 Coupe DeVille, 95 Sedan DeVille, 03 SLS, two 02 DHS's
    Join Date
    Feb 2004
    Location
    Minnesota
    Age
    63
    Posts
    9,613

    Re: Camshaft chain tensioner HELP!!!

    Quote Originally Posted by GXPN* View Post
    Yes the car has 198000 miles on it. The sad thing is it was running great and the head looks awesome no gunk or build up at all. So what your saying is that I have to get a new motor or rebuild this one. the followers never left there place until i moved them the cam looks good but there are metal shavings in the oil.
    ---------------------
    you can get more information in the Northstar Performance forum -

    http://www.cadillacforums.com/forums...al-discussion/

  8. #7
    GXPN* is offline Cadillac Owners Member
    Automobile(s): 2004 Bonneville GXP LD8 Northstar Engine
    Join Date
    Jan 2013
    Posts
    7

    Re: Camshaft chain tensioner HELP!!!

    ok cool thanks for the help

  9. #8
    GXPN* is offline Cadillac Owners Member
    Automobile(s): 2004 Bonneville GXP LD8 Northstar Engine
    Join Date
    Jan 2013
    Posts
    7

    LD8 non-interference motor?

    I read some where and just want to check if it’s true. There was a site that said the Northstar LD8 in my 2004 GXP was designed so if the timing chain ever went bad or the motor jumped time there was enough clearance that the valves and piston would not be damaged. Anyone know if this is true?

  10. #9
    Manic Mechanic is offline Cadillac Owners Fanatic
    Automobile(s): 2001 DeVille
    Join Date
    Sep 2011
    Location
    Magnolia, TX (NW of Houston)
    Age
    44
    Posts
    405

    Re: LD8 non-interference motor?

    EDIT: It is interference.

    Vernon

  11. #10
    GXPN* is offline Cadillac Owners Member
    Automobile(s): 2004 Bonneville GXP LD8 Northstar Engine
    Join Date
    Jan 2013
    Posts
    7

    Re: LD8 non-interference motor?

    What do you mean by "free wheeling"?

  12. #11
    Manic Mechanic is offline Cadillac Owners Fanatic
    Automobile(s): 2001 DeVille
    Join Date
    Sep 2011
    Location
    Magnolia, TX (NW of Houston)
    Age
    44
    Posts
    405

    Re: LD8 non-interference motor?

    It means under normal build specs the valves and pistons won't be able to contact each other, so you can turn the flywheel freely with the heads on and timing chains off without concern of valve train damage. It is the opposite of interference.

    Vernon

  13. #12
    GXPN* is offline Cadillac Owners Member
    Automobile(s): 2004 Bonneville GXP LD8 Northstar Engine
    Join Date
    Jan 2013
    Posts
    7

    Re: LD8 non-interference motor?

    Well the reason i ask the question is i think i may have jumped time when i went to take off the other day. I posted something about it on the deville forum (not knowing at the time there was a Northstar forum) but there was a bang sound then the engine sounded like some one put marbles in the valve cover. found all my cam followres on the LI cam could be pulled out by hand. Wondering if i bent valves and the might be stuck down.

  14. #13
    Manic Mechanic is offline Cadillac Owners Fanatic
    Automobile(s): 2001 DeVille
    Join Date
    Sep 2011
    Location
    Magnolia, TX (NW of Houston)
    Age
    44
    Posts
    405

    Re: LD8 non-interference motor?

    I saw your other post. I looked into this some more tonight and I must retract my post. I studied on my technical information and factory repair guide sites during lunch and could not find anything relating to the Northstar LD8 being an interference engine. And when timing my cams no instruction for anything I did mentioned it. I know the repair procedures are really random and there's not a step by step to assemble one from scratch but usually if an engine is interference their is plenty of warning. Not so on this one. After researching it again I've found much evidence of the Northstar in fact being an interference engine. I was careful with mine but I hope no valves are bent. I might drive it off a bridge if so. I also cannot think of any likely reason why all of your LI followers are loose other than bent valves, the fact that your tensioner was slacked and damaged only supports the jumped time and bent valves theory. Based on you previously stated high mileage I would take a good look at the rest of the car. If the rest is really good and you really like the car get a lower mileage 2004+ LD8 and put it in. Don't try to fix yours, it's already got 200K on it and not worth what it would take to fix it again. There's little to nothing to be gained from rebuilding the engine when you can't change it from the $1200 one in the salvage yard with under 100K on it. I'm just finishing a overhaul on mine and it's a lot of work. If a salvage 2000 spec engine wasn't just as prone to blow a head seal with my driving habits I would have swapped one in.

    Sorry I was incorrect. I made an assumption based on lack of information and never having heard of a N* bending valves in the past.

    Use this site to look for a salvage engine if that's what you decide to do: www.car-part.com

    Vernon

  15. #14
    GXPN* is offline Cadillac Owners Member
    Automobile(s): 2004 Bonneville GXP LD8 Northstar Engine
    Join Date
    Jan 2013
    Posts
    7

    Re: LD8 non-interference motor?

    Thanks alot for looking into it I figured that i had pretty big problems. I am going to start pulling the motor and looking for a new one. Once again thanks alot for the help

  16. #15
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    44,003

    Re: Camshaft chain tensioner HELP!!!

    Threads merged to keep same info in the same place.................

    For grins and kicks, Google "cadillac northstar engine interference" or something close. You'll get a lot of "yes, it is" and "no, it's not".

    For a pretty definitive answer, call Tim Carroll at Carroll Custom Cadillac in Washington state or the guys at CHRFAB.

    http://www.carrollcustomcadillac.com...Infospecs.aspx

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

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.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting