Engine parts cleaning during overhaul - Page 4
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 4 of 6 FirstFirst 1 2 3 4 5 6 LastLast
Results 46 to 60 of 88
Like Tree25Likes
Northstar Engines and System Technical Discussion Discussion, Engine parts cleaning during overhaul in Cadillac Engine Technical Discussion; Might be a good read for you Cometic MLS guys - no opinion intended or implied - just passing on ...
  1. #46
    drewsdeville's Avatar
    drewsdeville is offline Cadillac Owners Master
    Automobile(s): none
    Join Date
    Oct 2004
    Location
    WI
    Posts
    5,277

    Re: Engine parts cleaning during overhaul

    Might be a good read for you Cometic MLS guys - no opinion intended or implied - just passing on an article I read last fall.

    "MLS—The New Standard
    MLS head gaskets have been out for several years now, and they've gone from exotic components for only the most high-end race motors to standard equipment on just about everything from Street Stock engines to Cup motors. "MLS" stands for Multi-Layer Steel and refers to how these gaskets are constructed. Unlike a more traditional composite gasket which uses different materials pressed into one solid gasket, an MLS gasket is constructed of three or more pieces of steel that are only attached together at a few points, typically by rivets.

    But the most interesting aspect of the MLS design isn't the number of layers of steel it uses, but what is done to the two layers on the outside of the gasket. A bead is rolled, or embossed, into the steel that goes around the cylinder bores as well as the water passages and even the oil drain back holes between the block and heads. When the cylinder heads are bolted to the block, the gasket is compressed but the sealing beads aren't crushed flat. It's these beads that provide the seal. And in the event combustion pressure causes the head to lift off the block slightly, the beads are able to spring back a bit so that the seal is maintained between the block and heads.

    "There are actually many differences between our MLS gaskets and composite gaskets offered by other companies," explains Kevyn Kistner of Cometic Gasket, one of the leading manufacturers of MLS gaskets in the industry. "The most noticeable difference is the materials used in each design. Cometic's MLS gaskets utilize multiple layers of embossed 301 stainless spring steel which can withstand the constant abuse provided by today's high-performance and race engines. By utilizing this design we take advantage of an active seal that is capable of sealing even when a cylinder head starts to move around.





    "
    98eldo32v and 98eldo32v like this.

  2. #47
    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    43,333

    Re: Engine parts cleaning during overhaul

    Yep - I have that article and paragraphs in my files. I took that into consideration when I posted the query on the MLS theory for the Northstar. If you'll look at the Northstar Cometic MLS gasket, it's quite sophisticated.

    .........but I still want to get away from the idea that Northstar heads "slide around" (they do each have two pretty healthy dowel pins) - I maintain that the original bolts, as used, can't do the job over time, so perhaps, in conjunction with studs, the MLS would be the way to go.

    (Yes, my post implied that the gaskets, once crushed, are pretty incompressible - that's based on pulling apart the Olds engines for valve jobs and looking at the MLS gaskets used. No, I don't currently have an example in the shop.)

  3. #48
    mtflight's Avatar
    mtflight is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 White Diamond ETC
    Join Date
    Jan 2005
    Location
    Dallas, TX
    Posts
    2,528

    Re: Engine parts cleaning during overhaul

    Quote Originally Posted by Submariner409 View Post
    .........but I still want to get away from the idea that Northstar heads "slide around" (they do each have two pretty healthy dowel pins) - I maintain that the original bolts, as used, can't do the job over time, so perhaps, in conjunction with studs, the MLS would be the way to go.
    I've been intrigued by this, and have been studying the situation. The information you have shared on the design characteristics of stretch to yield bolts has convinced me that the head bolts are definitely a weakness of the engine design as a whole.

    The fire rings in the composite head gasket are only held in place by friction of the head bolts on the Z axis (up down).Said dowels hold the gasket material in place and the gasket material holds the rings in place on the X, Y axis (flat plane).

    Once the integrity of the gasket material around the open deck water jacket becomes compromised, the siamesed fire rings in the gasket are more likely to let blow-by gases into the water jacket. There is usually some tell-tale sign that this has happened, and it is usually paired with lack of gasket integrity (eg, a tear, a hole, flaking, rust, etc).



    I am not sure about the sliding of these rings, but AJ has mentioned bunching up of the head gasket in the waterjacket area, possibly indicating that the ring unit does break loose in some way and beats to its own drummer--at that point there would be cooling system pressurization and possibly coolant spilled into the bolt holes. I see a connection between the material that holds the siamesed rings in place on the 2D XY axis.

    We have seen the composite material in these head gasket disintegrate or crumble in the waterjacket area, sometimes in cars with alleged "good cooling system maintenance", sometimes appearing rusty or cardboard-like. This situation occurred less on the 93-96 iterations of the same engines, possibly having to do with gasket materials being better protected when coated with silicates, at least during the 2-year timespan between scheduled coolant changes. Those engines devoid of coolant exchanges are most likely the ones that account for the majority of existing failures of those years--suffering exactly the same way the 97 and up do.

    I therefore agree that studs in conjunction with MLS would most likely solve the riddle from reoccurring. In reading the article it seems that the surface finish is imperative when installing the MLS. Would scraping suffice, or how would one go about resurfacing them as best as possible?

    MLS gaskets are multiple layers of the same pattern. The dowels would hold the cylinder cutouts in place versus the OE gaskets that have "floating" rings that are subject to the integrity of the rest of the gasket materials, which are subject to many stressors and oxidizing in the coolant/water mix. Good cooling system maintenance is, of course, one less factor to worry about.
    98eldo32v and 98eldo32v like this.

  4. #49
    Tom's Caddy's Avatar
    Tom's Caddy is offline Cadillac Owners Fanatic
    Automobile(s): 2001 GTP / 2005 CTS / 2008 DTS
    Join Date
    Jul 2012
    Location
    Ontario, Canada
    Posts
    333

    Re: Engine parts cleaning during overhaul

    Great thread guy's, my question is, could the motor mounts be a result with this problem. In regards to the thread with gasket material bunching and the rings moving, at that point due to engine torque. I know people have replaced lots of bad motor mounts on this board. My DTS has a new redesigned motor mount I believe. I hope it has solved the motor mount issue, if anybody knows of replacing a motor mount on a 2006-2011 please let me know. All the best.

  5. #50
    mtflight's Avatar
    mtflight is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 White Diamond ETC
    Join Date
    Jan 2005
    Location
    Dallas, TX
    Posts
    2,528

    Re: Engine parts cleaning during overhaul

    Quote Originally Posted by Tom's Caddy View Post
    could the motor mounts be a result with this problem. In regards to the thread with gasket material bunching and the rings moving, at that point due to engine torque.
    Nice DTS. the gasket issue is completely internal to the engine and so in a different dimension than the mounts. If the mounts were holding on to the engine heads then maybe, but I doubt it.

    That would be a most surreal scenario. One way to decrease the stress on the engine mount, is to gently ease into the throttle when moving from a standstill, so that the stress is more linear--versus a quick strong jerk.

  6. #51
    CadillacLuke24's Avatar
    CadillacLuke24 is offline Cadillac Owners Connoisseur
    Automobile(s): Alexandra - 96 SDV
    Join Date
    Jul 2010
    Location
    Middle of Nowhere
    Age
    23
    Posts
    4,810

    Re: Engine parts cleaning during overhaul

    Tom's about the most proactive owner I've evern seen

    Motor mounts will take awhile to go bad, and you'll be able to tell. I think you can hear a clunk on acceleration, and when you brake torque the engine, it will jump.

  7. #52
    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    43,333

    Re: Engine parts cleaning during overhaul

    mt, felt/graphite head gasket material over/across ANY coolant passage/hole/steam hole in ANY engine looks like pure dog doo after so many years in contact with coolant. Old head gaskets that come off 1970's (or even a recent 1964 283 Chevy) are, ummmmm, impressive. Any portion in contact with coolant is a real spongy mess and the compressed portions are as brittle as eggshell.

    I don't feel that the bulged parts in the Northstar gaskets are contributory - the bulged parts are the normal result of hanging toilet paper out in the rain too long. The squashed, compressed, clamped areas are where we're looking.

    In no picture in N* Performance to date have we seen where coolant has migrated through the compressed gasket to a cylinder; we have seen where coolant has passed over/around the gasket and/or fire ring - loss of head bolt clamping pressure, and, as DD pointed out, the inability of the stretched head bolts to "roll with the punches".

    TC, it's very doubtful that a broken front center motor mount would contribute to head gasket failure. To muddy that water, there are those who question the wisdom of the Eldorado torque strut mounting to the left (front) cylinder head: Every time you call upon the engine for max output at max rpm that's another 300 lb/ft of torque applied to the left head - and it doesn't seem to make the Eldorado any more or less prone to head gasket failure.

  8. #53
    mtflight's Avatar
    mtflight is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 White Diamond ETC
    Join Date
    Jan 2005
    Location
    Dallas, TX
    Posts
    2,528

    Re: Engine parts cleaning during overhaul

    hey sub.

    So these gaskets always look that bad? It's a miracle they seal as well as they do. Maybe they are just not apt for this type of metal alloy and power output. The cheap bolts don't help.

    Basically you're telling me that we have a modern, high tech, high feature, aluminum long block, aluminum heads engine with a very old-school, old technology, outdated, composite felt/graphite head gasket. I assume the short term testing was extensive and it passed without issues, simulating many years of use. I wonder if they have any way to simulate the aging of the engine with old coolant? Or better yet, to have one of those look-like-poop gaskets ensure reliable head gasket sealing over time. That's probably where the engineering team had a lapse of judgement--it passed the short term simulations, and they assumed it would hold up like it does in any other iron block. Then they changed the coolant on the experiment, at the end of 96 and oh there's a little spike in head gasket failures right after. Time to redesign that seal with coarser and longer bolts... then again with more coarse bolts...the we will get it right eventually approach.

    I was under the impression that reliability in sealing the heads has been noted to be more critical in aluminum alloy engines than it is in iron block engines...something having with to do with metals expanding and contracting at different rates.

    I think the Northstar engine came with a prescription for a different type of gasket,one that is on par in technology. One could argue that MLS gaskets weren't common yet. However I read that GM has been one of the last big manufacturers to catch up to the times in finally using MLS gaskets. They finally figured it out by the time they put out the LC3 Northstar: match the gasket to the high sealing requirements relative to the output of the engine. Was this a page in the book about the dinosaur days of GM?

  9. #54
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    72,256

    Re: Engine parts cleaning during overhaul

    Quote Originally Posted by mtflight View Post
    If the mounts were holding on to the engine heads then maybe, but I doubt it.
    My right torque strut is mounted to the front head.

  10. #55
    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    43,333

    Re: Engine parts cleaning during overhaul

    I said nothing that would indicate that basic head gasket technology had not kept up with engine design over the years - I said that felt-graphite-whatever head gasket material, in contact with coolant for long periods, looks nasty. Head gasket manufacturing technology has not changed radically over the years - the basic system works and works well if the cylinder head is securely held to the cylinder block. Yes, some head gaskets use Teflon coatings or some such - but the basic gasket appears to be the same as 25 years ago. Look at the CF pictures of different Northstar overhauls - see any exotic gasket materials there ?

    If a portion of the gasket material is in contact with coolant/a cooling passage it has nothing to do with sealing a cylinder - it's simply excess material hanging out in the breeze. The compressed areas of the gasket form the "seal" - the uncompressed areas are simply along for the ride.

    Alloy and power ????? The Northstar is a little engine in terms of pure size and NA power - any kid on the street can hand-build a Chevy 327 that will eat a Northstar alive for power and torque, an use cheap good ol' JC Whitney FelPro gasket sets to do it. The 1967 Corvette 427/435 actually put out just over 500 hp and the whole engine was assembled with paper, cork and felt gaskets - there are still original 427's running today. I daresay that you and I both have several square feet of cork and paper gasket materials in our shop drawers.

    It's not the gaskets in and of themselves - it's the bolts, the threads, the open deck, and the siamesed cylinders that don't support the gasket in doing its job.

    EDIT: "Power" - The Northstar is a 279 C.I. small displacement high-winding engine. The old Chevy 283 is almost the same C.I. in an OHV pushrod configuration. Given the time and proper parts, a roller cam NA 283 can be built that would easily surpass the VIN 9 Northstar "power" (and torque) by over 50%.......... and not blow head gaskets............but 283's and 327's are disappearing - everyone's building the later 350 version of the SBC.

  11. #56
    Tom's Caddy's Avatar
    Tom's Caddy is offline Cadillac Owners Fanatic
    Automobile(s): 2001 GTP / 2005 CTS / 2008 DTS
    Join Date
    Jul 2012
    Location
    Ontario, Canada
    Posts
    333

    Re: Engine parts cleaning during overhaul

    Thanks mtflight, I love my DTS. I still think some people on this board that say the motor mount issue could be a contributing factor could have something there. I`m told by my Cadillac dealer and many people on this board, including my owners manual to WOT my DTS often. They give many benefits for this. And it is lots of fun. Sorry to some of you out there but I only use Dexcool but, stongly believe it is poison if not changed very often. There is a thread on this, from a former GM employee on this matter a good read. I use it because it is the best for aluminum, but on seals and gaskets it is very bad if left in to long. 1. Old Dexcool 2. bolts (shorter less course threads) 3. maybe gasket production 4. motor mounts 5. transverse motor. All this after years of WOT would cause failer in any engine, my 2 cents. All the best everybody.

  12. #57
    98eldo32v's Avatar
    98eldo32v is offline Cadillac Owners Connoisseur
    Automobile(s): 98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
    Join Date
    Apr 2010
    Posts
    1,788

    Re: Engine parts cleaning during overhaul

    "So these gaskets always look that bad? It's a miracle they seal as well as they do. Maybe they are just not apt for this type of metal alloy and power output. The cheap bolts don't help.

    Basically you're telling me that we have a modern, high tech, high feature, aluminum long block, aluminum heads engine with a very old-school, old technology, outdated, composite felt/graphite head gasket."


    WELCOME TO BEAN COUNTING 101 /COPORATE LEVEL.

  13. #58
    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    43,333

    Re: Engine parts cleaning during overhaul

    Quote Originally Posted by Tom's Caddy View Post
    I love my DTS.
    You might want to go way up ^^^ to the top black bar and study the entire Cadillac Technical Archive (speaking of articles by Cadillac engineers.............)

    Nothing wrong with properly maintained DEX-COOL.

    WOT with bad engine mounts is plain folly. Things break then - big time, and it's not head gaskets.

  14. #59
    mtflight's Avatar
    mtflight is offline Cadillac Owners Connoisseur
    Automobile(s): 1999 White Diamond ETC
    Join Date
    Jan 2005
    Location
    Dallas, TX
    Posts
    2,528

    Re: Engine parts cleaning during overhaul

    Quote Originally Posted by Submariner409 View Post
    Nothing wrong with properly maintained DEX-COOL.
    on a Northstar engine, per the manufacturer's instructions? 150,000 miles or 5 years?

  15. #60
    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    43,333

    Re: Engine parts cleaning during overhaul

    I, personally, would not go that far/long, but there are hundreds of thousands of engines out there that do .............. Not every car owner is as paranoid/fanatic as our crop of CF members................

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