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Verell Boaen (Verell)
Junior Member
Username: Verell
Post Number: 150
Registered: 5-2001
| | Posted on Saturday, June 22, 2002 - 11:41 am: | |
CORRECTION: 518 IN O-RING GROOVE WAS BADNESS!
The O-ring needs to compress more than the 518 allowed! When I installed my cams, the oil seal was off-center by 20 to 30 mils. On the top side of the cam there was a visable gap betweenn the seal lip & the cam. On the bottom the lip was compressed outward.
Of course I only remembered to check this after I'd already spent 6 hours installing the belts & setting up cam timing(DUH). I went to bed last nite bummed out because I thought I was going to have to pull the front cams again & re-do the belt timing.
When I woke up this am, I realized that I could just slip the top 1/2 of the o-ring out of the groove & clean scrape out the entire groove while rotating the aluminum ring. It was better than pulling the cams again. Spent 1-1/2 hours on a stool bending over the engine compartment, stretching to scrape out the o-ring groove, & trying to see what I'm doing w/ a trouble light & inspection mirror. Now I know how an oral hygenist must feel cleaning wisdom teeth.
Anyway, It's done & sure 'nuf the seals are now concentric w/the cams. |
Verell Boaen (Verell)
Junior Member
Username: Verell
Post Number: 146
Registered: 5-2001
| | Posted on Thursday, June 20, 2002 - 10:17 pm: | |
Mark,
As I said, this time I'm going w/tried & true gasket w/RTV as a dressing & a dab at the head-cover seam-o-ring joints.
FUTURE POSSIBILITY:
518 & no gasket. I suspect the head-cover seam is at the mid-line of the o-ring, but would want to measure it for sure. If so, then I don't see how the seal could end up 'off centerline'.
518 IN O-RING GROOVE WASN'T NECESSARILY BAD:
One thing I noticed after pulling things apart is that the 518 had filled in the grooves around the o-ring. Ie: The groove was now round instead of rectangular, & there was a complete mold of the compressed o-ring. What was really interesting is that the o-ring was barely compressed! I had to look hard to determine if it was compressed at all, & couldn't tell for sure! It did touch the groove side to side at the seam, & also touched the top & bottom of the groove. There was a very thin film of 518 covering the contact points, I don't believe the o-ring was actually touching the metal top-bottom, but may have been touching side-side.
Based on this, I'm not too worried about over-compressing the o-ring. There's still plenty of room in the groove for it to flatten out, & even flex some.
I am worried about what looks like a very marginal seal at the O-ring top & bottom. I'm wondering if my grooves were somehow cut for a larger diameter o-ring, or were just miss-cut. Anyway, since there was this nice round groove molded of 518 into the aluminum ring, I decided to leave it.
I did clean out the grooves in the head & cam cover. The net effect of this should be to slightly increase the o-ring's compression, hopefully ensuring a tighter seal.
I'm going to do a trial installation of the cam cover w/o any sealant & verify that the aluminum ring can still be rotated by hand, and that the cams are centered on the seals.
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Mark Eberhardt (Me_k)
Junior Member
Username: Me_k
Post Number: 66
Registered: 5-2002
| | Posted on Thursday, June 20, 2002 - 9:21 pm: | |
I didn�t realize they had an activator to bond it to rubber. I know there aren�t any free metal ions there without it. I still don�t think I would want it on the oring. The stuff gets pretty hard, maybe though??
I was working on a project at work a couple years ago and I spoke with an engineer at loctite, he told me primer was only need on things that don�t really corrode, like stainless and plastic, which is what I was working with. He said it was originally developed for aluminum applications were are lot of free ions, I took that to mean primer wasn�t required. I�m sure it can�t hurt and probably cures faster with it.
Are you thinking you�re going to leave the gasket out or just coat it? I�d be worried about over compressing the oring or forcing the cam seal off center line without a gasket.
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Verell Boaen (Verell)
Junior Member
Username: Verell
Post Number: 144
Registered: 5-2001
| | Posted on Thursday, June 20, 2002 - 12:34 pm: | |
Well,
Loctite does recommend the anaerobics for sealing rubber-metal joints. (see below). They also recommend using an
I'm not opposed to using RTV, in fact I recently recommended it for this application in another post. This time I'm going to go w/RTV. However, I think next major service I'm going to try using 518 to form the entire cam cover gasket.
Right now I'm sitting on the fence between RTV & the anaerobics. I think RTV is easier to strip/remove if you have to disassemble things again. It's a PITA to clean up before it cures. It also makes a reasonable gasket dressing. However, I'm more comfortable w/518 when forming a gasket in place. I also really like that the anaerobics take a long time to cure, so I can shift things around if necessary.
Last time I replaced my cam seals I used 518 to seal the gasket to O-ring gap. It conformed to the o-ring & slightly adhered to it. ie: Could easily be peeled off, but definitely was adhering. I had to pull pretty hard to get the cam cover to separate from the o-ring, and again to pop the o-ring out of the head. (Unfortunately I used too much & when it was squeezed out it tore the gasket in one place w/predictable results over time. There were no signs of oil leaking from the other 3 o-ring joints, just at the one w/the torn gasket.
I also used 515 to seal the cam seals into the aluminum ring. They were stuck in there hard & fast. When I finally broke them loose, a lot of the sealant came out adhering to the seal.
I've just used 515 again to seal my cam seals into the aluminum rings.
I chose to use 518 last time because of the following Loctite recommendation in a user FAQ:
Loctite RECOMMENDS 515/518 FOR CAM SEAL APPLICATION
http://www.loctite.co.nz/userforum/forum10.htm
They said: "we have found that in most cases the product which performs best on rubber coated oil seals is Loctite 515 Master Gasket. Other suitable products are Loctite 518 Master Gasket or Loctite Auto Gasket.
Loctite 515 Master Gasket, Loctite 518 Master Gasket or Loctite Auto Gasket are anaerobic compounds which have been specifically formulated for sealing flat flanges on machined surfaces. As with all Loctite and anaerobic gasketing compounds, this material has reasonably high surface adhesion properties, which will assist in holding the seal in the housing. In addition to this, its high viscosity prevents migration of the product from the sealing surfaces during assembly and cure.
Assembly instructions;
- To ensure a reliable cure, Loctite 7649 Activator must be applied to the rubber shell casing and allowed to dry, prior to assembly.
- Once the activator has dried, apply a thin smear of Loctite 515 Master Gasket, Loctite 518 Master Gasket or Loctite Auto Gasket to the outer shell of the oil seal and also to the bore of the housing.
- Drive the seal into the housing using the recommended tools.
- Allow 30 minutes for the sealant to cure, prior to starting the engine. "
In the product descripition I took the following to imply primer is needed w/aluminum:
"fills gaps to 0.050" (1.27 mm) with primer. can - be used on a variety of metal surfaces including aluminum."
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Mark Eberhardt (Me_k)
Junior Member
Username: Me_k
Post Number: 63
Registered: 5-2002
| | Posted on Wednesday, June 19, 2002 - 10:10 am: | |
You can go wrong with the KleenNprime. You need it on stainless. Anything aluminum has gobs of free ions so I usually just do the final clean with any of the brake clean products on the market and put it together. Gas or kerosene leave a residue. I wouldn't use 574,515,518 on the valve cover because I just don't think it will bond properly to the oring. I use a dab of silicone like the factory does(did). |
Verell Boaen (Verell)
Junior Member
Username: Verell
Post Number: 143
Registered: 5-2001
| | Posted on Tuesday, June 18, 2002 - 10:19 pm: | |
Larry,
The O-rings are nitrile, it's pretty tough stuff, so I wouldn't worry too much about a solvent hurting it.
I use thin nitrile gloves while working on my car. Wore them when cleaning the old dye off of my seats w/ lacquer thinner. Didn't penetrate them.
I'm not familiar with 574, but it must be similar to Loctite 515 & 518. They both require metallic ions in addition to no air to cure when used on aluminum. Loctite's KleenNprime both cleans the area (solvent is acetone), and leaves enough metallic ions to ensure a proper cure.
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Lawrence Coppari (Lawrence)
Junior Member
Username: Lawrence
Post Number: 53
Registered: 4-2002
| | Posted on Monday, June 17, 2002 - 11:19 am: | |
The 574 is an anerobic sealant, not a thread locker. It's used on balance shaft housings where there is no gasket (on my Porsche). It has no affect on threads. You just put it where there us metal to metal contact. It seals where no oxygen is present. It remains like toothpaste where it is exposed to air.
I have to try this. If it does not seal, I have lost nothing but a little time. I can always buy the gasket. |
bruno bandaras (Originalsinner)
Junior Member
Username: Originalsinner
Post Number: 107
Registered: 5-2002
| | Posted on Monday, June 17, 2002 - 10:28 am: | |
I clean with gas and wipe dry. I had a factory dealer service tech slop the stuff all over my car when they reassembled it. It seems they like to over do it. Just a dab in the right spots should work equally as well. I use the red -heat&gas&oil resistant permatex. Seems to work good. It does seem my oil pan leaks after a while no matter what I do. Loctite just scares me coming of. I've always been an anti seize guy. |
Lawrence Coppari (Lawrence)
Junior Member
Username: Lawrence
Post Number: 52
Registered: 4-2002
| | Posted on Monday, June 17, 2002 - 10:20 am: | |
This past weekend I replaced the timing belts on my 328. Cam shafts lined up fine and valve clearances were all within specified tolerances. The cam shafts were not leaking at the drive ends.
My next step is to reinstall the valve covers. When I removed them, there was considerable red sealant in the corners in at the ends of each of the three gaskets. There was more than needed to bridge the gap between the gasket and the O-ring.
I'm thinking about just a dab at the base of the O-rings rather than slathering it all over the place as had been done. I feel that the surfaces must be cleaned for any sealant to work. What should I use to clean the O-ring area? I worry about any solvent I might choose having a detrimental effect on the O-rings. Also, I assume you tighten the acorn nuts from the center outward as is typical for other vehicles?
What do you guys think?
Turns out that both my oil pan and gear box are leaking at their respective gaskets. I purchased the oil pan gasket and will install it. I think I'll try Loctite 574 on the gearbox providing there is no spacing problem by not using a gasket. |
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