Epoxy... Really??
 

Hi folks!
I can honestly say this is the one pelican forum that I never thought that I would be posting in...

Here is my dilemma. After melting the engine harness in my 87 930 I decided to take the time to diagnose and rectify some oil leaks that have been troubling me for some time. I am planning on replacing the crank breather gasket, thermostat o-ring, oil pressure switch, the distributor o-ring, the oil cooler seals, oil cooler hoses, valve cover gaskets, and contemplating the pulley seal and intermediate shaft seal, when I found this:

http://forums.pelicanparts.com/uploa...1346103172.jpg
http://forums.pelicanparts.com/uploa...1346103187.jpg

This blob of epoxy is just behind the #4 cylinder on the passenger side cam box.

I am assuming that I need to do a partial engine drop, pull the cam covers and inspect the inside of the box(s)?

What is the deal with the epoxy? normal? Covering a larger issue?

I also guess I should be adding cam cover gaskets to my ever growing Pelican shopping list as well as the pulley seal, and intermediate shaft seal (I am having a hard time locating a part number for this one).

Any thoughts and information would be welcomed and appreciated!

Best,

It's standard to have epoxy on the pin bosses. It is used to keep the area fluid tight. Clean the area of all epoxy and re-apply.

The pins have been known to walk out when the bores relax from age and stress. This is usually more of an issue with magnesium boxes.

So if the pin has indeed walked. To rectify I need to open the box re-insert the pin and then re-epoxy? Problem solved - best case?

The oil leak does imply a loosening on the bore, which may be brought on by non bushed arm binding. I would Inspect the arms IF they are not the updated wide and bushed arms. If they are the wide arms, then simply clean, inspect for cracks, and re-apply the epoxy.

Thank you for the tips! I will report once I open the box up.

Taking a look at things inside the chain housing won't hurt.

But you could just re-epoxy after careful cleaning and leave it at that. Engine builders often do that with all rebuilds whether leaking or not. Can't expect the epoxy to stand all that heat forever.

If something has gotten loose, the new epoxy will fairly quickly crack and leak again, and more heroic measures can be undertaken.

If this is the pin I think it is, it is also captured, though not as tightly, in the chain housing cover at its other end. Since it is supported on both ends, it isn't going to cause catastrophic failure if it moves a little.

Well I am at a point now where I feel it wise to break into the chain box and fix whatever has happened in there.
It all started with a burned engine wire harness and after removing the CIS and Intake manifold I decided that I may as well chase some oil leaks that have been pestering me for quite some time.
Also I am pulling the HVAC out of the old girl since... well, it has never been that stellar and I am in California.
So here I am with the exhaust off the top of the motor removed and getting ready to delve into gasket replacement when I found this hole. Jeesh... no time like the present!
I am hoping to do this with a partial engine drop, as I don't have space in the garage for the engine and the cars.
I guess the new question is this:
Can I simply remove the cover, re-insert the pin, re-epoxy, instal the new gasket, and button it all back up? Or will this be WAY more involved?
Thanks for the help and insight!
Best,

Sean,

The pin is for the tensioner arm. To do any work will require removal of the arm and risk needing to re-time the cam.

It may be wiser to simply put epoxy on it and inspect/fix it when you need a valve job or something.

Exhaust on top of the motor? Sounds like you've got more problems than just a leaky chain tensioner post....... ;)

Both top and bottom are removed.

LOL how punctuation can kill us some times!

Looks like you are already in pretty deep. How are the cam gaskets and orings? Dry? If not, you might want to consider replacing them while you are so close. Yes, it will involve re-doing the cam timing, and yes, you can do it in the car.

I will have to research about resetting the timing... I did plan on replacing the gaskets, but I had not considered the o-rings as of yet. I honestly figure that while I am this far into things I may as well do everything I can to stop any possible leaks... welcome to the slippery slope eh?

BTDT! :) Have fun. Do it once and do it right!

You keep thinking you will have to, and can simply, reinsert the offending pin.

I repeat - I'm not sure it came loose, at least not so loose that when you remove the chain tensioners and then the idler gear arm, you can pull the pin out with your fingers. Though if you can, that is something good to know, although it means a lot more work.

The pin is a press fit, and I don't think it is available as a replacement part, as it is intended to be integral to the chain housing. From reading posts here (you ought to do a search to bone up on the subject), it seems that if it has really gotten loose you need to have a replacement made to be a press or heat/cold fit into a slightly enlarged hole you machine into the housing.

Which probably means removing the housing. Which is now getting to be a pretty big deal, because I don't think you can remove the housing without removing the cam - the end of the cam sticks out a fair amount, but someone can correct me on this. To remove the cam, you have to pull all the rockers. You will have to remove the chain ramp, though, in any case.

I have retimed a cam with the engine in place, but it was a race prepared 911 and I could, among other things, remove the rear crossmember with a few bolts (I had modified things), the rear bumper and valance came off with four butterfly Dzus's, and it turned out I didn't actually have to retime the cam.

Speaking of which, I did this because I had forgotten to tighten the three 10mm headed bolts holding the cam holder, with its O ring and gaskets, in place, and it leaked a lot just driving it into the trailer . Somehow the cam never moved while I removed the big nut, and the gear, and put them back on. It seems the valve springs, by pressing the cam lobes in various directions, helped hold the cam in one position. So all I actually did was recheck the timing. But checking the timing is a whole lot easier with the engine up on a stand, becaus with it in the car you can't easily see if your dial indicator is on the flat part of the valve spring retainer or not.

In your case, to get the cover off (being on the left side is a boon here) you need to pull the sheet metal, prop up the rear of the motor, and remove the motor mount and crossmember. That should give you enough room to get the cover plate off to see what is going on inside. I don't think a partial drop is going to be of enough help, and you have to do all of the above to make any use of a partial drop anyway.

As to leaks in this area, there can be leaks from the joint between the chain housing and the case. And from the O ring around the gizmo which holds the cam in place, as well as the gasket on its other end. But lots involved in getting to these as opposed to some other gaskets (like valve covers), so I'd not do this outside of a full engine rebuild. Unless I knew they were leaking enough to make the effort worthwhile. And you ought to be able to pinpoint such leaks, if they are there, the same way you did the one you wrote about - by cleaning and looking.

Mike B works doing this stuff, so his responses tend not to ramble on as mine do. But you really ought to place a lot of weight on his advice, and not let this project get out of hand: either cleaning and new epoxy will stop this leak for a reasonable amount of time until it is rebuild time, or it won't and that time is at hand. The epoxy is there to stop any oil which migrates past the press fit, which isn't going to have any significant pressure behind it. If the pin wobbles or rotates, that means the hole has enlarged, but more to the point the new epoxy will promptly crack like the old.

So if you pull the chain housing cover, you might want to have that in mind. I wish you the best of luck, as so far I have not had this problem with the various chain housings I have in my engines.

clean, re-epoxy and call it a day. save it for a full engine drop when your doing a top end.

You "can" remove the chain housing without removing the camshaft and rockers. Once you're in there that deep, its pretty easy actually.

Well, I cleared the remaining epoxy and applied a light load to the pin to see if it would move. It feels fairly secure, though there is oil seeping by...

I am at a loss! Part of me wants to break into the housing and have a look and re-press the pin properly, the other half says epoxy over the thing and see what happens.

Though I am quite relieved that it is not wobbling around in the housing.

KISS (keep it simple stupid)

Depending on your reliance on this car as a daily driver. If you are not dependent on it, I would start with just re-epoxying and seeing how it goes. You are unlikely to incur any damage to anything if it does wiggle a bit and break the new epoxy free. An oil leak in this area will be your early indicator, long before any damage is done, that you need to get in there for some serious work. Your challenge with this approach is going to be getting all of oil out of the joint before you reapply epoxy.

Well said, Mark Brown.