Valve Cover Gasket Replacement on 348

Jerry-
It's not rocket science. Just make sure you put a dab of sealer where it meets the cam seals and head and the rear caps.

 

It's a huge job! Sell the car! Remove the intake boots and airbox, pull the plug wires, remove the ground wires on the valve covers and pull the covers off. Don't bother doing ONE side, you cheapskate. Do them both. Would you replace brake pads on one side? NO!

Enzo would laugh at you!

 

Kris- You're getting a little sarcastic in your old age!! Seriously, figuring out which wire goes where can be pretty complicated when all is said and done. (I'm kidding already!!) Then again, if Kris can do it, how hard can it be?? (OK, now I'm really kdding!! He said as he dialed the phone for his next service, to be perfomed by....Kris Newell??)

Cheers,
dce

 

Maybe I was a bit too sarcastic. The part that takes the most time is scraping the gasket. Use threebond 1211 sealer if you can find it. It's about $20 a tube. Dab silicone on the corners of the head by the cam o rings, and on the rear of the head. Lay the gaskets down, and then dab a little more silicone on top of the gasket in the same spots. Also spread silicone on the first 2 inches of the valve cover and the last 2 inches. One thing to look out for is the little black plastic fuel line clamp that holds the line to the valve cover. It has a small 6mm I.D. spacer in it that will fall into the valvetrain if you don't remove it before you take the valve cover off.

 

I agree with the part about only fixing the one that leaks. If it ain't broke.....
What's a camel tongue feel like? Good? Sticky? Any other potential uses?

 

Sounds like cam shaft seals. - very common.

Mine now leak and they were done 12 months ago - started keaking again after only a few months - crap design

I think you need to lift the cams out and its an engine out job. - I may be wrong with the engine out.

Let's know what you find.

Cheers

 

Mine is on the front right cam seal too. Aren't they all?

FWIW, resnow (aka Sandy) is doing an engine-out on his 348 right now. I *think* he's getting ahold of the TSB which explains how alleviate the problem by drilling one small hole. I might be all wet on this one.

Ferrarioldman, or Rifledriver... any comments?

 

Don't know about the 348s, but the QVs & 328s have a small (~3mm (~1/8") dia.) oil drain hole in the head just behind each of the seals. You can't see them w/o removing the cylindrical seal housing.

The holes are supposed to dump the oil back into the head's drain area where it makes its way into the sump. However, they're pretty small, so don't really do a very good job.

Even worse, they're usually plugged up with sludge which means oil is sitting about 19mm (3/4") deep behind the seal. Even when the entire engine has almost no trace of sludge, I've found these holes plugged up.

The holes are small & often overlooked when replacing the seals. At minimum clean them out.

Better yet, open them up to about 6mm (1/4"). Pack the 6mm drill bit's flutes & put an ounce or so of grease on the back side of the hole to catch the chips. Frequently pull the bit out to remove accumulated chips & refresh the grease. Remove the grease & accumulated chips from behind the hole.

It's possible that the FSB is drilling a missing one.

 

The TSB on the 348 was to drill the holes in the proper position. After having built the motors pretty much trouble free they did a typical Ferrari move....They changed it. If you have the cam seal housings off you will see that the return holes are very high in the casting creating a little swimming pool of oil right behind the cam seal housing trying to find a place to go. The factory provided a rather nice and very expensive drill guide to do the job but I have done without it. It does require the motor and the cams to be out.

The actual leak is almost never the actual cam seals. It is the big O ring around the cam seal housing. I gets pinched by the edge of the valve cover when it is being bolted down. There is another TSB telling you to radius the edge of the half round groove machined in the valve cover for the O ring. That will prevent the pinching. The O rings can be replaced in the car by cutting them and rolling them into place with the cut at the top. This works quite well with the caveat that the newer O ring material is so hard that I have had a great deal of trouble getting it to feed through. I still think it is a better program than pulling the motor just to fix a valve cover leak.

I also trim the VC gasket so that it will not cut into the O ring. I just use a paper hole punch to make a little room at the half round in the gasket and use a small amount of the Three Bond silicon Kris mentioned to fill the gaps and glue it all together. I only glue at the corners. You also have to watch and be careful to prevent the corners of the gasket from oozing out at the corners when you are tightening down the cover.

 

It is way easier with the engine out. Since you aren't pulling the engine you can get some more access to the covers by removing the rear wheels, and the rear wheel wells/splash guards. You only have to take off the front and top of the splash guards, to get to the extra access to the cam covers. It would also be a good idea to remove the air box, MAFS, and the tubes going to the throttle bodies. The more room you give yourself, the easier it will make the job. If you decide to use the triple bond sealer, use only enough so that it barely beads out the sides when you tighten down the covers. If you use too much it can get into the oil passages of the engine and really mess things up.

 

Brian, this is exactly the failure I experienced after my recent major service. If I recall correctly the cam seal housing has a small angled grooved machined at the bottom position to allow oil to drain back. Thought the leak was my cam seal but in reality it is my “O” ring. Is the hole you reference in addition to the machined drain groove? My 348 is a ’94 spider.

 

Mine leaks too Jerry. Don't sweat it... check oil levels, watch pressure, and just enjoy the car. I prefer to think of it as a rust inhibitor for the undercarriage.

Mine's a '90 (July 90 build) FWIW, I was under two different 94 spiders recently, and both were bone dry.

 

That is another TSB. The early cam seal housings had no drainback groove. The TSB said to replace with new housings with a groove but in reality you can just use a small round file and groove existing units. Also important it to install housings with groove in lowermost position.

Yes the drain hole is in addition to the groove.

 

Thank you Brian. I will have to locate a copy of the TSB and when I do my next service drill the required holes. John.

 

I followed the recommended procedures (pretty much like Rifledriver outlined) and my valve cover gaskets slid-out in the corners where I put the Hylomar.
If the job was to be done over, I would glue the gasket to the valve cover with contact cement and put a little hylomar by the O-rings. If anybody has experience with this I would appreciate hearing from them. I know the gaskets would be a little harder to get-off the next time, but I think it would be worth it.

Mark

 

Hylomar is not the right product, in fact Hylomar is not the right product for anything. Put the tube in the garbage. Do not glue the gasket to the cover. Use silicone, either the type I described or one of the Permatex ultra series and do it like Ferrari and every Ferrari mechanic in the country does it. If you are meticulous it will work great.

 

Too much of ANYTHING will push the gaskets out of the corners, away from the o-ring groove.

It takes surprisingly little to seal the gasket end at the groove.

I lay the gasket in place, then lift up the o-ring ends & put:
1) a small drip of super glue on the head about 3/8" to 1/2" back from the o-ring groove, and
2) a match head sized drop of RTV at the bottom of the o-ring groove. (Hylomar should work as well there, but this is the one place where I think RTV is better.)

Then very carefully roll the end of the gasket back into place & hold it for a minuite to let the super glue setup. You only get one chance to put the gasket end down, but it won't squeeze out.


Hylomar isn't slippery, compared to RTV. RTV is 10x worse.

 

Verell: The idea of a drop of super glue sounds interesting.

Rifledriver: A couple of years ago it seemed everybody was talking-up Hylomar, but have talked to some others with a lot of current expertise (much like yourself) and they are saying, like you, to use silicone--specifically Three Bond 1211. I quite using silicone after some seemed to damage an O2 sensor; not 100% sure the silicone was the cause (was the sensor safe black permatex). The Hylomar seemed like it might be a good alternative but I'm not really sure what it is made of because the Jaguar brand felt like silicone and the Permatex brand seemed to be more fluid. I'd really be interested in knowing what Hylomar is and what it should be used for.
Mark

 

Hylomar is a polyurethane gel. It's resistant to most common solvents(oil,fuel,coolant), and takes fairly high temperatures(250C !!!).

It was developed by Rolls Royce for sealing jet engines. Mazda recommends it for installing the o-rings that seal rotary engines. It's tackiness & viscosity help hold them in place during assembly as well as ensuring sealing. IMHO, it would be all but impossible to assemble the rotor housings w/o it.

Ferrari explicitly specifies it for sealing the differential housing to the transmission case.

Because it doesn't set up, and is very viscous, it will flow slowly under pressure. It's recommended that you go back & re-torque after 15-30 minuites when it's had time to flow & equalize.

There are a couple of hylomar flavors out there. Valco & Hylomar.ltd in the UK make ones that have a solvent in it. Makes it easy to spread it on thinly, then the solvent evaporates leaving the tacky hylomar behind. I think this is probably what Jaguar supplies. Only problem is it's hard to find here in the US. My auto parts store that used to carry Valco has switched to Permatex.

The Permatex hylomar is readily available, and is much thicker out of the tube.

Both seem to work equally well, but the Valco is easier to apply & get the film thickness down.

I prefer hylomar to RTV for areas likely to be dis-assembled in the future eg: Cam covers, Sump covers, Cam seal O-rings, etc.
Some mfg. web sites:
http://www.valco-cp.com/Hylomar.htm
http://www.hylomar.co.uk/
http://www.permatex.com/heavy_duty/Differentials.asp?automotive=yes&f_call=get_item&item_no=25249

CAUTION:
Using excessive sealant of any kind can cause engine damage. It can squeeze out inside & clog up small oil passageways. Enough sealant strings can actually clog the sump oil intake screen & oil starve the engine. If you've got a noticeable bead on the outside after sealing something up & torqueing it down, there's a bead on the inside at least that large!!! Strings of silicone will tend to work their way into the sump unless they're too large to fit thru a passageway. A string of Hylomar would tend to stick along the way somewhere, and could build up unless there was a lot of pressure behind the flow. Either way, you can end up blocking smaller oil passageways.

Rifledriver,
I know that you discourage Hylomar. re:
http://ferrarichat.com/forum/showthread.php?t=49761&page=1&pp=20&highlight=Hylomar
& earlier this post.

Could you describe the specific problems you've seen due to it's use (or more likely abuse)?

 

A couple of years ago everyone was talking up Hylomar because they just discovered it, it's been around forever and outside the traditional British car set everyone else discovered long ago like many British products that it just doesn't work. It has long been assosociated with names like Rolls Royce. Jaguar and Hewland, not to mention almost every other British make. What do all those all have in common? The British auto and motorcycle industry were the laughing stock of the world for being synonomous with oil leakage. And traditional products like Hylomar are one of the reasons. Twenty or so years ago on the recomendation of another mechanic I did try it and I tried very hard to make it work so my comments are not from a perspective of inexperience. It is just not a good product and deserves the bad reputation it has in this country where we as a group respect results more than tradition. I far prefer 21st or at least 20th century products. It is true that in the early days of the use of silicone the product was trash. It was just bathtub caulking marketed to the auto industry. There are many better and improved products out there now some good, some not. Silicones are also not all the same and different types and different brands are good for different applications. There are also some sealing jobs that silicone has no business being used for but 99% of the time on mechanical components I use either Three Bond silicone or Permatex 503. Don't forget when I put something together I have to garantee it and doing it over costs too much. I won't tolerate products that cost me money.

 

Verne and Rifledriver--thanks for the clairification on Hylomar. I am not going to use it anymore. A trusted friend (who I have not been approved to quote) recommended the 123 Silicone and this in combination with the endorsements of you guys we should all switch to silicone. I still think I may glue everything down with some contact cement and put Silicone on the head side.

Mark