Camshaft tower gasket

[crogers]

I am replacing my camshaft tower gasket and have everything ready to put back together but had a question about oil on the new gasket... I have the new gasket positioned on the head and I just put all the lifters back into the cam tower and just realized there is probably no way I am going to get the cam tower back onto the head without at least a little oil dripping onto the new gasket from the lifters. I have had the cam tower sitting face down for several days letting all of the oil run out but I have had the lifters soaking in oil, so of course they are full of oil and when I go to position the cam tower onto the head I can just see oil getting onto my nice, clean, brand new cam tower gasket. Is this a big deal if oil gets onto the gasket?

[crogers]

by the way, this is on a 1985 Porsche 944, sorry.

[mytrplseven]

My procedure was to lay a piece of cardboard on the lifter side of the cam tower to keep the lifters from falling out. This way what little oil drips, is collected on the cardboard. Roll the cam tower over and place on the head while holding the cardboard with your hand. Slide the cardboard towards the fender far enough to get a couple of bolts hand threaded in and then pull the cardboard out while putting the rest in. A little oil on the gasket won't hurt anything so don't worry about it.

[mazdaverx7]

I cleaned my cam box until it looked new. I degreased it, acid washed it, re-washed it and then blew it out with compressed air. Once it was dry I installed the lifters with engine assembly grease and that held them in place when installing the cam box. No oil drippage and the gasket mounting surfaces remained clean.

[DannoXYZ]

uhh, notice that there is at least one hole that sends oil from the head to the cam tower that passes through the gasket. Also there's a longitudinal channel above the gasket that delivers oil to each of the lifters. There's no way to keep oil off the gasket, as soon as you turn on the engine, that gasket's completely covered in oil.

I fought cam tower leaks on three different engines over the course of 6-months and dicovered some things.

First, the gasket is designed to slide along the cam tower and head. Actually, it's the head and tower that expands faster than the gasket when heated. The graphite coating on the gasket helps keep the gasket from sticking to the metal surfaces.

On one engine, I tried keeping the gasket clear of oil & grease by laying a bead of silicone on the inner edge of the head & tower. Nope, the gasket stuck to the head, was stretched by heating and contracting and developed a 1.5mm lateral channel from inside to outside and leaked oil through that river.

On another engine, I tried a little more torque to keep the gasket in place. Upon disassembly, I could see areas where the gasket got squeezed paper thin by the extra torque. It too developed a little 2mm channel perpendicular to the head and leaked.

On another engine, I tired different techniques using two different types of gasket sealant in different combinations. On bottom only, on top only, on both surfaces, even two combos with both sealants, one on top and the other sealant on bottom. Then reversed. All of them leaked exactly the same way with a 2mm split in the gasket.

All these methods tried to force the gasket to stay with the head and cam tower and stretched the gasket to cause it to spit and create a channel from inside to outside, resulting in leaks.

What I eventually found that's worked the best and have been leak-free on a daily-driver that sees about 100-hrs of track use per year, for the past 10-years; is to allow the gasket to "float" and not get stretched.

First, I rub extra graphite on both sides of the gasket. Then rub oil on the mating surfaces of the head and cam-tower. I usually have an assistant help me with lowering the tower on so we don't drop lifters or gouge the gasket with a sharp edge of the tower.

Finally, use a torque wrench to tighten the cam-tower bolts in the proper sequence. It's a surprisingly low amount of torque and bolt-tension to allow the gasket to slide between the expanding head and cam-tower (even lower compression due to the cam-lobes pushing against valve-spring tension and pushing the cam tower away from the head). From the widths of the split gasket's channels I'd estimate that the head/tower expands about 1.5-2mm longitudinally.

So far, my 944na's gasket has been leak-free for 10-years with this method, and my 951 is going on 5-years now. Along with 5+ years on numerous friends and customer cars.

[wildcat077]

I just reinstalled the cam housing after replacing broken piston rings and i used the cardboard method and it worked great ... i just cut a 4x19 piece and slid it out once the cam housing fell into the two alignment pins.I installed the gasket dry just as the previous leak free one was !

Trick is not to drop one of the top 6 mounting bolts into the housing once you finally have it in place

Cheers
Phil