Machining/cutting lower valve covers?

[911TT33]

Hey guys,

I need to trim a little bit of material from my lower valve covers because the side mounted turbocharger sits too close to the valve cover, and I’m worried the heat from the turbine housing will damage/warp the valve cover over time.

What’s the best way to do this? As shown in the picture, the turbo hot side housing sits too close to the lower valve cover. I’m planning to use a titanium blanket as well but there still isn’t much gap there.

[jac1976]

Hopefully someone with some thermodynamics knowledge will chime in. Although titanium has low conductivity, I feel like if too tight you may be dealing with conductive as opposed to simply radiant heat as the heat shield may couple the housing and valve covers. If that were the case, maybe adding a silicone barrier would help. And I’ll reiterate, I’m no pro on this, but you got me thinking this morning. So that’s good. Looking forward to further replies for nerdy purposes.

[Dpmulvan]

Zircotec the housing

[stownsen914]

Whenever I have exhaust near something I don’t want getting hot, I like to use a heat shield. As suggested above, you could put a layer of heat rejecting cloth like header wrap on the hot side of the heat shield. Attaching the heat shield to the turbo would probably be better, but possibly not practical. It’s probably fine to secure the shield to the valve cover.
A little more of an air gap between the turbo and the valve cover would be good to give the shield a place to live.
As for material, it may not matter that much in your case. Whatever material you use, the shield will be a bit of a heat sink. Material may impact how quickly it gets to that temp but not necessarily the peak temp as much. (That’s just an opinion.)

[rudedude]

I had to trim my lower covers to clear suspension mounts in my 914/6. Did it with a die grinder so I can remove covers to adjust valves. That was probably 30K miles age and never have had any issues with the trimmed covers. That being said I don’t know how you will ever remove that cover to adjust those valves without major disassembly.

[john walker's workshop]

How,re ya going to do a valve adjust?

[911TT33]

Originally Posted by john walker's workshop

How,re ya going to do a valve adjust?

I guess a lot of disassembly will be needed. How do they do it for the 993TT? I’m using the 993TT heat exchangers/headers on my motor.

[911TT33]

Originally Posted by rudedude

I had to trim my lower covers to clear suspension mounts in my 914/6. Did it with a die grinder so I can remove covers to adjust valves. That was probably 30K miles age and never have had any issues with the trimmed covers. That being said I don’t know how you will ever remove that cover to adjust those valves without major disassembly.

Yeah cool, thanks. I think I’ll use a die grinder too, just to open up that gap a bit more so I can fit a heat shield in there.

It’s the “fin” on the valve cover that’s protruding out and too close to the turbo housing.

[911TT33]

Originally Posted by Dpmulvan

Zircotec the housing

Thanks, sounds like a good option.

I also found this product:

https://funkmotorsport.com/product/thick-aluminium-barrier-heat-shield-0-5mm-thick-sheeting/

[Dpmulvan]

I’d think about a different set up.

[Flat6pac]

Why not just a set of aluminum SC valve covers
Bruce

[chrismorse]

I'm about to use some solid carbide grinding burrs to trim the fins on turbo valve covers to allow lower plug retainers to be installed.
They are readily available in various diameters in cylindrical, spherical, round nosed and cone shaped,
I recommend clamping the cover to the bench and retaining a firm hold on the die grinder.
c

[911TT33]

Originally Posted by Dpmulvan

I’d think about a different set up.

Not an option with 993TT heat exchangers unfortunately.

Trimming and some heat shield should do the trick.

[911TT33]

Originally Posted by chrismorse

I'm about to use some solid carbide grinding burrs to trim the fins on turbo valve covers to allow lower plug retainers to be installed.
They are readily available in various diameters in cylindrical, spherical, round nosed and cone shaped,
I recommend clamping the cover to the bench and retaining a firm hold on the die grinder.
c

Thanks. Yeah I’m thinking I might use a Tungsten Carbide burring bit and slowly machining away excess aluminium to make space for a heat shield inbetween.

Or taking the valve cover to a machinist to do a neater job! LOL

[Henry Schmidt]

We trim the lower turbo valve covers all the time for clearance and twin plug applications. BTW: the "fins" add support to prevent warping and trimming them really doesn't influence the warping issue to a noticeable degree.
We use a knee mill (Bridgeport) and a simple fly cutter. For the twin plug spark plug retainers an end mill and for the lower plug holes a carbide hole saw. The fully trimmed valve covers are for 914/6.
If removal becomes a serious issue, you can slot to top holes and replace the lower studs with bolts. That allows the valve cover to be removed in a confined space.

[911TT33]

Originally Posted by Henry Schmidt

We trim the lower turbo valve covers all the time for clearance and twin plug applications. BTW: the "fins" add support to prevent warping and trimming them really doesn't influence the warping issue to a noticeable degree.
We use a knee mill (Bridgeport) and a simple fly cutter. For the twin plug spark plug retainers an end mill and for the lower plug holes a carbide hole saw. The fully trimmed valve covers are for 914/6.
If removal becomes a serious issue, you can slot to top holes and replace the lower studs with bolts. That allows the valve cover to be removed in a confined space.

Wow, very nice, neat looking work Henry! 👍🏼

I’m planning to fit these new Hargett billet aluminium lower valve covers anyway (they’re twin plug prepped), so I’ll trim off that lower “fin” to create more clearance for the turbo and to slide a heat shield inbetween.

[Emo993]

This is all thats needed to clean the suspension ears, no turbo.