914-6 Hole in Firewall Options

[morehills]

I'm doing a fairly large project on the interior of my 1971 914-6 GT clone this winter. I'm converting to 911 steering and ignition, adding a GT roll bar and harness mounts and a few other bits and bobs.

While it's open, should I cut an access panel? Is there any impact on the structural integrity of the firewall? How difficult is it to lean over the engine and adjust timing without the access panel? While it would be more convenient, I wonder if it's really needed to properly time the car every few years. It's a '71 2.2 liter "E" cam engine.

Thanks for any advice. John

[Cairo94507]

If you have a factory 914-6, I would not cut the firewall; did not cut mine either. I have modded my 6 but the body is still essentially stock with the exception of my louvered front trunk floor to vent the oil cooler. I think the biggest hassle is if you need to change your fan belt or alternator. It can be done in the car, but it's a task best left to young, thin mechanics with long arms. The best plan for these cars is to just drop the motor for maintenance. Valve adjustment, address any leaks, new fan belt, etc. Timing them is a slight pain, but manageable with the engine in the car.

I think structurally, if you cut an opening in the firewall, make a nice metal panel that seals tightly when installed - maybe riv-nuts. I do not believe it is going to weaken the firewall. (IMG:style_emoticons/default/beerchug.gif)

[gereed75]

There are lots of threads and lots of opinions on this

http://www.914world.com/bbs2/index.php?showtopic=81727

Race car - absolutely. Street car ??? Remember, you have to cut fabricate fasten. For use you gotta remove seats and backpad.

For me a “no”. For others a “why not”. Timing is not a big deal. For as much as these cars typically get driven, belts last a long time. Engine likely coming out for valve adjustment and other maintenance. Service the belt then.

[Superhawk996]

There are lots of threads and lots of opinions on this

But only one right answer (IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/stirthepot.gif)

[brant]

Drop the motor for valve adjustment

Geez. I do the valves 6-8 times every summer and never drop the motor for it

[Superhawk996]

I haven’t read that thread in a while.

Here’s the thing that isn’t even discussed in that thread. An air cooled engine is way louder than a water pumper.

OEMs go to great lengths to seal even the tiniest holes in a modern firewall? Why?

NVH (Noise Vibration Harshness)

It is amazing how much sound can be transmitted through even the smallest holes, unsealed weld seams, and past rubber grommets, and foam. All modern cars have multi layer NVH solutions to help quiet things down. But it all starts with minimizing protrusions through the sheetmetal.

[Steve]

I've had my 914-6 conversion since 1986 and only recently cut the firewall to replace the alternator with my 3.2. Otherwise getting to the belt, distributor and valves has never been a problem.

[Steve]

I bought the PMS fiberglass cover, versus finding someone to cut up their firewall for a cover plate. https://patrickmotorsports.com/collections/...58367&_ss=r

[morehills]

I bought the PMS fiberglass cover, versus finding someone to cut up their firewall for a cover plate. https://patrickmotorsports.com/collections/...58367&_ss=r

Thanks for all the great replies and sorry to re-litigate this issue. So much good information here but it's sometimes hard to find.

[gereed75]

Do my valves routinely in car also. I guess I was thinking about next time. Engine coming out for a bunch of other work.

Not sure there is a best answer for street cars. No in an original six, owner preferences on a conversion.

I think if I were doing it I would maybe try to make a clean cut and then fab and weld in a bolt ring/flange and use the cutout to reseal the hole.

[SirAndy]

Is there any impact on the structural integrity of the firewall?

The clue is in the name ...
Firewall

Cutting a big hole in a wall that is supposed to protect you from an engine fire (to give you a few extra seconds to get out of there) is really only a good idea if you are prepared to deal with it in an emergency.
(IMG:style_emoticons/default/popcorn[1].gif)

[rgalla9146]

IF you choose to put the access hole in, there is no better cover than a piece
cut out of a junked car .
It will fit perfectly and look like it grew there.
Timing and valve adjustment can be made much easier by marking your flywheel
as done on original 914 6s Use the marks on your crank pulley to position the flywheel
for marking.
No need to be young, thin or acrobatic.
Changing / adjusting your fanbelt is a challenge. Get the right tools.
If using an aftermarket front mount be sure there is clearance to remove /install
the V belt
Practice replacing and adjusting before leaving on long journeys.

[930cabman]

I cut mine for the /6 conversion. It's a simple patch to put things back together

[Superhawk996]

Ya all must be changing fan belts like underwear to need that much easy access.

I’m wondering how many of you are driving modern cars where you can’t even see the serpentine belt? (IMG:style_emoticons/default/idea.gif)

[mlindner]

I put one in my GT Tribute, helps a lot with service. I built the car for myself, not to worried about resale. Best, Mark

[brant]

Ours

[Beach914]

I'm planning to do it on my GT conversion but will not even think of doing that on my -6 for obvious reasons.

I cut and saved a section from Frankencarcass back when I was parting it out.

[dr914@autoatlanta.com]

NO WAY!!!!!!

I'm doing a fairly large project on the interior of my 1971 914-6 GT clone this winter. I'm converting to 911 steering and ignition, adding a GT roll bar and harness mounts and a few other bits and bobs.

While it's open, should I cut an access panel? Is there any impact on the structural integrity of the firewall? How difficult is it to lean over the engine and adjust timing without the access panel? While it would be more convenient, I wonder if it's really needed to properly time the car every few years. It's a '71 2.2 liter "E" cam engine.

Thanks for any advice. John

[burton73]

@morehills

I have what you want. I was going to put in my V8 car body but went a different route.
I have 2, the bigger one may be better. Super clean part. I will list it in parts for sale.

Best Bob B Burton

Boxed in a 24x24x5 box. 10 lb for the big one as it cam from Garold a few years ago

[930cabman]

Ours

Looks very clean to me, I can't see how this can compromise the firewall?