fan shroud bolt question

[Gordon Maltby]

Does anyone know when the 6mm hex screw on the side of the fan shroud became a slotted head? This is the one that is behind the carb manifolds on each side.

[Jim Breazeale]

Does anyone know when the 6mm hex screw on the side of the fan shroud became a slotted head? This is the one that is behind the carb manifolds on each side.

Yes is did.

Regards

Jim

[Mike Wilson]

I thought I read somewhere that the slotted head hex bolts were on car fitted with Solex carbs.

Mike

[Dick Weiss]

The slotted 6 x 1,0 x 8mm hex head cap screw was introduced on the 912; Not on 356 engines altho it could be used
if Solex 40P II manifolds exist.

[John Brooks]

My 66 912 has bolts not screws. I was taught bolts go horizontal, sloted cheese heads point down

[Mike Wilson]

John: it is a hex head bolt but has a slot for a screwdriver. You are correct: bolts on vertical; screws on horizontal.



Mike

[Ron LaDow]

Does anyone know when the 6mm hex screw on the side of the fan shroud became a slotted head? This is the one that is behind the carb manifolds on each side.

Gordon, from memory, my first Speedster (3-piece case, 1500, all the weird parts) had hex bolts (I remember since it took 1/6th turn at a time to get them out).
The next earliest engine was probably the S-90 which currently lives in the current Speedster; '63. It had the slotted screws.
That only leaves you 8 years in between; happy to be of assistance!

[Brad Ripley]

Harry said this, pg 206 Rev 3.5 The only spec for that bolt in any parts catalog (incl 912) is of a standard DIN 933, 6 x 8 bolt. If it had a slot, there would be a suffix of "Sz" .

[Vic Skirmants]

I have to disagree with The Maestro. Can't ever remember seeing those bolts on any engines prior to 1965(?).

[David Jones]

I have worked on more than a few 356 engines but not as many as some members and I have NEVER seen a slotted hex head bolt in that position. I do agree on the slotted concept though as it makes it easier to extract. I shall search my 6 mm x 10 ATF bolt drawer and see if I actually have any. I usually remove the carb then use a 10 mm socket on a wobbly extension to remove them, tedious but less frustrating than dropping the bolt with the carb on then spending 10 minutes locating it.

[Craig Richter]

Surprising that the use of this odd little bolt could be controversial today. Like many of us, I'm not totally trusting in my old memory to bet the farm on an answer here; but I'm pretty darn sure my '60 S90 came with these slotted hex bolts. Hence, I thought it was a Solex thing. In fact, I thought they were so cool, I would search my coffee can full of nuts and bolts to find some to use on all my special motors (mostly with Webers on Solex manifolds) because they were easier to get in and out without losing.
To add to the discussion, have any of you encountered such slotted hex heads anywhere else? I recall finding many attaching the ground wire to the generator...

[Leo Hudson]

Have seen bolts that mount accelerator pedal to floor with slots in hex head.
Leo

[Gordon Maltby]

Wow, lots of response for a little bolt question. Thanks, Guys!

Brad, I read Harry's page on these bolts also: a definite maybe. It's not often that Harry admits he didn't have the answer.

A couple of things that are clear: It was used only on Solex carbs (with large manifold) and the two-piece side tin. It would make sense it might start with Super 90s, but there's not much real evidence to support that. Certainly 912 engines, but how much earlier?

I doubt it was originally used anywhere else, but parts always seem to "migrate" over the years.

Keep the evidence coming, please.

[Jim Liberty]

My 2 cents. I've seen these on Solex carb. Pre - A, and T - 1 cars. In fact I just put them back on the '55 Continental I just sold. They are also on my '54, I'm working on now. That motor is unmolested, and has been out of the car for the past 40 years.

........................................Jim.

[David Jones]

So the going price last week was a buck for 10 of these slotted hex head screws and now that you guys have made it a special part for those cars with Solex carbs the price went to $10 each. Think I will stay with Zeniths., or I can get my junior hacksaw out and start making counterfeits.