2 pc. Engines head studs and through bolts

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Ignacio Vivancos
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2 pc. Engines head studs and through bolts

#1 Post by Ignacio Vivancos »

Question for the experts.....are 2 pc and 3 pcs head studs the same or do 2 pcs engines use vw 25/36 hp studs?
Also, when was the through bolt used on 2pc engines? Only supers? Is the same as the later 3 pcs bolt?
Thanks
Ignacio Vivancos
Lakeway TX

56 A
69 911 T SWT
77 carrera 3.0
89 964 C4

mats carlsson
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Re: 2 pc. Engines head studs and through bolts

#2 Post by mats carlsson »

Hi Ignacio
No not the same. Not VW.
Thru case bolts, same
mats carlsson

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James Davies
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Re: 2 pc. Engines head studs and through bolts

#3 Post by James Davies »

As Mats says, head studs on 2-piece case engines are the same as for later 3-piece case Porsche engines. They need to be matched to the Porsche heads. VW heads are very different in size because the different valve layout.

The through case bolts were introduced 5 Feb 1954 for Supers and on 20 June 1954 for normals. This corresponds to to engines:

P-40707
P-50037
P-33189
P-21787

and up.

Of course if an earlier engine was overhauled by the factory or dealership, it was very common to drill the Ø 11mm hole at the top and bottom and install through bolts. So some earlier engines have these through bolts as well.

Ignacio Vivancos
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Joined: Tue Apr 01, 2008 10:19 am
Location: Lakeway, TX, USA

Re: 2 pc. Engines head studs and through bolts

#4 Post by Ignacio Vivancos »

thanks!
Ignacio Vivancos
Lakeway TX

56 A
69 911 T SWT
77 carrera 3.0
89 964 C4

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Norfried Bittner
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Re: 2 pc. Engines head studs and through bolts

#5 Post by Norfried Bittner »

Hi,
Does anyone have pictures of a case with this through bolt? I‘ve never seen any and I can‘t figure out where it would be located.

Thanks
Norfried
 

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Alan Hall
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Re: 2 pc. Engines head studs and through bolts

#6 Post by Alan Hall »

Norfried, Late '54 2-piece case with thru bolts. Locations marked. Always bothered me a little the head side of the upper bolt where the hole is partially open, seems like it might be the one and only good location to use a little bit of RTV.
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