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 » Wed May 02, 2018 11:57 pm

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
Austin TX

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

#2 Post by mats carlsson » Thu May 03, 2018 11:59 am

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 » Thu May 03, 2018 12:43 pm

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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Re: 2 pc. Engines head studs and through bolts

#4 Post by ignacio vivancos » Thu May 03, 2018 9:26 pm

thanks!
Ignacio Vivancos
Austin TX

53 PreA
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65 912
77 carrera 3.0
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Norfried Bittner
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Re: 2 pc. Engines head studs and through bolts

#5 Post by Norfried Bittner » Sun Nov 25, 2018 3:20 pm

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
 

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

#6 Post by Alan Hall » Tue Nov 27, 2018 12:55 pm

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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