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Crankcase Sump Thread Sizes For DB34 ? #778157 07/08/19 6:14 pm
Joined: Jan 2008
Posts: 29
M
M21 Offline OP
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M
Joined: Jan 2008
Posts: 29
Seems I asked this before but I lost my notes
o I will try again.

I got a DBD34 with some stripped threads on the bottom of the crankcase where the scavenge plate goes, and would like to find our what size the studs are. I don't have the original studs or nuts and the remaining studs are pretty chewed up. The catch is, there are a number of of combinations available, and most of the vendors don't bother to say what the size. The only one I could find that did list the size gives it as 1/4 BSCy. I'd like it as stock as possible. Best I can figure they should be 1/4" BSW on the case end, and 3/16" BSF on the other.

Also, if anyone has a crankcase handy, I'd be interested in knowing what how deep the holes are are in the crankcase - mine are only 1/2" which seems pretty short so I am wondering if there may not be some broken off bolt inside.

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Re: Crankcase Sump Thread Sizes For DB34 ? [Re: M21] #778175 07/08/19 9:37 pm
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chaterlea25 Offline
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Hi M21
The studs are 1/4in. Whit (20tpi) at the end that screws into the casing and 1/4 x 26 for the nut end CEI or BSF are both 26tpi
1/2in. in the case is plenty deep
Aftermarket alloy sump plates will need longer studs than original


John

Re: Crankcase Sump Thread Sizes For DB34 ? [Re: M21] #778284 07/10/19 5:42 pm
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Dave - NV Offline
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I too have been involved with the sump studs... The thicker after market, SRM, alloy sump plates are supplied with hex socket screws to replace the OEM studs. Even drilling the heads and safety wiring I found this unsatisfactory. Luckily I found longer studs at my local auto parts store, 1/4" 20 threads at one end and 14" 28 on the other end. This allowed fitting nylock nuts for security. I've found the case holes to be open to the sump that allows oil to seep by the studs, but a dab of sealant on the case end of the stud takes care of that issue. "On n on we go".

BTW, for many years I've used readily available US 1/4" 20 SS socket head screws for primary covers, cam covers, etc. I don't build Goldies for dead accurate 'museum pieces'.

Last edited by dave - NV; 07/10/19 5:46 pm.

Dave - NV

Moderated by  Rich B 

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