Author |
Message |
esde Samba Member
Joined: October 20, 2007 Posts: 6023 Location: central rust belt
|
Posted: Tue Dec 05, 2023 6:29 am Post subject: drilling a 36hp crank and flywheel for 8 dowels |
|
|
I have a stock 36hp crank which I would like to convert to 8 dowels. My understanding is that the 8 dowel pattern used on 356 Porsche is the upgrade. I'm looking all over for a drill jig for this pattern but not finding anything, does one exist and could anyone provide a link? The ones for the later 8mm dowel pattern are plentiful but will not work
If needed I may use a 356 flywheel to make my own jig, but I'd rather just buy the jig and spend my time elsewhere..
Many thanks. SD _________________ modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
|
Back to top |
|
|
56samba Samba Member
Joined: June 25, 2015 Posts: 262 Location: Germany
|
Posted: Wed Dec 06, 2023 1:49 am Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
I was in the same situation recently during the restoration of my Okrasa engine and couldn't find a drill jig.
Using a 356 flywheel as a jig worked surprisingly well. Subsequent reaming of the holes is recommended. |
|
Back to top |
|
|
Robert Chambers Samba Member
Joined: August 11, 2005 Posts: 219
|
Posted: Wed Dec 06, 2023 10:07 am Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
How about using a 356 or 912 metal flywheel gasket as a pattern? _________________ '63 OG 117 Herbie Replica
'56 Euro Oval Deluxe
'52 Standard Zwitter
'63 OG 117 |
|
Back to top |
|
|
esde Samba Member
Joined: October 20, 2007 Posts: 6023 Location: central rust belt
|
Posted: Wed Dec 06, 2023 3:54 pm Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
Robert Chambers wrote: |
How about using a 356 or 912 metal flywheel gasket as a pattern? |
Probably not as accurate/ easy as I would like. It's a lot more work to find the center of a hole in the gasket than the actual flywheel. I may use a flywheel, and get some 6mmx8mm bushings. This way I can drill through the flywheel with a 6mm pilot. Then remove the flywheel and bushings, drill to the final size and ream. _________________ modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
|
Back to top |
|
|
Robert Chambers Samba Member
Joined: August 11, 2005 Posts: 219
|
Posted: Wed Dec 06, 2023 5:27 pm Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
I have the flywheel. You can use it if needed. I plan to do the same thing to my crankshaft. _________________ '63 OG 117 Herbie Replica
'56 Euro Oval Deluxe
'52 Standard Zwitter
'63 OG 117 |
|
Back to top |
|
|
IN2VWS Samba Member
Joined: January 29, 2006 Posts: 2523 Location: Australia
|
Posted: Sun Mar 03, 2024 12:18 am Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
_________________ ( ⫏ ⫐ )
(ọ\ ¡ /ọ)¹⁹⁵⁴ ¹⁹⁵¹
(⦷ ⥢ Ĭ ⥤ ⦷) 𝗞_𝗔_𝗥_𝗠_𝗔_𝗡_𝗡 𝓖𝓱𝓲𝓪¹⁹⁵⁶
⨴⨵--⊗--⨴⨵ 𝕊ℙ𝟚¹⁹⁷³
𝟵_𝟭_𝟰¹⁹⁷³ |
|
Back to top |
|
|
TomSimon Samba Member
Joined: January 13, 2004 Posts: 751
|
Posted: Sun Mar 03, 2024 2:24 am Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
Very nice! Replaceable hardened drill bushings, a piece of professional tooling. And that patina! _________________ 2-time NASA Pro Racing Champion, Bonneville 130 Club and 150 Club Memeber, BRS Pro Gas racer |
|
Back to top |
|
|
esde Samba Member
Joined: October 20, 2007 Posts: 6023 Location: central rust belt
|
Posted: Sun Mar 03, 2024 4:46 pm Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
Amazing.
So, it has a VW number. Did any VW have an 8 dowel crankshaft from the factory? I'm wondering what the factory made the tool for?
Is one of the pins offset? Maybe it was to repair a crankshaft that had damaged holes? _________________ modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
|
Back to top |
|
|
RolandD Samba Member
Joined: January 15, 2017 Posts: 254 Location: Menomonee Falls, Wis
|
|
Back to top |
|
|
Braukuche Samba Member
Joined: September 03, 2004 Posts: 11040
|
Posted: Tue Mar 05, 2024 8:59 am Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
There’s no need to eight dowl it unless you are building an engine capable of running the same high RPMs as a Porsche 356. In that case why wouldn’t you buy a 69.5 stroker crank that’s already eight dowled? _________________ Go Reds! Smash state!
Retirement is here!
1956 Ghia
1959 SO-23 Westfalia
1960 double cab
1960 Baja Bug
1963 stretched double cab
1962 Golde sunroof Ghia
1963 356 B coupe
1963 Notchback
1967 21 window less rusty now |
|
Back to top |
|
|
esde Samba Member
Joined: October 20, 2007 Posts: 6023 Location: central rust belt
|
Posted: Tue Mar 05, 2024 3:03 pm Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
Braukuche wrote: |
There’s no need to eight dowl it unless you are building an engine capable of running the same high RPMs as a Porsche 356. In that case why wouldn’t you buy a 69.5 stroker crank that’s already eight dowled? |
That's not really accurate.
Drag race starts and hard shift are what usually oval out the dowel holes, but cars that are driven hard are well known to do it also. Especially. cars that are driven with a lot of downshifting/ compression braking. The 4 little 6mm pins are barely adequate for 36hp.
Of course at hight rpm, there is more mass (30lbs of flywheel and clutch assembly!) and that inertia is more likely to kill the pins, but it does happen even on stock street driven cars. _________________ modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
|
Back to top |
|
|
Iowa Mark Samba Member
Joined: May 06, 2004 Posts: 1072
|
Posted: Tue Mar 05, 2024 5:48 pm Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
esde wrote: |
Braukuche wrote: |
There’s no need to eight dowl it unless you are building an engine capable of running the same high RPMs as a Porsche 356. In that case why wouldn’t you buy a 69.5 stroker crank that’s already eight dowled? |
That's not really accurate.
Drag race starts and hard shift are what usually oval out the dowel holes, but cars that are driven hard are well known to do it also. Especially. cars that are driven with a lot of downshifting/ compression braking. The 4 little 6mm pins are barely adequate for 36hp.
Of course at hight rpm, there is more mass (30lbs of flywheel and clutch assembly!) and that inertia is more likely to kill the pins, but it does happen even on stock street driven cars. |
I have to agree. Way back in 1968 my 1957 stock bug spun the flywheel. I was just your typical teen-age boy driving up and down Grand Ave on a friday night. No, honestly! |
|
Back to top |
|
|
RWK Samba Member
Joined: June 24, 2009 Posts: 1417 Location: S.W. MI
|
Posted: Wed Mar 06, 2024 7:41 am Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
Could you drill the 4-6mm pins to 8mm? PM me, I could possibly build a drill jig, do you know the bolt circle, or radius from center, or pin center to center? _________________ 73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
|
Back to top |
|
|
esde Samba Member
Joined: October 20, 2007 Posts: 6023 Location: central rust belt
|
Posted: Mon Mar 11, 2024 5:50 am Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
RWK wrote: |
Could you drill the 4-6mm pins to 8mm? PM me, I could possibly build a drill jig, do you know the bolt circle, or radius from center, or pin center to center? |
To jump from 6 to 8mm, there would be .5mm between the dowels and the inside/ outside edges of the crankshaft, probably not enough material. To oversize the existing pins, you could use 1/4" (6.32mm), 7mm, or 9/32 (7.14mm)
I have started to make a jig, based on the pattern that DPR uses. If it works well, I will share the details. _________________ modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
|
Back to top |
|
|
RolandD Samba Member
Joined: January 15, 2017 Posts: 254 Location: Menomonee Falls, Wis
|
Posted: Mon Mar 11, 2024 6:09 pm Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
Please do share the geometry details.
Roland |
|
Back to top |
|
|
[email protected] Samba Member
Joined: June 24, 2015 Posts: 733 Location: Rialto. CA
|
|
Back to top |
|
|
RWK Samba Member
Joined: June 24, 2009 Posts: 1417 Location: S.W. MI
|
Posted: Fri May 24, 2024 7:45 pm Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
I have the 231b I believe it is for the 36, it has a bolt hole radius of 19mm, 6mm drill bushings, someone got a crank to measure? I don't!
The add says those are 231c and I see it has 8mm drill bushings, they are probably for larger 40 and up which is a 20.5mm hole radius, so measuring would be prudent.
I'll post pics of mine at some point, one of which has PN covered in patina _________________ 73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
|
Back to top |
|
|
RWK Samba Member
Joined: June 24, 2009 Posts: 1417 Location: S.W. MI
|
Posted: Sun May 26, 2024 5:59 pm Post subject: Re: drilling a 36hp crank and flywheel for 8 dowels |
|
|
Drill jig I picked up at swap, 6mm holes on a 19mm radius, 36HP 4 each drill bushings, for hole size (5.75mm) and follow up 6mm reamer, and jig for flywheel and crank.
Liners are 10mm ID, switch bushings around for each operation drill and ream, little handles make it easy, unlike production style jigs.
_________________ 73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
|
Back to top |
|
|
|