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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Tue Aug 28, 2012 2:14 pm Post subject: Engine out...what next |
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I have the 36hp out of the '58 Bug and will be taking the heads off to fit new push rod tubes and seals. I will be adding twin 28pci carbs on express manifolds and a 019.
Is there anything else I could do whilst the headsa are off. Should I be looking to increase the compression ratio?
Thanks
Richard _________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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Kjell Roar Samba Member
Joined: December 08, 2008 Posts: 1326 Location: Norway
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Posted: Tue Aug 28, 2012 2:23 pm Post subject: Re: Engine out...what next |
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RichardinNZ wrote: |
Is there anything else I could do whilst the headsa are off. Should I be looking to increase the compression ratio?
Thanks
Richard |
Yes, if you want more power. Quite easy engineering job for those who can. The intakes in the heads also should have a little port-job to flow better. _________________ I got a historic car, every scratch got a history...
My car, Aug. 4th, 1955 / an early 56: http://www.thesamba.com/vw/forum/album_page.php?pic_id=610438 |
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Rome Samba Member
Joined: June 02, 2004 Posts: 9640 Location: Pearl River, NY
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Posted: Wed Aug 29, 2012 4:18 pm Post subject: |
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How about some basic work, such as-
-chasing all threads on your head's exhaust studs (M8 x 1.25mm) and those for the intake manifold studs (M6 x 1.0mm, I think)
-replacing all exhaust valves as a precaution, and lapping the new ones to the seats
-chasing the heads' spark plug threads with a threading tool/restorer
-pre-stretching the new pushrod tubes to the factory spec, cleaning them with solvent or brake cleaner spray; then painting them with flat-black paint
-having the heads cleaned with solvent, then bead-blasted
-measure your heads' combustion chamber volumes as a baseline for determining your compression ratio
-measure each piston's deck height
-verify that the two cylinder's top surfaces are level and flat on each side of the engine
-check each valve spring for presence of rust blisters, and replace if found |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Thu Aug 30, 2012 1:20 pm Post subject: |
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Thanks for the help; will try to speak to some people here about a suitable machine shop. Also considering adding large intake valves at the same time, despite trying to keep my costs down!
Richard _________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Mon Sep 10, 2012 5:53 pm Post subject: |
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Can anyone offer advice regarding the bigger intake valves? I'll be running 2 x 28PCI carbs and wonder whether I should add 33mm intakes?
Thanks
Richard _________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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Kjell Roar Samba Member
Joined: December 08, 2008 Posts: 1326 Location: Norway
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Posted: Tue Sep 11, 2012 3:09 am Post subject: |
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RichardinNZ wrote: |
Can anyone offer advice regarding the bigger intake valves? I'll be running 2 x 28PCI carbs and wonder whether I should add 33mm intakes?
Thanks
Richard |
You can take up the original seat insert to Ø27mm (from 25 original) and still use the original valve. That wil probably be enough for a nice daily driver with 28 PCI's.
The Okrasa-set got Ø33mm IN valves, with Ø28 inner in the inserts, and you can probably put in an Okrasa-valve and take up the original insert to 28 mm. If you want more, you need bigger carbs.
But I hope someone can confirm that the Okrasa-valves can be used that way. I just talked to a guy who is a specialist in valve seats and porting (not much VW), he said it would work. As long as the insert's outer Ø is not smaller than the valve, it should work, and get the angels right. But he didnt want to go any wider than 28-29mm without putting in bigger seat inserts. _________________ I got a historic car, every scratch got a history...
My car, Aug. 4th, 1955 / an early 56: http://www.thesamba.com/vw/forum/album_page.php?pic_id=610438 |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Tue Sep 11, 2012 12:54 pm Post subject: |
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Thanks for the information; I've been to see a cylinder head specialist who (although not a VW specialist) instantly recognised them as 36hp heads...so I'm feeling confident in him! He is going to open up the seats on the intakes and hopefully we can use the 33mm valves.
Flycutting...is 2mm usual? Does anyone know what compression this gives with otherwise stock heads?
Thanks
Richard _________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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Kjell Roar Samba Member
Joined: December 08, 2008 Posts: 1326 Location: Norway
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Posted: Tue Sep 11, 2012 1:38 pm Post subject: |
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If you cut 3mm, you get around 37cc in the head instead of 45-47cc, and you will get 8.2:1 comp. with deck height around 1 mm. I think original deck height is 1.25 mm. will give 8:1.
Back in the 80'ies, I heard that 2.5 -3 mm was a good maximum cut, for a street engine.
Engine calculator:
http://cbperformance.com/enginecalc.html
I am planning my own 36 hp engine, will try to build it next year. Have saved up some parts for it, so its soon time to start building it. _________________ I got a historic car, every scratch got a history...
My car, Aug. 4th, 1955 / an early 56: http://www.thesamba.com/vw/forum/album_page.php?pic_id=610438 |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Mon Oct 08, 2012 12:20 am Post subject: |
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OK; moving forward now that my parts have arrived (thanks Mr Motorhead). The heads are at the head specialist; as I mentioned he recognised them as 36hp but isn't a VW specialist and I'm far from an expert too! He says that if they were later heads he'd (my words) flycut the face and also in the bore...both by a similar amount. But what about the recess for the copper rings that sit around the barrel. Are these needed and how accurate do they have to be? It'll add more labour time to have them and therefore more cost!
Thanks
Richard _________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Mon Oct 29, 2012 11:32 pm Post subject: |
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Heads back...2mm flycut and 33mm intakes in new seats. Measure at just under 41cc which gives me about 7.5:1 compression ratio. Also installed new exhaust valves and new exhaust guides. I won't use copper rings around barrels (and no heater) so didn't need to machine for these. Hope to get the heads on and engine reassemled at the weekend, mock up the manifolds and carbs and work out the linkage and try to get the correct jets for the carbs....see my other posts!
_________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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Beetspeed Samba Member
Joined: July 30, 2004 Posts: 429 Location: The Netherlands
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Posted: Tue Oct 30, 2012 2:15 pm Post subject: |
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Nice pictures! I like that your getting a little quench in to the combustion chamber when you flycut some more, which helps too _________________ '75 SB 1303 2,4ltr T4 turbo: 10.58 @ 129.9mph
'65 Ruska buggy 1192cc EFI 80hp N/A |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Mr. Motorhead Mad Scientist
Joined: January 06, 2004 Posts: 717 Location: Practitioner of 36hp alchemy
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djway3474 Samba Member
Joined: August 19, 2011 Posts: 2582 Location: The Real NDK So Cal
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Posted: Thu Dec 06, 2012 12:45 am Post subject: Re: Nearly complete! |
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That looks great. Any picts of the linkage and what did you use? I have a set of 30 manals that I have been looking into building some manifolds for.
I really like what you have done here. |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Thu Dec 06, 2012 2:20 am Post subject: |
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A few bits and pieces to complete; may be out for a spin at the weekend but very busy on other things at the moment. Can't wait, but also very pleased with how it looks (the Mr Motorhead stacks set it off).
Will post some linkage photos next week....
Richard _________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Posted: Thu Jan 03, 2013 9:35 pm Post subject: |
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OK...made no progres on this as have hit some problems and have had little time to look at it....I have no compression! The barrels don't seem to be sealing in the heads although there appears to be good clearance between the fins/face of the head and the barrel. To ensure this is the case I have clearanced this part of the head further (many hours carefully cutting a step in the head around the barrel area with a dremmel).
I'm wondering whether the push rod tubes are too long and pushing things apart? Compressed they measure 152.5mm. The official manual states that uncompressed they should be 154/155mm on stock engine...does anyone know what they compress to usually (with stock, non-skimmed heads) as mine should be compressing to 2mm shorter than this I guess?!
Many thanks
Richard _________________ Richard
'58 Beetle; NZ Assembled
Dual Carb 36hp
My Car https://www.thesamba.com/vw/forum/album_page.php?pic_id=1750253 |
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Bengt H Samba Member
Joined: September 11, 2005 Posts: 332 Location: Sweden
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Posted: Sat Jan 05, 2013 2:26 pm Post subject: |
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Push rod tubes should not bee the problem, I cut my heads 3mm without any tube problems. Good luck with finding your troubble. |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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Flavio Samba Member
Joined: May 14, 2008 Posts: 414 Location: Madeira Island, Portugal
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Posted: Sun Jan 06, 2013 3:30 am Post subject: |
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Hi Richard
Are you sure that the pushrod tubes you have are the correct 25/36 Hp ones ?
Flavio |
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RichardinNZ Samba Member
Joined: September 16, 2011 Posts: 280 Location: Auckland, New Zealand
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