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GüteAndTite Early Convertible Güru
Joined: June 16, 2005 Posts: 2144 Location: Low So Cal
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Posted: Wed Sep 28, 2011 4:01 pm Post subject: Need help achieving 74mm stroke in 36hp? |
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Hey guys,
after searching and reading lots of misleading information in threads on thesamba and not really getting anywhere , I need some help. Ive walked thru muck and have nothing but **** on my boots.
Im trying to achieve a motor that is 74mm stroke and use 83mm pistons. to build a 1602cc motor out of a 36hp case.
can anyone tell me the proper crank to use and the bearings and machine work to do so? i need details so i buy the right parts.
also what rods do i use? any mods to them? wrist pin bushings?
and finally what pistons and cylinders to use?
looking forward to learning what you guys know ! _________________ Official 58-60 "Early Big Window" Convertible Thread & Registry
http://www.thesamba.com/vw/forum/viewtopic.php?t=426481
F&S Saxomat Automatic Clutch System Thread
http://www.thesamba.com/vw/forum/viewtopic.php?t=462533
61-67 Delanair Air conditioning Thread
http://www.thesamba.com/vw/forum/viewtopic.php?t=457944&highlight=air+conditioning
PUNCTUATION CHANGES THE WORLD: "I need to help my uncle, Jack, off a horse" is way better than, "I need to help my uncle jack off a horse"
Last edited by GüteAndTite on Sat Oct 01, 2011 2:14 pm; edited 1 time in total |
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gimmesomeshelter Samba Member
Joined: May 08, 2004 Posts: 1466 Location: San Carlos, CA
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Posted: Wed Sep 28, 2011 6:14 pm Post subject: |
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Hello-
For the crank, you have several options:
1) Modify a 36hp crank. Many people have done this and have had good results. The upside is that it's relatively inexpensive, and you can use stock 36HP bearings. The downside is that the stock 36HP crank has a reputation for breaking.
2) Porsche 356 A/B crank. Expensive, but still uses 36HP bearings. You'll use Porsche rods, and that will end up changing your rod ratio.
3) Porsche 356 C/Super crank. Strongest off the 356 cranks, but will require that you either install $400 Porsche bearings, or have the crank turned down to 50mm (like the A/B cranks).
Regarding P/Cs, it's a little more difficult.
1) Nickies - very expensive, but you can order exactly what you want.
2) Shasta - expensive (2K), but he does semi-custom Durabar cylinders, and you can order custom flat top pistons.
3) AA PCs - the least expensive, but you'll need to mill the tops off the pistons, mill off the top cylinder fin, and change the slots for the rods that hold on your heads.
4) Modified 40 HP - you'll need to do a lot of hand work to trim the fins. I'm not sure what you'll need to do for the pistons.
Regards,
Paul |
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GüteAndTite Early Convertible Güru
Joined: June 16, 2005 Posts: 2144 Location: Low So Cal
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Posted: Thu Sep 29, 2011 9:34 am Post subject: |
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gimmesomeshelter wrote: |
Hello-
For the crank, you have several options:
1) Modify a 36hp crank. Many people have done this and have had good results. The upside is that it's relatively inexpensive, and you can use stock 36HP bearings. The downside is that the stock 36HP crank has a reputation for breaking.
2) Porsche 356 A/B crank. Expensive, but still uses 36HP bearings. You'll use Porsche rods, and that will end up changing your rod ratio.
3) Porsche 356 C/Super crank. Strongest off the 356 cranks, but will require that you either install $400 Porsche bearings, or have the crank turned down to 50mm (like the A/B cranks).
Regarding P/Cs, it's a little more difficult.
1) Nickies - very expensive, but you can order exactly what you want.
2) Shasta - expensive (2K), but he does semi-custom Durabar cylinders, and you can order custom flat top pistons.
3) AA PCs - the least expensive, but you'll need to mill the tops off the pistons, mill off the top cylinder fin, and change the slots for the rods that hold on your heads.
4) Modified 40 HP - you'll need to do a lot of hand work to trim the fins. I'm not sure what you'll need to do for the pistons.
Regards,
Paul |
Know anything about the 912 crank? _________________ Official 58-60 "Early Big Window" Convertible Thread & Registry
http://www.thesamba.com/vw/forum/viewtopic.php?t=426481
F&S Saxomat Automatic Clutch System Thread
http://www.thesamba.com/vw/forum/viewtopic.php?t=462533
61-67 Delanair Air conditioning Thread
http://www.thesamba.com/vw/forum/viewtopic.php?t=457944&highlight=air+conditioning
PUNCTUATION CHANGES THE WORLD: "I need to help my uncle, Jack, off a horse" is way better than, "I need to help my uncle jack off a horse" |
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splitpile Samba's Worst Speller
Joined: May 03, 2000 Posts: 5927 Location: back to living where hell meets the suface
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Posted: Thu Sep 29, 2011 9:52 am Post subject: |
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guteandtite wrote: |
gimmesomeshelter wrote: |
Hello-
For the crank, you have several options:
1) Modify a 36hp crank. Many people have done this and have had good results. The upside is that it's relatively inexpensive, and you can use stock 36HP bearings. The downside is that the stock 36HP crank has a reputation for breaking.
2) Porsche 356 A/B crank. Expensive, but still uses 36HP bearings. You'll use Porsche rods, and that will end up changing your rod ratio.
3) Porsche 356 C/Super crank. Strongest off the 356 cranks, but will require that you either install $400 Porsche bearings, or have the crank turned down to 50mm (like the A/B cranks).
Regarding P/Cs, it's a little more difficult.
1) Nickies - very expensive, but you can order exactly what you want.
2) Shasta - expensive (2K), but he does semi-custom Durabar cylinders, and you can order custom flat top pistons.
3) AA PCs - the least expensive, but you'll need to mill the tops off the pistons, mill off the top cylinder fin, and change the slots for the rods that hold on your heads.
4) Modified 40 HP - you'll need to do a lot of hand work to trim the fins. I'm not sure what you'll need to do for the pistons.
Regards,
Paul |
Know anything about the 912 crank? |
The biggest issue is rod to cam lobe clearance. Porsche 356 crank and rods will drop right in after you have the main journals turned down to 36hp main bearing sizes. I am still working on getting my 74 welded 36hp chevy rod journal crank to work. Doing major rod surgery _________________ Stocking distributor of "The Funky Green Panels"
www.BUSTORATION.com metal and more for your bus
"no more hacking my sig line" |
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GüteAndTite Early Convertible Güru
Joined: June 16, 2005 Posts: 2144 Location: Low So Cal
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spectre6000 Samba Member
Joined: April 19, 2009 Posts: 2014 Location: Broomfield, CO
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Posted: Thu Sep 29, 2011 11:13 am Post subject: |
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L&N Engineering. Charles is who you'll be talking to. You might have to provide a sample cylinder for him to make them from. I talked to him a while back about some 77mm 1300dp cylinders (late euro base model engine), and he said he would need something in hand to take measurements from. He has the ability to make cylinders as small as 85.5mm, and it'll set you back $2K or so for a set plus you get ARP head studs and custom pistons in the deal. Truly the way to go if you have the dough. The plus side is that if you use high quality stuff everywhere else, your pistons/cylinders will no longer be your rebuild timer. Those things should be good for several hundred thousand miles. Building off a 36hp base, you'll be dealing with bearings as your weak point... _________________ Jason Hopper
-'58 German Market Deluxe Beetle (in progress)
-'84 M1009 CUCV
-'81 K10
"Buy the best, cry once." -Gene Berg
"A cheap man will always buy the cheapest thing available, and then buys another one hoping for a better result, and then spends the rest of his life in misery complaining about it. A thrifty man will buy a good part once and never think about it again." -RockCrusher
"Don't feed the Shitty Parts Monster!" -Me |
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gimmesomeshelter Samba Member
Joined: May 08, 2004 Posts: 1466 Location: San Carlos, CA
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Posted: Thu Sep 29, 2011 11:48 am Post subject: |
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Hello-
Here's a pic of a 82.5mm cylinder from LN Engineering next to a stock 36HP cylinder.
Keep in mind that Charles doesn't studs for a 36HP case. His VW studs have 10mm threads, and neck down to 8mm. I had to buy 10mm studs from Raceware. Charles says that they'll work, but there will be more stress on the case.
BTW, if you want to read about the different 356 cranks, read Duane Spencer's book (http://www.amazon.com/Porsche-Performance-Guide-Du...amp;sr=1-3).
Regards,
Paul |
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spectre6000 Samba Member
Joined: April 19, 2009 Posts: 2014 Location: Broomfield, CO
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Posted: Thu Sep 29, 2011 12:42 pm Post subject: |
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Purty. Sucks about the studs... Are those what he recommended?
Has anyone ever made an aluminum 36hp case (not counting the really early cases)? _________________ Jason Hopper
-'58 German Market Deluxe Beetle (in progress)
-'84 M1009 CUCV
-'81 K10
"Buy the best, cry once." -Gene Berg
"A cheap man will always buy the cheapest thing available, and then buys another one hoping for a better result, and then spends the rest of his life in misery complaining about it. A thrifty man will buy a good part once and never think about it again." -RockCrusher
"Don't feed the Shitty Parts Monster!" -Me |
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gimmesomeshelter Samba Member
Joined: May 08, 2004 Posts: 1466 Location: San Carlos, CA
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Posted: Thu Sep 29, 2011 12:49 pm Post subject: |
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Hello-
Quote: |
Are those what he recommended? |
Yes, Charles recommended that I use the Raceware studs. I asked about 8mm studs, but the selection is very limited. I asked about having a custom set made using LN's spec, but it was going to be $600-1200 for one set.
Regards,
Paul |
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GüteAndTite Early Convertible Güru
Joined: June 16, 2005 Posts: 2144 Location: Low So Cal
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gimmesomeshelter Samba Member
Joined: May 08, 2004 Posts: 1466 Location: San Carlos, CA
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Posted: Thu Sep 29, 2011 1:21 pm Post subject: |
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Hello-
Quote: |
Know anything about the 912 crank? |
The C/Super/912 cranks are cross-drilled and have 55mm mains. The super/912 cranks are counter weighted, but the C crank is not.
Quote: |
what is the advantage of nickasils over regular steel jugs and pistons? |
The primary primary benefit is that aluminum cylinders dissipate heat much faster than cast iron. If you want to know all the benefits of Nickies do a search for all of Jake Raby's comments about them.
Regards,
Paul |
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Mr. Motorhead Mad Scientist
Joined: January 06, 2004 Posts: 717 Location: Practitioner of 36hp alchemy
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Posted: Thu Sep 29, 2011 2:43 pm Post subject: |
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gimmesomeshelter wrote: |
Hello-
Quote: |
Know anything about the 912 crank? |
The C/Super/912 cranks are cross-drilled and have 55mm mains. The super/912 cranks are counter weighted, but the C crank is not.
[Paul |
I ran (and just got back from a short run with in town) a 36hp engine with the counter weighted 912 crank cut for 50mm mains out on the salt a couple weeks ago in my bus. Anyone who hears it run agrees that it runs strong . It's cut for 36hp rods at a 72mm stroke with 83mm 40hp big bore pistons and cylinders (lots of hand work as Paul says). I've gone the 74mm route, but your choices on piston sets that are affordable for most folks really diminishes with that larger stroke. At 72mm it's pretty much your choice of rods since the clearance problems are minimal. The counter weights will require some cutting on the piston skirts, they are huge! (bigger than the weld on counter weights) I think it would run well even with stock 77mm pistons especially in a beetle. The costs I think would be within reach for most hobbyists. The most expensive part of running a Porsche crank is finding a set of Porsche rods that won't break the bank by the time they are ready to run.
Crank
Converted 83mm cylinders
_________________ 30 years experience in the sales of new and used auto parts!
36 horsepower parts for sale at http://www.aircooledresearch.com/
Or the new site at http://www.bugparts.com
Check out the Bonneville project:
http://aircooledresearch.com/docs/thebonnevilleproject.html#
"All limitations are self imposed."
Some Chinese guy |
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gimmesomeshelter Samba Member
Joined: May 08, 2004 Posts: 1466 Location: San Carlos, CA
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Posted: Fri Sep 30, 2011 1:28 pm Post subject: |
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Hello-
Quote: |
The counter weights will require some cutting on the piston skirts, they are huge! |
Or you can buy some FSR pistons from JE.
Regards,
Paul |
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TomSimon Samba Member
Joined: January 13, 2004 Posts: 751
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Posted: Fri Sep 30, 2011 4:38 pm Post subject: |
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There are a lot of different ways to go for sure...
I started my hotrod 36er's with a couple of used 912 couterweighted 74mm stroke cranks. I will need Porsche main bearings, like has been mentioned, $400/set ouch! But who said high performance was cheap? I also like the fact that the mains and rod journals are bigger than 36hp, for more overlap, making it a stronger, thicker webbed crank... I plan to supercharge at least one of these engines someday.
You also have to think about which clutch, and flywheel you want to use...
Check out www.blackline57.com and their picture gallery of the 36hp race engine build. They are reving that thing to 7500rpms! |
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Bengt H Samba Member
Joined: September 11, 2005 Posts: 332 Location: Sweden
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Posted: Sun Oct 02, 2011 11:32 am Post subject: |
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I built an Okrasa engine with a 74 mm A/B crank some years ago. Porsche rods and modified 356 cylinders with JE pistons, The cam is from an old Swedish grinder, 8.5 mm lift. Heres some pic
I had to cut the top coolingring of the cylinder and make the part that goes into the crankcase a litle thinner to get a better step for the cylinder to stand on. I took 1 mm of the rods to make a better clerance for the cam. The engine pumps out 81 hp @3900 rpm |
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AirCooledClassics Samba Member
Joined: August 20, 2004 Posts: 294 Location: Saskatoon, Sk Canada
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Posted: Sun Oct 02, 2011 11:33 am Post subject: |
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Unless you are going for a bonneville type car I would listen to mister motorhead and stop at 72 mm .The stroke creates a lot of issues. with the rod to cam and barrel spaceing issues. If you just want a fun engine without breaking the bank this is the way to go. On my 75mm by 83 engine I used 83mm 1500 pis/cyls with the case opened up and the barrels trimmed down I followed mr motorheads advice on trimming down the barrel fins and used 8mm case savers. I had the crank ground to chev rod journals and used aa 5.4 rods Thank god the are super strong rods because we had to grind and radius the cap a lot to clear the cam. I plan on daily driving this in my 53 zwitter and yet take it to bonneville.The engine should get tested this spring in my 1/4 mile car.Im hoping for 85-90 hp. Dont go to the 74 stroke unless you like posting a lot on this thread Hope this helps. _________________ 2010 Bonneville record holder Type 2, 36hp
NHRA Divisional Sports Compact Champion
My You-tube video
http://www.youtube.com/watch?v=GJoq3MtsPmc
My National Dragster article
http://www.dragracecentral.com/DRCStory.asp?ID=231552 |
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Bengt H Samba Member
Joined: September 11, 2005 Posts: 332 Location: Sweden
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Posted: Sun Oct 02, 2011 12:00 pm Post subject: |
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Here is the problem area, had to cut just 1 mm on my engine
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GüteAndTite Early Convertible Güru
Joined: June 16, 2005 Posts: 2144 Location: Low So Cal
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Posted: Sun Oct 02, 2011 3:26 pm Post subject: |
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so if i go with a 74mm crank, what bearings do i need to be looking for? i read somewhere that instead of weaking the crank and cutting it down to 50mm on the mains, you can instead cut the case down. I read that you can fit the 74mm 912 crank by using 356 standard bearings, which are apparently thinner than vw, you simply need to cut the case .250 oversize from vw 36hp standard and the whole set up drops in, this keeps the crank strong (porsche went from 50mm to 55mm to solve the problem of the crank flexing and breaking. does this sound like im following this all right?
i was also curous about 3 things- the center main on 58 and later cases is seperated from the case, while earlier cases are solid- which is better and why?
also, what is thru bolting the case and what benefit does it have?
should the case be fit with case savers like a 1600 DP case if I am turning this case into a 1600cc 36hp motor? can i use the same ones or need special case savers specifically for 36hp case? _________________ Official 58-60 "Early Big Window" Convertible Thread & Registry
http://www.thesamba.com/vw/forum/viewtopic.php?t=426481
F&S Saxomat Automatic Clutch System Thread
http://www.thesamba.com/vw/forum/viewtopic.php?t=462533
61-67 Delanair Air conditioning Thread
http://www.thesamba.com/vw/forum/viewtopic.php?t=457944&highlight=air+conditioning
PUNCTUATION CHANGES THE WORLD: "I need to help my uncle, Jack, off a horse" is way better than, "I need to help my uncle jack off a horse" |
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gimmesomeshelter Samba Member
Joined: May 08, 2004 Posts: 1466 Location: San Carlos, CA
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Posted: Sun Oct 02, 2011 5:15 pm Post subject: |
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Hello-
If you want to install 356C/SC bearings, you'll need to machine oil channels into your case, as well as add slots for the bearing tabs. You may also have to align bore your case, but keep in mind that a STD set of main 356 bearings = 1 over in VW bearings. I have an NOS case, so I bought STD/STD bearings, and I'll have to align bore the case 1 over. Competition Engineering can machine the slots for ~150, but align boring will be extra.
Here's a thread that discusses thru-bolts.
http://www.thesamba.com/vw/forum/viewtopic.php?t=439985&highlight=thru
Regards,
Paul |
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Bluemanx212 Samba Member
Joined: March 20, 2011 Posts: 55 Location: SK Canada
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Posted: Mon Oct 03, 2011 6:06 pm Post subject: |
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If you put in a real cam you will hit the rod and that looks like a stock or worn one with not much lift! That is one of the reasons why people are wanting to use some type of ratio rocker to get more lift! Use a piston in a cylinder to see where the rod actually is when you turn it overas well. |
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