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kangaboy
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Joined: August 28, 2010
Posts: 1063
Location: St. Louis, Mo
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 Posted: Wed Oct 10, 2018 12:35 pm Post subject: What needs to be replaced when swapping crank? |
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I have a stock 69mm German crank in my motor now. I have a counter weighted 69mm DPR crank on my work bench.
Current motor runs perfect, and doesn't have anywhere near enough miles for a full rebuild.
Besides maybe new bearings to accept the c/w crank (I don't know if it's been ground yet), what do I need to replace to tear the motor down and build it back up with the c/w crank? Maybe just make sure the lifters and pistons don't switch spots with one another, and a new gasket set?
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-74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
| skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out  |
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vwracerdave
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Joined: November 11, 2004
Posts: 15302
Location: Deep in the 405
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| Posted: Wed Oct 10, 2018 1:28 pm Post subject: Re: What needs to be replaced when swapping crank? |
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If your current engine runs perfect then why on earth do you want to tear it apart just to replace the crank? What do you expect to gain?
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2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
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kangaboy
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Joined: August 28, 2010
Posts: 1063
Location: St. Louis, Mo
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| Posted: Wed Oct 10, 2018 1:38 pm Post subject: Re: What needs to be replaced when swapping crank? |
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| vwracerdave wrote: |
| If your current engine runs perfect then why on earth do you want to tear it apart just to replace the crank? What do you expect to gain? |
A couple thousand more RPM...safely
Side note...I never had my stock crank balanced 
_________________
-74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
| skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out |
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mcmscott
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Joined: March 12, 2010
Posts: 4856
Location: sanger ca
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| Posted: Wed Oct 10, 2018 1:52 pm Post subject: Re: What needs to be replaced when swapping crank? |
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I have turned stock cranks past 7k without any problems
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There are no stupid questions, only stupid people,
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67 T-1
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Coyotemutt
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Joined: June 16, 2017
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Location: Pecos, New Mexico
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| Posted: Wed Oct 10, 2018 3:25 pm Post subject: Re: What needs to be replaced when swapping crank? |
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| mcmscott wrote: |
| I have turned stock cranks past 7k without any problems |
Note that the OP said he never had it professionally balanced. |
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mcmscott
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Location: sanger ca
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| Posted: Wed Oct 10, 2018 3:34 pm Post subject: Re: What needs to be replaced when swapping crank? |
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| Coyotemutt wrote: |
| mcmscott wrote: |
| I have turned stock cranks past 7k without any problems |
Note that the OP said he never had it professionally balanced. |
So it is good to 6k in stock balance. Factory german cranks are extremely rigid.
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There are no stupid questions, only stupid people,
68 Ghia
67 T-1
65 Notch
02 Mexican beetle
74 Thing
15 Long travel rail
07 Nomad
05 f-250 |
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kangaboy
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Joined: August 28, 2010
Posts: 1063
Location: St. Louis, Mo
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| Posted: Wed Oct 10, 2018 8:14 pm Post subject: Re: What needs to be replaced when swapping crank? |
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Can anyone answer the question without using a question or trying to give reasons not to do it?
_________________
-74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
| skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out |
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modok
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Joined: October 30, 2009
Posts: 26776
Location: Colorado Springs
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| Posted: Wed Oct 10, 2018 8:33 pm Post subject: Re: What needs to be replaced when swapping crank? |
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Most of it is common sense but I think I know what you are looking for.
Be careful any time you change the relationship between the piston and cylinder. The rings are used to stopping at the top at exactly the same spot and if you alter the crank or rod or cylinder then you may change that and it may cause ring sealing problems, or it might not......actually it probably won't in this case, but it can happen.
Engines in general, some people just go ahead and make it a practice to hone and re-ring every time the engine is apart and something changed that could have changed the piston to cylinder relationship, probably because they learned the hard way
If you replace a crank with a different one and the stroke is just slightly longer (which could happen easily) and the piston tries to go that much farther up the cylinder.....runs into the ridge at the top, breaks the ring lands... or screws up the ring, or it doesen't seal.
But VW engines they don't usually develop much ridge if any, unless they are REALLY old. So, yeah things can go wrong but if it's low miles it's probably fine, tho one rule is it's a lot safer to have the piston lower in the bore than before, rather than higher, but when you re-grind a crank the tendency is for the stroke to increase, which is why most replacement pistons have the rings slightly lower than OE.
You could measure the deck height before and after and see if it changed. most times if a guy is swapping the crank it's because it's ruined a rod bearing, so....you can't measure what it was before. |
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FreeBug
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Joined: March 12, 2012
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Location: deepest, darkest Switzerland
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| Posted: Wed Oct 10, 2018 9:21 pm Post subject: Re: What needs to be replaced when swapping crank? |
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You should get a bunch of washers of different thicknesses to have everything on hand, as you'll need to re-set the crank end play.
What Modok says: I would hone and re-ring.
And of course, make sure of inside clearances, C/W cranks need checking this; don't take it for granted that nothing in there touches...even just stock stroke.
P.S. do you have a flywheel balanced with the new, C/W crank? Clutch PP? New disc? Going to run 4 dowels or 8? |
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modok
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Location: Colorado Springs
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| Posted: Wed Oct 10, 2018 10:01 pm Post subject: Re: What needs to be replaced when swapping crank? |
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I don't think you have to re-hone, but it might be smart.
One thing BRAND NEW pressure plates, and cylinders, and heads, and flywheels, and brakes.... have in common is they warp a bit when subjected to the actual heat and forces they handle in service. No way to simulate it before the fact.
So if you run them for a while, then they are "seasoned", so you machine seasoned parts, they will tend to stay straight after that, better than if they were brand spanking new.
But, should you you re-hone every time you take the engine apart?
no, of course not. |
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kangaboy
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Joined: August 28, 2010
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Location: St. Louis, Mo
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| Posted: Thu Oct 11, 2018 6:17 am Post subject: Re: What needs to be replaced when swapping crank? |
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Thank you modok and FreeBug for the informative replies.
_________________
-74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
| skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out |
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57BLITZ
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Joined: June 12, 2012
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Location: DEEK - U.S.A.
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| Posted: Thu Oct 11, 2018 10:44 am Post subject: Re: What needs to be replaced when swapping crank? |
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| kangaboy wrote: |
| . . . what do I need to replace to tear the motor down and build it back up with the c/w crank? |
Tip . . . Be careful with your brass gear!
Do NOT remove your distributor until after you split the case and use care (or watch the guy that does it for ya!) when removing the gear/spacer/bearing from the crank.
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chrisflstf
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Joined: February 10, 2004
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Location: San Diego
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| Posted: Thu Oct 11, 2018 12:55 pm Post subject: Re: What needs to be replaced when swapping crank? |
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| Quote: |
| Do NOT remove your distributor until after you split the case |
There is no risk in removing the dist. That doesnt make any sense, unless you misspoke |
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FreeBug
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Location: deepest, darkest Switzerland
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| Posted: Thu Oct 11, 2018 1:39 pm Post subject: Re: What needs to be replaced when swapping crank? |
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| chrisflstf wrote: |
| Quote: |
| Do NOT remove your distributor until after you split the case |
There is no risk in removing the dist. That doesnt make any sense, unless you misspoke |
Once the distributor is out, you can damage the bronze gear quite easily, when turning the engine over, and you might turn the engine over to get the right bits in the right place during disassembly...is what I think he meant  . |
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57BLITZ
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| Posted: Thu Oct 11, 2018 3:49 pm Post subject: Re: What needs to be replaced when swapping crank? |
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| FreeBug wrote: |
| chrisflstf wrote: |
| Quote: |
| Do NOT remove your distributor until after you split the case |
There is no risk in removing the dist. That doesnt make any sense, unless you misspoke |
Once the distributor is out, you can damage the bronze gear quite easily, when turning the engine over, and you might turn the engine over to get the right bits in the right place during disassembly...is what I think he meant . |
Yes . . . thank you FreeBug . . . that's what I was getting at.
I should have said . . . Do NOT remove yer distributor unless you ALSO remove the distributor drive and spacer washers before turning the crankshaft.
Some folks set the distributor drive timing on the new crankshaft while the case is apart . . . the distributor could just stay in place for the duration.
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cbeck
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Location: high ridge, mo
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| Posted: Sat Jan 26, 2019 10:11 am Post subject: Re: What needs to be replaced when swapping crank? |
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Your wife told me today about the loss of your little red beetle. Hope every one came out ok. Also hope you got a fair settlement. Any pics you would care to share?[you know how we are]
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FreeBug
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Posts: 4278
Location: deepest, darkest Switzerland
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| Posted: Sat Jan 26, 2019 12:09 pm Post subject: Re: What needs to be replaced when swapping crank? |
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Aw, crap, sorry to hear that.. Been there.
I hope you didn't change that crank... |
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dennismcd707 
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Joined: October 09, 2017
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Location: Burbs of Detroit
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| Posted: Sat Jan 26, 2019 2:19 pm Post subject: Re: What needs to be replaced when swapping crank? |
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| modok wrote: |
One thing BRAND NEW pressure plates, and cylinders, and heads, and flywheels, and brakes.... have in common is they warp a bit when subjected to the actual heat and forces they handle in service. No way to simulate it before the fact.
So if you run them for a while, then they are "seasoned", so you machine seasoned parts, they will tend to stay straight after that, better than if they were brand spanking new. |
Am I understanding this correctly? I have a brand new pressure plate, so I should use it and season it first, then take it in for balancing? How much seasoning does it need before it can safely be machined (balanced)?
IMO..........I'd leave the crank alone! If you really want to find a good place for that other crank, save up and just build yourself an engine. The right way.
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modok
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Location: Colorado Springs
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| Posted: Sat Jan 26, 2019 2:49 pm Post subject: Re: What needs to be replaced when swapping crank? |
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No, run it for awhile then grind the face flat again.
I have tried many brands, and they all get to be about .002-.004 dished, and usually .001-.002 runout in a triangle shape, which can cause some chatter.
I do not know if the balance will change, hopefully not.
Good pressure plates are already balanced, and...if they are "good" or not.....I don't want to get into that subject. |
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