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Author Topic: Center cam bearing tightness? Is it crank case warpage?!  (Read 5573 times)
AirCooledCurtis
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Posts: 41


« on: December 30, 2012, 23:33:18 pm »

Hello, newbie on the forum, and I have a question on case warpage.  I got a later as41 case (not fuel inj.) from my grandpa that was checked, align bored 20 over, and had case-savers installed back in the late '80s.  I was wishing for a mild performance engine that would be better than the 60ish hp. I have now.  My mechanic that I trust looked over the case and all was good until he bolted it together and ran a cam ream bar through it.  a small bit of metal was taken off the center bearing, and my mechanic said that the case was subjected to some heat and warped it.  I believe that I heard of machine shops machining the middle cam bearing to relieve "cam bearing tightness".  Has anyone got ideas?  Is it usable?
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Greg G
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Posts: 179


« Reply #1 on: December 31, 2012, 03:32:13 am »

If he ran his center cam bore tool through it and make the bore straight, you are good to go. It is common for the center to be off a little on a used case.
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65bug
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Posts: 264


« Reply #2 on: December 31, 2012, 05:37:01 am »

Curtis,
      If you can afford it, you are FAR BETTER OFF to purchase a new case. Preferably one checked out by a shop that knows what they are doing. Even brand new cases sometimes have problems. So it's worth it to spend the money for a new case. A old case thats off will run hot, wear out prematurely, and have lousy oil pressure. I would not trust a case that old thats already had work done on it..
     
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DKK Ted
DKK
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Posts: 1879



« Reply #3 on: December 31, 2012, 06:21:40 am »

That's why BOTH my cases are Berg case's, they check there stuff...worth the money, especailly if your building a performance motor.

Ted
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VW Classic 2012
65bug
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Posts: 264


« Reply #4 on: December 31, 2012, 06:45:18 am »

Curtis,
       Also, welcome to the forum....... Wink
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AirCooledCurtis
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Posts: 41


« Reply #5 on: December 31, 2012, 17:48:01 pm »

Okay, the case has already been completely checked by a guy with 45 years of experience.  I just found it weird that the case shrunk there, instead of expanding.  I guess the only way to find out if it's usable is if it was a complete engine Undecided
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65bug
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Posts: 264


« Reply #6 on: January 03, 2013, 18:20:00 pm »

The case has been weakened already. Evidenced by the center moving around. More then likely a shit load of miles on that case. Get a new one and have it checked out. Preferably Gene Berg, or the CbPerformance supercase.
   Then have all your parts(new pistons and cylinders) balanced. Have the cylinders honed. If you get a Cb Performance case they are already full flowed and ready to go. A little patience and some extra bucks will ensure a long lived motor that runs cool and runs well.
    Make sure your case is clean clean clean!!! Blueprint your case. Go over every square inch of it and de-bur it. Flush out the passages multiple times. You will be surprised many times what comes out of them.
    Preperation and attention to detail will make yo a happy camper in the long run. What you spend now to do it right, will save you many times in the long run.
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John Maher
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« Reply #7 on: January 03, 2013, 23:06:44 pm »

It's common to see the centre cam bearing saddle close up a little on a used case. The front and rear bearing saddles are supported top and bottom, while the centre is unsupported from underneath.

When carrying out a line bore, I have a tool that sits in the front and rear cam saddles. It has a cutter set to stock diameter for the centre main only. On some crankcases it doesn't remove any material - on others it'll clean up the saddle exactly as described in the first post.

Like others have already said.... a brand new case is a good starting point for any performance motor. There was a thread on here (a couple of years ago?) that went into various crankcase prepping checks and tricks.
« Last Edit: January 04, 2013, 01:15:34 am by John Maher » Logged

John Maher

AirCooledCurtis
Newbie
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Posts: 41


« Reply #8 on: January 04, 2013, 02:21:13 am »

That's a lot like what I was thinking...  I will be on the look out for a new case.  Do any people use original german cases in their performance engines with success, or is it all the Brazilian stuff?
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j-f
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Jean-François


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« Reply #9 on: January 04, 2013, 16:31:40 pm »

There was a thread on here (a couple of years ago?) that went into various crankcase prepping checks and tricks.

I think you refer to this post. http://cal-look.no/lounge/index.php/topic,8007.0.html

Lot's of useful info.  Wink
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65bug
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Posts: 264


« Reply #10 on: January 05, 2013, 03:59:16 am »

Curtis,
       I prefer the original German case. Now all made I believe in Brazil. Aluminum tend to run warmer from what I have heard and been told. However, that's just what I have heard. A new Brazilian case will be worth it. Just get it from a reputable place that knows how to check them out.
       I would vote Berg #1 then Cb Performance Supercase # 2. Just my opinion. Do it right, and the motor will run extremely cool, with correct oil pressure and very few issues!  Wink
      I would also recommend even for a mild performance engine a sump for extra oil and full flowed as well.
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Greg G
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Posts: 179


« Reply #11 on: January 05, 2013, 05:00:33 am »

       what I have heard and been told.

are you basing all of your recomendations from this?
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65bug
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Posts: 264


« Reply #12 on: January 05, 2013, 05:57:29 am »

Greg,
     Like I stated, Aluminum blocks I have not used. That's what I have heard and been told by reputable people. I used a brand new case on my last 2165 build. No problems at all. I purchased a Cb supercase, that had to be re-surfaced around the cylinder bores, by Berg. Other then that the case was good................
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AirCooledCurtis
Newbie
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Posts: 41


« Reply #13 on: January 05, 2013, 18:15:15 pm »

I don't want to use an aluminum case, so that is okay.  Too bad it isn't as easy getting a good case for cheap like it was in the '70s when everything was low miles.
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Greg G
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Posts: 179


« Reply #14 on: January 05, 2013, 20:42:51 pm »

I think you would be fine using the case you have. I have built a boat load of motors with used cases that have been line bore and cam bored. Running the cam bore tool through a case that was line bored was a must when building a motor with a used case to insure the cam would not be in a bind when assembled. We would even run the tool through a new case to check it.
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65bug
Sr. Member
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Posts: 264


« Reply #15 on: January 06, 2013, 00:57:35 am »

Greg,
     I am sure it's what you know and who you know. I have heard of guys who have had no problems at all. Including you. I have heard others say they wont even go there. With my luck, my motor would not run right. My 1600 always ran too hot. So I just purchased a brand new case for this build.
     I have even been told if the machinists tool is off(or the machinist) your screwed. He's going to liine bore it crooked, then let the problems begin! Not doubting your judgement at all Greg, just giving my personal opinion and experience is all.
     If it's working for you that's great! And Thank you for the information on this.
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AirCooledCurtis
Newbie
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Posts: 41


« Reply #16 on: January 06, 2013, 01:15:20 am »

So the only thing that would be wrong with using the case is insufficient oil pressure?  If I threw together a stock engine (I have many left over parts from other engines) and ran it on a stand could there be a way to tell if it was good?  Or even then would it be a ticking bomb?
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AirCooledCurtis
Newbie
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Posts: 41


« Reply #17 on: January 06, 2013, 01:22:55 am »

I don't know if anyone has ever had sentimental attachment to a crankcase, but since this (and a lot of other nos goodies) was the core of a project my grandpa never got around too, I was really hoping on using it.  Sad
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AirCooledCurtis
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Posts: 41


« Reply #18 on: January 06, 2013, 01:34:29 am »

Mug shot of the subject in question...
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Greg G
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Posts: 179


« Reply #19 on: January 07, 2013, 20:58:51 pm »

Just like you would do with any build (new case or old machined case) you have to put the case to gether torqued and measure all the fits. Then install the bearings and check those. Compare the bearing bores with the crank and cam bearing journals to get your bearing clearances. Put the cam in with your bearings and check for free turing, put the crank in and check it for free turing, put both the cran and cam in and check for free turning. Check the bearings for any irregular rubs. Do this with all the other parts you have for the motor. Once every thing is good dry, then take it all apart and clean everything really good before final assembly.

I have had issues with new stuff as well as old.
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