Update on my over-rev'ed head... - page 6 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• #75 by Mark(The Miser)UK on 23 Mar, 2005 16:32
• Quote from: "fspGTD"

  I I think this was off because previously I didn't leave the cam locked when tightening the cam pulley bolt like is required to prevent things from moving when tightening the bolt.  So I re-timed the cam, following the bentley procedure of leaving the cam locked when tightening the cam pulley bolt this time.  (We should try and remember: lock cam when tightening the pulley bolt, unlock cam when loosening pulley bolt).
  
  .

  
  
   :idea: When I replace the cam sprocket I always clean the taper and then use a little abrasive kitchen cleaner to give a good non slip interference fit (Add creme and 'lap in' with sprocket. Remove wipe clean and replace. Reduces fear of sprocket slippage. Seeing some geezers have snapped their timing slots; I'd only 'nip up' with timing bar and then complete using a pair of grips holding between lobes. :idea:
  Rip me t oshreds if you wish; its just my personal method and I've never bent a valve :twisted:
• #76 by fspGTD on 19 Jun, 2005 15:43
• I've got a GTD autocrosser update!
  
  For the first time in months, I put a little attention to my Rabbit GTD 1.6lTD autocrosser.  You guys might recall last time I worked on it (look up four posts in this thread), I reset the cam timing and adjusted a couple valve shims to make them less tight.  That was after I had fixed an excess voltage drop problem across the starter solenoid (which boosted cranking rpms... although still not enough to be able for a boosterless cold start), and after that, checked the compression to find peak cranking pressures were low, although even.  Busy finishing off a master's degree, I have just let the project sit under the car cover since then.
  
  Now, feeling good following the success of VNT-turbo'ing dad's Rabbit 1.6, I decided why not take the car cover off my Rabbit and see if she might actually start?  I didn't try recharging the battery (which is a miniature, lightweight racing style), but found it checked out at a touch over 12.5 volts - seemed OK.  I got in the car and gave it a good full glow plug cycle as I usually do for hard starting motors.  I recalled waiting for the glow plugs to switch off let the engine crank over a little quicker, so that was my strategy.  I had also since the over-revv incident, installed a slow glow relay into this car, but man does it seem to take a long while until I actually heard it click off...  over 40 seconds I'd say and it's not like it's that cold out.  I was imaging my battery draining and draining...
  
  As soon as I heard the glow plug relay click and shut off current to the glow plugs, I started cranking.  It cranked quite brisky, feeling as if it might start, although after a few seconds it still hadn't reached RPMs with were self-sustaining.  The RPMs were starting to drop now, for sure the battery voltage was dropping.  I stopped cranking,and felt my heart sink a bit.  Decided to make one last attempt at starting the motor on this several-month old battery charge... I gave it a little bit of glow plug, just a few seconds this time - perhaps just long enough to make the light go out - and with glow plugs still blazing, switched on the starter.  It cranked over, yes, a little bit more briskly now... quickly increasing in speed quick enough, and yay - was running all by itself!    I started the thing without even recharging the battery after letting it sit for months!  
  
  Driving it was like being reunited with a good friend.  I enjoyed being reacquainted with it's characteristic mufflerless motor roar and turbine whine.  This thing is such a high performance machine...  especially after getting used to driving dad's daily driver Rabbit (which has bilstein HDs, stock GTI springs and swaybars) the GTD autocrosser just handles like crazy, despite decades-old, bald tires; one of them even showing some cord! (I know I need to do something about the street tire situation.)  Engine still pulls like crazy, just as long as I don't lug it so much as to keep the turbo working.  But with some shifting attention, the close-ratio five speed allows that, and the peloquin torque sensing diff puts the power down nicely.  With the copious fueling quantities, even off-boost it gets decent acceleration.  And it's just pretty crazy with the foot in the floor when the boost comes on!  
  
  And I became reminded there are still many old problems I've got to fix before I can start racing it again... there is a clunking/knocking I can feel through the pedals/floor when the clutch is engaged.  The fuel injection still needs some fine-tuning to make it easier to control the throttle - sometimes the RPMs don't want to return back down at all.  There is a bit of oil coming out of the blowby vapors I need to deal with and make it clean, even if it means installing a bulky and pricey MANN pro-vent.  The clutch pedal needs adjusting.  And I previously took the carpet out to clean, which I need to re-install along with all the trim that goes over the carpet.  But anyway, I was thrilled to have started it up on the first try (ok maybe second try.)
  
  Just wanted to let you guys know... I think the cam timing and/or loosening up the intake valve clearances made a difference with making the engine easier to start!  VW powertrain engineers knew what they were doing when they designed the intake valve to close as early as it does.
  
  I can't help think there was something that happened to the motor either during those brief few seconds when it was over-revving, or after when I was putting the head back on, that reduced it's low-speed compression.  High-speed compression, FWIW, seems great to me, at least if engine power is any incication.  I remember when I had the head off and was prepping for reinstalling the new one, cleaning off all the carbon deposits from around the tops of the cylinders... maybe I shouldn't have done that?  I remember taking the scotch-brite pad into the area where the top ring sealed, although I tried moving the pad in the same direction as the hone marks and also thinking the scuffing was only very light.  I also remember thinking that the bores looked as good as I could imagine they could, at least by my untrained naked eye.  I am wondering if I should try putting some non-synthetic oil in the sump and taking it for a long hard drive, to see if I might be able to get the top compression ring to reseal.
  
  Anyway, even if I can't make it any easier starting, I can probably use it "as-is" for another racing season or two.  I could lug around one of those big 40-lb optima batteries with me in the trunk to events and use it if the standard battery can't get the cold starting job done.  Maybe I could mount it to a little cart and hook up some big booster battery cables with a quick-release connection engaging to the main starter cables for some starting voltage assist.  But of course, if it's possible to cheaply do, I would love to try and raise the compression back up and make the engine start as easily as it used to.  Actually if I could get the engine compression as good as it used to be, it should not start better than it used to with the voltage drop in the starter solenoid fixed.
  
  I am looking forward to getting this car prepped for racing again and taking it out to the local events...  I haven't even raced on my new custom CNC-machined / lightened racing wheel centers yet!
• #77 by jtanguay on 19 Jun, 2005 16:24
• hey jake, check out www.oilextreme.com
  
  the idea is there, and if it works like they say it does, then that is the oil you need to win  :twisted:
• #78 by malone on 19 Jun, 2005 16:34
• That was a very interesting read, I still look forward to your progress Your VNT thread had me thinking of trying one in the near future for my 1.6TD.
• #79 by veeman on 20 Jun, 2005 07:22
• Nice update, Jake...  I know what you mean about feeling "reunited" with an old friend when you drive your racer again.  I brought my FSP car out the other day and remembered why I built the car in the first place.  
  
  Got any pics to show of those snazzy new wheel centers?
• #80 by fspGTD on 21 Jun, 2005 08:59
• veeman - I don't have any pics of the wheels installed on the car, but here is a pic showing the lightened wheels with race tires mounted:
  
  
  Since that shot was taken, I had the wheel centers anodized black:
  
  
  jtanguay - I don't think any kind of low-friction oil would be the hot ticket for getting rings to re-seal.  As for the claims of that dino oil being better than a quality synthetic, that oil has been out for a while now but I have yet to hear a positive recommendation coming from an unbiased source.
  
  I knew another racer years ago who was using (and peddling) that recycled dino oil.  When he pitched me on it he lost me after the part about "reprocessed and recycled dino oil" (I also had in the back of my mind knowledge that he stood to profit from selling it.)  It also didn't sound like he had tested it against a high-quality synthetic.
  
  He was racing a pretty seriously prepared diesel though!  He had a very nice gray turbodiesel mercedes sedan that he gutted and installed a roll cage into as well as all the other necessary safety gear for high speed time trials / lapping days.  He had r-compound tires too IIRC, and some healthy engine mods including extra fueling, boost, and a very well-installed intercooler.  I remember the body and paint (metalliic silver in color) were flawless and the car was clean.  It was pretty fun to see another guy out having fun racing a diesel.
• #81 by VWRacer on 22 Jul, 2005 07:30
• Quote from: "Mark(The Miser)UK"

  I feel I'm chasing you around the threads (I've shown you mine  why won't you show me yours 'Quantum mileage' that is :wink: )You can quote it in wine gallons if you like :twisted:

  Sorry I missed this, Mark. I am currently averaging in the low 40's/US gal in local driving on a mix of rural roads and city driving...no motorway.  
• #82 by Mark(The Miser)UK on 22 Jul, 2005 14:55
• Quote from: "VWRacer"

  Quote from: "Mark(The Miser)UK"

  I feel I'm chasing you around the threads (I've shown you mine  why won't you show me yours 'Quantum mileage' that is :wink: )You can quote it in wine gallons if you like :twisted:

  Sorry I missed this, Mark. I am currently averaging in the low 40's/US gal in local driving on a mix of rural roads and city driving...no motorway.  

  
  
  Blimey I've grown a beard and bought a third diesel Quantum since this posting. My current 'Q' will come off the road at the end of September for a 'scale and polish' It's doing about 40 US mpg (mainly town) at the moment. My replacement although 2 years older has only done 105000 miles. Running next to each other I can tell this new old one has a quieter engine all round. Even the turbo is ultra quiet. My usual runner has a kind of 'fishtail' warble to it which I'll miss. Funny how the turbos sound different. One I listened to on the first TD Quantum I ever sat in was so high pitched that it was uncomfortable to drive with the windows down. .. Seller claimed this was normal. That experience very nearly stopped me considering TDs... Luckily I tried one more!
• #83 by Josh on 24 Jul, 2005 14:34
• Jake,
  
     Were you running any kind of short-shift and/or weighted shift kit when you over-revved?  
  
      Curious,
        -Josh
• #84 by fspGTD on 24 Jul, 2005 23:25
• Yep, various pieces, some custom, some readily aftermarket available, including techtonics short shifter set at 30% and some missing linkz pieces.
  
  The part that increased friction side to side of my linkage drastically and I believe contributed to the missed shift was the missing linkz relay shaft shim:
  
  
  It felt great when I installed it initially, as I left the bolt not fully tightened to keep it from binding.  This was a big mistake!  As I used the shift linakge more, and the racing practice day progressed, the relay shaft bellcrank bolt tightened on itself, and it progressively bound up my shift linkage in the side to side direction of movement.
  
  It turns out the way Roger recommends installing this shim is to file/sand down the bushing so the bolt can be tightened fully without there being friction.  I have since had a word with Roger Brown about the importance of including installation instructions in hardcopy with his kits.  He has since then improved his online instructions, clarifying/emphasizing the correct installation instructions for this piece.
• #85 by fspGTD on 31 Aug, 2005 13:53
• I pulled the pan and inspected the bottom end situation on my Rabbit autocrosser yesterday.  Everything checked out A-OK: thrust clearance (.006"), rod to crank axial clearance (.006-.009"), rod bearing to crank clearance (.0015-.002"), and main bearing clearance (.0015 to .002").
  
  As I dreaded, I found that this motor has the one-piece integrated thrust/main bearing... although this one seems to be holding up well!
  
  
  It is interesting to note that this thrust bearing has a copper layer inside, which wasn't present in the failed one-piece integrated thrust/main out of dad's Rabbit 1.6lVNTD.  They were apparently made by different manufacturers.
  
  Some of the mains and rod bearings had some of their outer layers worn through in spots.  I took a couple mains down to my machinist/vw engine dude for inspection, and to get his advice.  He noted that in one spot of the 3rd main that he said you could tell it was just getting down to the copper layer.  But he said it should be fine to just run with both the old main and rod bearings given the good plastigage clearance readings.  Do you guys agree that these bearings should be OK to run?
  3rd main:
  
  4th main (which was the gasser type  :? ):
  
  
  Some pictures of the rod bearings:
  #1
  
  #2
  
  #3
  
  #4
  
  
  I found blueing on one part of the crankshaft, but thought it was odd when I dug in to find all the wearing surfaces looked fine.  My VW engine guy said he often finds this on VW crankshafts, and believes it is heat from the crank manufacturing process, not necessarily from from engine operation.
  
• #86 by DieselsRcool on 31 Aug, 2005 17:11
• Jake
  Just put in a new set of rod bearings and run it.
  
  Looks like checking crank end-play is going to be part of my oil change routine.
• #87 by QuickTD on 31 Aug, 2005 17:24
• For 50 bucks I would just change the bearings, its cheap insurance. Not sure what throw of the crank is pictured but the #4 crank throw has its radius induction hardened, that would explain the bluing.
• #88 by 2383 GTD on 01 Sep, 2005 03:47
• Jake,
  
  I have to agree, slap in new bearings.  Something to note when installing the thrust/main bearings; it is advisable to place a bit of a load in the direction of clutch release (axially, towards cylinder #1) before fully tightening the main cap which houses the thrust main bearing.  Sometimes, the uneven wear characteristics of the upper and lower bearing shells are directly related to not performing this "thrust/main bearing" setting operation.
  
  Incidentally, where is the best place these days to get bearings, both mains and rods?
• #89 by fspGTD on 08 Sep, 2005 12:33
• QuickTD: the blueing on the crank was next to the #2 rod journal.
  
  Also, I found this old post of yours where you replaced some rod bearings that were giving you trouble in your 1.9: http://www.vwdiesel.net/phpBB/viewtopic.php?t=69
  I was wondering if you recall if you plastigaged those rod bearings before you replaced them, and if so do you remember if their clearances were in spec?
  
  2383 - Thanks for the tip on installing the integrated thrust/main#3 bearing.  I've heard the same tip from other very credible sources, so there must be something to it.
  
  I would love to go ahead and replace all my rod and main bearings, new rod bolts, etc, but unfortunately right now I am pretty limited on budget.  I also need to consider that this motor might not have the best ring seal due to the hard cold starting problems last winter and spring.  I am still mulling over what to do...
  
  My rod bearings clearances (according to the plastigage test) were specifically: #1: .002", #2: .002", #3: .0015", #4: .0015".  All those are not only under the wear limit for old bearings (< .047") but is still within the specs for new bearings (.0011-.0035").
  
  I would love to be able to try revving this motor out above 6kRPM and not have it break...
  
  The rod nuts get toqued to 35 ft-lbs by the way, according to Bentley (IIRC), so supposedly they are re-usable, although I found on mine that the threads in the rod nuts were beginning to extrude out, which I don't like, so I think I'll at least replace my rod nuts with new geunine VW ones (at only a couple bucks a piece.)
  
  Does anyone know how much tensile strength the stock rod bolts/nuts are rated at?  Are they the standard grade 12.8 / 176kpsi?