Piston hitting valve - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Piston hitting valve by Wltrc on 31 May, 2020 16:01
• Engine in question is a 1.6d naturally aspirated, year unknown. Came out of a rabbit pickup. I have it bolted up to a transmission from a mk3 Jetta, 1996. Originally the tranny was mated to an aaz.
  
  I bought a supposed "ran when pulled" engine, the guy showed me a video of it running in the car before he pulled it (how old was the video? Who knows)
  
  When I recieved the engine there was no timing belt on it, no biggie I planned to replace it anyway. Got the crank lined up with the mark on transmission, pinned the injection pump and locked the cam with #1 cylinder showing both valves completely closed.
  
  Pulled the crank sprocket and checked the keyway, looks really good on crank and sprocket no signs of wear. New bolt going in of course.
  
  Got the new timing belt on and tensioned and proceeded to rotate the engine over gently by hand, got roughly a quarter turn and then "clunk" uh oh. Looks like piston #2 or #3 is making contact with a valve as they are the ones furthest out at the time of stoppage. I double checked all my timing marks and they are dead on, turned again and stopped same spot.
  
  Before I pull the #1 injector to check that it is in fact at TDC, is there anything obvious I'm missing? Is the timing mark on the newer transmission in a different spot? Also there is no vacuum pump attached at the moment if that makes a difference. Engine is not in the car just hanging from my hoist. I want to test fire it up before I put it in the vehicle
  
  Thanks in advance for any input.
• #1 by ORCoaster on 01 Jun, 2020 19:51
• You should pull the injector from the #1 cylinder and verify the TDC on the flywheel.  That may be off and that could be the trouble.  That is the easy button to push. 
• #2 by rabbid79 on 01 Jun, 2020 21:43
• I think I remember hearing something about gas flywheels having different timing marks than diesel flywheels?  Maybe there's a gas flywheel on it?
  
• #3 by libbydiesel on 01 Jun, 2020 22:47
• ...it's been known to happen that due to a failure of attention, the flywheel will get assembled without lining up the pins which just get mashed in the process.  That gives a couple different orientations that are decidedly wrong and will cause piston/valve contact when timed using the correct marks.  As ORCoaster mentioned, confirm TDC.
  
  One other thought comes to mind.  Loosen all the cam caps and see if it then spins over fine.  If not then the head has to come off.
• #4 by Wltrc on 02 Jun, 2020 14:34
• thanks for the replies, i pulled the injector out of number one cylinder and discovered that when the mark on the flywheel was lined up with the bellhousing the piston was about 1/4 of the way up. I took my time and very diligently got the cylinder to tdc and then marked the flywheel with a punch. The engine rotates around now perfectly, with lots of compression too i might add.
  
  Once I locate a vacuum pump I'll be ready to test fire this engine and if all goes well install it into the rig.
• #5 by libbydiesel on 02 Jun, 2020 16:44
• What method did you use to ensure that you were EXACTLY at TDC for #1?
• #6 by Wltrc on 02 Jun, 2020 19:37
• Used a bit of wire stuck down the injector hole, marked with a sharpie and rocked the crank back and forth and compared the mark on the wire with a horizontal plain until it was centered, if that makes sense. Without some kind of dial indicator apparatus I wasn't sure how to get it EXACTLY at TDC. My dial indicator wouldn't reach down in far enough to reach the piston.
  
  It rotates freely without any binding so guess I'll find out when I go to start it. Unless there's a trick to get the indicator in there?
• #7 by ORCoaster on 02 Jun, 2020 20:01
• Glad it was that easy.  Sometimes I tend to go way overboard only to take a giant step backwards, Mother May I?  Lots of possible reasons for the mark to be that far off but you won't go wrong now with the proper mark on the flywheel.  Did you remember to paint it white or yellow?  Easier to see than red like OEM ones.
  
  What did you use for your timing setting?  1.0 or something closer to that label on the strut mount?
  
• #8 by libbydiesel on 02 Jun, 2020 20:19
• Here's a method I have used for finding exact TDC that does not require any fancy equipment.  Remove the glowplug (and not the injector) from either #1 or #4 (#4 works easily for this).  Rotate the crank until it is rising on the compression stroke for the cylinder.  Then use a length of clear tubing pushed into the glow plug hole.  Make a good seal around it.  If necessary, use grease or sealant.  Then place the other length of the hose in a container (preferably clear) of water.  Rotate the crankshaft slowly and you will see bubbles coming out of the tubing.  At exact TDC, the bubbles will stop moving out of the tube and water will start being pulled in. 
  
  Considering the engine is not even installed in the car, I would pull the trans off and check the flywheel to make sure all alignment pins and bolts are properly installed in pressure plate to crank and flywheel to pressure plate. 
• #9 by Wltrc on 02 Jun, 2020 20:19
• I'm going to by a paint pen and make a mark on the chisel groove I made.
  
  Set the timing to 1.0mm
• #10 by Wltrc on 02 Jun, 2020 20:43
• Thanks for the tip I'll give that a go. As far as the flywheels concerned it's only for the test run, I've got a partial tranny bolted up so I can start it. If it runs well I'll be putting it in my Suzuki with an acme flywheel
• #11 by fatmobile on 04 Jun, 2020 15:14
•  For anyone else reading this.
   There is a mark on the other end of the crank.
  A bump on the sprocket that lines up with a hole in the pully.
   It's usually at about 7:30 when the engine is at TDC.
   That's if the crank key hasn't been moved.
   
• #12 by Wltrc on 05 Jun, 2020 10:56
• Thank fatmobile, it appears that little nub is sitting where you stated. I don't own a laptop and can't figure out how to upload pics from my phone or I'd do that to show you
• #13 by fatmobile on 05 Jun, 2020 22:38
•  Yeah, it's not accurate enough to time it with but it will most times let you know if your clutch is bolted on wrong.
   
   Also wanted to mention;
   when my pistons slammed my valves
   the crank turned all the way around nicely.
   Even with the belt off.
   So when you said your pistons are hitting your valves when you turn it by hand,
   I saw that as good news.
• #14 by Wltrc on 08 Jun, 2020 19:43
• It runs! Guess I got the timing right haha
  Didn't run it for very long because I had no coolant running through it on the stand, hope to get it into the Suzuki in the next week or so