Author Topic: TC not starting  (Read 500 times)

0 Members and 1 Guest are viewing this topic.

Offline Fotog

  • Sr. Member
  • ****
  • Joined: Feb 2019
  • Location: Huntingdon Valley, Pennsylvania, USA
  • Posts: 335
  • 72 Twin Cam
TC not starting
« on: Monday,July 13, 2020, 07:20:44 AM »
There are probably about a hundred threads here about this topic, but it's difficult to choose the correct words that will find them in a search.

I feel dumb that I can't figure out my problem and would appreciate your suggestions.  The car ran in May.  I have since had the camshafts out.  Now that I've put it back together, I can't get it to start.

Camshafts have been out twice.  First in April to replace intake oil seal and one exhaust shim.  After putting them back in and starting the car, I had a problem. I had popped the split ring that the alternator drive pulley bears against off of the camshaft unknowingly.  It was rotating and shaving bits off the head (no real damage) but then destroyed the new oil seal and (worse) damaged the groove in the camshaft that the ring sits in.

So I took it apart a second time and consulted with an engine shop to get it fixed.  While at it, I took the exhaust cam off also and took it to the shop along with the intake cam to have them characterized, since I didn't know the specifications of these non-stock cams and the shop could do it.

Re-installing them, I got to a point where I realized that I had somehow lost my TDC setting on the crankshaft.  It had moved.  So, I removed the camshafts, (valves are closed then, so you can turn the crankshaft all you want, right?) set it back at TDC, and re-installed the camshafts in the orientation that I had recorded with photos when at TDC.  Timing marks on the sprockets aligned with one another.  I thought, "ok, fine!"

-I turned it over by hand.  Fine
-I re-set the distributor on the jackshaft to the correct position for TDC
-Using a lamp, I connected it between +12 and the (disconnected) low-voltage distributor wire, and set the timing at 5deg BTDC static.  The lobe on the #4 cyl exhaust cam was pointing inward toward the intake. 
-re-connected the low-voltage distributor wire.

It wouldn't start.

Since, I have:
  • Checked the timing with a timing light as I crank:  looks great. @ 5deg BTDC.
  • Checked for spark with inline spark-testing gizmo on cyl #1 and #2.  Fine.
  • Pulled the fuel hose off of the outlet of the pump (rebuilt last year) and verified that there's pressure there when cranking.  Fine.
  • Checked compression on #1 cylinder.  Fine

But it doesn't start.  Doesn't fire at all.  Cranks over fine.  I'm stumped.  It's hard to imagine that it's not some timing issue, but I can't see what.  Thank you for any suggestions!

Vince


Offline TurboFource

  • Super Member
  • *******
  • Joined: Sep 2019
  • Location: Maryland
  • Posts: 1,957
Re: TC not starting
« Reply #1 on: Monday,July 13, 2020, 09:07:17 AM »
Is the timing 180 degrees out and firing on the wrong stroke? There are two TDC in the four strokes.
The more I do the more I find I need to do....

Offline jbcollier

  • Super Member
  • *******
  • Joined: Nov 2013
  • Location: Edmonton, Alberta, Canada
  • Posts: 5,834
Re: TC not starting
« Reply #2 on: Monday,July 13, 2020, 09:11:41 AM »
Remove the spark plugs.  Put it in 4th or 5th gear.  Hold a finger on #1 spark plug hole.  Nudge the car forward until you feel compression pressure on your finger.  Continue nudging the car forward just a bit more until the engine it is at TDC.  Pull the distributor cap.  Is the rotor pointing to the wire on the cap going to #1 cylinder?

Offline TurboFource

  • Super Member
  • *******
  • Joined: Sep 2019
  • Location: Maryland
  • Posts: 1,957
Re: TC not starting
« Reply #3 on: Monday,July 13, 2020, 09:24:45 AM »
It needs to fire on compression stroke not the exhaust stroke. All the things you mentioned would check as OK but it will never start if it's 180 out.
The more I do the more I find I need to do....

Offline 4129R

  • Super Member
  • *******
  • Joined: May 2014
  • Location: Norfolk, United Kingdom, not far from Hethel the home of Lotus.
  • Posts: 2,532
Re: TC not starting
« Reply #4 on: Monday,July 13, 2020, 01:57:37 PM »
That was exactly my first thoughts. Been there, done that.

I thought it was 180 out on the distributor, 360 out on the flywheel.

Offline Fotog

  • Sr. Member
  • ****
  • Joined: Feb 2019
  • Location: Huntingdon Valley, Pennsylvania, USA
  • Posts: 335
  • 72 Twin Cam
Re: TC not starting
« Reply #5 on: Monday,July 13, 2020, 02:01:18 PM »
Thanks, guys.

No it wasn't, JB.  Despite my attempts to be careful and exacting, I think it was about 90 degrees CCW of where it should have been.  Who knows how?  Amazing that it didn't occur to me to just look at the distributor.

I had limited time to look at it.  I re-set the distributor shaft relative to the jackshaft, turning it ~90 deg. CW to coincide with the wire for #1 cyl.  But my test light isn't going out when it should (indicating points opening).  The distributor body seems like it wants to be far off from what I recall as it's standard position.  I'll look into this further, but I was having a little trouble wrapping my head around it.  I do believe that the distributor can work properly in any one of four possible positions, and I re-oriented it previously so that I could get to the screws on the cap. 
-V

Offline 4129R

  • Super Member
  • *******
  • Joined: May 2014
  • Location: Norfolk, United Kingdom, not far from Hethel the home of Lotus.
  • Posts: 2,532
Re: TC not starting
« Reply #6 on: Monday,July 13, 2020, 02:19:26 PM »
Remove the spark plugs.  Put it in 4th or 5th gear.  Hold a finger on #1 spark plug hole.  Nudge the car forward until you feel compression pressure on your finger.  Continue nudging the car forward just a bit more until the engine it is at TDC.  Pull the distributor cap.  Is the rotor pointing to the wire on the cap going to #1 cylinder?

or take the oil filler cap off and look at the cam lobes to see if the cams are exhaust just closed on #4 cylinder, (with the hidden inlet cam on the other side about to open on #4 cylinder).

Offline Fotog

  • Sr. Member
  • ****
  • Joined: Feb 2019
  • Location: Huntingdon Valley, Pennsylvania, USA
  • Posts: 335
  • 72 Twin Cam
Re: TC not starting
« Reply #7 on: Monday,July 13, 2020, 03:56:09 PM »
I did look at the cam lobe, which looked correct.  But I didn't take the cap off the distributor and look as I should have.   It's at my old house, sale closing in a few weeks, and the Europa and some other goodies are still in the garage.  Other stuff going on and I feel under the gun.

Offline Fotog

  • Sr. Member
  • ****
  • Joined: Feb 2019
  • Location: Huntingdon Valley, Pennsylvania, USA
  • Posts: 335
  • 72 Twin Cam
Re: TC not starting
« Reply #8 on: Thursday,July 16, 2020, 09:43:31 AM »
Back at this... I took the cam cover off again, and the cam positions look right.  I'm satisfied.

But I'm having trouble getting the distributor base and rotor in positions that resemble the way that they were, while making the cap screws accessible and opening the points at the right time.

Is there any possibility that a change in the position of the jackshaft  relative to the crank via the chain has caused things to "be different"? 

-V

Offline 4129R

  • Super Member
  • *******
  • Joined: May 2014
  • Location: Norfolk, United Kingdom, not far from Hethel the home of Lotus.
  • Posts: 2,532
Re: TC not starting
« Reply #9 on: Thursday,July 16, 2020, 09:55:57 AM »
If you turned the engine over with the chain very loose, then the jackshaft would not have rotated in time with the crank.

But the jackshaft only drives the distributor and the oil pump.

If you did that, then the distributor needs unbolting, and putting back in the correct position.