Need some help.. car will not start after top end rebuild

[x98boardwell]

I have searched and couldn't find anything. Below are the facts. Can you help me figure out what is happening?

1) Top End Rebuild
2) Car ran good before I took out the motor
3) Did not remove distributor from motor... only cap with wires attached (twin plug)
4) Sent cylinders, cams, cam towers, rocker arms, shafts, cylinder heads, new rings etc... to Walt at Competition Engineering (all good here just listing what was done)
5) everything back and installed which we did cam timing, valve adjustments, torqued everything to spec (I have done all this before just not cam timing....) and then buttoned it back up.
6) installed back in motor
- all electrical is correct
- distributor and cap and wires are where they were when I removed motor
- all plugs are gapped to .55 for 911S motor
- all plug wires are in correct order
7) I confirmed spark at the plugs and coils
8) I confirmed carbs (double stacks of weber 40's... nothing changed here) were providing fuel
9) Two Permatune boxes which were working fine as well. Car was down for less than 2 months.
10) The ground strap is good


Why won't it start? It has backfired a couple times but for the most part will not even respond other than just turning over.

The only thing i can think of is cam timing.... but motor turns over smoothly and sounds good when turning over whether by hand (during rebuild) or by the starter. How would car react if cam timing was off??? Would it still spit and sputter before bending valves, etc.?

Any thoughts as to why this could be happening? Not much has changed other than new motor... how could ignition be off sooo much if I never removed distributor and marked cap as well? All wires are also on correct and were all labeled.

Any thoughts? Here is a pic of it before.

Thanks for the help in advance,
Bryan

[Flat6pac]

Run a compression test, if your cams are wrong it will show there
Bruce

[Eagledriver]

You said you didn't remove the distributor but did you have it pointed at number 1 when you installed the cams? The distributor could be 180 out. I just did a similar rebuild on my car and had to make sure the rotor was pointed at number 1 with the cam numbers up.

-Andy

[docrodg]

+1 on distributor line-up. Also, is it possible the cams are 180 out? Try disty first, then cams. You got fuel and fire so gotta be in timing of disty or cams.

[x98boardwell]

How do I change the dist if is 180 out? What do I switch... the cap? This is a true twin plug motor with one cap and not two. Wanted to make sure I mentioned that.

Also, should I also rotate motor to top of cylinder one and see where rotor is facing? What would be the easiest way to tell that I am on the compression stroke side of the turn?

Thanks,
Bryan

This photo was from before but a good shot of the cap/dist.

[docrodg]

Do a compression or leak-down check while at #1 TDC and see what you get as Bruce suggested. If you have no compression or full leakdown then your cams are probably 180 out. Best way to check the disty is to pull off valve covers and rotate engine over to ZD1 mark while watching valves for #1. If the valves are not open you are at #1 TDC. Look at rotor on disty to see if it is at #1, if not remove disty and insert at proper rotation.

[earossi]

Go back and review how you timed the cams. The starting point for timing the cams is with the "dot" on both cams facing "up". In that spot, you set the timing on the left bank (#1 cylinder). You then need to roll the engine over to get the #4 cylinder into the same sequence of the stroke before setting the timing on that right cam. So, is it possible that you timed both banks at the same crank setting? To do so, would result in a motor that will turn over but not run. If that is what happened, go to PCA Workshop on Rennlist and go though the cam timing explanation on the engine rebuild story that is on that site. Mike made exactly the same mistake as I have described above and it took him a llot of effort to retime that right cam shaft with the engine still installed in his 993.

Just a thought.

[Eagledriver]

Originally Posted by earossi

Go back and review how you timed the cams. The starting point for timing the cams is with the "dot" on both cams facing "up". In that spot, you set the timing on the left bank (#1 cylinder). You then need to roll the engine over to get the #4 cylinder into the same sequence of the stroke before setting the timing on that right cam. So, is it possible that you timed both banks at the same crank setting? To do so, would result in a motor that will turn over but not run. If that is what happened, go to PCA Workshop on Rennlist and go though the cam timing explanation on the engine rebuild story that is on that site. Mike made exactly the same mistake as I have described above and it took him a llot of effort to retime that right cam shaft with the engine still installed in his 993.

Just a thought.

This post is wrong. With the dot up (930 up) the engine is on number 1 FIRING stroke, not overlap stroke.

If both cams are 180 out then you'll have normal compression and the engine will run fine once you rotate the distributor 180 degrees.

Turn the engine until the rotor points and number 1 spark plug. check that you are on number 1 compression stroke (ready to fire) at that time. You can tell because both valves will be closed on number 1 and the intake valve will be just starting to open on number 4. You can also pull the plug on number 1 and note that you have no compression (air leaking out the spark plug hole) as you turn the engine so the rotor points at number 1.

-Andy

[Eagledriver]

To re time the distributor you need to find number 1 TDC on the compression stroke. Then if the rotor is pointing at number 4 you'll need to take the distributor out of the block and rotate the shaft until the rotor is pointing at number 1, then reinsert the distributor. You'll have to use a timing light to fine tune afterward.

Your solution of rotating the cap 180 degrees will work if your cap will go on that way. You could also change all the wires 180 degrees. Either of these solutions are not much (if any) easier than doing it right and the next owner or person working on the car will get confused.

-Andy

[x98boardwell]

All very helpful... So your saying if my cam timing is 180 off I can address with just turning dist like stated above? That is possible. I will try all of these before I pull the motor to save a ton of time if I can help it... Wish me luck.

Thanks again for all the help,
Bryan

I am/was feeling a little defeated

[x98boardwell]

This is the twin plug distributor that is on my car. How do I know where #1 is based on the rotor? I can see a white or light purple dot on the rotor and then a couple marks (look to be by a marker) on the dist.

Because this is twin plug I'm wanting to make sure that everything is in order and I can identify clearly where #1 is and where it should be on the dist.

Also, in the second photo if I am TDC on the flywheel can you tell by looking at my rocker-arm on #1 if I am in compression stroke or exhaust? Picture #2 shows this.

Thx,
Bryan

[sjf911]

If you're at TDC of the compression stroke there should not be any tension on the rocker and it should wiggle very slightly with your fingers.

[x98boardwell]

Guys, I am in need of some help with determining what is top dead center for the distributor. I think I am 180 out if that dot is TDC.

[sjf911]

TDC for cylinder #1 should be marked on the crankshaft pulley not the distributor

[x98boardwell]

Yes, I understand that. But, when I put the motor back together I had the dist 180 out from where it needed to be. MY thought is that everything else in the motor is fine and correct but I need to rotate the dist (internal gear) 180 so that I am back on track with firing.

If I can tell where #1 firing order is on the dist (by whatever those marks mean) then I can determine if I'm 180 out and will know where to stop when I rotate.

Does anyone have any knowledge of this style dist? I have another post on this forum where it is outlined as well.

Thx,
Bryan

[x98boardwell]

And thanks for helping Steve... my language with TDC vs. Firing Order was off.

[john walker's workshop]

basically, if you're on #1 TDC, you can put #1 plug wire wherever the rotor is pointing and complete the cap wiring from there, either CW or CCW, depending on which way the rotor turns. if you want to know where it's really supposed to be pointed, use henry's diagram in your other post. it'll run either way.