Daviboy

Hi guys,
I have this posted on Pelican as well but thought I may get a few more ideas over here.
I have recently been re-building my engine with varying degrees of success. What I have is basically a stock euro sc but with the addition of 964 profile cams, custom JE pistons 9.8:1 made for 964 cams.
Heads rebuilt with all new valves and springs etc. I followed all the advise in the books and thought I had it perfect, I set the overlap at TDC to 1.26mm which I believe is 964 spec. However when I went to start the engine it would not run, checked all the usual stuff and still would not start so I began to suspect cam timing.
Pulled valve covers and chain covers and set engine to TDC for #1. Discovered left cam was out of sync with right so then loosened off the cam nut on the left bank, cam must have moved while tightening??
So reset and re-did the cam and timing, re-assembled and tried again. Nothing well not nothing it fired and ran maybe for a revolution then died and would not re-start.
I did not know what was wrong so had a leakdown test done and seems I have a bent valve somewhere on #1 don’t know if exhaust or intake yet.
I have had to come back to work so now I am trying to gather the required information to get this fixed when I get home 3rd November. I plan on tearing engine back down to check all cylinder heads/valve, then re-start the cam timing process.
I have good spark and all ignition components check out fine. Any help advise in getting this set up running appreciated.

This is the procedure I used to time the cams

1 Set engine at TDC for #1 both cams dot upwards
2 Installed pin in sprocket and tightened down cam nut on left side, right side loose no pin installed
2 Set #1 intake valve lash to 0.1mm
3 Place dial indicator on #1 intake valve retainer
4 Rotated engine until dial indicator starts to move then slowly till reading 1.26mm on dial indicator
5 Loosened off cam nut removed pin and then rotated to Z1 mark
6 Re-install pin and tighten down cam nut
7 Checked by rotating engine through 360 deg all good at 1.26mm overlap.
8 Moved to right side and repeated procedure

However I think that I had #1 at TDC instead of rotating to get #4 at TDC. I believe from what I have read I should have done left side #1 then rotated engine to #4 TDC set right cam with dot upwards then repeated procedure for #1. Is this correct?

whalebird

I think a lot of builders will use a dial gauge on #1 and #4 simultaniously. I like to make a TDC mark on the back of the engine with a wire pointer on the flywheel before starting this procedure. It can be quite accurate.

Ed Hughes

Any time i've done my cams. I've rotated thru a few 720 degree (crank) cycles to check and recheck my timing. You do the #1 first, rotate the crank 360 degrees and set up and do #4. You start with both of the cam marks up to begin. Time the lh cam, check, rotate crank 360, then go to rh cam/#4. At this point, that mark is pointing down. Again, check and recheck several times.

Also, make sure you have the cams on the proper side. The lh cam has a "wider v" as you look at the first lobes.

Just take your time. It's like calculus, once you grasp it, a lightbulb goes off.

Daviboy

Ed,
Thanks for the information. Actually got it from a member at PP. I know where I went wrong, I timed left bank i.e. #1 then did a 720 revolution to check, then I went and did the right bank #4 with cam dots facing up thats my basic mistake. As you say the light bulb went off and almost blinded me. I was rushing as I wanted the engine finished and in the car. I now know what to do but will still strip down to the heads to check for any valve damage first.

Daviboy

Update when I got home I got the engine out of the car and stripped down to the heads. Checked the valves all straight however only 3 of the 12 were actually seating properly. Took the heads to a Porsche approved shop and had the seats reground and spring height rechecked. Got heads back installed in engine set cam timing (964) to 1.3mm checked double checked all good. Buttoned everything back up and got the engine back in the car. She fired up second try although was quite a hard start and had to give some throttle to keep running. Took her up to 2000 rpm for the required 20 minutes then shut her down and changed oil and filter. After that I restarted her again still quite hard start and when I let off the throttle she died and would not hold idle, although I think it is due to the fact I have not set the timing yet it may be retarded. However I have a question if I cannot get the engine to hold idle how can I set the timing? Have someone sit and hold their foot on the throttle at ~950 rpm or as close as possible then set timing. I dont want to set total advance at 4000 rpm as she has not been run in yet. Any opinions on best way to do this?

psychoideas

I set the static timing on my 2.7 with the 'light globe' method. But I used a multimeter.

Of course I have points in the dizzy.

Do you have points in your 3.0?

Daviboy

Frank
No points on the 82 3.0 litre

psychoideas

You could always mark the position of the dizzy, then advance or retard it slightly, then start it and see if it is better or worse.
If all else fails you can return it to the mark you made earlier.

Good luck with it.

Shame about the points.........

Daviboy

Frank,
That exact same thought came to me earlier one of those 'Doh' moments, thanks for the confirmation though