Guidance Please? 1967 L71 Engine Reinstall & Run-In

[Richard M.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Timothy, Thanks very much for the reference photo and info. When I get back from the Regional I'll get back on it and setup for the mod.

Duke, I will be using the VC1765 B26 advance.....thanks. I'll also take some better photos of the modification area before I do anything.

Rich
p.s. Weather here is wonderful. Chilly this morning with a forecast of dry, sunny and warm in the upper 60's to low 70's for the next several days.
Wish you all were here!

[Timothy B.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Rich,

We just got approx 8" of that heavy heart attack snow in Bel Air Md.

Hope you and everyone has a great time in the spring weather and enjoy the show..

[Richard M.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Update. Well......This is my first TI experience, and I have to tell you it hasn't been a good one. It has been very frustrating, but you know, it's sometimes good when things don't work because this is how we learn. And boy have I learned much.

I was up till about 2 AM Sunday night(Monday morning) finishing up to hopefully run it during the daylight Monday. We got the engine running last night, but the TI didn't work. I ended up installing a points distributor to run it. Bang, started right up. We ran it for about 1 minute at 2000-2500 rpm. 75 psi at the gauge. Boy did it sound sweet with those factory sidepipes. I pulled the pass side valve cover to check the oiling. Because we used the distributor without the special oiling groove in the cam bearing location, I wanted to check for proper oiling there. Did a quick restart, up to 2k rpm. Very low pressure there. We shut down.

So back to the TI......I've gone through Dave Fiedlers diagnosis procedure and suspect we have a distributor specific problem. I have tried 2 TI modules and the system doesn't work....no spark. What is really strange is that when we crank, there is no spark, but when the key is released from "Start" to "Ignition On", we get a spark and the engine tries to fire. I checked for 12V at the #12 ignition pink wire during crank and it's there. We checked our distributor timing at #1 TDC and it is installed correctly.

So we cannot run the engine any longer until I get this fixed. I should have sent the TI distributor out to be tested when I got it.......My Bad.

More later,
Rich

[Timothy B.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Rich,

What makes you think it's a distributor problem when it fires in the ignition switch run position? The test I know is approx 700ohms across the two distributor wires.

In the ignition switch crank position current should flow from the solenoid to power the harness through the connector, did you check for power at the solenoid on the pink wire? My opinion FWIW is to look at the solenoid and or wiring first.

Make sure all the grounds are good.

[Duke W.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Years ago when the TI I installed on my SWC took a dive for the second time, I removed it and reinstalled the original single point dist. that I had overhauled and "blueprinted".

I checked the dist. pickup coil using the procedure I had for the HEI and IIRC the pickup coil resistance should be about the same.

I then set the TI up on the bench - dist. harness, amp, and coil/spark plug attached a 12V battery and used an electric drill to turn the dist.

Initially there was no spark, but I traced the problem to corrosion on a terminal at the amp connector, cleaned it up, and then got a spark.

I put it all in a box and sold it to David Burroughs 15 years later to install on the '67 "12-mile L-88" that it came off back in 1968.

I've not seen Dave's troubleshooting procedure, but the system can be bench tested/troubleshot as I did.

Duke

[Richard M.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

quick update.....I found the problem using Dave Fiedlers diagnostic procedure. Great document.

It was the TI distributor pickup coil. Reading was intermittent. Should be 500-700 ohms. I took the distributor apart and did brain surgery on the pickup coil. The #14 leads connected to the winding wire were the problem. One was soldered, one was NOT. Must've been like that a looooong time. I was able to take it apart and re-solder.

Engine now runs with TI!!!!

More later....Rich

[Richard M.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

We did it.... The engine has been run-in. About 1/2 hour varying from 2000-2500 rpm. No major problems. Ran strong. IR temp unit showed about 180 degrees next to the temp sender on the intake. Exhaust manifolds running from 300F on the front ports to about 400F at the rears.

After the run-in we attempted to set the timing at idle. Something is strange. Tough to get a proper idle with the vacuum line plugged and vac can disabled. It actually will backfire some. I haven't converted the vac can to manifold vacuum yet.

Tomorrow I'm going to recheck distributor clocking. I think I may be off one tooth as I cannot advance timing properly to the 5 degree spec.The vac can hits the intake manifold and no more room. I need to recheck distributor alignment once more but I'm pretty sure I'm on it. Either that or I have to deliberately clock it off one tooth.

I am going to experiment the ported to manifold vacuum change. I'll plug the port at the carb and tie the vac can into the manifold directly at the intake port for the power brakes. I have a dual port fitting I can use to try it.

Rich

[Timothy B.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Rich,

Put the car in forth gear and roll the rear tires a bit until the damper mark aligns with the timing cover mark approx TDC. Remove the distributor cap and look to see if the rotor is aligned to #1 on the cap. You may need to jump the distributor one tooth clockwise.

After you are satisfied and the oil pump drive is engaged, repeat the TDC check to be sure it's correct. Put the vacuum advance in the middle of it's travel and it should run..

On a small block sometimes the aftermarket cams require the lower distributor gear be turned 180* but it's a last resort to getting the vacuum can and tach cable to good position in that tight area. The correct orientation is with the dimple on the lower gear aligned to the rotor tip as you know.

You can also tee into the choke pull off if it's easier as that port is full manifold vacuum. Remember about the vacuum can specs mentioned in a earlier post because this will affect idle. If the 201 vacuum can takes 15" to pull to the stop and the engine makes 13-14 the idle will be unstable.

[Richard M.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Hi Tim,

Yes I just added the 2-port fitting on the manifold for the carb to get manifold vacuum. Also easier to tee in my vacuum gauge. Now I have to see if I can fix my dial-back timing light that I burned up yesterday to get ready for some tune & tinker time later on today.

Thanks,
Rich
p.s. hope the weather gets better up there soon.....Hey, I just got an idea....why don't you come on down here and help out! Sunny and warm here today.

[Duke W.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Set the crank at about 10 deg. BTDC, not TDC. When the dist. is installed correctly, rotate the housing until the stationary and rotating pole pieces line up. That should put the initial timing in the ballpark.

The OE recommended 5 deg. is very conservative. If you can run it higher without detonation the engine will be stronger.

Once you have the timing dialed in and the VAC connected to a full vacuum source, you must go through the idle speed/mixture adjustment. Target 900 and the manifold vacuum should be about 14" Hg.

Duke

[Richard M.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Hi Duke, Thanks for the info. One thing which was strange....At one point in the idle, I forget the exact RPM, the car ran very rough. We noticed the VC1765 B26 vac can diaphragm was oscillating. We could feel it and hear it. I clamped the vac hose and it all got better. My vac gauge was reading about 14" during adjustments. I need to readjust carb settings etc.

We took it for a ride to test it under load and it's really running good. Very strong. I think I have the basics setup and just have to get in and dial it all in now. I am learning much.

I have to get the lash adjustment done, and get back on the timing checks you recommended. I'm taking the day off today. I need a little breather.

I'm going to get back on it this weekend after a little R&R. I'll let you know how it goes. All in all I think I'm doing ok so far.....

Thanks,
Rich

[Richard M.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Set the crank at about 10 deg. BTDC, not TDC. When the dist. is installed correctly, rotate the housing until the stationary and rotating pole pieces line up. That should put the initial timing in the ballpark.

The OE recommended 5 deg. is very conservative. If you can run it higher without detonation the engine will be stronger.

Once you have the timing dialed in and the VAC connected to a full vacuum source, you must go through the idle speed/mixture adjustment. Target 900 and the manifold vacuum should be about 14" Hg.

Duke

Ok bear with me here......I've made good progress.

I felt I was off a tooth on the distributor and I was. Duke, I did exactly as you said......success! I set that right, vac can now at correct orientation to allow more advance, put the timing light on and miraculously I was at about 6 degrees advanced with vac can line clamped off. Vac gauge around 14-15" Hg. Idle around 900, un-crimped the vac can hose, I then lost smooth idle, vac can(Napa VC1765 B26) heard oscillating and can feel it rattling. Brought up idle to 1000, smoothed out, no vac can oscillations, much better.

I may be missing something, but there is no speed/mixture adjustment on the 2300C right? Just idle? I see no reference to speed/mixture adjustments in my books & data. edit.... I now see the mixture screw on the left side of the 2300C. Leaner in(cw). Richer out(ccw).

So I shut down, took off the hose from manifold vacuum source, plugged that, then I connected vac can hose to ported vacuum on the 2300C port. Restarted. Engine smoothed right out, brought idle to 900, vac gauge still 14-15" Hg. I played with idle, got it down to ~650 and still quite smooth. Brought it back to 900 and took it for a ride. WOW. Ran great. Shut down after idling a while. It properly shutdown, no dieseling, pops or anything wrong. Restarted hot a few moment later by just touching the key to "Start". Started up perfectly. Did this a few times and it's perfect.

I'm thinking I don't want to screw anything up. It's running great. I have not done the final valve lash adjustments yet. I'm planning that soon. Remember they're still at 025/025 from the rebuilder.

Rich

[Duke W.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

When you connect a full vacuum source to the VAC, the idle speed should jump up, but it might be rough due to too lean a mixture.

Part of converting the vac. advance to full time is running through the idle speed/mixture adjustment. Start with the initial setting specified in the CSM then adjust to the highest speed/vacuum, then readjust the idle to 900 and go through the procedure again and repeat until there is no change.

I've never heard of what your experiencing from any L-71 owner. All were quite pleased with the effects of full time vacuum advance. What are you using as a full time vacuum source?

Also, the symptoms make me suspect that the new B26 may not be functioning properly. Use a Mighty Vac to pump it down. Verify that it starts at six, is fully pulled at 12 and it doesn't leak.

Duke

[Timothy B.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

Rich,

There should be A/F emulsion screws on each side of the primary metering block of the middle carburetor. These screws control the amount of A/F emulsion the engine receives through the curb idle ports not the A/F ratio itself.

I would try the idle timing at 10*BTDC, then with full manifold vacuum to the advance control you should see about 25* total idle timing. You probably will need to lower the idle at this point to a speed that provides approx 14" vacuum so the 12" control will stay pulled. You will also need to adjust the emulsion screws to best steady vacuum and may need to adjust idle again after.

Nothing wrong with leaving it ported, as soon as the throttle is tipped open you get this timing back.. I think it runs better and cooler with manifold vacuum advance though.

[Richard M.]

Re: Guidance Please? 1967 L71 Engine Reinstall & Run-In

I just went through all of the checks and this is what I have.

1- Mighty Vac test on the VC1765 -> Starts to move @ 5.5" Hg, fully open at 10.5" Hg

FYI I also tested the used MS 163 and repro MS201 15 while I had it set up.

MS163 16 Starts to move @ 9.0" Hg, fully open at 15" Hg
MS201 15 Starts to move @ 12" Hg, fully open at 19" Hg (this seems very wrong) I have to dig up the specs, not right now.

2- Setup 2300C for manifold vac. I am using a dual port manifold fitting, one for the PB, the other for the vac advance. If you recall I wanted to experiment this way before modifying the 2300C.

3- Got to operating temp. Idle at 900. Blocked off vac can(pinched hose), advanced timing to 7 deg. (10 seemed a bit much but I can try that later also.)

4- Adjusted A/F mixture - Vac gauge around 13"-14" Hg. Temp around 180-190 deg while doing all of this. I got it to stumble each side leaning too much. I backed off from there about 1/2 turn out, while watching the vac gauge until peak Hg reached, again around 13 to 14.

5- Reconnected vac to can. Idle went up as expected. Reset to 900. Running ok. Using my dial back timing light, I saw around 23 to 24. Brought up the revs to about 2000 and I'm at about 36 to 37 degrees with everybody in.(vac adv & centrifugal). I was playing around for quite a while and temp around 200 so I let it cool down a while.

6- Rechecked everything. Drove around the yard a bit. Decided to test it on pavement. Just as I pulled out the engine died. WTF! One thing I forgot to check.....the fuel gauge. Tanked it up with a few more gallons of my 50:50 mix of avgas & 93 octane and off I went.

Summary - Seems pretty good now. Temp underway around 180. I am going to switch back to ported and tinker some more to so what is going to be best. I think now that I had good results with manifold vac I may stick with that in the end. It seems to run better at idle, and cooler as well due to the better advanced timing. Thanks for the guidance guys. More later....

Rich
p.s. I was gonna put the top down and keep going for a long ride but I need to get other stuff done!