Okay... a few more numbers and some info from the engine builder.

Haven't rechecked timing but I did check the compression with the carb wide open. Got a 140 this time.

Talked to the engine builder. He was a good old boy. Told me he rebuilt it quite a few years ago and the guy spent a lot of money on it. All this was from memory but.... new crank, SRP pistons, Crane hydraulic roller cam, stock heads. He seems to think that it came out to about 10.2:1 compression ratio.

He also though that the timing should be around 38 all in and suggested small bushings and the lightest springs in the distributor to get the timing in quicker off idle.

So... let me get some plug wires built and installed and I will check timing with the vacuum advance off of it... and maybe set it back a little.

Please tell me if you think this is out of bounds or sounds off somewhere. I am open to any other suggestions as well.

Doug

 

10:2:1-my motor is 10:5:1 and I use pump gas. Looks like this will be a quick fix for you.
Cool.

 

OK. As far as timing goes, start for a bit lower maybe 34 to 36 degrees(you can up it later if need be). In order to set that, the vac line is off the distributor and plugged.

Hook up the light and start the engine, and note it may not idle fast enough to keep from dying so be prepared to run the curb idle up if it does. I like to use 1000 rpm as a standard for setting things up so set it at 1000 with the line unplugged.

Hold the light on it and run the rpm up to find the max centrifugal advance that you have, and at what rpm you get it. All in at 2800 to 3000 is good for a start(lighter springs will make it come in sooner which could contribute to you pinging problem).

Set it at 36 just for grins. Drop back to idle(1000) and note that timing reading. It should fall between 15 and 20(maybe) It doesn't matter on the initial timing that much as long as the engine cranks OK and doesn't kick back against the starter. The important one is the centrifugal number of around 36.

Now hook up the vacuum line to full manifold vacuum, (not ported vacuum) and check the timing after resetting the idle. You should see something between 30 and 36 at idle. Now run the engine up to the rpm where you maxed the timing out and check the timing. You should be seeing between 48 and 54 degrees. I've run them between both these numbers depending on the engine. My current 427 SBC likes 48 degrees total and 16 and 34 to be happy. Yours will likely be different but at least you can be in the ballpark with the settings.

Hope you're not confused. Go see where it is now and post it up..

Dave

Sorry I'm not better writing instructions, if you want a phone call, PM for my number and I'll try to assist you, it's easier than typing!

 

Let me throw another thing out there....

When I went to do the compression test the spark plug wire came apart in my hand. I bought new wires and put them on this afternoon. While replacing them three more came apart when I pulled them off of the plugs. I haven't seen any lie these in a long time. They had a steel braid over the outside and he had all the braids connected to the valve cover bolts and then the distributor cover on the other end.

After talking to the engine builder, he told me that this engine got rebuilt a while back and the old guy who had it never drove it.

I replaced the plug wires and fired it up. Incredibly responsive... off idle hesitation gone. Warmed it up and took it out for a spin. Made a couple of full throttle blasts... no knocking at all. Better response and more power than it's had since I got it.

So... could the wires have been the culprit all along?

I'm not sure at the moment that I want to change anything. It's a whole new car right now.

I am 48. I have been tinkering with cars all my life. I say tinkering.... I have never gotten into too much other than timing belts, head gaskets, general maintenance... stuff like that. I have never changed a set of plug wires and had it make so much difference in a car.

Please, give me your opinions. I want to learn more.

Thanks.

Doug

 

Good news! The wires could easily been the issue. Would be good to get all the numbers from it just in case something goes haywire and you have to get back to where you started.

Have fun!

 

What got me was te 120# compression check. with what I read seems a bit low. what octaine gasoline are you running?

 

I don't know if you saw where I went back and did it with the carb open. I didn't do that before. The second time it was 140.

I will check all the numbers again and see where everything is. It is nice to have a baseline in case something else happens.

Thanks for all the advice and help. I really appreciate it.

Doug

 

Doug, it looks like you have it sorted out. I'm glad it was so simple. Now you have a baseline if you ever decide to play with ignition timing. If it runs as good as it sounds, you're going to have a lot of fun. You may want to bookmark this thread for future reference...and make friends with Claysmoker, because he definitely seems to know what time it is- pun intended. Now enjoy that beauty, and post a few more photos if you get a chance. I'm a sucker for a nice blue Vette.