Tuning specs for '60

[C B.]

Would someone please get me up to speed on the tuning specs that should be used with todays fuels for my 1960? It is a 270 horse 2-4, four speed and I am reading conflecting old documents on timing, spark plugs, carb adjustments etc. I assume that the lower octane fuel requires adjustments to prevent engine damage. Also, please direct me to a step by step procedure for adjusting the two WCFBs. The engine has had nothing done to it except oil/filter changes since 1980 (less than 1,000 miles put on it in that time) so I need to do it all. Thanks

Creighton

[Joe L.]

Re: Tuning specs for '60

Creighton------

I think that I would just go with the original specs. I don't think that you really need to make any changes to compensate for modern gasoline. Your engine was originally built with a 9.5:1 compression ratio. Unless that's been significantly increased along the way, you should have no problem, at all, with 92 octane pump gas. As a matter of fact, you may be able to get by with 89 octane mid-grade.

So, I'd go with the original tuning specs. If you have problems with the way the engine runs at those specs, then you may need to use alternate specs. But, don't worry about that until it happens and I don't think it will.

[Richard M.]

Re: Tuning specs for '60

Creighton,
Send me your email address using the button and I'll email you the 2x4 carb adj info out of the owners' manual(I'm figuring you don't have one yet). One thing though, on the 270hp high lift cam engine, as I have on my 59, you may not get a good adjustment as described in the procedure. I've found the high lift cam engines are a little too erratic to get a good "feel" when adjusting balance between primary(rear) and secondary(front) carbs.

Also, word of caution. If your front carburetor throttle shafts are worn, never, ever, floor the accelerator pedal to start a hot engine. After starting, accelerator pumped fuel in the front carb will sit there with nowhere to go. If the shafts are worn, fuel will spill onto the int/exh manifolds......and potentially cause a fire. I know this as 15 years ago it happened to me. A copy of a post I sent on another forum recently below. A bit dramatic as I like to spice up things a bit, but the story is very true.
Hope it helps,
Rich
........
Go get a soda and a bag of chips for this one.........

Arghhh!!!! Reminds me of an episode about 10 years ago when my wife and I left a downhill parking lot on a hot summer day in NH. My 59 had a hot start problem then. Car has dual fours, old wcfbs. I made the stupid mistake of flooring the throttle, you know, to open the throttle plates to get more air, to start. But I should've only half throttled, to get the primary carb open. Flooring to start a hot engine with dual fours dumps lots of fuel into the front carb too. You know where I'm heading with this don't you. So we go to leave the lot, downhill, waiting for traffic to go by to turn left to get on the highway for a 2 hr journey for an overnight stay in the mountains, top down, beautiful day with my lovely bride of many years.

Finally traffic passes by, I turn left, shift into second, and "BANG", I thought, s__t, backfire, it'll be alright. Next thing, I smell it, that horrible feeling set in. Oh my God, FIRE! Yes, the engine was on fire!
Pulled over just before the on ramp. Wife tried to get out, her sneaker laces got caught on the window crank, she panicked. I tried to keep my cool, OK Rich, stay calm, we can fix this, had to get wife out first, then just reach under the dash, pop the hood. I prayed, Please God, don't let the hood release cable break on me, just this once, I promise I'll go to church this Sunday, really, honest. The hood popped open, I saw smoke coming out towards the windshield. I figured the car was doomed. 10 years of hard work gone.....no, had my mini Halon extinguisher in the center glovebox, and a full size in the trunk. Grab the Halon stupid, no time for the trunk!

Got out.....wife was screaming, I was starting to panic. Opened the hood and there it was, a round cone of fire completely surrounding the beautiful 2x4 air cleaner she got me for Christmas 10 years earlier from Ecklers. The flames were about 2 feet high......Ok, how does this Halon thing work....pulled the pin and in one circular motion around the air cleaner I shot the yellow & black flames. What seemed like forever, but actually seconds.......OUT! No flames, nothing, gone, poof. I stood there looking for more, ready with my handy dandy fireman's friend to kill anything that even blinked yellow. Nothing. We looked at each other, sighed, said a few explatives, and sat on the curb hugging each other. She was crying. I was shaking my head, wow, that was cool! These Halons really do work!

After a little while, I let the air cleaner cool off, took my Mothers polish out of the trunk. Cleaned off the black soot from the edges of the air cleaner(came out like new), put it back on and started the engine. All's ok. Got in the car, took a right onto the onramp and had a beautiful ride to the mountains for the weekend. Car was fine.

Morale here......make sure you check those cables often, they will let you down when you least expect it. AND, carry a fire extiguisher close to you in the car for those sudden emergencies. We were lucky. Also make sure those throttle shafts on your old wcfbs are not worn so badly that they let unspent fuel leak out onto those hot intake and exhaust manifolds. That was the reason for my episode. When we went downhill out of the lot, the fuel in the front carb leaked out the shafts as the carb was not sucking fuel as it was not being told to with less than half throttle. Fixed that with new ones and a rebuild when we got home.

Rich
ps Went to Church twice that weekend. Second time to cover us for the ride back home.
====

[James G.]

Re: Tuning specs for '60

All good comments here. Need more info Creighton. Is this a "NEW" car to you? You say only 1000 miles since the 80's. Even in those days BUBBA ONE and TWO installed 12:00 to 1 pistons, and huge high life aftermarket camshafts in Corvette engine rebuilds.

I feel as the others however, if the engine is 100% original, todays gasoline (92 octane) will work fine in the car.

The fact that the car has been sitting for so long is not good for the operation and performance of the engine. 99% of the problems with Rochester Fuel Injection Corvettes is the distributor and lack of proper maintance. Over the last 50 years many FI owners took off the unit and condemmed them due to poor drivability. The real problem is someone tried to out engineer the engineers, and change distributor vacumn advances cans, install different advance plates etc......all for more power. Well their TIM ALLEN attitude only magnified the problem more and never fixed the real basic driveability problem.

So my advice is find a modern tune up store that has the new electronic test gear like exhaust analysers (to set the carburators correctly to proper HC and CO emmision levels), modern scope machines to check full advance and vacumn advance in the distributor and ignition dwell( install a good set of points) and of course base timing.

Ignition wire condition and distributor cap condition can all be checked ELECTRICALLY at this time also. Just because it looks good doesn't mean it is good.

The basics of tune up are the same today as they were 100 years ago. 14 parts air, to one part fuel and have the explosion happen at top dead center of the power stroke. And the performance tune up shops love the challange to get your old 270hp car up to its original spec.

Give us an update history on the car and engine spec and I can help you more. Hope this helps.

[C B.]

Re: Tuning specs for '60

Thanks guys for your input. I followed your advise and stuck to the basics. I set everything up as suggested in the owner's manual and it turned out pretty good. I know a pro tuner could make it run better but I am very pleased with the outcome. I am going to try to drive it more. I went back to figure up my miles per year. Thirty years (1977-2007), driven 4,524 miles; equals 151 miles per year average. Boy, I need to get out more. Thanks again for your help.