[barry425]

I am so glad that you opened the door to talk about Doug Roe's experience. When my Vega had the original 90 hp 4 cylinder in it, I purchased a Doug Roe head. When my engine was stock, it got 21.4 mpg on a measured course strictly on the freeway. I had the block decked for the tight quench and bolted on the Doug Roe head, which had a heart shaped combustion chamber (instead of the stock open chamber). I took the car on the exact same course, filled at the same pump in the same gas station and got 43.0 mpg.
I then took the car to a chassis dyno and the specialist started tapping his gauges. I asked if something was wrong. He asked if I had done something to the engine. I felt about 1 inch tall, thinking that I had ruined something. I told him that I had modified it and asked why. He said that it was making 58 horsepower at the rear wheels. I said that it was a 90 horsepower engine, thinking that I had ruined the engine. He said that a GT engine (110 horsepower) only makes 35 hp at the rear wheels! So, I had doubled the gas mileage, almost doubled the horsepower, and the icing on the cake was that it was smoother than a V-8. That engine lasted 94,000 miles, which if you recall, was some kind of a record for that engine design. Most became boat anchors at 40,000.
I did the same thing to the first V-8 that I put in the Vega. It was a small journal 327 with the .010 quench, quadrajet carb, modified (to fit) cast iron manifolds and a 400 turbo hydro. This engine took me to work and back for 20 years, logging 300,000 miles, and still passed smog when I took it out in favor of the reworked LT-1.
You can theorize and bench race all you want, but I made it work for, let's see, 37 years now. If you can't believe the truth when it is told to you, look me up in Diamond Bar, CA, and I'll take you for the ride of your life.
B.A. Murphy (in the book)

[vinniekq2]

Originally Posted by barry425

I am so glad that you opened the door to talk about Doug Roe's experience. When my Vega had the original 90 hp 4 cylinder in it, I purchased a Doug Roe head. When my engine was stock, it got 21.4 mpg on a measured course strictly on the freeway. I had the block decked for the tight quench and bolted on the Doug Roe head, which had a heart shaped combustion chamber (instead of the stock open chamber). I took the car on the exact same course, filled at the same pump in the same gas station and got 43.0 mpg.
I then took the car to a chassis dyno and the specialist started tapping his gauges. I asked if something was wrong. He asked if I had done something to the engine. I felt about 1 inch tall, thinking that I had ruined something. I told him that I had modified it and asked why. He said that it was making 58 horsepower at the rear wheels. I said that it was a 90 horsepower engine, thinking that I had ruined the engine. He said that a GT engine (110 horsepower) only makes 35 hp at the rear wheels! So, I had doubled the gas mileage, almost doubled the horsepower, and the icing on the cake was that it was smoother than a V-8. That engine lasted 94,000 miles, which if you recall, was some kind of a record for that engine design. Most became boat anchors at 40,000.
I did the same thing to the first V-8 that I put in the Vega. It was a small journal 327 with the .010 quench, quadrajet carb, modified (to fit) cast iron manifolds and a 400 turbo hydro. This engine took me to work and back for 20 years, logging 300,000 miles, and still passed smog when I took it out in favor of the reworked LT-1.
You can theorize and bench race all you want, but I made it work for, let's see, 37 years now. If you can't believe the truth when it is told to you, look me up in Diamond Bar, CA, and I'll take you for the ride of your life.
B.A. Murphy (in the book)

sounds spectacular,post a video for us to see! cant wait

[barry425]

When my daughter gets home next week, I'll try to have her video the car, engine, and a couple of burnouts. I don't want to race on the street and lose my car. I've been meaning to take it to the drags, just haven't had the time yet. I'll have her video that, too. Meanwhile, I'll see if I can find some still photos to post here or on Facebook.

[barry425]

I just posted photos under "Barry425's Journal". Check it out.

[Landshark928]

Originally Posted by barry425

I am so glad that you opened the door to talk about Doug Roe's experience. When my Vega had the original 90 hp 4 cylinder in it, I purchased a Doug Roe head. When my engine was stock, it got 21.4 mpg on a measured course strictly on the freeway. I had the block decked for the tight quench and bolted on the Doug Roe head, which had a heart shaped combustion chamber (instead of the stock open chamber). I took the car on the exact same course, filled at the same pump in the same gas station and got 43.0 mpg.
I then took the car to a chassis dyno and the specialist started tapping his gauges. I asked if something was wrong. He asked if I had done something to the engine. I felt about 1 inch tall, thinking that I had ruined something. I told him that I had modified it and asked why. He said that it was making 58 horsepower at the rear wheels. I said that it was a 90 horsepower engine, thinking that I had ruined the engine. He said that a GT engine (110 horsepower) only makes 35 hp at the rear wheels! So, I had doubled the gas mileage, almost doubled the horsepower, and the icing on the cake was that it was smoother than a V-8. That engine lasted 94,000 miles, which if you recall, was some kind of a record for that engine design. Most became boat anchors at 40,000.
I did the same thing to the first V-8 that I put in the Vega. It was a small journal 327 with the .010 quench, quadrajet carb, modified (to fit) cast iron manifolds and a 400 turbo hydro. This engine took me to work and back for 20 years, logging 300,000 miles, and still passed smog when I took it out in favor of the reworked LT-1.
You can theorize and bench race all you want, but I made it work for, let's see, 37 years now. If you can't believe the truth when it is told to you, look me up in Diamond Bar, CA, and I'll take you for the ride of your life.
B.A. Murphy (in the book)

Nice looking Vega!

Pistons hitting heads is not theory. Telling folks on an internet board that .010 quench is fine is irresponsible IMO. It have may worked for you. But without knowing the intended viewer's set up, it's dangerous to broadcast to all. I've seen forged pistons rock in the cylinder +0.005". That cuts your 0.010" in half. Then factor in up to a 0.02" rod bearing clearance. Now you're down to 0.03" clearance. Any rod stretch and BAM. Any carbon build up and BAM. Too close for comfort for the typical build. You have to factor in rod bearing clearance, manufactures tested rod stretch at what RPM. Pin clearance, floating or pressed, piston to wall clearance and piston rock. Piston material and any growth from heating.

Not to mention seldom do folks actually measure their clearance for quench. They use a calculator with manufacturer specs. Those specs could be a hair off due to manufacturing tolerances. A couple items off a hair and BAM. A static 0.010" clearance is not a Dynamic clearance of 0.010" once warmed up and running.

[F-BIRD'88]

Originally Posted by barry425

Hi F-Bird'88,
You didn't read my blog, apparently. I'm running a negative deck (pistons stick out of the block) and my quench is not .033, but .010 piston to head clearance. Since you are not acquainted with Doug Roe's engineering, I would not expect you to understand.
The gas in California is regulated more than other states. We even have different blends mandated for summer and winter. The octane is calculated by: research+motor/2=octane
I've already tried 100 octane gas ($9 per gallon) with Moroso Octane Boost and advanced timing. No good. It pings like crazy because the tight quench makes the fuel burn faster in the combustion chamber.
By the way, when a flat top piston sticks out of the block, your factory calculations for compression ratio go out the window.

Your engine is knocking cause the fuel does not have enough octane.
Its not going to get fixed with Octane booster.
Put some real 110 octane unleaded in it and test at 34-36deg BTDC.
I don;t use "factory calculations" I know how to calc it when a piston is sticking above the block deck.
YOU are running the engine in a detuned mode with 28deg BTDC to avoid
detonation from the extreme compression ratio.
You think you have reinvented the wheel but you ahve not.
Your claim of doubling the engine power with .010 quench clearance is total BS.
And I am well aware of Doug Roe's writings.
You'd think the OEM's would have picked this up if it actually worked as you claim.
All you are doing is running a extreme compression ratio engine in a detuned mode with retarded timing. Run the einge on a real engine test dyno or run the car down a drag strip on the two fuels (real race gas, not octane booster) and you will see what you are missing.
Your claim of 8000 rpm power using that little Erson cam is another BS.
You may be able to free rev to 8000rpm in neutral but you wil not make any real power at that rpm. There is a big difference between spining your tires in the street and actually making real horsepower.
The difference between .010" quench and .035" quench is 0.
In a real test on a real dyno. .010" will kiss the head at high rpm.

NHRA superstock racers/engine builders that actually do make big power from "stock " engines
that rev to 8500rpm + set the measured net quench to .055". Any smaller and the piston kisses the head. and no benefit from a smaller quench. .010 smashes the piston .
They know and have tried all the tricks including this. None of them use it.
Their cars are actually fast. Don't think you will find any of them running a tiny Erson Hi flow I hyd cam...LOL

By the way when you actually do test with real race gas in the tank instead of "octane booster" BS you wil find that the engine wants 36-38deg and will not detonate even if you time it to 41-42deg.
The real race gas I use genereally will not knock at all reguardless how much over timing is applied. Get som real gas and retest.
Then take a head off and see the piston kissing at rpm.
And measure your real quench clearance.

4.03 bore 3.48 stroke 64cc head -5cc valve relief (4 valve relief piston) -.030" deck clearance ( piston above deck at TDC)
4.166x .040" felpro gasket The engine cr is 11.15:1

Doubling the HP on a stock OEM old vega motor is not hard to do.
These were one of GM's saddest OEM engines. a 4 cylinder Vega was as lame as it gets.
Even the Cosworth head version was a dud.

Its not going to happen on a SBC by running .010" quench clearance.

[cobalt327]

For a street engine and 99% of competition engines, 0.010" quench is too tight. Besides the obvious problems of having the head and piston hit, there can be clearance problems between the valves and pistons, as well as top ring infringement depending on the piston design into the chamfer at the tops of the cylinders, unless things are closely inspected and corrected as needed.

The statement:

All quench benefits are lost if the piston to head clearance is greater than .030 inch.

Is just not true, period. The majority of the benefits are seen at distances as wide as 0.040"-0.045" and benefits are still seen in a diminishing fashion out to as much as 0.055".

Running that hydraulic cam grind to 8000 rpm is well past the power peak, no reason to shift that late; the vehicle will ET better shifting considerably earlier.

I run 91 octane (California) with timing set at 26 degrees...

Max power timing on the early small chamber SBC heads is ~36 degrees. If you take away 10-plus degrees of timing, you could probably run kerosene. But even running it on 91 octane pump gas, the engine will be significantly down on power.

[F-BIRD'88]

Don't bother posting videos of your 500hp magic quench engine Vega doing burnouts.
We got the picture, already.
As for a ride of your life I bet this fubar thing will have trouble clicking off a 13sec quarter mile
assuming it does not self destruct, first.

[1Gary]

Aaaaa,the Cosworth Vega was a pet project of mine while working at Chevy.You'll find a number of them with my signature on them.
The first yrs they where released before they got DE-tuned where outstanding performers for a 4 cylinders. We resolved the silicone mix so the two center cylinders didn't settle like the foundation of a house on the blocks and because of the Cosworth that problem was resolved totally for the whole Vega line of engines.

To rev the Cosworth engines to 7 grand and alittle beyond was no problem.I know because I built them!!. And we got to test drive one outside of the plant.Was told any tickets where on us!!.

F-Bird.................what do I say??. Well guess more of the same,huh.LOL.A dud??.Nawwww.........!!!.

[cobalt327]

You might notice the poster said "my Vega had the original 90 hp 4 cylinder". Not a Cosworth. Iron coated pistons on an aluminum bore was a bad idea for that engine. One of the biggest turds GM ever made. I owned the only one that I know of that went the distance on the original engine- "the distance" being it ran until the body literally fell off the car during a Rochester winter, the fenders flapped like a drunken seagull whenever the duct tape ripped off at the hoodline.

It ran the whole time I owned it w/a broken head bolt, I could spin it by hand. Don't know why it never blew the HG...

[64nailhead]

Cobalt & F-Bird,
Being a novice to engine building, Barry mentioned something that I've never heard of: polishing the head chamber in an effort to get a better/cleaner burn to eliminate detonation. I'm asking how effective this is and if there is a benefit for lower compression, say 9.5 - 10.5 compression when making tuning adjustments for a novice like myself. I ask because I'm going to be changing my head gaskets to get a more desirable quench distance and I could polish the chamber at the same time.

Barry,
IMHO I have to agree with others that .010 quench seems unrealistic for anything other than engine that is going to be torn down and rebuilt on a regular basis due to alot of factors such as, rod stretch - which is a number that is going to continue to increase as the rods get older and more heat stressed as the number of heat cylcles increase; as the rod bearings and wrist pins wear with normal use; as the valves and guides wear with normal use; carbon build on valve face and piston surface with normal use (especially with a carb setup.) I may be all wet with this, but I would never dare to try a such a low quench for fear of a catastrophic failure.
With that being said, from looking at your pictures how did you manage to get an electric fan on the engine side of the radiator. My son and I have put a sbc into a 77 Astre (Vega lookalike). We are running a swp with an aluminum radiator and we have 3/8" of clearacne between the water pump pulley bolts and the radiator. We mounted an electric fan on the front side of the radiator. The only time it has come close going over 220 is on the 4th run on a rolling dyno (not enough air flow.)

Cobalt, my 1st car was a 73 Vega that I paid $125 for in 1986. It needed a downhill grade to 70 mph and it melted down at 68K. Your right, it was piece of turd!

Trying to go fast without wrecking our engine - Jim

[barry425]

As far as timing goes, you simply don't get it. The close quench causes a higher turbulence in the combustion chamber. Instead of the flame starting at the plug and traveling across the chamber to the fuel, the fuel actually travels to the flame front. The reason that you set the timing advanced of top dead center is to allow for the lag in time of the fuel burning. You want the maximum cylinder pressure to occur just as the piston is starting down from TDC. Higher octane gas burns slower than lower octane, so the timing can be set slightly more advanced, HOWEVER, unless the engine is in detonation there is no advantage in advancing the timing and running higher octane fuel. It just costs more for gas that will waste itself out the exhaust valve (because of the slower burning). I've already made all these tests that you are recommending. My setup works the best. If you haven't tried it, don't knock it (pun intended).

[Landshark928]

Originally Posted by barry425

Higher octane gas burns slower than lower octane, so the timing can be set slightly more advanced, HOWEVER, unless the engine is in detonation there is no advantage in advancing the timing and running higher octane fuel.

That is an internet myth. Octane rating does not impact flame burn rate, it is based on the hydrocarbon content of the fuel mix. A perfect example is Sunoco Maximal, which is their fastest burning fuel, and coincidentally one of Sunoco's highest octane fuels at 116 (R+M) / 2. A lot of Pro Stock teams rely on Maximal for those sub-seven second runs. When they are turning 9,000 rpm or more, the fuel has to burn pretty quickly to achieve complete combustion.

The octane number of a gasoline has little to do with how fast it burns or how much power the engine will make. Octane number is the resistance to detonation (pre-ignition). If the octane number is high enough to prevent detonation, there is no need to use a higher octane gasoline since the engine will not make any additional power. Octane number is not related to flame (burn) speed either. Variations in octane quality are independent of flame speed. There are some high octane gasolines in the marketplace with fast flame speeds and some with slow flame speeds. It depends on how they are put together.

[barry425]

Landshark928, I'm sorry, but you are just plain wrong about the octane/burn rate. Also, this is a fact that was widely known before the internet was even conceived. Would you mind telling me how old you are? Just curious.

[bygddy]

Originally Posted by barry425

Landshark928, I'm sorry, but you are just plain wrong about the octane/burn rate. Also, this is a fact that was widely known before the internet was even conceived. Would you mind telling me how old you are? Just curious.

Age is displayed on your right above posts