Massive Vintage Engine on Dyno

"Aliens" of the 50's/60's are standard today. We have to consider that today's gasoline is COMPLETELY different from what we had 50 years ago. The "oldfashioned" mogas was simply straight saturated hydrocarbons plus a hell of a lot TEL. Some of us may remember, when in the 70's unleaded gasoline was introduced neither the oil nor the automobile industry was prepared, phasing out lead simply resulted in an octane drop of 5 to 10 points, and power of a standard 5 litre V8 small block dropped from 300 to 170 hp. Since then gasoline specification changed constantly, first to substitute the TEL by other octane components, and then to substitute some of them again due to environmental reasons. The description "reformulated gasoline" says it all.

The main problem is Methanol, which is allowed up to 3 % in standard pump gasoline. It is an excellent solvent, and therefore hoses and gaskets must be resistant. But also other components have solvent properties, and damage not only elastomers and some polymers, but sometimes even casted aluminium or other alloys. Our modern cars are fully resistant to this, so it is always recommend to use new materials for fuel lines, sealings, etc. No problems with the Webers yet? Check the O-Rings, either they are Methanol resistant already, or they look like black chewing gum....!

 

Great pix of 0846. Thanks for posting and keep 'em comming as it progresses.

 

Jim, everyone - thanks for the info - sorry for the *slight* hijack.

Cheers
Kevin

 

A LOT easier, safer, (and cheaper) to replace parts like this once a year than to have to tear everything down because you didn't

 

If you use gaskets and sealings as used also in modern cars they are resistant, not necessary to replace them once a year.

 

There is one thing that need to be sorted out here, I think:

Adjusting ignition timing will eliminate knocking only if it is caused by the too high burning speed of low octane gasoline. If the mixture "self-ignites" then adjusting ignition will not handle the issue properly; the comression must reduced or octane rating boosted to get the process under control. Best wishes, Kare

 

Kare,

If you have runaway ignition, then the problems are quite serious. I would think this is much less common than knock.

Regards,

Art S.

 

Self-ignition should only happen if the difference between required and actual octane figure is very large. Modern engines can handle octane spread of up to 7 points, may be even 10, by knock sensor and automatic ignition adjustement. My former car standard needed 95 RON (premium), but if not available I could fill in 91 RON (regular), and even 87 RON works based on report of the new owner in Middle East. However, somewhere there is a limit which cannot be adjusted by ignition timing anymore.

 

"burning speed" has nothing to do with octane. Flame front propagation and octane are independent variables.

 

Modern unleaded fuel contains benzene, now only 1% though it used to be more - pretty nasty stuff, as well as being a solvent.

In F1 racing in the turbo days and even into the early-to-mid-1990s there were some very exotic and downright nasty fuels in use; BMW's 1983 fuel was incredibly dense, and one mechanic got a drop on his plastic watch which promptly dissolved.

Some gave a lot more power than others; one time a small F1 team got hold somehow (bribery!) of a churn of fuel from one of the big teams and tried it at a test - the driver said at last he'd got a decent engine and went 1 second a lap faster, but they had to race with their usual stuff.

(clue: the big team gave a certain driver the first of his many WDC's a couple of years later, in a season when there were many allegations of rule-stretching)

Paul M

 

Benzene is carcinogenic, therefore its use is prohibited resp. limited to 1 %. Complete prohibition is impossible because small amounts are already in the crude oil.

Benzene was a major component in high-octane gasoline from the 30's to the 60's, mainly in Germany, because it was available in large quantities as by-product from coke ovens. There was even a special fuel named "BiBo" from ARAL which was 50 % straight-run gasoline plus 50 % Benzene.
Benzene is no miracle stuff, its RON is only about 100, other aromatics like Toluene and Xylene have 118 resp. 114. But it was a typical surplus product before the petrochemical industry discovered it as important feedstock.

BMW in the F1 turbo era was connected to Wintershall as fuel and lube supplier. WH was a small refining company belonging to the BASF group. BASF is a large chemical company, which together with the other German chemical giants formed the "IG Farben" conglomerate in the 30's. IG Farben invested a lot of research into gasoline, because Germany was cut off from TEL supplies, they even invented synthetic fuel from coal, a process today still used in South Africa. Main topic of their research had been coal based chemicals, much of them could not be found in petroleum. They found some really exciting substances, but available quantities had been too small for commercial use.

A lot of these research files had still been in the company archive, and had been used by the BASF lab people to create a completely new racing fuel. The target was not "octane", because RON was limited by the FIA to 100, but calorific value and perfect burning properties. Some of the components had been so exotic that they had not been commercially available, so they produced the required quantities in their laboratories. The result was a cost price of several hundred dollars per litre, but also an excellent performance.

 

When you notice the engine is not running properly, it may be very difficult to determine what exactly is going on inside combustion chamber. It may even be very difficult to tell whether that knocking occurs inside your engine or your head (not kidding). If you have a glowing piece of dirt inside combustion chamber, it will easily ignite the mixture during compression, which leads into one flame front too many. When fuel mixture is consumed too early, you will hear the engine knock. The sound tells that the peak pressure was reached too early (<10 degrees ATDC) so that the crank instead of cranking starts to resonate. In theory the sound may be a little different depending on what is going on, but I would be pretty sceptic about anyone's analysis unless it is a clear case of detonation (explosion instead of controlled burning).

 

Kare,

You may be right regarding pre-ignition due to carbon build up. My undrestanding of this is that it is occasional and somewhat random, resulting in an occasional ping or knock and rough running.

Sustained pre-ignition has very serious consequences and is usually more serious than a glowing piece of something. It is a different phenomenon than run-on (run-on is when your engine keeps sputtering after you have shut off the ignition). Run-on is actually the basis of a new combustion concept called HCCI (Homogeneous Charge Compression Ignition). Pre-ignition occurs under load and can cause your engine to explode, not just knock.

I've been in the control room of a dyno cell of an engine manufacturer when pre-ignition or runaway ignition occurred on an engine under development. I can assure you it is not a subtle difference.

Regards,

Art S.

 

Congrats on the grand 'secret' project - it's very exciting.

Any word on the dyno test for us?

If it wasn't enough Hp, I've heard TomS picked up a couple of spares you could use....
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Yeah Jim how's it going ... I hope she's running alright, etc.

Pete
ps: Don't let real work get in the way

 

It probably rankles some that Ferrari was beaten by a NASCAR engine.