L Series Block Brace

[johnc]

ITS refers to a SCCA road racing category and class - Improved Touring S. The Improved Touring category severly limits engine modifications. Basically no internal changes beyond basic balancing and parts bin blueprinting. You have to run stock cards or FI but you can add headers and ignition modifications. The top L6 engine builders were getting close to 200hp out of an L24 engine built to those rules and the top builder got an SAE certified 208hp.

[JustinOlson]

Here's a good picture John posted a while back about his lightened crank:

 

Your shop teacher should stick to teaching kids how to do oil changes on Camrys. Below is a lightened and knife edged L6 diesel crank that had at least 20 hours of hard racing on it at NA power levels over 320 horsepower.

 

[Tony D]

"I was curious if there was any special prep work or machining, like rocker profiling or lightening, some nutty valvespring design, etc -that sort of thing. Something beyond what all the Datsun books originally written in the 70's detail for race engine prep. 20-30 years is an eternity in the racing world."

 

It is exactly that kind of thinking I am addressing when I make these kind of statements. In one sentence the disclaimer looking for widgets, but by the end of the sentence says that they are looking for just that!

 

Plainly stated, no, not much HAS changed in engine building except that the technology that has ALWAYS been in place at higher levels of the motorsports realm is slooooooooowly filtering downwards to the grassroots levels. Stuff that people take for granted when prepping an F1 engine in the 70's is roughly what top amatuer racers are doing to stay competitive now. The lag in technology form top tier series is decades...and usually because of costs involved.

 

The CNC machine has made porting something that is an appliance on SBC engines, but even then little details here and there on a port will still need some attention for that last umph...

 

There is not any shortcut to power, it lies in Three Basic Tenents:

 

1) Preparation.

 

2) Preparation.

 

3) Preparation.

 

It's hard work, painstakingly melticulous setup, measuring not once, twice but three or more times. Good measuring tools, competent setup and component selection...

 

The same stuff top tier guys have been doing for years. There's no shortcut. The books written in the 70's may seem dated, simply because they don't address this head or that. But when you actually read what they are saying, it's far less a 'building blocks on what parts to use' and more 'do it this way'...

 

Honsowetz works for Ed Pink Racing Engines now... Kind of tells you something outside of 'inside connections'.

 

Parts only do so much, Technique makes every engine better.

[johnc]

Don't forget, in 1915 Miller built a 3 liter, supercharged, four valve head, chain driven dual overhead cam, stainless steel valved, block cradled, all aluminum four cylinder racing engine that made 200 hp on 72 octane fuel.

 

There really isn't anything new in racing.

 

EDIT: I was wrong on the engine specs I posted above. Here's the correct info:

 

Engine Specification:

 

4 Cylinder all aluminum alloy, 289 cid, 3-5/8 bore x 7" stroke, 136 H.P. @ 2950 R.P.M., Single overhead cam, stainless desmodromic valves, dual intake and exhaust ports 4 valves for each cylinder, dual sparkplugs and magnetos.

[WEBEZEEed]

Johnc.... 208 h.p. is that wheel or crank?

[johnc]

Crank.

[HS30-H]

4 Cylinder all aluminum alloy, 289 cid, 3-5/8 bore x 7" stroke, 136 H.P. @ 2950 R.P.M., Single overhead cam, stainless desmodromic valves, dual intake and exhaust ports 4 valves for each cylinder, dual sparkplugs and magnetos.

 

 

If you are talking about the Miller TNT/T4, then that would be 1920 rather than 1915.

 

No disrespect to Harry Miller ( or more specifically Leo Goossen ), but Peugeot, ALFA, Delage, Humber, Sunbeam, Frontenac, Maxwell, Premier, FIAT and Ballot engines were using similar specs and producing comparable power some time before Miller engines were.

[Tony D]

I can't recall, there was some well-off enthusiast who commissioned a replica engine to be built. This engine was some European DOHC design he thought 'the technical pinnacle of development' from the early 1900. Bugatti rings familiar, but I may be way off.

Anyway, his theory was that the limiting factor in the engine's output was not the engineering, but rather the materials available, and the supporting technology to manufacture them.

When his engine was built, compared to the original, the differences in power output was staggering. Something like a factor if six compared to the original output. Using modern metalurgy and machining techniques, the engine was capable of 8000+ rpms, and making something like 580HP whereas the original was spun to somewhere around 2500 or 3000 and made around 80HP... This build followed the original prints, there was no port redesign, just modern materials and precision tolerances.

 

I wish I could remember a name or something, it was a fascinating article. Oh, to be the one to have the money to do such experiments! LOL

[76s30]

Now theres something done very very little..... desmodromic valve train. Very cool old school approach to reving high.

[tkach]

This is a wonderful topic that really addresses detail within work and craftsmenship. Can anybody suggest some reading that deals with the subject matter at hand? Ie preping good race motors or 70's F1 engine building?

[MONZTER]

This is a wonderful topic that really addresses detail within work and craftsmenship. Can anybody suggest some reading that deals with the subject matter at hand? Ie preping good race motors or 70's F1 engine building?

 

 

Not much reading, but some great pics http://gurneyflap.com/engine.html

[Careless]

Now theres something done very very little..... desmodromic valve train. Very cool old school approach to reving high.

 

not neccessarily old school. Ducati's still use it. But the problem is that most of the advancements in that area of valve train design are patented by Ducati... so

[76s30]

by old school I meant its roots. way way way back in the early days of racing and metalergy. the technology to make the valve springs we can today did not exist which is ONE of the reasons engines where quite large displacement and only turned 3-4 k. desmodromic valve train was the high tension valve spring of yesterday. Not that it still doesn't have a place, may manufactures have tried it over the decades. none recently. I'm pretty sure ducati stoped making a desmo model years ago. theres a cool article in "Engine Masters" about desmodromic valve train. I can't remember the issue off hand though.

 

rotory valves are cool to, though I'M yet to see them on a running engine, any one see a vid or article about them?

[Tony D]

Rotary Valves in Big Busses. There is a company that converts diesels to run on CNG or LNG, and they use Rotary Valves. It's in the archives here or at ZC.C, they wouldn't return JeffP's inquiries...

[nbesheer]

No Ducati still uses Desmo, at least on the Supersport 800.

[Tony D]

F1 was Desmodromic in some applications recently.

 

The DEVAS system uses electro-hydraulic actuation of valves....camless engine, uses Electronics to control opening and closing rates, time at dwell (duration)....with the DEVAS system the need for an inlet throttlebody is negated---all airflow through the engine is controlled solely through valve lift and duration. With infinitely variable valve timing, lift, and duration, this is totally possible.

[OlderThanMe]

F1 was Desmodromic in some applications recently.

 

The DEVAS system uses electro-hydraulic actuation of valves....camless engine, uses Electronics to control opening and closing rates, time at dwell (duration)....with the DEVAS system the need for an inlet throttlebody is negated---all airflow through the engine is controlled solely through valve lift and duration. With infinitely variable valve timing, lift, and duration, this is totally possible.

 

There was an article in Automotive engineering magazine in the last 4 months about the camless valvetrain. Very interesting article.

[johnc]

If you are talking about the Miller TNT/T4, then that would be 1920 rather than 1915.

 

I was talking aobut the engine he built for Barney Oldfield's Golden Submarine. Barney ran the car starting in 1917 but Harry (and others) were back east trying to get the Bughatti U16 aero engine to work (it never did). The engine used in the GS was designed by Harry, redesigned by Leo, and built in 1915/1916.

 

One of the first engines Harry Miller modfied was a Peugeot, which probably gave him some of the ideas he used in his later engines.

[Dave240Z]

Just to add a little more to this old engine stuff....

 

Anyone heard of sleeve valves? They were popular pre-WWII, most notably in Bugatti's. At the time, they were preferred over poppet valves which leaked and lacked the ability to rev over a wide rpm. The sleeve valve, basically a sleeve that fit around the cylinder, which either moved up and down to expose the ports, or rotated via a gear from the crankshaft is a very simple design and required very few parts. It eliminated the cam,springs,valve stems which provided for very efficient packaging with no worries about valve float. However, these also leaked quite a bit (although less than poppet valves at the time) and once poppet valves were perfected, they fell out of favor. Perhaps the rich enthusiast who rebuilt a Bugatti engine with modern materials and tolerances did so with a sleeve valve engine? I would love to read that article. I've always wondered what some of these classic engine designs would be capable of given modern materials, tolerances and compression ratios.

 

Another fascinating little engine is the BRM V16 which debuted in 1953 F1. It was a supercharged 1.5L V16, capable of 12,000rpm and 550hp. This was later followed up with an H16. Crazy stuff. Unfortunately, these BRM engines were notorious for their lack of reliability.

 

Here's a sound clip of it running full throttle at some track.

Imagine hearing this in 1953 amid the other contenders.

http://gpl.krej.cz/mp3/BRM%20-%20full%20track.mp3

[Daeron]

http://en.wikipedia.org/wiki/Desmodromic_valve

 

I figured rather than ask what a desmodromic valve was, I would find ot for myself and answer the question for anyone else.

 

GROSSLY oversimplified (I am fishing for corrections if I am wrong) it uses a second cam lobe (plus some other valvetrain hardware) to close the valve rather than springs, right?