LMP Can Am M1C build thread

Hello forum members, here is the build thread for my dream car. This already has taken a while, and it will take a bit more so be patient. This is a Can Am car that I ordered last year from a very talented and passionate fellow in Germany (www.lmp-engineering.de) who has been great spec'ing the car for my tastes and budget. I received the car in February and immediately moved to New York from Los Angeles. I am doing what work I can whilst the car is in my trailer in a storage yard (not very accommodating...) You guys with the small garages don't know how lucky you are!

The car will have a 525CT Chevrolet sealed crate motor (about 530HP/470 TQ) and is set up to run either a ZF/ZFQ or a Hewland DG300. I have yet to decide, but have plenty of time. It will have a dry sump with two coolers and a rather elaborate fuel system. I am mostly just amassing parts at this point as opposed to turning wrenches, and have made a few bargain purchases thanks to NASCAR and ebay. Here is one of my experiences so far: http://www.gt40s.com/forum/gt40-tech-chassis-brakes-tires-wheels/33089-thank-god-nascar.html

I did get the calipers, and they were as advertised (brand new set and one slightly used set). I have still been looking just for fun and I have not seen anything before or since in such good shape for such a price (and a complete matching set to boot). I really got lucky.

I also acquired some J-hook AP discs that are a catalog match for the calipers and all this should cram (fingers crossed...) into my 15 inch diameter rims which are the same diameter that NASCAR requires of it's competitors.
 

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The workmanship on the chassis is exemplary. The tubes were 3-D laser cut and the TIG welding is spotless throughout. The panels were bonded and riveted and I have yet to see a rivet out of place. The whole car was designed in a computer to be as close as the original, with minor updates added in terms of metallurgy and geometry learned from when the car first was manufactured forty-five years ago. I don't know if "heirloom quality" is an applicable term to a race car, but this one sure seems to be built and finished to be around for a long time.

I am working on the brake system first. I have all components except for some ancillaries, rotor hats and brake caliper mounting brackets which will need to be custom made. I will need to measure for this and it is quite challenging.
 

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Jim Craik

Lifetime Supporter
Joe,

Welcome, that's a great looking project. I remember going with my dad to Laguna Seca back in 1965? And seeing Bruce and I think Chrs Amon, driving red ones, I just loved them.

You probably know more about this than I, but I think Mr Mclaren designed the M1C after doing the test work on the early GT40s. I see a little similarity in the nose clip.
 
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What a great time it must have been to be around Monterey for a race at Laguna, Jim.

I am aware of some GT40 DNA mixed in among the early years of Bruce's career, in the form of the Ford X-1. The X-1 had it's designs rooted in the GT-40 and was Ford's attempt at making a successful group 7 car. A lot of Bruce's early design work sprung from his relationship with Cooper as well, but to be honest many cars appeared to borrow from one another in terms of aesthetic and aerodynamic design at this time.
 
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Got some gauges in the dash. Still waiting for fuel pressure gauge and not sure what to do with the tach (mechanical Jones/Moroso or Racetech electric).
 

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Looks Nice, Ive been fancying Racetech gauges for my car for ages now.

Cheers

Fred W B
Thanks Fred, I admire the classic business-like simplicity and quality of the Racetech clocks myself, but I've been torn about what to do for a tachometer (don't really care for the Racetech versions). I really admire the classic Jones/Motorola tach's but they are mechanical, which doesn't lend itself well to my car which will neither be running a distributor nor a mag. There has been a NOS Moroso/Jones tach on ebay forever and I decided today that I am going to make it work somehow, even if it means having it converted to electronic operation by North Hollywood Speedometer. I fully anticipate having it work mechanically however, and will strive to do so. I will acquire a right angle drive mechanism from Pegasus to be driven off of the crank, water pump or sump pump. Can't wait to get it installed to make the dash complete in terms of instrumentation.

I added a fuel pressure gauge today, dash warning lamps and some badging in case I forget which switch or clock is which (likely as I get older...). I also did a trial fit of the pedals. Happy Independence Day everyone.
 

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I received the tach and it is magnificent. It must weight two pounds and the case could probably stop a .22 (not an exaggeration). It is not a lightweight piece and looks like it would be at home in any piston powered military aircraft. Even the box it came in exemplifies American quality.
The installation is imperfect, as it is not countersunk flush to the dash, but I like what it adds to the cockpit regardless. The proper size hole for mounting would require a cut on the dash that I'm unwilling to do at this point. I may in the future. It is also perilously close to what originally was supposed to be a hole for a tach recall/telltale reset switch. I may fill the space with a mechanical telltale reset made from a shutter release cable for a camera (the Jones tach has a telltale reset on the back of the case), or I might put in a low fuel pressure warning lamp. In it's current state however, the tach somewhat obscures whatever light I might install in that space. No matter, the current results are satisfying up to this point and the rest I will sort out later.

I did manage to be so brave as to cut two holes in the dash; one for the fire system pull cable and the other for the brake bias adjuster dial. I came home to find the mailman left two military-style switches for the fuel pump and ignition and hopefully he'll return Monday with two aircraft breaker switches that I ordered.
 

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Any progress on this one? I know you said you moved to NY & winter back there isn't too condusive to working on cars LOL Here in So. Cal. it's overcast & supposed to rain. If it's any consolation.
Mike
 
I was looking over your pix. The side pods (fuel cells) look too square for the body. M-1 through M-6s had very rounded sides. John Collins let me use his M-6 jig to bend some side pod tubes for a car I started many years ago. They were about 8" radius as I recall. The pix look like an M-1 upper body on an M-8 tub. Sory to be a wet blanket or anything it just looks a bit "off" to me. The early can-am cars with their rounded bodies have always been a fav. of mine.
Mike
 
Any progress on this one? I know you said you moved to NY & winter back there isn't too condusive to working on cars LOL Here in So. Cal. it's overcast & supposed to rain. If it's any consolation.
Mike

Just moved back to So Cal and work on the car has been proceeding a little slow because that and my career. The body may be "off" but it looks fantastic to me. I don't think the car was meant to be an exact replica, and even so, you'd be hard pressed to find an M1 series that was identical to another after they got into customers hands and modified or repaired after damage.
 
It's not so much the body which does look great. It's the combination of the side pods (fuel cells) & the body. The body is very round & the tub is squarish. Where in So. Cal are you? I'm in Orange Co. would love to take a closer look at it.
Mike S.
 
I can bring some light into the background of our design and sorry that I only saw your interest now. Basically there are two different reasons why our side pods look differently. On the one hand we did not want infringe any of th Mc Laren copyrights and we respect their brand. Therefore our entire chassis design deviates. On the other hand the original M1s had a fairly slim steel frame with limited torsional rigidity. Basically the fuel tanks were just hung under side bars off the main chassis. The more round side pod covers were more body panels than having torsional core fucntion.

In our car we use the side pods to increase torsional rigidity, i.e. the body panels are rivedted and glued to the steel frame. (actually the glue is the key not the rivets). Hence the AL panels work as sheer plates which take the torsional stress and indeed they therefire are more similar to the later M6 and M8 designs. The reasons why we designed the side pods more square was fuel tank capacity, ease of manufactunring and last not least they are because they are more effective in preventing air flow from the side of the car getting under the car into the low velocity regions and thus reducing downforce.

We appreciate your interest in the old Can Am style cars - keep up the good spirit of this great era !

We will deliver a full spec ready to race car to California this month so that you may have the chance to look at it if you are interested.

Wolf
 
I may be more into the esthetics of the original car. But the square side pods coupled with the rounded body are incongruace. A curved side pod would in fact be more tortionaly stiff than a square one. A circle (or arch) is stronger than a square. That's one reason airplanes have round or oval main structures (fusilage). The respect for the original company would be better served by a more original looking design to the tub. At least in outwards appearance. True, manufacturing is easier with square but would curved really be that much harder? Fuel capacity would hardly be a big concern. They would more than amply carry enough fuel & more than the average production cars fuel tank. I would love the opportunity to take a look at one of your cars. Please do let us here on the forrum know when & where we might see one.
Thanks
Mike S
 

Terry Oxandale

Skinny Man
I'm really wonder how much more rigidity, of perhaps 13 feet of straight-walled framing circumference around the frame, would be appreciably decreased by turning 2 of those feet from a constant radius curve on either side (the M1C), into what we see in this example of perhaps 5 or 6 inches on either side. Regardless, love the project and enjoy seeing the progress.
 
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Airplane fuselages are circular for pressurization loads, not torsional resistance. Also, any material farther from the centroid of the shape increases stiffness, although a circular tube is most weight efficient for reacting torsional stiffness. I don't know anything about fuel capacity requirements, but a rectangular shape would allow you to place the fuel lower in the car.
 
No airplaces were built with "cigar" shape fusilages well before pressuization was ever thought of. A tube is several times stronger in tortional strength than a box shape. That was one of the engineering design facts that the aircraft industry reccognized long before the auto racing engineers did. Same with monocoque construction. Collin Chapman of Lotus was one of the first to reccognize these facts. A square will deform quite easilly if not for a diagonal brace or diaphram. That's why triangulation or stressed panels in a space frame are crittical to strength in all dirrections. The Romans reccognized the arch as a far superior load bearing structure to a square. It transfers the loads much more uniformly from one direction to another. A good book to read on the subject is Len Terry's book on race car design (the exact title escapes me).
Mike S
 
You might want to read up on "frames." A good text is "'Analysis and Design of Flight Vehicle Structures" by E.F. Bruhn, although I admit it is over 800 pages long.

Until stressed-skin aluminum structures became commonplace, aircraft were built from wire braced members made from wood or metal, or metal trusses, and were fabric covered. Prior to pressurization, some aircraft were built with circular cross sections and mid wings to reduce aerodynamic drag at the fuselage to wing intersection. Once aircraft started to be pressurized, there was no other way than circular cross sections (and variations thereof like figure-8).

If a round tube is several times stronger in torsional strength than a box shape, please provide a comparison of torsional strength between a round tube and a square tube of 1" diameter, not a vague assertion.

Here is something I found with a quick internet search:

4.0 Tubes

"To begin the discussion, observe the following plot of the relative torsional stiffness for different types and thickness tubes.



We can see that larger diameter tubes result in a higher J/A value, or torsional stiffness efficiency. Additionally, square tubes appear to be more efficient for a given size. This is because they distribute the material farther away from the center than a round tube.
The Romans built primarily masonary structures and didn't build many race cars that I am aware of. I also don't think that Roman arches see much torsional loading in practice, primarily compression from the weight of the structure.

BTW, I've read Terry's book.

This is way off topic though. My apologies.
 
I'm not an engineer & perhaps my saying a circular form is several times stronger than a square. Was a bit of an over statement. So I too did a search & according to egineer.usaask in regards to torsional resistance it had this to say "Efficient resistance to torsion requires as nearly circular cross-sections as is practical". From personal experience I can say that you'll twist a square tube long before you will a round one of equal size & thinkness. A tube is a single uniform plane & as such is much more efficient at transfering loads uniformly than perindicular planes as in a square. But as you said it is a bit off subject. Divergance from the original design of the McLaren M1 was the actual subject of my posts. The asthetic of the original & the fact that it was quite succesful as a racing car. I was pointing out the difference from the original. Believe me I'm not above "customizing" but when dealing with an iconic car such as a McLaren? In my opinion (take it or leave it) combining squared side pods with the rounded body. Just does not look right. It looks like an M8 tub with a M1 body.
Mike S
 
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