18 replies to this topic

[2F-001]

Does anyone have any links to, or other sources of, information on the Polimotor (plastics-based 4cyl race engine, originally used in IMSA Lolas, then productionized to an extent and used in among other things UK speed events).

The articles I had amassed, I've lost; I have a possible opportunity to buy one second hand and so my interest is renewed.

Any ideas anyone...

[desmo]

I vaguely recollect the Ford Polimotor project as a showcase for polymer and composites in engine applications. Hardly set the world alight though did it? Interesting nevertheless. These Google search results might be a good place to begin looking. I'd be interested in any facts or anecdotes you can dig up on the subject, it was a bold stroke in it's time to be sure. The boffins at the Nolstalgia Forum may have some further insights into the engine, I'd go over there and give them a try, the knowledge present there is mindblowing!

[2F-001]

Thanks Desmo -
I've just subverted a thread on TNF towards a chat about alloy block Cosworth Vega, so thought I might be pushing my luck a bit over there!

Still scouring my flat for the articles I had collected... it caused a brief flurry of excitement in UK hillclimbing... I don't think the project was especially well funded, particularly the productionizing of it, and I understand from someone who had a deposit on one that the originator Matty Holzenberg (sp.?) has to cease operations due to ill health. One view I heard expressed was that one or two people here took one supposedly with a view to help with development and build up customer/sevice/agency aspects, but in reality tried to take a cheap engine deal and then flog them on. I believe it compared quite favourably with the broadly equivalent Hart 420R and Swindon Vauxhall motors of the time, and was a good bit cheaper - at least initially. Really, I just love the idea of it; and since I have a fairly lightweight car already there is some logic (not much mabe?!).....

If I unearth more I report back on it...

[Engineguy]

From my post here a year ago:

Funny you should ask... I happen to have in front of me a six-page brochure that Amoco Chemicals sent to me in October of 1985 (I never throw this sort of thing away).

Title: TORLON Plastic Engine Parts by Amoco Chemicals

First page tells about the 1985 IMSA season in which the Polimotor Lola GTP Lights car had several top five finishes.

Second page shows the engine... appears (and from my memory) head is metal (Cosworth BDx? Ford was involved with Polimotor at some point I think). Seperate cylinder block, upper crankcase, lower crankcase (sump), are cabon fiber fabrications (resin injection molded using phenolic resin, not epoxy as I recall).

2 litre, 318HP @ 9500RPM, weighs 168 lbs, 100 lbs of which are the 59 plastic parts.

Designer of the engine and owner of Polimotor is Matty Holtzberg.

"Torlon parts are perfectly suited to the engine, because they are strong and tough at temperatures up to 500 degrees F. While some other plastics may take this temperature, Torlon poly(amide-imide) offered Holtzberg a material which can be fabricated to precise detail via injection molding. This economical process lowers unit cost, a critical factor for commercialization of the technology, given the relatively high price of the plastic when compared to traditional materials."

Third page: Torlon Plastic Engine Parts Race-proven in IMSA Competition

"These photos represent the Torlon parts actually used in the Polimotor Plastic engine" (photo shows hybrid piston, piston ring, fat con rod shaped like drag racing aluminum con rod, and wrist pin)

"The head on this piston is metal, and the skirt is made of Torlon polymer. The part is 35% lighter than an all-metal piston. Decreasing the weight of powertrain components reduces secondary shaking forces, which are of major concern in today's four cylinder engines."

"The number-one piston ring in the Polymotor Lola is metal, because it must transfer heat away from the piston. The number-two ring is made of Torlon polymer."

"The con-rods in the Polimotor Lola are made of Torlon-C, a developmental advanced thermoplastic composite from Amoco Chemicals. It represents a 49% weight reduction versus metal."

"Torlon parts are not only tough, they can absorb impact energy better than metal, which is one reason why the material is suited for wrist pins."

(another picture shows hybrid intake valve, valve spring retainer, and bucket-type tappet)

"More than 75% of the weight of an intake valve is cut by substituting Torlon stems for steel. Torlon valve spring retainers weigh only 9 grams each, while a comparable steel retainer weighs about 22 grams."

"Inverted bucket-type tappets made of Torlon polymer contribute to the lower weight of valve train components, which reduces inertia and decreses the spring load needed to prevent valve float."

Fourth page: Shows Torlon timing gears... used "as-molded"... no hobbing.

"Torlon poly(amide-imide) is an injection moldable thermoplastic which maintains high strength at temperatures up to 500 degrees F. Torlon polymers are characterized by outstanding modulus, impact strength, shear strength, fatigue strength, and creep resistance."

"Five years of dynomometer testing preceded the Polimotor Lola's debut at Watkins Glen in July 1984.... in endurance races lasting up to five hours, the Polimotor engine runs at 8,000 to 9,000 RPM. And the Torlon parts don't melt..This isn't science fiction, laughs the affable Holtzberg."

Terry Lappin, Manager of the Engineering Resins Department at Amoco... adds, "plastic engine parts can stand the stress of racing and before long may appear in passenger cars too. We are capable of producing commercial quantities of Torlon engine parts now. It's up to the car companies."

Fifth page: coupon for copy of Torlon Engineering Polymers Design manual.

Properties of Torlon 7130
"There are several grades of Torlon polymer, each designed to maximize specific properties. Graphite-fiber reinforced Torlon 7130 was used to mold parts for the Plastic Engine. Properties of Torlon 7130 are shown below."


This was 15 years ago! I'm going to do some checking to find out current development in this area.


... and from my follow-up post...

quote:
--------------------------------------------------------------------------------
from Automotive Industries historical review 1975-1985:

PLASTIC ENGINE

Our December 1980 cover lines said it all: "What...A Plastic Engine?" Matty Holtzberg, founder of Polimotor Research Inc., showed us his 168 lb, 2.3 L ohc motor, which he based on Ford's production 2.3 L 4-cylinder.

The engine used graphite-reinforced composites. Ceramic coatings covered the pistons and intake valves, and the only non-composite pieces were the cylinder liners, crankshaft, camshaft, valve springs, exhaust valve and combustion chamber. Though the engine worked, at $28,000/example it was much too expensive.

Holtzberg moved to a dohc design with the block, head, oil pan, cam cover, oil and water pumps, and intake manifolds made from a phenolic resin-based moldable composite. This 2.3 L design weighed 175 lb, made 178 hp, and needed 50% less machining than a steel design. Holtzberg's engine never reached production, though a 320 hp version had minor racing success.
--------------------------------------------------------------------------------

I stand corrected... apparently the head (except for the combustion chamber surface) was also made from the phenolic resin composite

[Colin]

Last year I did some work with a guy at Boeing Helicoptors in Arizona who used to work for Ford R&D in the 70s and 80s. He told me one of their research projects was duplicating a 302 Mustang V8 engine block in plastic, with carbon fiber reinforcement. I really thought he was BSing me, but this must have been the stuff! I asked him lots of questions about it, and apparently Ford's primary interest in it was for fuel economy; back in the late 70s and early 80s here in the US, the standard Detroit V8s were castrated by the fuel crisis and government-mandated fuel economy. Not only did the plastic block cut nearly 100 lbs. off the engine, but because of its lower heat transfer rate, combustion temperatures were higher so there was more complete combustion, better fuel economy and reduced emissions. However, premature detonation (knock) was a problem after extended runs at mid-to high RPMS because combustion chamber temperatures would build up massively. Also, just the engine block itself would have been several thousand dollars each, so he said they only built the one and dropped the project. According to him, they did have it driving around in a Mustang though.

[desmo]

It seems to me that if even half the claims stated for Torlon as a structural material are legit, then one might relatively easily construct a superlightweight F1 engine using Torlon for the hot spinning bits and walk away with with a WMC in one's pocket. If. There's gotta be downsides that nobody wants to talk about, or it would have been done already. Or are the F1 engine manufacturers really that hidebound? Nah...

[Engineguy]

Originally posted by desmo
It seems to me that if even half the claims stated for Torlon as a structural material are legit, then one might relatively easily construct a superlightweight F1 engine using Torlon for the hot spinning bits and walk away with with a WMC in one's pocket. If. There's gotta be downsides that nobody wants to talk about, or it would have been done already. Or are the F1 engine manufacturers really that hidebound? Nah...

F1 engines are of course running fully DOUBLE the RPM the Polimotor was running... that might immediately eliminate the feasability of several of the components.

[GunStar]

And didn't they outlaw all those "exotic" materials. It may actually beat out the maximum stiffness mandate, or, with todays tech, be so flippin indectructable, that the big money boys will take it out so far and fast, that nobody could keep up.

[desmo]

Engineguy: "F1 engines are of course running fully DOUBLE the RPM the Polimotor was running... that might immediately eliminate the feasability of several of the components."

I don't doubt for a second that you're correct, but why would higher rpm favor metal over polymer bits?

And as far as I am aware, non-metallic engine internals are indeed legal for F1 as long as they aren't CF or Aramid composites- crank and cams of course excepted whose "basic structure" must be made of steel or cast iron. I like that basic structure language, that sounds like a loophole one could drive a (steel matrix mmc crank and cam equipped) truck through. Ja?

Nostalgia Forum Thread on Polimotor.

[Cory Padfield]

GunStar,

Torlon (poly amide-imide) by itself has quite meager properties when compared with other materials. For example, its tensile yield strength is ~ 190 MPa, its tensile elastic modulus is ~ 5 GPa, its mass density is 1.4 * 10^3 kg m^-3, and its thermal expansion coefficient is 30 * 10^-6 deg C^-1. While these are quite good for a polymeric material, and could be improved with a reinforcement (e.g. glass fibers, mica particles, etc.), they certainly do not exceed those of other materials, for example a magnesium alloy. So, that is the main reason it hasn't started a revolution...

desmo,

Regarding material performance vs. rpm, the argument against a polymeric material is that it has relatively poor properties to begin with, and with increasing rpm (i.e., higher stresses, higher thermal input), they would deteriorate more than an equivalent metallic design.

Cheers,

Cory

[GunStar]

Not like the current engines are designed to last long anyway. I also mentioned, that with money, teams could really "improve" Torlon to the point where it could take on a current engine. How many people have really spent serious money developing it since the death of IMSA¿

[LMP900]

About 15 years ago, I met a guy called Matty Holzberg who ran a company called Polimotor which made engines with carbon fibre blocks. The engine was raced in (and I believe won) Camel Lights in a Lola T616, and was very light. The carbon part was basically a structural box which stopped the oil and water from falling out - an unfair simplification, but that was the essence. At the moment we have an F1 car with a carbon chassis and a carbon gearbox case - so how about a carbon cylinder block? And then we could mould the whole structure - chassis, engine and gearbox - as a single unit...

[Double Apex]

I don´t think there´s any teams currently using a carbon gearbox. It was experimented at Stewart a few years back and later abandoned.

I don´t know about carbon engine parts but I´m sure stuff like this has been discussed here before, so maybe the search could help you.

But anyway, I don´t see the single unit mold happening. Would be a bummer to change the engine! ;)

[Cory Padfield]

The Polimotor engine did not use carbon fibre - it used an unreinforced polyamide-imide resin called Torlon, at the time made by Amoco. This has been discussed here before, so use the search function to read about it.

[TheMita]

The use of carbon fiber or other composites is banned by the technical regs in most parts of the engine.

[Pioneer]

5.5 Engine materials :
5.5.1 The basic structure of the crankshaft and camshafts
must be made from steel or cast iron.
5.5.2 Pistons, cylinder heads and cylinder blocks may not be
composite structures which use carbon or aramid fibre
reinforcing materials.

[LMP900]

What constitutes a cylinder block? It would be possible to have a thin-wall metallic liner/water jacket with a carbon/bismaleimide resin structure to carry the internal and external loads. My all-in-one concept was tongue-in-cheek, as was the whole thing really, but that's a good thing. Race car design should be like opening Pandora's box with the thin end of a wedge while standing on a slippery slope. And try not to get hurt in the process.

[YKTS]

The polimotor was used in 1993 and maybe later in the UK in hillclimbing by Deryk Young. The car was a front engined Vision clubmans car, with the wheel arches removed so that it ran in the open wheel 2 litre class. Cannot remeber how well it performed, should be some details of it in the season review video, recall seing some brief articles in Autosport about the engine, mainly details that have already been discussed in the thread already.

[Mark Beckman]

Originally posted by desmo
Hardly set the world alight though did it?

You've been around long enough to know it takes more than just the motor.

I would like to find a 2.0 litre motor producing 320 hp weighing 80 odd kgs under my christmas tree, I can assure you that would set my world alight ;)