Where to you locate an alternate engine?

[TomL]

After thinking about this whole issue some more, I came to about the same conclusion Chip did. If you don't closely circumscribe what can be done, you'll start and arms race on engine location that will make any already overly expensive class (that's another topic) even more so.

I think cars using the stock engine should leave it where it came originally, and swapped engines should be installed as close to the standard location as feasible.

How about this language for the engine location rule?

Engine location (RWD vehicles)-

1. Cars which utilize the engine that was originally in that chassis shall retain the stock engine location.

2. Cars which utilize an alternate engine shall install the alternate as close to the original engine location as possible.
a) The engine's fore and aft location shall be no further back than one of the
following:
1) The alternate engine's mating surface with the transmission shall be no
further back than that of the engine originally installed in the chassis, OR
2) the alternate engine's number one spark plug shall be no further back
than the number one spark plug in the engine originally installed in the
chassis. Where the chassis had more than one type of engine available, the
engine with the number one spark plug that is furthest forward shall be used
for this measurement.
3) In no case may the alternate engine's rear mating surface be further back
than the firewall.
For FWD engines installed in RWD cars, the firewall may be modified to clear the
intake manifold or engines accessories.

b) The engine's crankshaft centerline shall be be located within one inch
horizontally and vertically of the centerline of the originally installed engine
measured relative to the front crossmember. A lower engine location is
permitted for alternate engines which cannot fit under the standard hood
at this height. Such engines can be mounted no lower than is necessary
for major engine components to clear the hood skin by a maximum of one
inch.

I think this language would cover nearly any likely engine swap, and would keep the alternate engine very close to the stock location. A couple of explanations: the language in paragraph a) 2) about two original engines is intended to cover situations such as James Spurling's BMW Z3. In that case, without the "two engines" language, he would theoretically be able to install the alternate six cylinder engine with its number one plug at the location of the number one plug in the four cylinder engine. Also, this would make the FWD-to-RWD swaps comply with the same rules as everyone else, except they have would still get the firewall modification allowance.

I don't know if there needs to be some language on FWD alternate engines, since side-to-side relocations would be difficult and fore-aft limited by the half shafts. The main question is should rotation be permitted to improve halfshaft alignment? I seem to remember that IMSA used to allow engine rotation of up to 10 degrees for this purpose back in the old Proformance series for FWD cars. Maybe that should be allowed?

On the complaint that we don't know what all these measurements are, I think Chip has it right. They don't have to be known at tech, although it would be easy to acquire them for the common cars (Miatas, Rx7s, BMW Z3s, 325s, etc.). If there is a protest for some other car, the information can be found to resolve it.

[Z3_GoCar]

Good start on it Tom, but I think we need to insert a tolerance in any positional measurement. Stock mounts do sag and move over the years, maybe say +/- 0.125" In my case I even used the motor mount brackets off my original motor. I looked it up and they were all the same part number.

[Knestis]

Where do you locate an alternate engine?

An auto breaker's yard in Brighton?

K

[Greg Amy]

These are good ideas as a concept, but lack the ability to enforce. First, show me where in the factory documentation the location of the engine is listed (show me the spec in the FSM where it says the location of the engine's centerline), within the tolerances you're specifying, and second, tell me how that's going to be measured at the track. And it does have to be measurable at the track. No SCCA region is going to pay a bond to quarantine a car to take it to some frame shop for measurement of the engine location, assuming it can even be done. I doubt any competitor will pay that bond either; hell, we can't even get people to drop a $25 protest down for incorrect weight stickers!!!

But secondarily, no one has simply answered the question: so what? Who cares? Who cares if alternate engines and transaxles are not in the close-to-stock location? You can't use "cost" as a reason for limiting them, as cost cannot be contained. Convince me the downsides of simply saying the engine has to be maintained in the engine compartment with no mods to the car. Convince me the performance benefit of leaving it open like that.

I'm becoming more convinced that trying to create regs to limit engine location will not only be ineffective, it will result in only keeping the honest people honest while the dishonest person will just spend a lot of money to get around it.

GA

[Chip42]

I'm just trying to help, I think ST has huge potential but it has a lot of growing up to do. when I was a kid, I was going to be an astronaut, too. now I'm a middle-level engineer who sells racecar safety parts on the side and tries to eek out a few hours a week in the garage.

cost and all that is irrelevant - agreed. engine position should be controlled for ALL engines, stock USDM, non, etc... the intent SHOULD be to locate the thing in what is the stock position and orientation, or roughly where it would have been from the factory had it come in that car. not lowered, rotated, set back, etc... it's a matter of weight distribution and driveline alignment. if a swap gains you benefits over stock in this regard alone, it's a problem. find a way to make sure engines are located in acceptably stock-like locations. the all in the unmodified engine room rule is a start.

prod has such rules. (no engine movement from stock and allow limited rotation of transverse about the crank and vertical motion of "RR" engines) see 9.1.5.E.1.m.6 and 9.1.5.E.1.o.6
IT has such rules - stock position only. see 9.1.3.d.1.s
hell, even STO has restrictions on engine position. see 9.1.4.1.E.3 and 3.a. these USED TO be more lenient, I guess there's precedent that allowing too much freedom was a bad idea, eh? STO will show you your problems because that is where the big money shops first.


it's not that hard, just be big picture. place a reasonable restriction on the location and orientation of the engine. you WILL see rotation SOON, of stock and otherwise. it's natural law. stop it before it becomes an issue.

and trackside check the cam in just about ANY IT car. oh, right, unless it's a miata AND you have a cam doctor on hand, you can't. don't worry if the rule is trackside enforceable. you are specifying an intent, egregious over-runs of that intent will be dealt with by competitors and will be obvious. otherwise it's not going to BE protested.

the last thing you need to worry about is tech, half the time they can't even figure out what GOES in ST, and at what weight. I love tech guys, hell I am one (well, not so much since my daughter came to be, but we'll correct that as soon as possible), but they are being asked to "know" a whole hell of a lot. many of us can't agree on "simple" rules. it's up to experts and COA per the protest process, not trackside tech.

[Greg Amy]

it's not that hard, just be big picture. place a reasonable restriction on the location and orientation of the engine....you are specifying an intent, egregious over-runs of that intent will be dealt with by competitors and will be obvious.

Bingo. Completely agree.

So that brings us back to the current reg. The current reg specifies an intent, and offers reasonable common-sense interpretation. It will NOT stop the guy that wants to play the "letter of the rules" game, but it will make the honest guys honest that understand and wish to comply with the spirit of the rules. If we start getting into body shop manuals, and plus-or-minus 1 inch, and coaxial location and all that, we're effectively codifying and inviting that "letter of the rules" game. And I just don't think that short of explcitly listing all allowed combinations with all possible engine permutations and detailing location of the same, along with a full team of educated technical inspectors to enforce it, that we can win that game.

We do have a request on the table to clarify this issue, but I don't think getting into minutiae is going to resolve it. - GA

[Knestis]

Been watching this conversation with some interest...

...and have come to agree with Greg that there's really only so much that can be done to contain this issue, in practical terms. How about the proposition that the confines of the engine bay, firewall, subframe, and bodywork will define practical (if not absolute) limits? Absent any provision to modify those elements, there's really only so much latitude for locating an alternate engine.

It's not like we can flip the entire engine around and tip it over like was done on some Euro touring cars, possible because it could be bolted to an aftermarket dog box...

K