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From SCCA RallyCross Forum - Allow rebuilt engines in Prepared Class

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  • From SCCA RallyCross Forum - Allow rebuilt engines in Prepared Class

    Posted by Robert M Martin 4 months ago

    As I read the rules, a rebuilt engine, where any part has been machined, puts a competitor in Modified class, as both Stock and Prepared engines must meet Manufacturer's specifications. Is this the intent? Seems like an awfully big step for a ground down crankshaft. I would think Stock should be stock but Prepared should be allowed a rebuild as long as stock CR is maintained, stock stroke is maintained and bore is not increased over 1 mm.

    The reason I ask this is that the car I just bought has a "Remanufactured by Nissan" plate on the engine and who knows what they did!
    Bob


    Ed Trudeau wrote 4 months ago

    Since you jumped on mine, I'll start the comments for you.

    Short of doing a teardown, how would anybody know what is in any of the engines competing? The minute that anybody suggests doing teardowns would also be the minute that we destroy the whole RallyCross program, because no-one would want to compete anymore.
    So having said this, the only way to deal with what you are describing is to "assume" that a remanufactured plate means that displacement, compression ratio, and valve timing are rebuilt to factory specifications for that engine model.

    If you have a remanufactured 2.5 motor in place of the stock 2.0 like a lot of Subaru guys do, then that is a whole different game and you go directly to mod. It's easy to see on Subarus, but maybe not as easy on other makes, so you have to have honest competitors or vigilent competitors in the class.


    Keith S Lightfoot wrote 3 months ago

    A rebuilt engine could be Stock class-legal if it is rebuilt to the manufacturer's standard rebuild specifications. This could include basic machining (e.g. cylinder honing, decking) and OEM grade replacement parts (rings, bearings, pistons, valves, guides, springs, timing chains, etc.). Modifying the engine during a rebuild (e.g. increasing stroke, boring, using higher compression or lighter pistons, porting, polishing, etc.) would move the car to Modified.


    Pete Remner wrote 2 months ago

    I think we're splitting some very fine hairs. Clearly a remanufactured engine is built to OE like specs as per accepted normal service procedures. If someone had their rotors turned with a brake job they wouldn't be thrown into Prepared, remanufactured wheels may be slightly wider due to rim straightening and repair, etc.
    I always pictured the overarching definition of "Stock Class" as things you would see with regular vehicle maintenance and repair. The allowances for alignment as long as it uses service manual approved procedures/additional parts supports this.


    Robert M Martin wrote 2 months ago

    Hi, Pete. Coming up this weekend? Fair warning - we are banning studded tires.

    Anyway, the rules do not say "normal service as per the shop manual". They say "manufacturer's specifications". I just checked the manual for my car and while the text refers to overboring, the specifications are clearly for stock bore size and stock grind on the bearing journals. So, if the remanufacturer of my engine had to grind the crank or bore the cylinders, that would put my immediately into Modified (well, not my engine but let's say yours!). Seems a bit excessive to me.

    Bob


    Pete Remner wrote 2 months ago

    Fortunately or unfortunately we can't have a specific rule for every possible possibility. From a practical standpoint, a rebuilt engine meets the spirit of the rules.

    Now as was alluded to by Ed, if you took the opportunity to update/backdate and put a more powerful engine in... Best hope that nobody in class inspection is wise to you. One of the benefits of such an open class structure is that the dominant cars get popular and people know all their details.
    Love to come up but all of my cars are in winter storage and the only one left has a cracked windshield.
    Mark Macoubrie
    RXB
    Kansas City Region
    2005 STI 41 PA

  • #2
    Pete Remner wrote 2 months ago

    Fortunately or unfortunately we can't have a specific rule for every possible possibility. From a practical standpoint, a rebuilt engine meets the spirit of the rules.

    Now as was alluded to by Ed, if you took the opportunity to update/backdate and put a more powerful engine in... Best hope that nobody in class inspection is wise to you. One of the benefits of such an open class structure is that the dominant cars get popular and people know all their details.
    Love to come up but all of my cars are in winter storage and the only one left has a cracked windshield.[/QUOTE]

    Say I have a pristine "ran when parked" vehicle that I want to put a functioning (relatively) same specs motor in to start rallycrossing in the stock class FWD. As long as it's the same motor does it fall within the "spirit of the rules?" And if so how technical are we getting? Like only EJ25D for EJ25D, only SOHC for SOHC, or would any non-turbo Subaru 2.5 work (think all the EJ25s were after Subaru went all AWD but just using for example)? Or is all of this way too much thinking and I should just do what I can and show up? I'm asking out of trying to be fair while being cheap...and not wanting to get smoked in modified because I swapped a dead motor for a less dead motor of same specs.

    Thanks in advance for dealing with my newb questions.
    Last edited by carppa; 04-26-2018, 01:24 PM.

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    • #3
      So then "by the rules" it would appear that only serial number matching cars with 100% OEM parts are legal in Stock or prepared? No aftermarket parts? I would guess that puts every car in the program in MOD. No repairing your car with anything but OEM parts, All trim parts must be OEM even the discontinued ones. I know this is pushing it but it kind of leans in that direction when we become draconian in requiring 100% original. Since most, well ALL of the cars on RX are older used cars, we must assume that many have replaced a LOT of parts over time. Engines, transmissions suspension parts, trim, interior and even body damaged parts are going to be from aftermarket or bone-yard sources. We are all our own mechanics. The sport is made up of us. Thus, the rules should reflect the reality that cars require repairs and rebuilds and we need to allow cheap fixes including swapping parts from other cars of the same vintage and model. We already know that putting a motor from a HP model into our base model is a no-no unless you also put in all the other package parts to go with it. However, lets be real here. Picking up a $200 shell with no motor is a common start. Then dropping in another motor from a badly crashed body that we did a quick backyard rebuild on gets a running and usable car that can RX without fear of scratching it.

      Also, on a similar note, why not allow swapping manual for auto transmission or the other way around? If you find a deal an a car with Auto and want to make it a stick, why not? It's legal to have either. It should be allowed to make more vehicles available to RX. There are a lot of AT equipped cars that probably are getting passed by due to the wrong trans choice by the first owner.

      Remember, we allow cars to compete together with 3,4,6,8,10 or 12 cylinders. Any year, any model, any make. The simplicity of the classes is one of the things that makes RX great. A Geo runs against a Focus R. A Miata runs against a BMW and so on. Slight differences are not going to make a winner out of any car. If the 99 has a better cam in it than the 98, so what? You COULD run the 99 and be legal but you happen to have a 98 with a bad motor. In RX we see that Miata's are great even with less power so it's a better handling car. You will not get 50% more power with stock (or stock replacement) parts. Overall, I think that rebuilt or used engines and transmissions from same make, model, and generation should be allowed. Standard rebuild preceedures include, over-bore, crank turning, head surfacing, valve regrinding, Stock replacement parts sourced from non OEM should be allowed (Autozone, Advance, Rock Auto, etc). As it stands today, if it's not specifically allowed in the rules, it's not legal. With every car out there instantly illegally running non-original parts.
      Last edited by Dynatorch; 04-26-2018, 11:56 AM.

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      • #4
        I don't think anyone is suggesting 100% numbers matching everything. But if your 1997 Bumblepuppy needs a new framus and you grab it from another Series 2 Bumblepuppy (built from 1996-1999), or if you grab a replacement stock-replacement framus from Dorman (because they made two million Bumblepuppies and they all have framus problems), that meets the spirit of keeping it stock or as reasonable a facsimile of stock-like as can be expected in the real world.

        Now, on the other hand, just because it used to be cheaper to put an EJ257 shortblock in a blown up '02-05 WRX, doesn't mean that engine swaps are okay.

        I'm hurt by this too, I really REALLY want a stock engine in that dang '81 RX-7, but 12A parts are so thin on the ground that I just dropped a late model 13B in it and resigned myself to never rallycrossing it, because locally MR is a very tough and fast and competitive class and I'm competitive and already have an MR car.

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        • carppa
          carppa commented
          Editing a comment
          I tell people all the time that the Dorman framuses are just as good as the fancy aftermarket stuff but no one believes me.

      • #5
        I vote to have it written into prepared class rule set something to the effect of “engines rebuilt to oem guidelines are class legal”

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