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Lessons Learned/Racecar Prep (LONG)

 
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924RACR  



Joined: 29 Jul 2001
Posts: 8320
Location: Royal Oak, MI, USA

PostPosted: Wed Oct 20, 2004 4:41 am    Post subject: Lessons Learned/Racecar Prep (LONG) Reply with quote

With Jeremy's permission, I'm including some of my scattered and random thoughts from my feedback to him about this past weekend. The Cliff Notes version is that we observed many things about his setup that could benefit from improvement, and these are my accounting of those. Keep in mind that many things that were good and went well were not included in this listing. This is more or less me and my crew coming in as consultants and giving a report card.

My intent in posting these here is not as an accounting of the weekend so much as a list of pointers to those just getting started or looking to get started in racing, in the hopes that they may benefit you.

Here's my direct comments, starting with #53:

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Motor - sealed up very nicely, probably has good compression. But the bearings are guaranteed to be used up, with oil temps of 300 deg. Run compression and leakdown tests to verify this. Pull it, replace the bearings, headgasket, obviously oil pan gasket, re-lap the valves (lightly should do it), re-adjust the valves, and the motor should last for some time very happily.

Once you add an oil cooler, that is. Mine is 5 3/4" x 11" TruCool model, 24 row, about $45 from RPW. It's mounted below the left front frame rail:
http://www.vaughanscott.com/construction/Oil_cooler/DSCF0029.JPG
http://www.vaughanscott.com/construction/Oil_cooler/DSCF0031.JPG

Use -10 AN hose and fittings throughout. Use a remote filter mount to hang the filter up out of the way of the header, on the right front frame rail:
http://www.vaughanscott.com/construction/Oil_cooler/DSCF0038.JPG
http://www.vaughanscott.com/construction/Oil_cooler/DSCF0037.JPG

Additional plumbing/fittings in there is for the accusump and oil thermostat, the latter which you can probably do without, the former would be nice but you might be OK without also, and which is a big added cost, hard to do for both cars.

Obviously, you know you need to deal with the trans. I recommend you swap in another used one and run Redline synthetic. I only recommend rebuilding a trans if you can get your hands on a diff (limited slip or other) to put in at the same time, it's so much of a PITA to shim these trannies up. But your call.

Minor detail - get some copies made of the hatch/door keys made for both cars... insert one key in the hatch and wire it there to stay put. If it's necessary in an emergency or pit stop to access in the hatch, no-one will have to search for the key. Even better, remove the lock pins and use rubber draw pulls (think Jeep hood). I'll probably do this soon myself. Likewise, remove the hood catch and replace with hood pins. Nothing worse than fumbling around under the dash looking for the hood release during a pit stop. This did happen, I had to go find the hood release. Not helpful.

The only other couple of things are electrical and tuning. As I think you'll agree, both your electrical systems (both cars) are a mess - you don't know what is where. There's actually a couple of issues here. First of all, the fact that there's no documentation of how the cars are wired (meaning your dad must be on-hand to explain or a massive waste of time reverse-engineering the circuits), and secondly the wiring standards are not good enough.

This may or may not have contributed to the blown rotor in #53. This was very likely a contributing factor to the bad misfiring in #35 (seen on the data, blatantly obvious). It certainly isn't helping your efforts to run the cars reliably. Electrical problems are always the worst and most time-consuming to troubleshoot.

So you need to have wires and fuses properly labeled, just as the switches are. BTW - move those switches in 35, they're in a bad spot. I proved this twice; once when I inadvertantely killed the motor during warmup (also why I don't like toggle switches, BTW, much prefer rockers), and again on-track when I was trying to actuate the wipers. You should have also wired that switch through the proper wiring on the wiper motor and wiper switch, because it will not park properly. This means that instead of focusing on driving my line, I was REACHING THROUGH the spokes of the steering wheel and messing with the switch, trying to get the wipers to stop in a good place so I could see the track unobstructed.

I don't think you need me to explain how unsafe that was. The switch layout on 53 looked very nice.

So make sure the fuses and wires are labeled as clearly as the switches are. This is something I still have to deal with in my car, for sure, it's not up to standard either, but we're planning on dealing with that this winter. Actually, we're going to go one better and re-do all our wiring (some of it's pretty marginal) and replace the fuse box with a breaker box. I believe I saw (when I was picking up those blower fans at the marine supply place) some 12V circuit breakers. I've seen these used in GT cars before, and never knew where to get them. The downside is that we'll need to fabricate an aluminum box to mount them in. The upside is that we won't run out of fuses ever again. Consider this as a good improvement for you guys to make.
http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&productId=16292&catalogId=10001&classNum=295&subdeptNum=124&storeNum=9

They're push-button style, from 5-20Amps, panel mount, priced at $10 each. Given that you'll need no more than 10, it's well worth it IMO. Like I said, I would've done it a while ago if I knew where to get them.

Then you can run one heavy-duty wire from your main kill switch, properly routed and secured, maybe a 4 gauge, to your breaker panel (in easy reach of the driver, of course), plus the big one to the starter. Then power goes from there to everything, and they're all labeled.

Wiring standards... don't crimp, it's a great way to have things fail; solder after crimping, and use heatshrink over every bare metal area. Use the paint-on stuff where the heatshrink insulation tubing won't work. Throw away all your old wires, period. Greg commented that some of your spare wire was corroded when he went to strip and use it. Not helpful, when you're going for reliability. Wire's pretty cheap and easy to get in the spool, in the right size, at Home Depot. Lowe's actually has better selection, especially with connectors. Just make sure all your wire purchased is stranded, not solid-core (which will break internally when subjected to vibration). Use a ratchet-style crimper, as I have, even for the insulated terminals. When using insulated terminals, get the ones from Lowe's that have heat-shrink built in... you crimp, then solder, then heat to seal. We'll be converting over to these completely.

Wherever possible, get away from spade type connectors entirely. Get weatherpak for critical stuff (and still solder the connections). Longacre sells them, though you might be able to find them on the shelf locally - I've seen them at Pep Boys. Everything must be sealed as if it's going on an ocean cruise, against saltwater, and properly secured, as if it's going to be subjected to 6000RPM on the top of the cam cover. Wires should all be secured and even better run through conduit.

You have a nasty misfire in 35, it would seem. You need to pick apart the ignition wiring and fix this, but do it to both cars. By compression, your motor (in 35, at least) should be even stronger than mine. You need to understand why it wasn't. You may need to switch ignition wires to RF-supression ones in order to get the radios to be useful. You may have a bad one anyway, causing misfiring and poor power. Have to check this stuff. But all the wires to the ignition box on the front left fender need to be checked, and better yet replace all the terminals in the connector (the brass spade female connectors), soldering on the replacements. Somethin' ain't right there. Yoy may even need to put the car on a dyno to isolate the problem and get it running properly. But this is the only area where you really have to interface nicely with the stock wiring.

Gauges - don't like mechanical ones. The big no-no is the oil pressure gauge. If the wire to an electrical sender breaks, what happens? The gauge goes dead. If the tube to a mechanical sender breaks, what happens? You dump all your oil into perhaps even the cockpit, certainly where it shouldn't be, possibly obscuring your vision, possibly a fire hazard, you probably will kill your motor and stand a good chance of burning up your car. Not good. I recommend you consider, at a lower priority, putting the stock gauges back in action with new, dedicated wiring.

Another thing on your gauges - you should have it clearly marked, with even a piece of tape or paint, what values are OK and not. Sure, you can do the math and figure it out, but knowing how you are at a glance is better than trying to do arithmetic as you're sliding onto the back straight at 90mph!!! Where the needle is relative to a go/no-go mark is a whole lot more intuitive than a raw number value.

Mirrors - to my surprise, I found out I didn't like your mirror setup when I got out in 35. While the mirrors you have give you good overall coverage - they're too split up IMO. You don't have one mirror only that gives good data on everything that's happening. I have the wink panel mirror that tells me pretty much everything that's happening behind and to the side at a glance. In 35, I have to scan all of them to get the full picture, which means more time wasted and/or I miss someone in the mirrors. Consider putting in Wink mirrors.
---
Now my added comments regarding #35, and general procedural plans...
---
As already discussed, #1 question is what state is the motor in. Compression check on all 4, see which are out, then pull and tear-down. I'd like to hear what the result was. Confirm that the bearings are in good shape, as I believe them to be. Confirm if it is a blown headgasket, or if a piston is holed.

You'll want to deal with the alternator mounts, as noted; I also strongly recommend you get the cooling ducts back on the alternators. You may wish to assess where you are with starters too. I've been very happy with the results from wrapping the header and putting in a good fresh Bosch rebuilt starter. Figure out what's up with the electricals, fuel injection, and why those engines aren't running right. They shouldn't be so hard to start cold.

The one comment I'd make about handling on 35 - it did feel OK, wasn't uncomfortable, was predictable enough, etc. But if it were my car to be driven in sprint racing, I'd want more rear bar. Make the rear swaybar a bit stiffer, loosen the car up more, and get better turn-in. As I recall, this means you want to stiffen the torsional resistance, meaning shorter arms on the bar. Move the adjustable links to the front, maybe 1/2", and try that out. You shouldn't have to brake so hard entering corners, it should be much happier to turn-in and reach the apex. You will likely end up entering and apexing faster. It'll be looser, you'll have to be paying attention, but it should be cooking. That or loosen up the front swaybar, actually - make the arms longer (again, 1/2" at a time), that would even make more sense (increase front grip instead of reducing rear grip). But try this when you're ready.

Biggest questions to get to, here's what I think you need for procedures (and my recommendations):
Engine build, possibly - what are the items which are done regardless. I think a headgasket is a 100% given, necessary item, after re-working a bottom end only to find, at the track, that the headgasket was blown too. A quick hand-lapping of the valves might be a good idea to ensure good sealing. This will require valve adjustment too, of course. Should plastigauge the bearings, new or used. New cam oiler tube elbow. Not sure what else, but it's a start, I'll pass on extras as they come to mind.

Engine break-in, for sure, you need a better procedure. Assuming new motor, just installed: crank without plugs till oil pressure registers, may take a while. Install plugs and wires, fire engine up. Adjust timing ASAP then mixture (by best throttle response, err on too rich for sure) and idle. After idling for no more than 5 minutes, shut off and inspect for leaks, smoking, anything wrong. Assuming it's all good, re-fire and allow to idle and warm up till t-stat opens, maybe another 10-15 minutes. Once the t-stat is open, top off and bleed cooling system. Then shut down and let cool. Shouldn't rev the engine over 3000rpm during this procedure. Car is now ready for track use. Should be loaded with dino, not synthetic, oil, of course.
At track, first session is a gradual build up of temps and throttle openings, maybe 3000rpm max for first 3-5 laps, then maybe 4000rpm for another 3-5 laps, then 5000rpm, allowing occasional pulls to 6000rpm at full throttle (but only in lower gears, for quick duration). Proper cool-down lap after this must be done, at lower rpms - 2000-3000 with cooling fan switched on. Park and hood up, let cool fully. Can then go ahead and run a race same day, or second session. Not sure the revs should be run all the way up to 6000rpm even at this point. After day is complete, preferably next AM when everything's cold as it's gonna get, re-torque the head. NOT while hot. Continue to run the same oil for the first weekend, then change it out. With an oil cooler added, this should be no problem. If oil temps get high, reduce the revs.
I'm not sure any more that even just one weekend on dino oil is sufficient to bed fresh rings and bores; my Total Seal rings certainly haven't yet bedded in, so I'm going to have to run again with dino to try and make them seal better.
I would lean towards picking smaller, shorter, slower tracks to break-in the motor; allow revs in lower gears, but preventing sitting at 6000rpm or so around an oval.

As mentioned, I'm concerned about how you're tuning your engine, especially spark... I believe we're running mechanical only at this point. The overall goal, as I recall, is for 34deg advance when maxed out. Since mechanical advance is maxed by 2000-3000 rpm, simply subtract however much your max advance is from 34, that will give you your static setting at idle. As I recall, we have an idle setting of something like 15-17 deg, meaning that the total max mechanical advance in the distributor must be like 20 deg. I set fuel mixture for the moment by throttle response, after timing is set, but will be going away from this as soon as I get my EGT's. You should also be able to set these using a tailpipe sniffer, as I'm guessing your dad might have one in his shop? Go for stock setting, maybe a little rich, unless you are going to dial it in on a dyno.

Unless you've forgotten to compensate the cam timing. Are you running an offset key to correct for the changed height between camshaft and crank? It's necessary. Calculations will need to be performed in order to figure out how much you need (a little trigonometry). Fortunately Dodge/Mopar 2.2L aftermarket parts fit right in, and they're readily available from the dealer or online. Makes sense, since they were designed virtually as copies of the VW motors.

False grid and paddock before sessions - you already have my checklist and lap timing page, so you already have my checklists. Start using them, and have whomever initial when complete. Do the paperwork or go sit in the stands, no argument. I know who checked my brake fluid Saturday afternoon Aug 20th, before the GTS Blitz race. I know who to ask after the fact if the oil looked or smelled funny then too, or if it was lower than usual. Do you?

Post race cool-down, driver and car - do you know what to do? We do. Hood up (let the engine cool), videocamera off, pin in firebottle, check hot tire pressures, give driver water, etc., etc. Driver hydrates, data is downloaded from the dash, and driver and crew chief discuss the results, tire data, car performance, and decide on adjustments (if necessary) for the next race.
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