Originally posted by slickS14@Nov 3 2005, 01:28 PM
Stevel, What problems are you having with your car being "tempermental"? Just curious, I never have a problem with my car unless its an error on my part in preparation.
Ok, here's a list of stuff we've run into. It's good tips for you fellow 240SX guys. Note, we run in ITA so we have the SOHC 12V motor so we may have different experiences. Granted, I will blame a bigger percentage on lack of prep or precaution, but we've still run into some issues I wouldn't expect. Here we go.
Overheating, basically if you do it once the motor is toast. We had to put the biggest damn aluminum radiator in these cars to keep the temps down on track. The one we used is rated for enough cooling capacity for 400hp and the sad thing is the radiator really isn't overkill. I don't expect a motor to be OK after a good overheating, but this goes beyond replacing a head gasket and making sure the head and deck is straight. The pistons just can't take it and crystallize, so it's really done at that point.
Header (exhaust manifold), make sure they're wrapped or coated. Because you WILL run into problems, big ones. We unknowingly cooked several distributors as a result (on the SOHC motors the dizzy is too close to the header). The crank angle sensor is internal to the dizzy on these cars and when they heat up bad things happen. It causes the timing, especially at high load high rpm operation, to deviate from a safe range. Basically, the CAS gets hot and reports an incorrect angle and the ECU changes timing accordingly. Unfortunately it usually reports a reading such that the ECU waaaay advances the timing and you get severe detonation followed by rod knock and eventually a rod exiting the side of the block. Even a handful of laps running like this can cause enough damage that the rod will eventually let go. Also, we've had problems with ignition coils going as a result of heat also, though it's usually more apparent as the car usually won't start. When we have dizzy problems you usually won't notice it at idle as the motor isn't as hot as it would be on track but when up to full temp and running full bore out there is when the timing advances, and at WOT at full speed on the track usually you can't hear the pinging until it's too late. Unfortunately the dizzy doesn't just die, but continues to seem fine but when it gets hot it just causes the timing to way advance. Then it cools down and seems to run fine and the motor runs great, so it took a while to figure this out as evidenced by several blown motors.
Power steering overheats really easily on these cars and bubble the fluid out the reservoir. DON'T overfill. Not a big deal and hasn't caused a DNF but your competitors usually don't like it when you are spilling fluids. I think I might try to put a power steering cooler on if I can make a cheap setup. I would recommend it to everyone. Also, make sure you that copper/brass (not sure exactly) crush washer where the power steering line goes to the pump. Have extras on hand. We've lost these at the worst moments and tried to get by just cranking the bolt down to no avail. It will leak and leak a lot. So, keep a spare few extra. Again, I believe that is a dealer part also.
These cars are very sensitive to vacuum leaks and there are a lot of places this can happen. We remove so much emmission equipment and bypass the throttle body water inlet that it has bit us a couple times. If the intake manifold/upper throttle body isn't totally sealed (and it can be hard to tell otherwise as it may not even leak any water or run badly) it will cause a lean condition since the FPR is a rising rate based on vacuum, and if there is an incorrect vacuum reading at the fpr due to a leak you will run dangerously lean on the top end. I've had this happen a few times and searched everywhere for leaks on the intake manifold/upper throttle body and you can't visibly see it or detect (at least I couldn't) even with spraying it and checking for bubbles but we would have a severe lean condition and that was the only thing left. And between the intake manifold to head and the upper intake manifold/throttle to lower intake manifold sections there is a large area where you can have air leaks. So, be meticulous with getting those areas perfectly clean before putting the gasket on and sealed properly.
Electrical issues. Go thru the entire engine harness and make sure all the connectors and wires are good. I know this seems like a no brainer again and should be done on every race car but these particular engine harnesses don't seem to hold up too well (at least relative to other race cars i've worked on/seen) and the connector and clip system they have isn't the greatest. We've had several connectors pop off and cause problems and with how the engine hides stuff it sometimes isn't easy to get too. We've had the alternator plug back out every so slightly and cause an intermittent shut down. We've had injector plugs come loose and we'll be running on 1 less cylinder. We now just zip tie the connectors to the injector instead of using those little nissan clips and use zip ties on other connectors when we can.
Gaskets. Again maybe a no brainer but make sure you replace them all, especially the injector o-rings, on both ends of the injector. We are usually good at replacing whatever is needed but we'll try to reuse what we can. They usually look good at inspection but will fail/leak at the worst time and be spraying gas all over your hot engine. And these usually aren't things you can pick up a NAPA or autozone. Usually a dealer part. So, make sure to replace them no matter what.
Fuel problems. We've had FPR's fail as well as fuel pumps and injectors that weren't up to par. Unfortunately they usually all don't cause problems at the same time, but one after another so you fix one fuel problem and the next creeps up. Again, maybe a lot of people will just replace them no matter what but we were working on a budget and tried to reuse as much as we could. But, we won't do that again. Without question replace the fuel pump with a new one as well as the bag filter on the end of the pump, replace the FPR with a new one and get the injectors cleaned and blueprinted. A fuel pressure gauge is a great idea also to know you're where you should be.
Other. Unfortunately these cars will actually run fairly well and start with a multitude of sensors disconnected. Make sure you have the air temp sensor connected. I don't know if it will cause a problem but we've forgotten that one plenty of times and while I don't think it has caused any problems I don't like to leave it to chance anymore. A big one that I couldn't believe is make sure the TPS is connected. Again, I know it sounds stupid but when you have 3 cars and you're blowing motors because of other unknowns you overlook stuff. The car will actually start and run well at idle and part throttle without the TPS connected at all but at WOT obviously it is probably dangerous. IMO, a car shouldn't even start with the TPS disconnected.
Exhaust. We try to get these cars as low as we can but run into problems with lowering more from exhaust than we do from lack of suspension travel or the car bottoming out. From the header we run to trying to get the exhaust tucked way up we just can't get the car as low as we like. We have run this low and it's caused nice new header to get dented, collectors to break at the weld, and some DNF's just from the exhaust hitting and falling off. And the funny thing is most of the damage we do isn't on the track, it's going on/off the trailer or in the garage where it will hit and do the damage but won't actually fall off until the middle of the race or on pre-grid. This is odd because most cars will usually run out of suspension travel before you can get that low, but the problem here is the header/exhaust.
Pulleys and belts. Make sure you check the bolts that hold the tension on the belts. They can work themselves loose pretty quickly. We've had the tension come off on the belt that runs the water pump. Not good! We now check/tighten them everytime they go out on track.
Hmm, what else? I'm sure there's more. Again, maybe to some of you veterans all this stuff sounds normal but when we started with these cars a lot of this stuff we just didn't know and found out the hard way thru missed races, blown motors, or DNF's. We just didn't expect this many problems. I, myself, am historically much more familar with hondas and most of the problems above I would never run into on a honda. They are much more ready-to-go out of the box so to speak.
IMO, these cars are finicky (sp?) and need a lot of attention. But when it all comes together it's such a huge reward as they have a lot of power and torque and the handling is a dream and so simple with these cars. They are very very fun to drive and very neutral that you can really toss them around without them biting you too badly. That's why I really like driving them. The combo of the nice power and torque curve of the motor, the rwd and the excellent handling I really like these cars for ITA. But it's been a long process and the race team we have I wasn't even there at the beginning when they started with these cars so some of the issues I wasn't even there to run into, they were solved so to speak by the time I started dealing with 240's.
Some more good notes. Here's things I would replace without question if I were building a new car. Keep in mind this isn't a complete list by any means and is mostly geared towards the motor. IMO these things go beyond regular maintenance items like water pump, clutches, brakes, plugs etc.
- Radiator, get the biggest one you can stuff in there.
- injectors and all the o-rings on both the fuel rail side and manifold side
- fuel pump
- fpr
- ignition coil
- distributor
- alternator
- wiring harness (not new but be very thorough inspecting and repairing it. They don't seem to hold up well)
hmm, that seems too short a list. Again, some of these things we should have realized because they are 15+ year old cars now, but the shitty thing is usually the parts didn't completely fail but rather malfunction intermittenly and it made it difficult to diagnose what the actual problem was. We have finally gotten to the point where we have reliability and the kinks worked out and are now at a point where we are very competitive (or at least the car is) so we now have a great knowledge base. Currently we are a 2 car team, expanding to 3 over the winter and most likely a 4th also. So, we've had a lot of experience with these cars over the last several seasons.
Look for BB Racing to be supplying parts and services specifically for Nissans and 240s' in particular for the IT community. We feel there is not enough of this. Look for things like custom chipped ecu's, IT ready suspesions, radiators, headers and exhaust tested on track and the dyno (no guesswork, we've found the best combos and are improving all the time), intakes (now that the MAF rule has changed this is opened up), pulley's, pistons, head components, etc. We are looking to make a ton of IT ready to go parts for you guys. We're getting ready for a big expansion to our team and new products. Keep an eye out for it. Please refer all questions regarding our business to IM or email. To the mods, if that is out of line as far as advertising, I apologize. Let me know if it should be edited. You can hold me to it, but when we do make these products available (over the winter sometime) we will buy ad space on here.
Thanks for reading all of that guys. I know it was long but I think extremely informative.
email bbracingusa [at] gmail dot com
steve
