Jeff G 78

That article was written by my friend Billy Johnson. Great guy and a damn fast racer.

No worries Zed, just trying to help clear things up. I deal with tire sizes every day and it's amazing how many variables there are just in sizing, let alone compounds and constructions. Tire engineering is a black art for sure.

Okay, to help people understand, I went to TireRack.com and copied the specs of two Hankook 225/50R16 tires and a General tire. The first Hankook is a medium performance tire and the second is a max performance summer tire. Note how different the tread widths are between the two tires. Keep in mind, these are both by the same manufacturer and they still vary greatly. The third tire is the same size, but a General. Note again how different the section width and tread widths are. Multiply section width by 25.4 to get the nominal tire width as advertized. The General is small and the Hankooks are much bigger than nominal.

Rob, I'm an automotive engineer. Trust me on this.

Other way around Zed. 205 would be the sidewall. The tread width is always narrower, but some tires are much closer to the sidewall width than others.

Be careful as every car and every brand/model of tire is different. Some cars don't rub and others rub badly. Tires can vary greatly in size depending on the shape of the tire. Some are trapezoidal and others are square. The more trapezoidal the tire, the less chance of rubbing, but also the less tread on the road. Tire widths are measured at the widest part of the sidewall, not at the tread and even then, there is no real standard. Much like tread wear ratings don't mean much.

Gold wheels can look cool, but I think the fad is all but passed. They look good on blue Subarus.

I have one Z with a flat top/N47 engine and my race Z has a flat top/shaved P79 engine. Both work great, but I chose to use the P79 for my race car. I did not change valves or shim the towers. There is another way to build it without major mods. Pretty simple actually. I only run about 9.5:1 CR on that engine, but it makes great power.

Will do. My next move will be to cut the oil filter apart just to see how much it caught. I saw nothing in the head or in the oil I drained from the pan. When I drained the oil, I put a clean shop paper towel in the drain pan as a filter. I ran my fingers over every mm of it and found absolutely no specs. Even with a light shining on the paper towel, there were no signs of debris. With the number of teeth missing, it had to go somewhere. The inside of the oil pump looked pretty darn good considering what had happened. If it wasn't a race car, I wouldn't hesitate to reuse the pump. It had micro scratches that I could feel with a fingernail, but very little visible damage. Again, oil pressure was great right up until it stopped running.

Good advice. Again, I have never had a crank bolt come loose, so I don't think it got retorqued between races. When you bent your crank, did the bearings get damaged? Just curious.

I'm now fairly confident that you are correct and that I will find a bent crank. As long as nothing inside is damaged, it will be a simple repair.

The good news is that I have a garage full of spare engines, so if the crank is bent, it won't be a huge loss. One engine has already donated a few parts.

Oh, I forgot to answer the RPM question. We run it to no more the 7,000 RPM in theory, though I have had four drivers in it for a total of 20 hours, so who knows what could have happened in that time. Going forward, I will have a data acquisition system that will record all vital engine data.

Thanks Chickenman, I will check the crank runout for sure. To answer some of your questions, the engine is an '82 L28. The original head, block, crank, rods, and pistons were used. I had the head milled 0.050" and adjusted the timing using the SBC eccentric cam dowels per the "How to Modify..." book. The guides have been slotted and moved in to get the proper chain tension and position. I run a turbo oil pump and stock ZX distributor. Oil pressure held very steady throughout the race and never got too high or low. The crankshaft damper is a used ZX unit that Guy (Diseazd) gave me. I always paint a line across the edges of each pulley so I can tell if it ever starts to slip on the rubber bond. One other thing that happened, though I cannot say if it was a cause or effect, was that the crank damper bolt came loose as well. The car ran great for the first four hours of the race (engine had 14 hours on it from a previous race). The driver got into the car at the four hour mark and after about 90 minutes, he reported that the car was missing at high RPM. We had seen this before due to fuel boiling, but it was a cool and very rainy race, so that seemed odd. We left him out on the track and he reported that the miss was getting worse and that the car now was starting to buck. A lap or two later, it died just before pit-in. He entered the pits and coasted to our pit stall. We tried the usual diagnosis and couldn't get it to fire. That's when we found the loose crank bolt. Yesterday when we found the stripped gear, we figured that the missing and likely backfiring due to bad timing caused the harmonics to "kick" the damper and loosen the bolt. If the crank is bent, it still won't tell me if the crank bent first or was a result of some other issue. The crank was checked when I built the engine and it was within spec per the machine shop.

Zed Head, the shaft came from the donor ZX engine which appeared to be all original with unknown mileage. The cylinders were in perfect shape as were all of the journals. I'm sure you are right about the filter collecting any gear debris, but I'd hate to blow up in my next race because of stray shavings. Thanks Guy, I will look around. The engine is all 1982 ZX stuff and since I rebuilt it, has about 20 race hours on it. Previously, my L26 engine had about 60 race hours on it and the gears looked like new. Oddly, the gear on the crank has no damage at all, at least when viewed via borescope. I will replace the pump, shaft an crank gear.

Last year during an 8 hour endurance race, my 260Z started missing and running like crap before it dies completely. We tried to diagnose the issue at the track and finally had to throw in the towel that race. We could not get the car to start no matter what we tried. Everything looked normal with the timing, valve springs, plugs, etc, but it wouldn't start even on starter fluid. We parked the car in the garage and until today, we had no idea what was wrong or how much damage was done to the engine. Today, we pulled the plugs and looked in the cylinders with a borescope. Everything looked great. We then looked down the front cover and all looked normal. The chain, tensioner, and crank gear looked good, but I couldn't quite see the drive gear on the distributor shaft. We then pulled the oil pump and all became clear. The drive gear on the shaft was a mess. The teeth were stripped. We then drained the engine oil into a paper towel and found no debris. Next, the oil pump came apart and looked okay, but there were signs of small debris going through it. Hopefully, when we pull the engine and tear it down, we won't find any damage to the journals. I think we'll be okay, but it's a shame to pull it apart again. What causes the shaft gear to strip? I have never had this failure before. The shaft gear looked great when we built the engine which now has about 20 race hours on it. The oil pressure was always good right up to when the engine quit, so it was clearly still spinning, it just couldn't keep timing correct.

My Z is in a friends garage, so I don't have anything handy. I do plan to go over and work on it this weekend though, so I will try to get some pics. Keep in mind, my car is a race car and function was far more important than looks when I routed the lines. For a street car, I would have done things differently.

Awesome! I need to get that stuff for my wife's FJ Cruiser. I coated the whole frame with POR-15, but I haven't done the inside of the rails yet. Toyota frames are horrible for rusting out. I had a scrap her old 4Runner due to frame rot.

What is the process to coat the inside of all the cavities where you welded new metal? I would think that is the most critical to get coated to prevent future rust.

I'll have to watch it again. I viewed it a dew days ago and wasn't paying that much attention to the background. I wish I didn't live 2500 miles away from those great roads. Michigan has the worst roads in the country. They are all straight with no elevation and filled with car-eating potholes.

Not positive, but almost all of the car videos of this type are filmed on Angeles Crest Hwy or Angeles Forest Hwy which are both together. They are North of Pasadena. I am on the roads several times per year and they are fantastic. Both have tunnels where you can enjoy the car's exhaust music.

I run the '81 - '83 close-ratio box along with a 3.90 gear in my race car. The shifter is a bit of a pain. I bent the rod to fit, but the rubber shift boot doesn't fit very well due to the shifter position.

https://www.amazon.com/Red-Line-50304-Transmission-Transaxle/dp/B000CPCBEQ

Same gear oil for both.

I strongly suggest Redline MT-90. Don't just throw any old oil in there.