Phred

I was there, and BTW, this wasn't the first time something like this has happened. The rumors flowed through the Datsun tent like wildfire. The tent was a large rectangular affair, supplied by Datsun, and where most of the Datsun competitors were kept in paddock. Everyone, with a wink in their eye, talked about it. Most didn't think it would happen, but a few were serious. If there was an actual drawing of straws, nobody talked. And when race time came, there were a lot of knowing glances being exchanged. But when it actually happened, nobody could believe it. The Runnoffs, in years past, could be a genuine challenge to ones commitment as a race driver. I personally witnessed some serious acts of intimidation. And in most cases, if you were not on top of your game, you could get run over. Freddy Baker was (and probably still is) a very good race driver. My guess is he just couldn't believe someone would take him out so early in the race. If his race would have gone full distance, he would have been ready for full contact racing in the last few laps. Many racers are like frustrated fighter pilots, and drive accordingly. So I counted myself neutral in this affair, as I had engines in both Datsun, and British Leyland cars. Phred

I guess I should have known that. I held an SCCA license for 18 years. SCCA and their stupid rules. They'll let you spend thousands of dollars building the trickest E-prod car in the world, but you can't put a spoiler on it. Yet it was legal on a C-Prod 240. Not to change the flow of the thread, I still like the pics, and Greg's car. Phred

Great Pics. I'd sure like to hear his comments on why he has chosen to run without the legendary BRE type rear spoiler. Phred

I used to cross drill L6 cranks, both vertically, and diagonally. They were very hard cranks. Carbide tooling was need to do the job. In addition, we re-heat treated ( Ion Nitriding ) the cranks after machining, or grinding journals undersize. Part of the heat treating process is normalizing, where the crank is heated, and "annealed". So, to make machining easier, I did a two part heat treat, I picked up the crank after it was normalized, ( made softer ) did all my machining, then had the final heat treat done. The heat treat will re-align the metalurgical grain, and remove any stress risers created by any machining process. For reference, if you can find a Lycoming, or Continental aircraft crankshaft to look at, ( 4 or 6 cyl. ) you will find the same rod journal lightening as you have described. The aircraft cranks are very strong, and reasonably light. They are also nitrided. Most Ford Cosworth racing cranks are lightend through the rod journals as well. But, it's a major machining excercise, and costly. So, consider the use and design of a stroker crank. The idea is to create more torque with increased stroke, and therefor you should be able to gear the car to make power without using higher rpm. The the loss of rotational mass so close to the shaft centerline, will probably not be of much benefit. You could probably make the same rotational improvement by simply using a very light flywheel. I don't want to discourage you, but I have "been there, done that". If you have deep pockets, and it's an all out race car, go for it. But don't expect to see any improvements if it's a street car. Good luck. Phred

I have a 71' rad which has been recored with a four row core. For sale for $200, but shipping would probably be high. Phred

I havn't got much time here, but I have a pic of the adjuster. The top 14 mm nut is the adjuster, the 17mm is the lock nut. Don't try to turn the 14mm adjuster without first loosening the jam nut. The 17mm nut is sometimes pretty tight, but the adjuster is rarely tight. Point the lobe up, and set intake at .008, and the exh. at .010 cold. good luck. Phred

Here is an original 71' that has been recored with a four row core. It's for sale for $180.00 but would be more of a pick up item, as shipping would probably be $$$ since they are kind of heavy. Phred

The first thing you need to do is get informed. And you've started by asking questions. A lot of your questions can be answered, and you can gain a lot of Z info, by buying "How to Modify Your Nissan & Datsun OHC engine" by Frank Honsowetz. You can have this book shipped to you by Motorsport Auto, or order it from your nearest bookstore - ISBN 1-55561-237-7. Phred

See this thread for good info on Zinc/Phos. It is very important info all Z owners should know. Phred http://forums.hybridz.org/showthread.php?t=137868

All the heads/blocks I've done were full race engines, so I don't have any particular info on your setup. My guess is you won't have to do anything. If you choose not to check it, to verify it's not hitting, Just leave the spark plugs out, and turn it over by hand. But you need a small amount of clearance, and just turning it over won't tell you that. To verify, do a pre-assembly with one int. and one ex. rocker installed with only the inner valve spring installed. Set cam timing, run the valves to max lift, and push to open the valve further. The valve will open a little further before it crashes into the block. How much more it opens will tell you the clearance. Safe minimum distance is .060 Int., and .090 Ex. Phred

xray, Head flow is controlled by the restrictions inherent in it's design. In most cases, the restriction to flow is from the valve. Meaning, the stock port is capable of flowing more air than the valve will permit. Initially, by increasing the area ( valve size ) of the valve head, and valve seat, the head will pump more air. Increasing the size of the ports is the last step in optimizing head flow. If ports get too big, and this happens all the time, the velocity of the flowing air will decrease, causing a decrease in low/mid range performance. Big ports help top end performance, not bottom end, which is what street cars need. The first step for street performance, is eliminating as much restriction as posible by the use of slightly larger valves. Experience is needed here, as too big of a valve can cause flow to be disrupted by not allowing enough space in the combustion chamber for air to flow around that big valve. To realize the good effects of a larger valve, different seat angles should be used to allow the air to smoothly flow over the seat area. As you see it can get quite involved. Properly tuned, an engine that pumps more air can produce more HP.

It all depends on the bore size, valve lift, and valve size. It should be checked to give you peace of mind, and to possibly save some damage. If you feel good about your die grinder skills, you can do it yourself. It also has a side benifit of smoothing the flow within the cly./chamber. Two important notes: DO NOT grind down below the top ring! Stay above by about 1mm or so. Place a used head gasket on the block, and scribe the block, around the inside of the gasket. Then very carefully grind the block as in the pics below. The pics are of an "O" ringed L24 block. Phred

He IS timeless. I met him twice. Although I'm sure he wouldn't remember, I will. The first time was a quirk. I was living in Gleneden Beach, Ore. when he was making "Sometimes A Great Notion" released also as "Never Give An Inch". Around 1970 I think. I had crashed my Bugeye into an earth bank near where he was living while doing the film. I was by myself standing next to the crumpled Frogeye. He drove by on his way to the filming location, and stopped. He got out of his Corvette, and came up and asked if I was ok. I just complained as how much it was going to cost to fix. He said something like "take care, and you'll be ok". I felt stupid after I thought about what I had said. It was weird to be able to see him up close like a normal guy. A few years later at Road Atlanta, I was at the Datsun sponsered test day prior to the SCCA runoffs. I was sitting on a guardrail in the old pits during practice, and he just walked up and sat down. We shared a few sentence's about who was going fast and who wasn't. I didn't mention our meeting a few years earlier. Around racer's, when there wasn't any spectators around, he was just another guy. When all the spectators showed up on race day he pretty much just stayed in the motorhome. Great memories. I'll always remember him as he was. Very special. Phred

Wow, I've been building engines since those first came into the states, and I've only seen one, and it wasn't in an engine. I thought they had all been broken or replaced. I remember reading the BRE cars broke their eary cranks, before the later style was available. I believe the later cranks are a direct replacement fit. Phred

Here's a few pics from Old Oregon. Phred

This one has had a little work done to it, but you can see how the area around the spark plug has been filled in on the last E88 open chamber design. Carl Beck; can you confirm that this style is indeed the last of the E88 chamber designs? Phred

jmark, The finish in the pic is "as recieved" from Stahl. It's just paint. I am waiting till after I dyno my next eng. to refinish them with one of the high tech coatings. I really like the dual exh. sound, so I took the time to build a full dual system all the way to the outlets. You can easily buy or build a two into one merge collector for a single pipe system. When I first saw the race Z's in the early 70's, they had duals with megaphones straight out the center in back. So that's what influenced me. I used all mandrel bends and heli-arc'd the whole thing with a short crossover just ahead of the muffs. At the rear, I did a zig-zag around the fuel cell and built a resonator with two small race type muffs welded together. They have a 2.5 ID x 4" OD x 12" long, and I finished it off with a couple stainless tips. The only bummer with the side to side layout was I had to enlarge the cutout in the rear bodywork. I tried a stock type verical layout, but the lower muff was too close to the ground. Back in 98' when I bought this header, it was $512.00. I'll be interested to know what they go for now. Phred

These are 1.5" primary, 2" collector. Worked great on ITS 240, and on street 240. Will use them on a 3.0 since I have them, probably a bit small for 3.0, but should work fine for street racer. Phred

Mike, You just have the wrong rings. If you have a 4mm ring gap on a stock bore, thats all it can be. BTW, most blocks are closer to 3.390. Don't worry about the machinist removing too much with the hone, it should only take a few thou to clean up most blocks, as they generally don't wear that much. Ring gaps change at the same rate as Pi. For each .001 in. the bore increases, the ring gap will increase 3.1416. Ed has good data, and will always be a safe rule to follow. In real life, rings on L NA motors can be safely set a little closer. Even SCCA ITS engines show no ring butting with a lean mixture at .015 on the top ring. Hope you find the right rings for that tractor motor. Phred

Viparz, The dowels are required for alignment of the cam bearing towers. Upon removal, they will sometimes they stick in the head, sometimes in the towers, sometimes in both. I ordered new ones from Nissan a few years ago, and they were still available. L24/L26/L28 all used the same part. Phred

Stock head thickness is 4.250 More technical info is needed to diagnose your problem. Also note, a head with valves/cam etc. can be set up on the bench to eliminate all or most of the unknowns you list. Phred

Galaxybj, Don't worry about the shinny link. Its probably an aftermarket chain,and most of those didn't have marked links. The shinny link is really only usefull when the front cover is off, and you can see the dot on the crank gear. Then its just a visual check, with the one shinny link on the crank dot, and the other on the cam dot. Just be sure the crank is at TDC, the rotor aligned, and the notch in back of the cam gear is resonably lined up with the mark on the cam thrust plate. If the gear notch is trailing the mark on the thrust plate, the cam is slightly retarded, due to surfacing or chain stretch.Try the #2 setting, which will advance the cam 4 degrees. Phred

Legend, Arne had some good info, but I think compression is the least of your problems. Your pics show some of these potential killers. First, the pistons appear to show some piston to head clearence issues. The shinny areas where no carbon is present, is an indication the piston is slightly hitting the head. Not to mention the different dome styles, two with flat tops, the others with valve reliefs, indicate they came from different sets. That means they will probably have different compression ratio's, as well as possible Valve to piston clearence problems. More than likely the worst issue will be the piston weights will be different, causing a serious internal imbalance at speed. The other indicator is the red anodized valve spring retainers. Not a good idea for a street drivin engine, and questionable on a track only car. Which would make me question the springs and cam. How much lift? How much V/P clearence? How much spring pressure? How much pist./head clr.? And finally, how much compression? If you don't know these things, you have another engine that is blown up. It just hasn't happened yet. Please pick up a copy of Frank Honsowetz' "How to modify your Nissan/Datsun engine". Engine modifications can be frustrating and expensive. Once you become informed, its a lot of fun. Hang in there and do it right. Phred

Years ago (pre ARP), I Installed 9mm rod bolts in sveral sets of 8mm rods. As an engine machinist, I had all the proper drills, reamers, and milling machine to duplicate the factory fit. Later when ARP came out with good 8mm bolt kits, I used many of these on stock to race engines. I never had one fail. Special note: All these rods were resized after changing bolts. Also, at minimum, these rods were balanced, and the race rods were lightened and shotpeened. Last time I checked, the 9mm bolts were still available: 9mm bolt 12109-N0110 9mm nut 12112-N0101 Kronoss, For your medium performance race /street engine, I'd go for the ARP 8mm bolts. Simple install, no need to change rods, no special machine work required, peace of mind when revs climb. I would still highly recommend giving these to your engine machinist, with your new rod bearings, and have them resized to .002 clearance. If the engine is to be raced more than street driven, shoot for .0025 clr. Phred