Zedyone_kenobi

Thanks Madkaw, the opinions form you fine fellows are always welcome! I have thought about finding another head a P79 perhaps or something with a bigger combustion chamber and having some serious port work done to it, and then one day swap out my hardware with it. But that would be a bit of an undertaking. I would however get me down to closer to 10:1 and at the same time get me some FLOW...

Leon, well said!! I agree with your assessment. My BP7ES are going in this weekend, but I am not sure it will make that big a difference, but it certainly is in the direction of goodness. I have been wanting to get the engine on a dyno for a while, since it is totally broken in. I just need to find some time. I also echo'ed your opinion about all the variables and knobs that can be turned. Right now the problem is not really that bad. But I am liking the idea of dropping some 1000 octane and playing with timing until I get 'the ideal settings', then try to figure out how much I am losing with 93. According to independent lab reports NOS octane booster increases the octane by right at 1.8-2 points per tank. So figure i start with 93 at about 95 all my pinging stops and the car runs very well with 14 degrees at 900 rpm, and 34 degrees max at 2800 rpm. I have not advanced it beyond that as it starts up, runs and keeps AFR dead nuts on all the time. In fact it runs perfect. This is where my engine build got a bit off track. We wanted to use OEM Datsun L28 flat tops in the build. But we could not get any .005" over bore. OR rather Eiji could not find any and I came up empty as well. But being the impatient person I am I ordered some ROSS forged pistons (completely overkill) that were 0.005" overbore. However they were a few thousands taller. We had to choose smaller lift cam because of this as we had valve clearance, but not the recommended amount. So we put a slightly smaller lift cam in. This is also the source of my extra compression. I think we were shooting for around high 9's or 10:1. Add a taller piston and blame, 10.5+:1 and the need for uber fuel now exists. I do not want to come across as angry or mad. In fact I LOVE how my car runs. It is strooooong. In fact my only real complaint is that I should have bought 45 DCOE's instead of 40's. The purpose of my post was to warn others and to ask now that I have taken this path of high compression, is there anything I can do other than add octane boost or retard timing to ease the situation?

Let us all have a talk about compression, and timing. How much is too much, how to deal with it. And how to achieve the max amount of advance you can while not pinging. Enter the subject. My Datsun Spirit STR2.8 liter engine. L28 N42 Engine Block, N42 Cylinder Head base 87mm (bore) x 79mm (stroke) = 2817.8cc Combustion Chamber Volume: appx 43.5cc Piston above deck: appx 0.25~0.30mm Compression ratio: 10.5 : 1 Camshaft: STR274F Duration 274 Max Valve lift: 12.00~12.19mm Lobe: IN: 106, EX: 110, Lobe Center: 108 I have driven this engine hard for 2000 miles or so since it was installed. It has run beautifully. During 1000 mile rally the car ran without a hitch, but I purposely dialed back my timing to take into account for iffy gas as small mom and pop gas stations I may encounter. After the rally I crept back up to 34 deg BTDC at 2800 rpm and drove her. At low RPM in 3rd and 4th when the engine is under heavy load I noticed copious amounts of pinging. I run 93 octane only locally. Long story short, I cannot run 34 deg of max advance without dropping a bottle of good quality octane boost in my car. With the mileage I drive, that means about 5 bottles a year. Correct timing is so important to getting the max HP out of your engine. Every degree of timing can yield substantial HP changes. So what is the max timing a street engine can run. Naturally I have cast my stone. And I find with my particular set up, 34 degrees is about all I can run with 93 octane and a bottle of NOS octane booster (don’t laugh, it was ranked 3rd best out of the top 10 in an independent study, plus I like the blue bottle) Can the veterans of the Z world chime in on this. What steps can you do after the engine is built to help avoid pinging. I have not tried some BP7ES plugs which are colder ( I have them in my garage though) . I currently run a 190 deg thermostat. Would a 160 help? I love how my car runs and the extra 65 dollars a year in octane boost really does not bug me that much considering how well the car responds to it, but for others building an engine, what should be the max limit on93 octane gas. I would have to say 10.5 is too much. Granted the camshaft over lap and lift all have an effect on this. But lets get a good conversation going.

49 degrees! Great googly moogly

This is good to finally know Blue. It makes perfect sense what you are saying. And it is a good indication that the rules of thumb of DCOE tuning very greatly on what carb model you have and how old it is. It also just adds to the realization that you really need a wide band O2 to get them spot on, as there are way to many variables for a one tune fits all approach.

A starting point would be this. You need to find the progression hole cover screw. Number 5 in this picture You want to crank the adjsutment screw so that it touches the tang starts to open the butterflies to the point where you have the first progression hole completely covered up, but with any throttle movement you start to uncover them. Look at A in this picture. Once you get them all just like that so they hard stop at this position, you are in a position to get the car started. ANd the REAL fun with webers will start! This is just a picture for education on function

His brakes have been awesome. They bled perfectly and have been working like a charm. I noticed a more immediate brake pedal when I installed them, and the brakes bite harder. I would not hesitate to do this again.

I sense a roll bar, and maybe even a wheelie bars... I fear the worst.

unfortunately I am sure he will put a V8 in there. Not much love for the non-american crowd on his show.

I generally like Stacy Davids show. He is pretty straight forward guy and he does give good advice. Plus I can actually feel his enthsiasm coming through the TV. Which is nice wthout feeling forced or fake. Great work!

I wish him luck and safety and fun. I only will say this. Coming back for fun is wonderful and should be encouraged and respected! Coming back to try to be as good as you use to be, only serves to tarnish who you were should you not live up to expectations. People have the gaul to say Michael Schumacher may not have been as good as he was because he did not dominate in the Mercedes when he came back. I like to laugh in their faces. Have fun John Morton, I will cheer for you. But be careful! Fans are a ruthless bunch.

OOOO you had me at that NGK sticker!

This a very cool thread. I could see myself getting these made and attached to magnets, just for fun!!!

Ahem the dukes of hazard proved you can make a 100ft jump and while the chassis LOOKED like it bent 30 degrees, in fact it was not and the car was freshly washed and waxed when it comes to a stop. It is all just simple physics really. I have to be honest, I watched for the blond longer than I care to admit.

I have to hand it to you, the work you are doing is impessive and kudos for doing it right, but the stretched tire look to me is aweful, not my cup of tea. Keep us posted on the rest of your hard work.

Tractor engine huh? Just a little something to pull a mower around, eh?

Do you have a P-51 mustang collection getting started in the back of the garage Guy?

Just let me know bud...I will do what I can within my power to help.

Blue!!! I missed a chance to hang out. Things have been just crazy at home for me. My poor wife is working insane hours. I have been grounded. I hope your stay in Houston was a good one!

The answer about the cost is really it depends.... Do you have a core or does DS need to source one for you. What if any head work do you want done. How wild do you want to go. DS engines can cost a wide range of prices.... I would check out his website Datsun Spirit, Inc. He has ranges of what his engine packages cost.

Travel'n Man, I am about to pull my dash out and pull the tach as it has grown lazy and refuses to work above 4000 rpm. Where did you send your tach for refurbishment?

ooooooo good point on the rear tail light panels. You can get the OEM paint color at Classic Datsun Motorsports click on 240Z and then click on MIsc

I feel like I have seen this car before... but with different wheels. The diamond plate over the radiator and center paint stripe is reminding me of something. but let me say welcome welcome welcome! You have them makings of a great Z car. Do you have plans for it? I would highly recommend getting some more appropriately fitting wheels and tires. Those looki like Weld Drag wheels like you would order from Summit or Jegs. If so they are a great wheel, but more at home on a Camaro than a Z. That is just my opinion mind you. the emblems have been shaved and the rear exhaust has been welded closed. That is interesting. How is the interior? I would also recommend getting a nice set of SU carbs for it. The downdrafts you are running may be leaving some HP on the table. In the mean time, keep the pics coming and welcome. Keep us posted with your car, what you need help with and what your plans are!

THATS IT I am doing this next. The result are just too fantastic!!! And if it does no work, I will just slap a damn cap back on it. BRAVO everyone who has done this!!!

I love threads like this. It inspires me to pull off my dashcap and see what lies underneath. I will have to try this before it gets to hot.