Zedyone_kenobi

That was darn near poetic buddy, Well said!

No go on dyno day fellahs, Had to pull kid duty on friday. Wife got called into work and I was playing with my little one. I will have to reschedule... Bummer.. but me and my 6 month old had a great day!

Those 71 numbers are for the non emissions cars Blue, as you know the 71 US emissions dizzy equipped ran 5 degrees initial advance.

Blue, get some clay and build you a model. THat is how Peter Brock would do it!

I have scheduled some dyno time on Friday morning to see what my car puts down. I will bring some jets and a timing light with me! Should be fun, but I am dealing with a shop full of Brotatoes who only work on LSX engines and Vipers. Out of curiosity what are your reservations?

Good to meet you DAVE! Great to hear form a TX guy. I may have to swing by to see your ride very soon! I am in League City next to Kemah

My lift is around .480 Guy, with a 274 duration. Maybe more duration would help. Still like I said before, with additives I am fine. I have heard the P79 head is more resistant to detenation... I am enjoying this thing very mucy, and I would buy another Engine from Eiji if I wanted another. But I still have plans to overhaul my stock engine in some way. Maybe I will make it into a screamer...

I was going to play with the springs in my Mallory to make the timing come as late as possible, but even with the heaviest springs, the curves are not that different. But it is in the direction of goodness, so it cannot hurt. My goal is to make the carbs, the head, the cam and the timing all working together to achieve the same goal. In my case that is a huge midrange torque hump with a fall off all the way to 7000 rpm. Everything I have done up to this point is to maximize mid range power. The smaller carbs, the high initial advance on the cam, the selection of a mild cam, etc. It is all about parts working together. It seems this pining issue means I have exceeded a boundary somewhere, but I can fix that with timing, or fuel, or plugs, or even a head gasket change. This is all part of the fun of building the engine and it also adds to the appreciation of how hard it is to build an OEM engine that must be used by an entire country with different fuels, climates, elevations, etc. and still be robust and fun. The more you modify an engine, the more you appreciate how good stock is.

I was going to play with the springs in my Mallory to make the timing come as late as possible, but even with the heaviest springs, the curves are not that different. But it is in the direction of goodness, so it cannot hurt. My goal is to make the carbs, the head, the cam and the timing all working together to achieve the same goal. In my case that is a huge midrange torque hump with a fall off all the way to 7000 rpm. Everything I have done up to this point is to maximize mid range power. The smaller carbs, the high initial advance on the cam, the selection of a mild cam, etc. It is all about parts working together. It seems this pining issue means I have exceeded a boundary somewhere, but I can fix that with timing, or fuel, or plugs, or even a head gasket change. This is all part of the fun of building the engine and it also adds to the appreciation of how hard it is to build an OEM engine that must be used by an entire country with different fuels, climates, elevations, etc. and still be robust and fun. The more you modify an engine, the more you appreciate how good stock is.

Okay, I pulled my build sheet. Carl, this is for you. the L28 stock bore is 86mm, and mine is 86.5mm, not 87mm (Sorry about that, he listed OEM, first then actual, and I cut and past the OEM bore, not actual) I went and looked at the actual Excel sheet Eiji made me with the bore measurements on it, so I am sure about it. Also, A OEM Nissan L28 headgasket was used, as were OEM L28 rods. I am hoping this friday I can get my colder plugs in and if I can find a cooler thermostat.

I will get the exact numbers for you guys since curiosity has been shown. NO worries I know my cam was advanced by a large amount. Remeber that. Eiji told me when my cam came in it had a weird pin location so he had to degree it 6 degrees advanced. Gives great low end, but will probably petter out on the top end a tad. I wanted a midrange engine, so we both agreed to move forward. The huge initial advance was probably the cause for the low clearance piston to valve. Still, I could recam, but that may involve new lashpads and all that as well. I just want to reiterate. My car drives wonderfully, and the power is just great, but I wanted an open talk about sets ups and cam duration and compression, etc. And as usual you guys have answered the mail!

I will get the exact numbers for you guys since curiosity has been shown. NO worries I know my cam was advanced by a large amount. Remeber that. Eiji told me when my cam came in it had a weird pin location so he had to degree it 6 degrees advanced. Gives great low end, but will probably petter out on the top end a tad. I wanted a midrange engine, so we both agreed to move forward. The huge initial advance was probably the cause for the low clearance piston to valve. Still, I could recam, but that may involve new lashpads and all that as well. I just want to reiterate. My car drives wonderfully, and the power is just great, but I wanted an open talk about sets ups and cam duration and compression, etc. And as usual you guys have answered the mail!

This thread is all I could hope for! Such great information for myself and all others that may be looking to build an engine Bravo guys for keeping such splendid useful information here! What a great collection of thoughts!

Well I have the E312 from my orginal L24 still on the original engine. I hate to take those apart. I still want to refresh the OEM engine that came with my car. It was running strong when I pulled it. If you can get the overlap up due to a big cam you can alleviate some of those high pressures for sure. I would not be surprised if you have Zero issues. But let us know if you do.

there is no such thing as too cold in houston.

So running a tigher lash on the intake valve would keep it open a hair longer. That is something to think about. I will try the cooler plugs this weekend. And I have to find a good quality 160 thermostat.

The fuel will evaportate right out of the fuel bowls. There is nothing ot stop it. When I turn my key and let my electric pump prime the carbs, it runs for several seconds before you hear the pump load up indicating its pushing against a dead headed system. I do not currently run a flow through system, but it is in the plans.

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.