Chickenman

Exactly. I ran ISSCC D-Prod racing years ago, and their engine rules are basically the same as SCCA. We were twisting 7,2000 out of L24's back then ( Late 70's ) and making good power. Engines last forever.

Two things you have to do. 1: Download the current SCCA rules and go over them with a fine tooth comb. Have preconceived notions about nothing. 2: Details, details details. . You blueprint and maximize every thing. When in doubt, find a friendly Racer. Or ask a scrutineer. ^ That actually gives you a fair amount of Leeway. The MS (or any other brand Programmable ECU ) is a HUGE improvement. Proper AFR's are essential. And the ability to program Spark curve helps as well. The Exhaust and headers allowance really helps. Probably more head work going on than you realise. Port matching is allowed, so is CC combustion chambers, Multi-angle valve and seat grind. Replacement of Valve guide allows some gains ( Tapered guides ) and likley Tuliped Valve Stems are allowed. Reduction in friction is also a big area. Reduction in ring tension, engine build ( Bearing clearances ) to use lightweight synthetic oils. All are areas' for gain.

Off shore made crappola. Check it with a mechanical gauge.

Temporarily hook up a mechanical gauge to double check the pressure. The electrical oil pressure sensors are well known to fail with age. And then they will read low. Cloes to zero at idle is common with a faulty sensor. May be nothing at all wrong with the engine.

This is how it came. out of the shipping box. Lack of Cam towers doesn't concern me.

I will be finishing off the seats with a 3 angle cut. Looks like PO just did a quick two angle. 30 degree top cut to get Valve seating in right spot. That wasn't done yet. Lap the 45 degree cut. 70 Degree cut is already there, but may need touch up. Need 45 mm Intake valves because the current 44 mm are too small for the seat diameter. May have to unshroud Intakes a bit. Exhaust valves are 38 mm currently. Pretty freakin' big. But good for a Nitrous or Turbo motor. Wasted on my NA motor. I may be able to cut them down to 37mm to gain some unshrouding. Some touch ups to some nicks in a couple of the chambers. Radius the sharp edges in the combustion chambers from the surface skim cut. Some other detail work. CC the heads. Trying to find Machine specifications for overall head height from face to VC rail. Measure 107.39mm in total height. But from casting numbers and amount of material left below Casting numbers it looks like the head is nearly Virgin. My N47 head on the other hand... has virtually no material below the casting numbers. Looks like its been shaved big time. But measures out at 108.17mm. Problem is. I don't know if N47 and P79 heads are the exact same dimensions fin overall height. They may not be. Some guesses from people. But I'm seraching for the Fcatory specs. On of Honowitz's books is suppossed to have them.

I haven't done anything to this head...Yet. This is how I received it from E-Bay. Best $150 bucks I've ever spent... well maybe this second Best. There was this girl... errr,.. never mind.

Here's the P79 head I just bought. Someone spent some considerable time on it. Pressure cabinet cleaned All new steel seats. All new bronze valve guides. New 38mm Manley SS Pro Flow exhaust valves. New 44 mm SS Intake valves . Intakes are wrong valves . Short style P79/P90 . We use N42/N47 style as they are longer. Gives you some more clearance for valve lift and as Camshaft is a re-grind, eliminates having extra thick Lash Pads. The exhausts are the longer style. Five are Manley, but one is a shorter valve and is not the same as the others. Not a big deal, as Manley still makes Valves to order. Going to order six Manley 45 mm Pro Flow Intake valves and one 38mm Pro Flow Exhaust Possibly Isky valve springs as well. They are new and sure as heck not stock. I'll put them on a spring tester and get the rate. Head will be a winter project. I'll finish off the Valve seats properly. Clean a couple of minor things up and do the #5 and #6 Cooling mod.

Backup switches are very useful. Especially if your do any sort of Competition. Sitting at an Autocross or Hill climb lie up and some ones goes off. Turn on the Fans manually to get airflow through the engine Bay. especially useful with Carb's..

No need to put any sealant in there. Nissan engineers were just being extra diligent when they designed those baffle plates. 100 Times better design than what passes for an oil baffle on Small Block Chevies. Blue Loctite on screws and you will be Golden.

Pay attention to the short side radius as well. Make sure it id not too sharp. Especially on the Intake side. The exhaust liners actually give a nice smooth radius into the port bowl. Edit: I'll send some pictures of my P79 " project " head that someone did some nice blending on. Big valves though. 45 mm Intake and 38 mm Exhaust!!

Bowl blending 101. One of the first things you do. Perfectly fine.

Only marking on the back side of my Cam are the numbers 0650. It's an " A " Datsun core.

No all new bespoke castings, but based on a Cannon Weber 45mm manifold I believe. It's all in the FB blog.

No tricks done to the factory Fuel system, other than fine tuning the AFM with a 4 Gas analyser. The Factory ECU has a fairly rich WOT base Map. It can usually handle the increased Fuel flow. Anything additional you need could be handled with an Adjustable FPR. But I didn't need one. After setting WOT fuel Pressure you can dial the midrange in with fine Tuning on the AFM. All brand new CTS aetc. My car EFI system is like new. Even the wiring harness is in showroom condition. Bills Datsun Shoppe in Clackamas Oregon tuned the AFM and he has a lot of local L-28's running factory ECU's with Big Cams, headers exhaust etc. It all depends on what yo know. Helps if the ECU drifts a bit rich with age instead of a bit Lean. Like I said.

With Plenum Option:

With gutted carbs as ITB's:

Here's the link on FB in Church of L. Plus some pictures of the L-4 manifolds. https://www.facebook.com/groups/995586513795146/permalink/1826020180751771/

BTW... the is an Option for an affordable ITB ( or Plenum ) setup from local fabricator that we are trying to get into production. Byron Meston does a lot of fabrication for the Datsun community up in BC. He just built a new Machine shop... but is waiting for three phase power. Here's the thing. He has been sitting on literally a Pile of L-4 EFI custom built IR manifolds for well over 5 years. They are beautiful works of machine. He a great fabricator... but not so good at marketing. When the local Z community found out about these we went nuts. Because he can make the same thing for L-6 engines. He's just been too busy with work, family, other projects and building his new shop. He's waiting availability of a 3 Phase power unit for th shop. I'll post up link later to his L-4 manifolds . Hop on the band wagon and pester him to put the L-6 version things into production.

Almost the exact setup I have on my 280Z right now. L28, N47 head , F54 block with FT pistons. approx 10.5 CR. N42 Intake with 60mm Weber TB. MSA headers, 2.5" exhaust Cam is a bit of a Mystery. Engine builder was a bit secretive( don't know hwy ) . Was only told it was 280 degrees .480" lift. I've driven enough Z cars with the Shadbolt M445 to recognise it's characteristics Wel.. short story. Engine makes power like a SOB. Easily pulls HARD past 7,000 RPM. Had to put a Rev limiter on the danged thing. Surprisingly the stock ECU handles the large cam just fine, although I would suggest a true standalone ECU for it's adjustable, especially on a Race car. But starts on first turn of the key every morning. Warms up fine. stable idle at 1,000 rpm , even though it is a pretty lumpy camshaft. I'm sure the compression help there. Gas mileage is fine. No driveability issues. Engine is a rocket. haven't had a chance to put it on a Dyno... too busy enjoying the car. But other experienced Z owners are surprised at the Power it has. It's so good that I have a Haltech E11 sitting on the shelf for 3 years. I'm finally going to install it... because = I have it. But for day to day. It's not necessary. Now, I'm not suggesting that everyone is going to have the same luck with their ECU. Mine is a bit of a Unicorn and it's working amazingly well. The factory AFM is NOT affected by the lumpy idle, and if you look at how the factory AFM idle circuit works you will see why. Idle air goes through a the mixture bypass on the AFM. Falpper does not fluctuate. I've wtached it with intake hose off and engine idling. Only weak point of the factory AFM is that it Tops out at around 4,500 RPM. On my car I do get a bit of a lean sport between 4,500 to 5,500. After that the ECU is on the WOT MAP , and at least on my ECU, it is rich enough to handle the engine Mods. But like I said... my ECU may be a bit of a Unicorn. Any aftermarket ECU like aan MS2 would completely solve the fueling issue though. The N42 Intake Manifold. Yeah, the runners are small. ITB would make more power. But it's certainly not horrible. As I mentioned, my engine will spin HARD pat 7.000 rpm any day and evry day. And the mid range torque is awesome. It will do on a DD.

I agree... Cam Timing looks OK. Definitely not off a Tooth by those photos. Did you physically confirm TDC using a Piston stop method, or just go buy the Damper Mark? Piston stop method is most accurate. #1 Piston at TDC has to be dead nuts on in this situation. That being said , I may however, have found some incorrect Ignition settings in the MSQ you sent me by E-mail.

Actually I think the latest supersession on the L-series outer springs changes up to the Z31 springs. I'll have to double check that later.

BTW.. car I was assisting was at a Dyno shop. Went from a sluggish 198 RWHP Max at @ 15 lbs Boost. To 315 RWHP on 13lbs Boost. Engine easily spun straight up to Rev Limiter at 6,500 RPM . On a Baseline Tune ( one of my own Tunes ).... straight out of the Box. Just by correcting Cam Timing. Much more HP to come. Way more ( GTX3076 ). But this was just an initial test at low boost on a " Safe Rich " baseline tune. But it made more than Dyno operator was expecting at low Boost and no Tuning

That's really not all that big of a Cam. It should work fine with NEW factory valve springs. The low lift of the Shneider cams ( 0.460" ) makes it pretty easy on the valve train. Certainly a bit stiffer spring wouldn't hurt, especially on the Intake. .. but you don't need anything excessive. However, you may have a different problem. It is very possible that the Cam Timing is off by one Tooth. This will produce the exact symptoms you are describing. Engine hits an absolute wall at around 5,000 . Engine will just feel sluggish overall. It will build boost, but slower than usual and just doesn't want to accelerate like it should. I've had this exact problem on my Turbo Audi, and I just finished helping a customer who had a problem Big Turbo L-28 that just would not rev past 5,000 rpm. Engine was down on power and just seemed sluggish. Ran smooth... but way down on Power and wouldn't Rev. Data logs revealed the problem to me. . MAP values at idle on decel were not correct. Only two things can cause that. Huge Vacuum leak or incorrect Cam timing. Turns out the Cam had been installed 1 tooth retarded. Same problem on my own Audi when I had the Timing belt changed. I let a local shop change it... Well because = Audi. " The Four Rings of Pain " . Car just would not Rev. Built boost OK-ish ( a bit slower than normal ) , but way down on Power and just would not REV. I could hold it WOT in 2nd gear and it wouldn't go past 6,000 RPM/. Fixed Cam timing. Gained about 75 HP and engine revved to 7,200 RPM limiter. I've tuned many L-28's with Big Boost and stock Nissan Valve springs. New factory springs should easily Rev well past 6,500 RPM on that Cam. I've tuned local Turbo cars with T3/T4's with mild Turbo cams like you have and factory springs . The things were scary fast at only 10 and would ZING right past 6,500 no problem. My own car ( Normally Aspirated L28 10.5 CR ) has a larger Camshaft than what you have. On NEW Nissan stock springs it will happily spin well past 7,000. I've hit 7,200 a few times. Now have a Rev limiter on it to keep revs limited to 6,800 RPM I would double check your Cam Timing via FSM. It could very well be a Tooth off. If you have a Vacuum gauge, see what it reads on Decel. Just backing off normally or going down a hill, you should pull about 25 in/hg vacuum. If you are down around 20 in/hg ... you can be pretty sure that your Cam Timing is out. All other things veing checked of couse like Vacuum leaks and ignition Timing. But low Vacuum reading on Decel is a sure give away for incorrect Cam Timing. especially combined with the no revving past 5,000 RPM. You won't be floating the valve at 3,000 RPM on Decel.

^ Yep. That sound Logic-al