HuD 91gt

Pictures of my inexperienced work.

I've been in the middle of rebuilding my first engine for many months now. I decided to tackle a little bit of headwork on my own. I was having issues lining up the head gasket, and tracing a mark for the fire ring onto the head itself. It seemed to me, if I used the "wear" marks on the head, it would accomplish the same effect. So I did what I could, and tried to take as little material off as I could while still relieving the area. I'm done about 90% of the work I want to do and decided to toss the head gasket on the head to check my work. Still having issues lining up the head gasket (Or doing it properly), I do believe I overdid the unshrouding on one of the cylinders. Is the head junk now? I'm using a Ishono/Stone gasket from MSA. The block is over bored .040". Are there gasket with larger fire rings? Or should I be shopping for a new head and maybe sending it off to one of the local specialists (Or perhaps Hybridz locals).

Looks gorgeous. Now where can I get those fuel line mounting blocks. haha.

And this is exactly the reason why I warned everyone that I had never done it! Haha. I did it with compressed air, but I guess that's pretty tough when the heads not bolted down yet.

Don't take this as gospel, as i've never even taken the head off my vehicle. (That's a lie, i've taken a couple off, but yet to re-install). But wouldn't it be easiest to install the head without valve springs. Align the cam/sprocket with the timing chain where it needs to be. Then put in the valve springs? The small amount of fiddling i've down with my head, i've always found spinning the cam with that flat notch to be a bit of B*&ch. Opinions?

Pm'd

Thanks for the correction. Makes sense.

Ok that's what I thought. Custom valves or go OEM. Thanks for the input.

Hello, I currently have my P90 head under the knife. I am attempting my first port and polish job. Currently unshrouded the valves, blended the seats into runners, as well as polished the chambers. I'll be smoothing out the runners here shortly without doing any reshaping. Although, I did slightly smooth out the metal around the valve guide on the exhaust side only. I currently have Colt Cams up here in Vancouver BC grinding away on a cam for me. I've purchased the Schneider springs/retainers from MSA and have yet to decide if I will run the outers only, and stock inners or run the whole setup. TBD. Next up is a new set of valves. I just got off the phone with SI valves in California and they no longer stock their swirl polished valves in the P90/P79 lengths. He mentioned people who generally need that, are already replacing all the valve train and it is all adjustable. He still stocks the OEM stainless units. The only swirl polished unit's he stocks are the shorter version from the earlier heads. I am not shaving the head any large amount as this will be used in a turbo charged application. I honestly can't fathom what is adjustable in the head other then large amount of valve guide being ground away. What am I missing, and can I use the shorter valves in my application? Secondly, I've searched and searched and SI valves was the only place I found who made valves for the P90. Anyone know of any other options? Cheers

Isn't hoke working on a 350z transmission adaptor?

Isn't home working on a 350z transmission adaptor?

When you go to sell, let me know!

8.8:1 vs 10:1 on different head, with different flow characteristics. I've been through what your searching, and tearing down, or "rebuilding" a motor is not worth it for the minimal performance increase you will see. As for the turbo cam in the N/A application. The wider lobe separation will certainly not help with your detonation issues. Having no experience using two identical cam profiles other then lobe separation I can't really say what it will do. But all the articles tell me you will be losing power. Whether it's worth it over the stock cam? Who knows. I probably wouldn't spend $100 on lash pads to find out. If your willing to do some DIY headwork, and N42 on flattop pistons could be a great option for you. But if you are just doing some mix and matching with parts, it's not worth your time or money. The '83 N/A motor should be a good runner. If it is, let it be and build a turbo motor.

Sorry, I didn't really answer your whole question. I was just mix and matching the pieces that you had. You don't really have too many options. Flattops and the N42 are great. Unless you have some good ignition control, or a cam with some more overlap then the stock one you will probably have some detonation without bringing back the timing a good bit. The N42 with dished pistons is going to give you a stock 280z engine. The dished pistons and the P79 is going to give you a stock low compression L28et with funny shaped exhaust ports. What you do from here is up to you since you'll have to be purchasing parts anyhow.

P79 and a dished piston block for the turbo, stock cam or non hydraulic turbo cam N42 and a dished piston for the N/a. Stock cam No brainer if you've done any sort of research at all.

I just realized when I clicked on that link i've contacted you before on usedvictoria! I was looking for the L28et you had for sale with the 260z! Small world, since your so close I may want your services in the future! Very cool!

Looks great! Loving the progress thus far. Sometimes take way longer as I'm experiencing now. Keep up the good work and dedication!

Sorry to bump this one from the archives. I've been searching on how to use the 1981 ZXT 90 tooth wheel on a megasquirt setup using a hall sensor. I'm currently in the research phase, and have yet to actually read the entire megasquirt manual. BUT, is there is reason you can't just grind off a single tooth, rather then making it a 30-1 wheel? Will the megasquirt software not allow a 90-1?

Edit

^ please don't spread inaccurate information to what could be unknowledgeable people. There are plenty of people running L Series turbo engines at ~9:1 compression. Just because something is not the norm, doesn't not mean it will not work.

Great article! Thanks for the read. The car is currently off the road right now and i'm trying to get it back to being roadworthy as soon as possible. The bottom end is at the machine shop getting inspected, and I need to send out my worn out cam shortly. Your probably right, a quick call to ISKY or the like will get me on the right track. Cheers.

Totally understandable. My situation is that I can't really do the entire thing at once. I don't have the space. If I were to take on a project like that there are way too many variables to go wrong. I live in a major city, in an apartment. Space for working on projects is time limited. I can't be without a running vehicle for long (I just can't leave it). I am starting with a 240z. L28et requires, an update to the entire fuel system, from tank to injection. Dealing with a different ignition, not to mention the unknown condition junkyard motor. For me, going in steps 1)Building a moderate compression N/A motor on carbs 2) Fuel system 3) Engine management (Megasquirt) 4) Finally complete the injection/ignition and install the turbo portion. Doing it this way enables me to slowly go through the project, work out the bugs then carry onto the next step. It may not make sense for most, but it does for me. Rebuilding the motor is the base of the project, first and foremost. I am simply asking if there is a mild grind available which I will require for step 1), the N/A carb'd motor which may work better in the turbo application then the turbo cam itself but also be able to run to a satisfactory level in the N/A setup for the time being. Since I have a stock unusable N/A cam and I don't particularly want to run the turbo cam in the N/A motor, I may as well get one which will work in the turbo application as well. Make sense?

Completely understandable and sort of expected. Considering my end goal is not an extremely high powered machine, I figured a slow adaptation from a N/A to the turbo variety would be acceptable. As suggested above, the A-C cams would be completely acceptable and work for all instances. But I specifically have a cam which is worn and needs a regrind. There must be some sort of combination which may improve performance over trying to imitate the original N/A cam? As I said before, I do have an L24 engine laying around, but I don't want to start piecing it out. The idea that people use the N/A cams in the turbo motors to get a "Sportier" power band leads me to believe there is a cam which works for both instances. Will it be an outright performer in both? No, but thats not exactly what i'm looking for.

Hello, I'm about on my 5th plan for an engine build right now. Im currently building the bottom end of an F54 block with oversized flat top pistons. Original plan was to use my N47 head, which needs new valve train, a (round port)header etc. looking at the costs, I think I am going to purchase a local L28et and rebuild the P90 head for the time being and essentially create a overbored stock 280zx motor with square ports. I will eventually use the rest of the accessories to turbo the motor with the flat top pistons as I believe it will create a nice streetable motor. What I'm looking for is a mild performance cam which will be suitable for the vehicle in the n/a application, and also will be suitable for the motor once turbo charged. From what I've read, a cam with minimal overlap would be desirable. Can I assume any of the "stage 1" cams would be ok for this sort of application, secondly should I even bother? The turbo cam would be fairly anaemic in a n/a application. My other option is the stock cam from my L24 motor (I forget the code stamped on it, but it is the standard version, not the rare one). Personally I'd rather get my N47 cam reground rather then mix matching parts from my complete l24 motor. But it is an option. Any input is appreciated.

Thanks for the reply oddmanout. That's the issue, i've already purchased one unknown engine and it is now disassembled ready for the machine shop. Another one is a risky move. A lot of work goes along with the L28ET for us 240z guys as well including the fuel system. One step at a time. I'll have to get more details on the turbo unit.