NA 3.1L=>head & camshaft questions. No shortcuts, max

[19762802+2]

I was thinking about starting a separate build thread for this year's engine upgrades, but I thought twice about it since this thread might be more appropriate.

 

Now that this thread has been removed from the L6 stickies list and now a "FAQs-->Powertrain-->L6" thread relocated by the Admins, I thought I would pose the question to the Admins / readers since we're a forum after all:

 

Should I continue to post my race engine upgrades and related dyno findings on this "FAQ" thread or start a separate build thread?

 

My thoughts are that this case it's nice to see in one thread how all aspects of the engine are tied in through the head, and chasing around the new choke point relates to output of the motor on the dyno.

 

Thoughts? If I get no replies I'll probably post the pics and data here.

 

I would keep it here or at least if you start a new thread link this thread to that one and the new one to this one and skim over what has been done etc. But in my opinion it would be nicer to keep it all in one thread, Easier for someone to go through everything in one thread then read 2 threads.

Edited May 8, 2011 by 19762802+2

[wondersparrow]

I agree. I have been coming to this thread for years now and it would be so much work to make a new bookmark

[zredbaron]

This update has been in the works for about 6 or 7 months now.

 

About six months ago when I first pulled the engine out I had the head flow tested. I wanted the numbers for future ITB calculations. The shop that he subsidized for measurement evidently was so impressed by the head that they hung onto it for a week and were very complimentary regarding its performance. As far as I know, flow numbers are about as comparable as dynos between shops, but here's something I put together for myself and I thought I'd share:

 

 

I was particularly pleased that in terms of VE if I could pick anywhere on that graph to have my lift, it would be about .565", right where my cam actually is. I guess this is what happens when you have the camshaft developer also doing your head work. Thank you, Mr. Jim Thompson and JohnC for the referral. What was that about seven years ago I think? Man, this thread is ancient. Haha.

 

For whatever reason, the flow shop ran both with and without the spark plug in the cyl. and provided both sets of numbers to me. Hmm.

 

I decided to also have the crank balanced to 10,000 rpm. I can only run to 7.6k because of the outer-springs-only design, but I wanted to be able to hold the redline like it was my job and be smooth about it. Of course as a part of the balance was my new clutch and flywheel set:

 

 

 

 

The new flywheel is 12 lbs, but what I like about it is that it's weight-relieved stainless steel, not aluminum with a modular friction surface. I'd rather have a solid one-piece rotor, just because it makes me feel better.

 

Also while I'm at it, I picked up some lightly-used titanium valve spring retainers on eBay. They feel like about 1/4 of the weight as the ones they replaced.

 

The outer-springs only design that the cam was profiled for are now installed, too -- 25% less seat pressure.

 

And finally, he indexed all of my spark plugs with the head out in the open. The outer electrode is tucked against the side of the cyl. wall so the flame front propagates toward the center of the combustion chamber.

 

Details. More to come but that's all the time I have for now.

Edited July 24, 2011 by zredbaron

[zredbaron]

Unfortunately there is a decent set of pictures that I'm missing (lost my iPhone). Should be recovered one day, but that doesn't help me right now.

 

Since this thread is part performance and part personal project, here are some fugly "before " pictures:

The engine has been removed, but the electrical system still needs to be cleaned up, camber plates welded in and the engine bay is to be resprayed, too. Also note how nasty the back firewall is and also how not clean / distinct the radiator firewall is.

 

 

My recent repaint in 2009 wasn't a frame off restoration, so underneath the cowl and fenders I found some metal that hasn't seen daylight for about 40 years, presumably.

 

Right around here I took some odds and ends to a fellow member of my Z club who does some soda blasting on the side:

He's blasting my intake manifold here. (Kevin Surface, Tidewater Soda Blasting)

 

All the odds and ends I had him spray. the hood springs are my custom duplicates of the OEM springs but of a lesser diameter for JohnC's carbon fiber hood.

 

The kick plates and thermostat housings were tossed afterwards, as I was able to cheaply acquire Nissan parts from MSA.

 

The motor mounts were toast:

You can see daylight through the side of it and the cracks were quite noticeable since the engine was recently rebuilt in 2008. I guess that's fair when you have just about double the flywheel horsepower from stock.

 

Right around this time JohnC helped me source some new motor mounts from Japan and mentioned that I could reinforce the mount brackets if I desired. I decided to take it to my local machine shop and I asked them to weld on new steel plates and then file the welds smooth afterwards. The theme here is for all my performance mods, especially the fabrication mods, to seem as if they came from the factory this way.

 

This is how I got them back:

 

Then I had them powder coated black, which match the Kameari mounts nicely:

The new mounts are an extremely hard poly/ABS type of plastic. They were a serious pain in the ass to install, but that motor is now *in there!*

 

Side note: I've upgraded the dimensions of my image uploads as a reflection of the times (ie data speeds and screen resolution). Are they too big for anyone?

Edited July 25, 2011 by zredbaron

[zredbaron]

Stahl headers are a work of art.

 

I was giddy to say the least when they arrived:

I was so impressed that these were hand made and that the merge collector, hand made from another shop, slid right into place. Phenomenal work.

 

They really stood out next to the outgoing street performance headers. Each three way collector was 3-dimensionally coned into a diameter equal to that of the previous collector's final output.

 

Checking for a fit on a similar head. Really make the stock intake ports look small!

 

The ports were a point of contention with my local Z specialist. He talked down to the quality of the headers, stating that for the price I paid they should be ready to bolt up. I disagreed; at this level of performance they leave the extra material in place and EXPECT the customer to port match the headers to their head. How could Stahl know how much I've ported my head?

 

So of course I had my head shop port match them:

...which obviously really opened them up and made a huge difference.

 

Then I sent them off to SwainTech's White Lightning ceramic coating. Took about 4 weeks to get them back:

 

They also coat as much of the inside of the pipes as they can (for NA engines only).

 

Until I recover my iPhone pics, this is the best shot I have of the merge collector from SPD. JohnC also set me up with this beautiful piece of craftmanship. Truly remarkable once you look inside at how smooth it is and how perfect the tig welds are.

 

You can really see the difference in terms of flow potential:

 

 

You can begin to see how the scavenging effect is going to make a huge difference

Edited July 24, 2011 by zredbaron

[PalmettoZ]

How close are you to assy and firing it up? Looks great. Are you planning to get it going with the carbs and then switch over to ITB's?

[zredbaron]

Truth be told, I fired it up a few days ago for a few mins and immediately left it in Arkansas in my trailer. I'm out in CA right now visiting family and following up on some job leads. Still compiling all the pics together, but I'll get it up eventually. (So to speak.)

 

Brutal not getting to run it on the road without a muffler before I left. Arkansas could give a ****, and I plan on making some noise and tuning it with my butt-dyno (no AFR, either).

[zredbaron]

Split project thread:

http://forums.hybridz.org/index.php/topic/101309-weld-in-camber-plates-custom-strut-braces-engine-bay-respray-project/

 

In the above thread I'm posting pics of the fabrication work and engine bay respray prior to installation of the rebuilt engine.

 

As for ITBs -- Yes, eventually. I'm going to keep these carbs and see what I can get out of them and compare. That may be the only upgrade at the time, too, which would be interesting for dyno plot comparison. For the record I'm running 40mm Webers, which means a max venturi of 36mm, which were installed with air horns and a cold air intake plenum for years now. ITB's aren't for a year or two down the road, perhaps.

[zredbaron]

This is everything unloaded once I reached my Dad's ranch in Arkansas. He has a large metal building that's fairly new (5-10 yrs?) and therefore is a wonderful place to work on a car. Too bad it was so damn hot! I literally had to work at night. Even then I sweat my ass off. Humidity is the devil.

 

Edited July 27, 2011 by zredbaron

[zredbaron]

Next up, the pulley system, etc:

I also had the water pulley powdercoated. Part of my Kameari order included this adjustable alternator bracket. Wasn't that expensive, so I included it with my order for the motor mounts. Also new in this pic is the 280Z alternator with internal voltage regulator + diode conversion from MSA. Much better than my crappy setup before, which included a broken wire that prevented charge reaching my battery. Essentially I raced last year off of the battery as an expendable electrical tank. Oops, no wonder I had to charge it all the time.

 

Getting ready for the headers. I verified my spark plug wires were still consistent after 600 miles, they were. In the 2008 rebuild I went into the weeds with them. I called Electromotive and they evidently use this specific EMI suppressed wire that's 800 ohms/ft or whatever it was. They told me they send the most spark energy to the CC with about 1250 ohms of resistance. So I cut all my wires the same length to match that resistance. I checked them all this go around and all were in the 1250-1275 ohm range, so I'm good still.

 

No amount of cursing will convey how long it took me to get the Stahl headers installed. The frustration was further compounded by my attempt to keep the ceramic texture as clean as possible (dirt magnets!).

 

I first assembled the headers into their final 6-2-1 design, and bolted them together and fastened the spring retainers. After wrestling the headers and the manifold bolts for about 30 mins, I finally gave up and decided I couldn't get the flange to clear the bolts unless the header was disassembled. So I took it all apart.

 

Even then, it was a ton of wrestling just getting them on.

 

Then came our favorite game of getting the thick washers that retain the bottom of the intake manifold onto the bolts. The thick primaries interfered in a laughable fashion. I spent a lot of time on a bench grinder shaping one of my custom spacers. The spacers were essentially thick washers with two tiers of thicknesses. The Stahl flanges were much thinner than my Canon intake manifold, so I needed a step washer to properly fasten both sides.

 

Surprisingly enough, I don't have a picture of the stepped washers anywhere. You can see them installed, so I'll try and show that later when I'm with the car again.

 

After messing with the bench grinder and the step washers for at least an hour, I finally got the headers bolted up. I get under the car and start assembling the primary collectors and merge collector. Fail. The merge collector wasn't even close to having the real estate to slide over the exposed pipe.

 

Back to the drawing board. I loosened the headers, removed them, and assembled the primary collectors without the merge collector. I put this assembly back on the head and loosened the nuts as far as I could. This play allowed me to tilt the bottom of the headers just enough to get the merge collector over the exposed pipe. Whew! Took me another 30 mins to get it all the way on. Then I went back and tightened the header on and checked for clearance. Sure enough, the merge collector is pinned against the firewall's corner. Sigh.

 

But wait, I forgot about the stepped washers! FML, now I have to loosen everything again, and wrestle the intake manifold to get the damn washers onto the bolts. Probably another hour later, I *finally* had the headers bolted up. Took me at least another 15 mins to get the retaining springs on. For one of them I simply could not get my hand to it:

 

The obstructed portion of the merge collector is exactly where the pipe is touching the firewall's turn. It's not barely touching, it's solidly flush. I don't know what that means for the pipe or the car, but I'm not removing those headers. Someone please break it down for me? I'm thinking I'll use a turnbuckle if I have to cinch it away from the firewall. I could do it with the headers hot so they are slightly more malleable and may cool into a new position slightly. Anyone see any red flags?

 

I did eventually get the carbs installed. God, I hate our manifolds.

 

 

So of course I would love for anyone's opinion on the issue with the headers being up against the firewall corner....

Edited July 27, 2011 by zredbaron

[zredbaron]

And final assembly drew near. I literally started at 9pm that night, and in these pics it was about 9am the next morning. I was leaving for the airport at 11am and had to wrap this up, get it running and slap the car in the trailer for the next 4-6 weeks. There weren't the bodies to push it up the trailer ramp, and no one wanted my car left out in the commonly opened building. Ready, go!

Getting close. I don't think I had drained the old fuel yet.



I'm pretty sure this is right around final assembly. Minus the valve cover breather hose.



This was definitely complete because I can see coolant on the ground. Evidently I only finger-tightened one of the thermocouple housings. Oops.

And finally, a short video with audio...
 

And yes, that's as far as I've gotten. I won't be back in Arkansas for at least another month. Edited October 10, 2014 by zredbaron

[zredbaron]

I'd like to point something out / pose a question regarding the video.

 

I was surprised both at how much quieter the car was than expected and also how smoothly it idled (relative to before the rebuild, when it was actually tuned).

 

After talking to a friend, the conclusion regarding it being quieter than expected is that this is due to both proper exhaust scavenging and the larger diameter primaries / merge collectors. Mostly because of diameter of piping.

 

As for how smooth the engine ran.... the carbs were in no way synchronized, jetted or even tuned for idle mixture. I'm not sure if this is a testament of the tuned exhaust, crank balance or both. (Not to discount the importance of fuel + ignition, but both were present before this smooth condition.) This video was taken about 20 mins after the engine was first started and warmed up. I'm particularly inspired by the fact that the only time you can *see* the engine move was at startup when the cam's overlap just about kills the start.

 

I wonder how much of it running so smoothly is the crank balance vs. the exhaust scavenging. Thoughts?

Edited July 27, 2011 by zredbaron

[zredbaron]

Bump.

 

No opinions on the headers being physically pinned flush against the firewall/floorboard?

[JMortensen]

Slide hammer the floor away from the header, or remove the header and persuade the floor away from it a little with a BFH.

[zredbaron]

Thanks. I wasn't sure whether I'd be deforming the floor or the headers.

[Tony D]

Generally if you look at most race cars, there is a little box that has been added in that area to clear properly calculated headers. You took pains to get collectors where they 'need' to be, and sometimes that doesn't jibe with what packages well in a street car. Clearance the car, not the collectors!

 

As for engine mounts, here's a snap of a former F1 Lead Engineer's thoughts on what L-Engine Mounts should look like (as well as a take on tranny cross-member):

I'll be in his shop in about two weeks time. I hope my baggage allowance is sufficient, I feel I won't have a lot of money left over when this trip is through!

Edited September 11, 2011 by Tony D

[zredbaron]

Those are gorgeous. Saved the pic of the crossmember. Thanks for making my mounts seem amateur! I *used* to be proud of them....

 

Just kidding, of course.

Edited September 24, 2011 by zredbaron

[duragg]

You still running that Sunbelt #2 cam mentioned earlier in the thread?

 

Tj

[zredbaron]

Yep: 326/315 @ .565". You may be able to call Integral Solutions and order it as the "Sunbelt Race Cam #2." That's what my cam spec sheet said, if memory serves. That said, it was specifically profiled for the flow characteristics of Jim's port work...

 

Also, it was suggested to me that I post this recent tuning video to follow up on the headers build. That, and it will be six months before I'm with the car again to properly dyno it.

 

 

(It's fairly lame from a performance driving perspective, but you can hear the motor, at least. It's more tuned at the end, of course.)

Edited October 7, 2011 by zredbaron

[JMortensen]

Sounds yucky.