V-12 Engine into 308 Build, over on Grassroots

I distracted myself with GC height. It is about 16.4"


Image Unavailable, Please Login


We won't talk about why I decided to use the engine crane......

 

This oil passage is a gravity oil return, there is 0psi pressure so its a slow leak and the same leak I was driving around with last fall...a quart an hour when the engine is hot? Something like that so the only engine risk is running low on oil but I have 14 quarts....I could probably lose 10 and still have good oil pressure but the ecu will shut down the engine if pressure drops below my rpm based pre-sets. Very low risk beyond the the people pointing and laughing shame of it

 

There's a word for it and I'm blanking it at the moment. But I think you might be at the point where you need another set of eyes to look over and point out things you might of missed.
I'm very thankful Nick's been happy to oblige and do that for me on various projects. There's a blindness that happens when you get deep into a project that's complex as that.
Not meant as a negative at all, just something I've noticed over the yrs on projects, having somebody else walk thru and they'll always find something that you'll go "oh crap, how'd I miss that!"

It's all very impressive what you've accomplished. You're on the home stretch!

 

For me, mornings bring a calmer view of things so this rear panel that bent when the car fell off the jack that had met all spun up last night...water under the bridge.
Image Unavailable, Please Login

The trunk itself is undamaged, so no biggie
Image Unavailable, Please Login

My high tech pressure tester says the head is now sealed, that's good news
Image Unavailable, Please Login

I reset the front ride height. There is about a 1/4" of preload in the springs now so 4" under the frame is about as height as it goes unless I put a longer shock in, but 4" is the set point as all good.

Then a quick camber check
Image Unavailable, Please Login

LF=1.54 RF=1.32
LR=3.28 RR=2.43

I was targeting F=2.5, R=3 so it needs some work and I haven't checked toe but can see the front so still in a toe out condition so for sure that also needs help

Back to engine work for now.

 

Oh its WAY past that point!. I'm way more the idea guy than detail guy. At work I have a team for details, when I was racing my H-D way back the guy running the shop who provided some sponsorship was very detail oriented so a huge help...but on this project its mostly just me. The forum posts at least provide a chance something really dumb will get spotted. and its always the little stuff...like "hey, did you check the oil in the trans?"

 

The big leak is fixed, passenger side floor is dry. On the driver's side there is a small3" puddle the seems to be coming from either the cam cover itself or the endplate. I'll try re-sealing the end plate tomorrow since that is easy.
Changing the plug gap did nothing. Now that the start enrich is getting close to right I can see running color on the plugs and the rear bank is absolutely leaner with 2 mostly white plus, no doubt the 2 that drop. The cylinder MAPs looks fine and I did a compression test, 180-190 everywhere. I THINK what I'm seeing is that when the injectors came back from flow test I installed them in order, lowest in 1, highest in 12 and 12 is for sure the blackest...so that has to be part of the issue. Looking back to before I sent the injectors out I set +/-25% values in the trim tables. I'll play with cylinder trims for a bit and see if I can get it happier.

 

If you like doodads.... https://gyraline.com/ I have one. It's super clever and has definitely come in handy. It's way faster than my toe strings and notes. It's free to check out, but if you want caster/camber then you have to pay.

They published their study results vs. an alignment machine.

https://gyraline.com/pages/study1

 

I pulled the plugs and they looked a whole lot more right.

Still some black ones so I tweaked the trims some more and I'm back to where I was before with +/-25% numbers and that bothers me a bit. I looked over the TB sync data and its fine. Checked the TBs with a feeler guage, .003doesn't quite go through. Really thinking the trim value it the delivered fuel, not including dead time which is about 1.2ms out of a 2.2ms total pulse time so 11% of the pulse? Not to bad really.

Then I decided to go back to tuning by ear and adjust the fuel until it runs good....I'll see what the plugs look like when it cools down but it does run good and this gives a sense for how it builds revs even when I'm being a bit gentle with the throttle

 

And it drives again.

The clutch is adjusted about exactly right....push the pedal its disengage and drops into gear nice, but move it at all and the car is in motion. No wasted travel at all.

It wasn't fully warm on the drive and was wanting to drop cylinders...still lean I thing but I'll look at the plugs. I did a pretty hard pull followed by a pretty hard brake and the neighbors out doing yard work did not appear amused....so I guess I did it right Image Unavailable, Please Login

 

Heck yeah! Great job.

 

Ok, this going to get into a technical question. I wonder if you're fighting a mixture efficiency at idle. Proximity of TB blade to injector, air velocity thru the gap and low pressure zones on the opposite side of the TB blade. All that and it's distance to the valves.

That was something I had to work thru in the design for Nick's ITB 4L. With the monster TB's. Did my best given clearances and deck height etc. Still makes a fight for idle to keep it burning efficiently below 1k rpm. But Nick prefers 1200 idle.. so win/win.

 

The answer is ....I have no idea really. I think its a bit like the oil leak.....about 12 things all causing similar problems that need to be untangled. Step 1 is get all the cylinders acting about the same I think...that should be possible. After that....well I know all my exhaust slip joints leak so the O2 readings could be nonsenses. I know there is nearly 20% reversion and charge loss to the exhaust so can bugger tuning. I know I have a single narrow cone injector pointed at the port split which is unhelpful. And the list goes on.

So the plan is starting turning knobs and see what happens and what can be done and see where it gets to the "I can live with that" point....and start changing parts if it doesn't I guess.

 

Single cone pattern, yeah that's a big one to overcome. Wall wetting at low duty cycle is going to be a problem. There's dual pattern injectors, just need indexing of course.

Tune by ear and nose is probably going to be the winner for idle. Get nerdy with an audio spectrometer and track wave form at idle for ignition and combustion smoothness. Did that on an old Mercedes to isolate a misfire.

 

yeah...I've run single cone injectors on 4V engines a good number of times without much issue. I'm sure its not prefect but I've never had any issue tuning it since I'm not an OEM so "a touch rich" is just fine. The big game I see lately is "decapping" aka removing the nozzle from OEM injectors to increase the flow and they run fine too.

I'm really think I'm dealing with a bunch of little things. I have a nice differential manometer.....I think I can print a couple venturis to set on top of my TBs and have a differential mass flow meter to confirm the sync....then maybe glue my adjuster screws and be done thinking about it

And just work though the rest of list like that. One check mark at a time.

The logs do show it going quite lean at throttle open so probably time to start setting up the accel enrich stuff......I THINK what I wrote will work.....probably....I may play with it tonight after I look at the plugs and see how that is going.

Lots to do......

 

this is what I'm thinking for mass flow....print a couple of these venturis that will plug into the stack. Leave one in #12 which is my linkage attachment point and move the other around with the differential manometer attached at the bosses. I'm kinda guessing at a good bore, the small the stronger the signal but the more it alters flow, this is 25mm.

Image Unavailable, Please Login

 

Yeah, but they do make air meters for TB.. common to the carb people. Mass flow meter, analog though. Or you could go high tech and get the digital flavor..

 

Wait, just buy something off the shelf specificly designed and sold to do exactly what I'm trying to do when I could screw around trying to invent it? What sense does that make?

Plus I already have a cool meter looking for a purpose.

I did a little quite math and decided a 6mm bore is probably way closer to what I want so I'll print the but with enough meat to let me open it up to 15mm if needed. In my head this will make the job fast and accurate

Image Unavailable, Please Login

 

When you're right.. You're right

I probably missed it, are you trying to sync based on CFM, mass flow? I thought you had individual vacuum readings on the TB's. Then again, thinking this out, a quick mass reading would help with dialing in the fuel mass needed at idle. Be interesting to see how efficiently the burn is with timing and all the million other combustion design parameters. Wall wetting loses etc.

Given you can print off, I'd then get a wild idea to eat time with..I wonder.. let's increase the trumpet length to see how it smooths out the idle and low rpm..or maybe adding stipling texture to the walls of the trumpet to induce better boundary flow and see if that helps the idle flow at very low throttle angle and opening.. You know sheer due to velocity.. Things like that

 

I think you answered you're own question

Yes the goal is to sync based on mass flow to be certain the mixture differences are injector/fuel related. MAPSs all match pretty well, TB a For sure I can correct them with cylinder trim settings...I just want to be sure that is the best way to fix them. A piece of mind thing.

Image Unavailable, Please Login

 

I've been playing with cylinder trim to balance the plug colors and for sure the TB adjuster have been moving so new plan is get the TBs sync'd and adjusters glued. I did a little quick math and I'm thinking my venturi mass flow meter wants to be way closer to a 6mm bore than 25mm
Image Unavailable, Please Login

But I put enough material in it to allow it to be bored to 15mm or so...because I didn't do careful math. But when I went to hit print I realized I don't have enough resin and the print so print tomorrow whenever it gets here and this is likely a Saturday job then let the glue dry over night. I'm thinking RTV or a urethane adhesive more than jbweld, at least for now.

In the meantime. Yesterday I was less happy with the clutch...it seemed to maybe drag a little into 1st and reverse so I want to give it a touch more travel.

There seems to be more brake pedal travel on hard stop then I think there should be so maybe bleed again.

It is SOOO nice having the power steering working again, what an improvement in driving pleasure. but I kinda don't love the general feel though, at least not on my couple 0.2 mile around the block drives....almost too light and there is 0 self centering going on. There are 3 assist levels for the PS and I have it in the middle but I think I need to get the toe set and maybe figure out how to check the caster before doing anything else.

Thanks for the heads up on this option. I'm android which is beta it looks like but for sure interesting

and I've not address the small oil leak on the cam cover yet.

Lots to do....

 

Outta curiosity and playing with AI recently.. I fed the curiosity to grok.. assuming 42mm throttle and 6% idle opening... It calcs a 8mm bore. Could be GIGO as well, it's all about framing the parameters correctly.

Screen shot for giggles...
So much for that...

 

Pipe Flow and Venturi Calc for 42mm Pipe with 6% Throttle
Calc by Grok (xAI)
Setup:
Pipe ID: 42 mm (Area = π*(0.042/2)² = 0.001385 m²)
Throttle: 6% open (Effective area = 0.06*0.001385 = 8.31e-5 m²)
Venturi: 150 mm upstream, open to atmosphere (P₀ = 101325 Pa, T₀ = 288.15 K, ρ = 1.225 kg/m³)
Downstream: 20 inHg vacuum (P = 9.92 inHg = 33593 Pa)
Goal: Min venturi throat diameter for accurate mass flow measurement (choked flow)
Step 1: Mass Flow Through Throttle (Choked)
ṁ = C_d * A_throttle * P₀ * √(γ/(R*T₀)) * (2/(γ+1))^((γ+1)/(2*(γ-1)))

ṁ = 0.6 * 8.31e-5 * 101325 * 0.004116 * 0.5787
ṁ = 0.01205 kg/s

Step 2: Venturi Throat Area (Choked)

ṁ = C_d * A_throat * P₀ * √(γ/(R*T₀)) * (2/(γ+1))^((γ+1)/(2*(γ-1)))
A_throat = ṁ / (C_d * P₀ * √(γ/(R*T₀)) * (2/(γ+1))^((γ+1)/(2*(γ-1))))

A_throat = 0.01205 / (0.98 * 101325 * 0.004116 * 0.5787)
A_throat = 5.09e-5 m²

Step 3: Throat Diameter

A_throat = π * (d_throat/2)²
d_throat = √((4*A_throat)/π)
d_throat = √((4*5.09e-5)/π) = 0.00804 m = 8.04 mm

Result:
Minimum venturi throat diameter = 8 mm (ensures choked flow for accurate mass flow measurement).
Thanks to Grok for the number-crunching!

 

Sooo.. Anyone else here feel like a dumbass? Lol

i’m still trying to plug in parameters to our coffee maker.

 

I pulled the mass flow from DM6 (set barometer to roughly match idle MAP) and also from the IDLE MAP, VE, rpm, displacement.. Then convert to volume and into Bernoulli eq and I'm expecting about 2kpa signal. My biggest fear is the pulses are to big to get a good comparison in differential mode. bought 10ft of hose thinking the length will help damp it. We'll see saturday

 

Treat it like any wave signal, avoid the Hz of the pulse. Back of envelope.. 1k rpm is 16.67Hz so say ~3 meters or even 1 meter to avoid resonance. So yeah 10ft could work. What's your idle rpm? That's where the magic happens.