Qjet resource

427L88 · Dec 6, 2020

Hahaha, brother if anything I was being too civil or chivalrous as I don't really give a rats ass what she thinks and she has been trampling on this thread since the beginning. Frankly, I should have been my natural self and told her to take her EDEL posts and "Cliff's kit" and shove them up directly up her ass. WHich is likely what I would have done to any "guy". And have. As

k Bill Burke.

everyone's a fckng expert. In fact, I think hardly ANYONE is.

I have a friend who is a "systems engineer", and he asks the most boneheaded questions about mech systems I ve ever heard, at least to me being a dumb numbers guy, and him being a trained ME, so DONT ASSUME!

TO end this thread on a positive note I THANK THE LORD for the real experts out there including Mark Jones, who built me a STUNNING BBC, and to Eric, who somehow got the beast happy to feed through a Qjet, which a few of us non-experts attempted w/o success.

NO BUST TO TOM MOBLEY, who gave me a great core and tune he thought might work, the most unusual episode was when the truck 5000- series Qjet went OFF>ON>OFF>ON at WOT, thankfully at only 4000 rpms or so, but still at near 600 FT LBS! That shit was violent.

That's when I knew Mark was spot on when he told me a QJet would barely feed this beast a healthy dose of air and fuel. After two ( three incl mine) attempts, Eric got it done. 3rd times a charm Vintage Musclecar Parts! ( I'll only include the experts, Tom Toal , Harold Bettis and Eric here )

For the record, this MJ467 is a bracket engine in "drag". Literally. Between the Qjet tune, and the VAC ADV, I've discovered it has to be treated and respected as such. Just as Mark told me.

And also for the record, I had the block VIN-stamped and a proper GM sequence build date with MJ as the prefix......Meaning it stays in this 67 SS396 # 178953 until way after I'm gone, if I have anything to do with it. That means HEEDING EXPERT ADVICE when required, so it hits that "duty cycle" !

The only follow up question I have for Eric will be if I decide to have him make my ancient 4871-2 race 850 look brand spankin' new. As it feeds the beast so darn well w/o drama. I may have to learn to LOVE 13 mpg and figure out how to strip that dang Eastwoods carb paint off it for a proper plating. Methinks he'd charge DOUBLE with that stuff on!

THANKS Y'ALL! 👍

VORTECPRO · Dec 6, 2020

nashville beth said:
You just lost a fan.

Some how I'll find a way to go on living..........Cause I will always defend Eric, solid guy!

VORTECPRO · Dec 6, 2020

nashville beth said:
.

You be any way you want to be, I have no problem with it, male or female I don't care, how come its always the engineer who's giving me trouble LOL, I got one of those already and his name is Harold............................

Vintage Musclecar · Dec 6, 2020

Thank you Mark, I appreciate that more than you know.

VORTECPRO · Dec 6, 2020

nashville beth said:
You said an engine will need higher octane gas if a small amount of vacuum advance was added. That makes zero sense.
Mark Jones is a skilled builder. Why are you dragging him into the conversation ?

In the past I've had customers run vac advance on the higher HP engines, which resulted in the center being burned out of the head gaskets, the people wanting to use vac ad probably do not have engines like the ones I sell. My automatic cars always run the dist locked, run very fast and do not torch the head gaskets, run 160 degrees. Now NB line up next to my shop truck and show I'am wrong about my tune up.

427L88 · Dec 6, 2020

CAUTION: TRUE EXPERTS ROAM HERE ! 👍

77 cruiser · Dec 6, 2020

Had your Wheaties this morning ha Gene.

VORTECPRO · Dec 6, 2020

427L88 said:
CAUTION: TRUE EXPERTS ROAM HERE ! 👍

When the engines come off the dyno the felpro steel gasket is stuck to the head, I then take a MRGASKET ultra seal gasket coat it with a very thin layer or GE clear silicone slide it between the head and hear TQ from the center out and keep TQing until they are not lose, finally they will not be lose after several TQings. I can only imagine the problem getting that gasket off, sorry.

Vintage Musclecar · Dec 6, 2020

Many moons ago, I had a mild 406 that spent time in my old Monza and later in a `77 Z28. I drove it for years without issue. I experimented with different timing events while it was in both cars, but only experimented with vacuum advance when it was in the Z.

I've told this story repeatedly, but once more for old time's sake; when it was in the Monza, I experimented with the advance weights & springs in the HEI. I normally ran it with 2 medium springs, but one day I stuck in the lightest springs. My butt-dyno told me it felt a LOT stronger down low--but my electronic ET timer in the car told a different story. Going from medium to light springs slowed the car down .4 and 4 mph. Traction was not an issue, btw. I re-installed the medium springs and the missing .4 and 4 MPH came right back. Note that this was with a stock 1600 rpm converter and a 2.93 gear in the 7.5.

That's one "one size fits all" myth debunked.

Is there a time & place for a fast advance curve? Absolutely. Was this one of those times & places? Nope.

Later on when the 406 was in the Z, I experimented with vacuum advance in an attempt to improve gas mileage. (fact of the matter is, my right foot was my biggest detriment to gas mileage). I don't remember the specifics of the changes, but I always ran premium fuel and never ONCE heard the engine spark rattle. It wasn't 1 month after I'd hooked up the vacuum advance that the engine lost a top ring land--while I was sitting at a traffic light--idling--in the middle of town--facing UPhill. It just shut off and locked up tight. Had it towed home and found a mangled spark plug on #6, pulled the heads off and the remnants of about 1/3 of the top ring land were scattered about the bore--along with a nice vertical crack running all the way down the bore.

Again--NOT ONCE did I ever HEAR the engine rattle.

427L88 · Dec 6, 2020

77 cruiser said:
Had your Wheaties this morning ha Gene.

Hey, I rose too late to take an early stalk in the woods which needed to start at "zero dark thirty" so...let's say I woke late, but ready for a patrol!

Eric, I ran the VAC ADV with my garage built 427, and oft had to disconnect it on the open road as it'd ping pulling up hills. You noticed bad gas too. This was a GM can limited to 8 @ 13 Hg.

PS Mark, no issue sir. I blame myself, for not scraping clean and chasing threads as is customary before i shoe horn it in, ESPECIALLY with those oh so pretty and fickle WHITE tubes. Talk about temporary insanity. They cost me near what a Holley 830 annular would have. Which I am GLAD you talked me out of. ( my old Holley race and your engine were made for each other I'm thinking) Wish I had talked myself out of white ceramic tho. PITA. Needs touch up already.

ALSO Mark, I have to admit, dumbass over here left the 7k 427 chip in the MSD. I wondered why I'd never bumped the 6500 chip I thought i had in as I KNEW I ran her up above that maybe 6500-6600+.

Brother, IT NEVER STOPPED PULLING!

As much as I LOVED the sound of it all and DANG does it still pull up there, a newly bought 6300 rpm limit chip has been installed as per operating instructions and no VAC ADV used ! Maxima 10-40w oil also now fills its veins. ( they have AWESOME customer service btw! )

OK so NOT being an engineer, one thing about 13 mpg is that , even sans VAC ADV and OD, with the 3.31s and tall 27.5" rear meats. 70 mph is clocking at around 3200. 55 mph is around 2600. So if I go 60 ar near 3000 rpms, and all stays the same, at least the mill sees its total 36 degree timing. So the 13 was clocked just under the 65 mph speed limit here. I DONT like pushing this mill much above 3k for hours at a time. Its the VIN thing.

Vintage Musclecar · Dec 6, 2020

Gene, you might want to check your speedometer calibration, something appears a bit off.

You're running a 4 speed with a 1-1 4th, correct?

Using the formula MPH X Gear Ratio X 336 / tire height:

55 MPH = 2224 RPM

60 MPH = 2426 RPM

70 MPH = 2830 RPM.

427L88 · Dec 6, 2020

Oh its likely my very "coarse scale " blinker tach and brain. Useless POS frankly. ( the blinker, not my brain!) All I know is I hold approx 3K rpm to just stay with 65 mph traffic, so its likely 3000 @ 70-72 mph or so. I prefer to keep it 2650-2800 which is just under 70 to maybe 65.

Hard to drive 65 in a 65 MPH zone anymore. I know 55 mph is a "lazy" 2500rpm -ish on the blinker.

nashville beth · Dec 6, 2020

VORTECPRO said:
In the past I've had customers run vac advance on the higher HP engines, which resulted in the center being burned out of the head gaskets, the people wanting to use vac ad probably do not have engines like the ones I sell. My automatic cars always run the dist locked, run very fast and do not torch the head gaskets, run 160 degrees. Now NB line up next to my shop truck and show I'am wrong about my tune up.

Just curious; why didn't you back down the initial timing ? Or limit the total timing ? Or suspect bad gasoline ?
Vacuum advance is added under light load, so why would you blame it first ?
I don't appreciate the condescending tone coming from this group. I didn't tell Gene what to do.
------
Gene : I don't really give a rats ass what she thinks and she has been trampling on this thread since the beginning. Frankly, I should have been my natural self and told her to take her EDEL posts and "Cliff's kit" and shove them up directly up her ass. Which is likely what I would have done to any "guy". I have a friend who is a "systems engineer", and he asks the most boneheaded questions about mech systems I ve ever heard
------------
Beth: really classy Gene. Just like Eric claimed; you three are a class act

Tom Mobley · Dec 6, 2020

little early for cabin fever yet.

I will say it hurts my widdle feewings to see our best members gouging at each other though. Locking

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