March 16, 2025, 06:05:02 AM

Author Topic: My 4.3 vortec 84 FB  (Read 127809 times)

Offline freeskier7791

Re: My 4.3 vortec 84 FB
« Reply #300 on: March 26, 2019, 09:59:15 AM »
That's cool. Longer runners are always worth it!  I suspect since that intake is so open the velocity was not great enough when the throttle blade opens up rapidly. 
https://www.youtube.com/thedriftingdad
1985 Mazda RX7 GSL Drift Car

CCVT

Offline rk970

Re: My 4.3 vortec 84 FB
« Reply #301 on: March 31, 2019, 02:37:49 PM »
Well shit...!!!
Still burning 1qt ~200miles..
Off with its heads...




You can see the black streak from the guide to the chamber.



Oil burn sludge on the back of the intake valve after 480 miles.. 


I don't have a mic small enough to measure clearance, but if I pull the valve 1/4" off its seat I got approx .008" wobble from a dial indicator.   
Now I have to figure out why they got wiped out so quick,


Any thoughts?

Offline freeskier7791

Re: My 4.3 vortec 84 FB
« Reply #302 on: April 01, 2019, 07:40:33 AM »
Has the guide worn and not the valve?  I wonder if the materials are not compatible?  Can you install some sort of removable guide?  What do the valve seals look like?
https://www.youtube.com/thedriftingdad
1985 Mazda RX7 GSL Drift Car

CCVT

Offline rk970

Re: My 4.3 vortec 84 FB
« Reply #303 on: April 01, 2019, 12:15:10 PM »
I got a telescoping gauge,  .003" clearance on the top of the guides, .004~.005 on the bottom and its not symmetrical.   Valves are stainless with chrome stems.   Stock clearance is supposed to be .0012~.0015.  I tried three different types of guide seals. 

Offline rk970

Re: My 4.3 vortec 84 FB
« Reply #304 on: May 25, 2019, 05:13:19 PM »



I taught myself how to use a sewing machine.






I am in the process right now of using SEM color coat on the window crank and redoing the arm rest (so all the black matches.

Offline digitalsolo

Re: My 4.3 vortec 84 FB
« Reply #305 on: May 25, 2019, 07:41:00 PM »
Wow, that came out really well!
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...
2007 Aston Martin V8 Vantage - Gen V LT4/TR6060, upper/lower pullies, headers, tune.
2021 Tesla Model 3 Performance - Stock...ish.

Offline rk970

Re: My 4.3 vortec 84 FB
« Reply #306 on: June 17, 2019, 07:51:09 PM »
It lives... 






New guides, and I had to use 2.02/1.60 valves,  grinding the seats again for the 1.94/1.50 would of sunk them in a little to far for my liking.  I used a Black&Decker valve grind set and a neway 75° to cutter to open the bowl up.  Intake seat is .045" width, 60° is .030" and then the 75° down to 88% of the valve diameter and blended into the bowl, short side radius is also worked.  Exhaust seat is .060" the 60° cut is .080" and the 75° goes down the 90% of the valve dia.   Top of each seat is a .040" 30° cut then a 15° and blended into the chamber.  Chambers are now 64.5cc so I lost about 1.5cc from a little bit of unshrouding work.
I lost a little bit of intake vacuum at idle like .4~.6" so I believe that the low lift flow is much better now (it acts like its got more came in it) and it definitely pulls harder on the top end now.  I installed the springs at 1.770" to give about 11lbs more on the seat pressure.  And used pushrods .050" shorter to get the geometry spot on..








So, why yes that is spray urethane foam in the spare tire well...  any hoo.. I did not want to use a 35 year old spare donut tire.. I did not take pics but i did make a top part also and a lid from 1/8" masonite..  In the usps box is a tire patch kit/tools and gloves. 




Offline rk970

Re: My 4.3 vortec 84 FB
« Reply #307 on: June 25, 2019, 07:58:04 PM »
Last thing to do in the interior is the seats. 






The horn button is on and I did the final alignment on the front end. .070" total toe in, -.6° camber and about 5° castor.  It would put the beat down on the 87 rx I had, I can get on it real early on corner exit its almost comical..
The sad news is the oil burning is still present.  One Qt in approx 800 miles a great improvement from 1qt in 150.  I have disconnected the PCV valve and blocked the fitting from the intake manifold. It seems to be drying up, I only got 700 miles on the bottom end. This thing is making me go f*(king nuts.  Its not the guides (that was a problem), not the rings (no smoke under hard acceleration and no excessive blowby)  So either my PCV is picking up a lot of oil vaper, intake gaskets not sealing the valley or the oil level is to high.  I am going to have to pull a dipstick/tube assembly at the junk yard from a early 90's S10 2wd and measure it (that is the oil pan I used and modified)
You can see in this pic I had to notch the pan for the drag link clearance, I am beginning to think the oil from the forward sump (approx .6~.7gt) may be sloshing into the main sump under hard acceleration and causing an excessive oil level and getting into the crank. The oil may may be flung into the rear cylinder and overwhelming the oil control rings.  Any thoughts?

 1/2 tank of fuel weight is 2351lbs.  I know, light right..No Power anything and no sunroof.  I had to do a weekend job and I took the rx, I drove around going back to the island (did not take the ferry) averaged 25mpg, I thought that was really good since most of it was at 70+


Offline digitalsolo

Re: My 4.3 vortec 84 FB
« Reply #308 on: June 25, 2019, 10:26:26 PM »
It's a viable theory on the pan;  that oil usage is really weird.   :(

I'd say that's pretty damn good fuel mileage.
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...
2007 Aston Martin V8 Vantage - Gen V LT4/TR6060, upper/lower pullies, headers, tune.
2021 Tesla Model 3 Performance - Stock...ish.

Offline freeskier7791

Re: My 4.3 vortec 84 FB
« Reply #309 on: June 26, 2019, 06:57:35 AM »
how much oil are you putting in the engine?  do you have any idea how much that sump portion you built holds?  2351 lbs is impressive, I was at 2477 lbs with my car.
https://www.youtube.com/thedriftingdad
1985 Mazda RX7 GSL Drift Car

CCVT

Offline rk970

Re: My 4.3 vortec 84 FB
« Reply #310 on: June 26, 2019, 08:24:58 PM »
The weight sounds about right for our cars. v8 vs v6, you got a sun roof and you wheel/tire combo and suspension mods may be heavier also,

Offline freeskier7791

Re: My 4.3 vortec 84 FB
« Reply #311 on: June 27, 2019, 08:00:34 AM »
The weight sounds about right for our cars. v8 vs v6, you got a sun roof and you wheel/tire combo and suspension mods may be heavier also,

The wheels and tires are definitely heaving on my car.  I need to reweigh with the Ford 8.8 rear, I am going to delete the sunroof as well, and add a cage.

It really is amazing how little power you need to make the FB a pretty outrageous car.
https://www.youtube.com/thedriftingdad
1985 Mazda RX7 GSL Drift Car

CCVT

Offline KCDAN

Re: My 4.3 vortec 84 FB
« Reply #312 on: June 27, 2019, 12:18:36 PM »
I must say, this car is coming along incredibly nicely.. great job.

Offline rk970

Re: My 4.3 vortec 84 FB
« Reply #313 on: June 27, 2019, 09:53:35 PM »
Cross my fingers, I think I may have beat the oil consumption.   I set the oil level to 3 5/8" below the pan rails. Long story short I pulled the engine last night to remove the pan, took a measurement to set the oil level 7/16 below the counter weights, filled it with water, measured said water volume and reinstalled everything last night. (yes I was that pissed off).  I feel like it has a zipper to whip out the engine. I am exhausted right now..
 :banghead:  Dam thing takes 5qts +- 2oz.. with the filter.. and that was the lower mark on the dipstick.
I drove it around for about 1.5 hrs tonight, plugs are nice and dry.. If I add 8oz extra oil it will start to show up on the #3,5 and 6 plug.  Lesson I learned is that the shape/style of the oil pan can also correlate on how to set the oil level. 

Offline digitalsolo

Re: My 4.3 vortec 84 FB
« Reply #314 on: June 27, 2019, 10:31:48 PM »
Interesting accidental learning experience.    I love the car, hope you can enjoy it more now.
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...
2007 Aston Martin V8 Vantage - Gen V LT4/TR6060, upper/lower pullies, headers, tune.
2021 Tesla Model 3 Performance - Stock...ish.