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First drive post head work
https://slantsix.org/forum/viewtopic.php?t=34831		 Page 1 of 2
Author:  wjajr [ Sun Apr 12, 2009 8:55 am ]
Post subject:  First drive post head work
Now that the cooling system seams to be functioning properly, except for a little drip from an unsealed bolt under the intake manifold, I took the Dart for a "spin" today in the neighbor hood.

I haven't put the vacuum gage to it, or performed a compression test, butt, seat of the pants accelerometer indicates a substantial performance gain. She will now spin the tires on damp bare pavement which could not be done before the head work. Acceleration seams to be a bit better also.

Tomorrow I will recheck valves, compression test, and play with timing light & vacuum gage to get her running better. Presently the exhaust note sounds a bit smoother, with a nice staccato beat something not present before the upgrade. I'm encouraged.
Author:  Aggressive Ted [ Sun Apr 12, 2009 11:37 am ]
Post subject: 
Bill,

Very good! That is good news. :D

Be sure and get that leaky intake stud sealed......they can wipe out a intake gasket by blowing hot steam in no time. I used Loctite.
Author:  69a100 [ Sun Apr 12, 2009 3:16 pm ]
Post subject: 
Soooo, What head work did you do? Bigger valves, porting, etc.? Please tell.
Author:  GENT [ Sun Apr 12, 2009 3:22 pm ]
Post subject: 
You couldnt spin the tires on wet pavement before? I though you had a 4bb. and cam and such? No? My stock 86,000 mile 1 bbl. slant will roast the tires on wet pavement,and at least turn them on dry.

Sounds awesome :D I bet you love the slant now. Most guys I know will get fed up with the slant,but as soon as they upgrade from stock,and are able to roast the tires and beat a Kia off the line they are happy. :twisted:
Author:  wjajr [ Sun Apr 12, 2009 5:36 pm ]
Post subject: 
Aggressive Ted:
Quote:
Be sure and get that leaky intake stud sealed
Not an intake stud, but a bolt that fastens the lower half of a hot water chamber under the carburetor that I fabed up to improve cold weather drivability. If this were still on the bench it would take two seconds to fix, but mounted & plumbed probably an hour will be burned on it.
It is the inboard hex bolt that is dripping.
Image

69a100:
Quote:
Soooo, What head work did you do? Bigger valves, porting, etc.? Please tell.
Shaved 0.075", installed hardened exhaust seats and over sized valves 1.70" & 1.44", and a port & gasket match. I now have calculated compression of 9.5:1 up from stock 8.4:1. When I pulled the head, #1 & 2 valve seats were rather nasty as if the engine had sat for an extended length of time with those two were not seated.

GENT:
Quote:
You couldn't spin the tires on wet pavement before?
This car from day one has been a performance disappointment. On paper it looked rather ballzy, hot cam, 390 4v, Clifford intake & headers, 3.55 sure grip, EI, and a reverse valve body 904... Nothing was up to snuff. I spent a few months repairing brakes, wiring, top, floor boards, locks, front end, and fiddling with the choke so it would start & run to get it on the road. After driving it for the summer I added new torsion bars, front anti sway bar, sub frame connectors, and new rear springs. This winter it was time to address the gutless engine. December I rebuilt the carburetor discovered the secondary vacuum diaphragm was ripped, and had the wrong power valve & secondary spring. This rebuild improve performance a bit, but driving it in December I found I had a carburetor icing problem.

This winter I pulled the head to see what was going on. It was stock, with two corroded nasty valve seats. So I decided to upgrade to big valves, higher compression, and better breathing. Also I installed a thermistor that Holley sells to slow electric choke opening by reading coolant temperature, and added a hydronicly heated hot spot under the carburetor to end carburetor icing in cold weather. Now that the engine is back together, still not tuned, but close, the car runs much stronger.

Monday I plan taking the vitals; vacuum, timing, compression, and tuning the carburetor choke so I can start it up at 35 degrees and drive off with out a prolonged warm up.
Author:  GENT [ Sun Apr 12, 2009 8:42 pm ]
Post subject: 
I rooting for you man,us 67 GT Slant guys need to stick together :D

Yep,4bbl and big cam in a low comp,stock head slant=no good. Its cool you got to learn that the hard way,it will make you really appreciate it when you get it right.Who did the porting? Any flow numbers?
Author:  wjajr [ Mon Apr 13, 2009 3:51 am ]
Post subject: 
GENT:
Quote:
Who did the porting? Any flow numbers?
Me. First attempt at porting. Followed Doc's instructions, and figured less was more after reading & viewing other material on the web. My machine shop guy, a fellow that has had his work go out to Bonneville, and builds all kinds of race engines gave me an A. That was just before I paid him, so there may have been some grade creep there...

As for flow numbers, last summer 21 mpg, December 10 mpg, and about two washings per tank of gas... LAL I have no way out here in the boondocks to bench flow my work, and I'm not going to be racing it, so it probably doesn't mater, although that information would be interesting to have.

I purchased this car end of February 08', and didn't get it on the road until mid May 08'. This project has been a magical mystery tour for me trying to figure out all the modifications that were made to the car. From what I can gather, the previous owner did the car over in the early nineties, put 50K miles on it up to about 2000, and than parked it. From July 07' to Feb. 08' it went through four owners by the time I purchased it. I have chronicled most of the repairs in this site, as well as asking advice from the gang here. To date I have rolled on about 1500 additional miles.

Next stop, the transmission, that R/M valve body has to go, and possibly a higher stall torque converter swapped in to replace the standard stall unit. Idle at 1000 rpm, 800ish in gear. Presently she locks up around low to mid 1600 rpm, or that is when the wheels brake traction anyway.
Author:  Dizzydean [ Mon Apr 13, 2009 5:42 am ]
Post subject: 
I agree we should stick together :bow: I am doing the same thing to my 67,currently working on a donated 73 drivetrain for it. Started removing all the paint and the 100# of bondo to find a wrinkled driver fender and a 68 pass fender. Anybody have a spare pass fender? Ill post some pics later 2 day. Curruntly doing the porting on the head as time permits. Post a couple pics :wink: [/quote]
Author:  66aCUDA [ Mon Apr 13, 2009 5:42 am ]
Post subject: 
Bill
Dont forget your Dizzy curve. I was flat amazed at how much power you can leave on the table with the wrong one.
Frank
Author:  wjajr [ Mon Apr 13, 2009 10:05 am ]
Post subject: 
66aCUDA:
Quote:
Don't forget your Dizzy curve.
Funny you should mention that. I just screwed around with the carburetor trying to get a lower idle speed and better vacuum readings, as well as a compression test, and timing at different rpm.

First compression readings #1-#6: 150; 145; 150; 147; 155; 140. The old stock readings ranged from 140 to 125, so nice improvement. I did not cc the head after the valve job. When the head left for the machine shop after porting work etc., all cylinders were with in one cc of each other.

Timing:

With vacuum advance (R7) disconnected, running light red spring, and black long heavy spring & 11R governor, 3.55 rear & 904:

950 rpm +12* vac @ 8" lopie idle
1150 rpm +14* vac @ 9-10" less lope
1200 rpm +14* vac@ 11" very little lope
1450 rpm +34* vac@ 13" smooth
2000 rpm + 34* vac@ 15"
2500 rpm +34* vac@ 16"

I'm open for guidance as what to do if anything with the curve.

Carburetor; Holley 4160 390 4V rebuilt Dec 08':
Orange cam, #2 hole, no off line bog
Jet #512 - plugs tan
Power Valve 2.5
Lightest secondary vacuum spring.

Present tune:
Idle screws out 3.5 turns with throttle plate closed: jumpy vac. 0"-10" @ 800 rpm pronounced lope

as above 3.5 turns:
1/2 turn in on throttle plate adjust screw; jumpy vac. 4"-10" @ 900 rpm lopey

3/4 turns in on throttle plate adjust screw, steady vac. 10" @ 1000 rpm slight lope. In gear at 3/4 turn; vac. jumpy 0"-4" @ 800 rpm pronounced lope.

I'm thinking that this engine & carburetor combination is a candidate for a drill holes in the throttle butter flies. Any comments welcome.
Author:  68barracuda [ Mon Apr 13, 2009 12:35 pm ]
Post subject: 
Quote:
Bill
Dont forget your Dizzy curve. I was flat amazed at how much power you can leave on the table with the wrong one.
Frank
AMEN to that the whole HEI-betterwire-ZFR5N-MO-3000-Bluestreak caboodle and a recurved dizzy - still in deep doodoo because I left two black streaks up the driveway - after that mod..over enthusiastic right foot

Now when Valiant owners contact me regarding the lazy slant I point them towards my Local spares shop - with a shopping list and instructions

90% of the time their ears need to stop the top of their heads from falling of due to the HUGE grin the other 10% shakilly ask about disc brake upgrades after they tried their new found power..and couldn't stop :lol:
Author:  terrylittlejohn [ Mon Apr 13, 2009 3:53 pm ]
Post subject: 
i would close up the slots in the dist to get total timing to 32degs@ 2500rpm and 17deg at idle with 2 stock light spring, remove the heavy long spring and make the rest of you tune up match that timing curve, you will like how it feels. do you have the low gear set in you 904?
Author:  wjajr [ Mon Apr 13, 2009 5:17 pm ]
Post subject: 
terrylittlejohn:
Quote:
do you have the low gear set in you 904?
I don't know. The transmission has a build code for 1976-77.
Quote:
total timing to 32degs@ 2500rpm and 17deg at idle
Would this be with vacuum advance disconnected?

+17* seems like a lot at idle. I had it at 14* at idle for a while but the engine wanted to kick back when turned off.
Author:  66aCUDA [ Tue Apr 14, 2009 6:01 am ]
Post subject: 
Bill
I forget what cam we have in there? The idle numbers look off as far as Vac.
Frank
Author:  wjajr [ Tue Apr 14, 2009 8:34 am ]
Post subject: 
Frank,

Camshaft specifications are unknown. I think it is an Erson due to small stickers on rear windows, but who knows. I measured the lift when the head was off at roughly 0.438". That lift matches Erson # E470301, rpm range 1000-4000, RV cam, smooth idle and broad torque range. However this engine dose not like to idle under 1000 rpm and dose not have a smooth idle below 1100 rpm. The valve springs measured out to match P524947.
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