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java230
java230 UltraDork
1/23/19 9:09 p.m.

Following along. Been eyeballing lq4's

SkinnyG
SkinnyG UltraDork
1/28/19 12:05 a.m.

Well, after a fair bit of research and debate, I'm not going to significantly hog out these heads.

I smoothed the port-to-valve-seat transition, and that's about all I'm going to do. I will not be removing the rocker-stud boss in the intake port. While removing this might increase top-end performance, it could potentially introduce an air/oil leak through the threads (though some Permatex thread sealer should take care of that).

I also will not remove the swirl ramp in the intake ports, as I feel that is important for throttle response, fuel economy, and low-speed torque. I -may- (have not decided yet) remove the weird hump just under the exhaust seat, though I read somewhere (but cannot find) that it helps improve flow around the short-turn-radius.

I did, however, significantly smooth up the combustion chambers, as I did not like how the valves were sinking into the head leaving a "ridge" just outside of the seat area.  This might reduce the compression ratio, but hey, that means more boost, right??

Of course, on one side of the fence you have "Awesome!  That's the best mod you could do right there!" and on the other side you have "Dude! You just ruined those heads." Well, I did what made sense to me.  We'll see if I get lucky.

Since I didn't have any old valves, I turned down some round stock to 0.313" and threaded one end 1/4-20, and cut out some 1/8" flat and turned them to protect the valve seats.

AngryCorvair
AngryCorvair MegaDork
1/28/19 8:46 a.m.

I love what you do, but IMO unless you’ve got a flowbench and a huge stack of data, you’re not gonna improve an LS head with “what makes sense to me” versus just making sure it’s in good OE condition.  That’s a universal statement, not specific to SkinnyG.

SkinnyG
SkinnyG UltraDork
1/28/19 9:30 a.m.

I'm not a big fan of seriously altering ports. I like smoothing the sharp edges (which I did), and narrowing the guide boss (which I didn't do).

I think of it as a waterslide - if you sail around a corner and hit a sharp edge, you're going to want your money back.

I am a bit nervous about going too deep with these; they are a -really-good-casting- compared to the old Gen1 heads.

SkinnyG
SkinnyG UltraDork
2/3/19 10:11 p.m.

Because I'm stupid. And it's not completely finished yet.  I'll be polishing the tops of the pistons too.

SkinnyG
SkinnyG UltraDork
2/18/19 9:27 p.m.

After re-shaping the valve-seat-transition in the combustion chambers because the machine shop really sunk the valves, I cc'd one head to see how much I'd have to skim the heads. Again. These 317 heads are supposed to be 71cc, and I measured 72.5+/-0.1 

I'll get some pics of doing the other head soon.

I understand that lower compression is better for boost, but higher compression is better for not boost. These chambers take me from 9.4:1 to 9.26:1

pres589 (djronnebaum)
pres589 (djronnebaum) PowerDork
2/18/19 11:04 p.m.

This seems minor to me.

SkinnyG
SkinnyG UltraDork
2/24/19 8:13 p.m.

Finally got around to cc'ing the other head, they are 73.2+/-0.1 

With a low of 72.5 and a high of 73.3, we're about 1.1% variation.  That's seems pretty good for a daily driver.

The OCD doesn't like it though.

I'm going to go back over the smaller cc head and see if I can replicate the measurement, just to make sure I am not out to lunch.

 

SkinnyG
SkinnyG UltraDork
2/24/19 10:34 p.m.
SkinnyG
SkinnyG UltraDork
4/8/19 7:46 p.m.

And polished the pistons.

Crank is in and plastigaged, gotta gap the rings, and hopefully this week pistons go in.

SkinnyG
SkinnyG UltraDork
4/15/19 10:48 p.m.

Been meaning to get the pistons in, but got distracted prepping the V8 Firefly for sale.

As a different distraction, I cleaned the LS valve covers by soaking and scrubbing with Pine Sol, then a good spray of Zinc Chromate primer, then gray engine paint.

The V8's in '61 seem to have been painted gray, although some say the 283 was gray and the 327 was Detroit green. But I can't find consensus, and gray is easy and matches the gray I want the interior to be. 

SkinnyG
SkinnyG UltraDork
5/5/19 9:11 p.m.

I mistakenly ordered Gen3 rings for my Gen3 block. Turned out the engine had Gen4 guts inside.  I found out my mistake after gapping the first rings and discovering they didn't fit the pistons.

So I ordered a new set of Gen4 rings, and gapped them 0.026/0.028" (should be safe for upwards of 22psi boost or so) and installed 'em!

 

Darchangel
Darchangel New Reader
5/10/19 5:38 p.m.

Came for the Firefly, stayed for the trucks.

Can I just say I wish you'd have been a shop teacher at my high school when I was there? Heck, as far as I know, my old high school pretty much disassembled the voc-ed program a few years after I graduated in 1988, sadly...

I had a good metal shop instructor. It was a hard choice between metal shop and auto shop, but I totally would have taken auto shop if someone like you had been teaching.

SkinnyG
SkinnyG UltraDork
5/10/19 6:51 p.m.

Thanks kindly!

I'm a firm believer that if you're teaching high school mechanics, and you don't have a cool ride, you're doing it wrong. I've been dailying the Super 7 while the '77 Silverado has been getting the diff done.

The other thing I really have only one hobby - cars.

Mind you,

Also have done Chopper Bicycles:

And Midget Karts, powered by modified Toyota starter motors:

 

And Cigar Box Guitars:

And a buddy has offered me a 9" axle out of an 80's Ford pickup for a back axle.  Probably stronger than the 12-bolt axle I have and was going to use, but this is probably a wise purchase, long term.

He also offered a 9.75" Ford with a limited slip, but I was having a hard time figuring out how to make the front bolt pattern and brakes work. A 9" is the easy button; the "55 Chevy" of the axle world.

Seriously better than the 3.90 HO32 axle that's in there, for which the only limited slip is the Lincoln Locker.

SkinnyG
SkinnyG UltraDork
5/15/19 9:23 p.m.

Oh my.

Something is afoot (see bottom of page 2) ......

 

AngryCorvair
AngryCorvair MegaDork
5/15/19 10:00 p.m.

That uh grass uh is uh kinda uh patchy.

java230
java230 UltraDork
5/15/19 10:05 p.m.

Awww yes, gonna be good! 

ShawnG
ShawnG PowerDork
5/15/19 11:37 p.m.
AngryCorvair said:

That uh grass uh is uh kinda uh patchy.

You sound like our Prime Minister.

AngryCorvair
AngryCorvair MegaDork
5/16/19 7:21 a.m.
ShawnG said:
AngryCorvair said:

That uh grass uh is uh kinda uh patchy.

You sound like our Prime Minister.

I'm much smarter.

SkinnyG
SkinnyG UltraDork
5/21/19 7:25 p.m.

Some recent acquisitions.

A set of 18" Jeep steelies. I may or may not widen them or alter the offset:

Those wheels may actually work well with the axle I just bought.  The '61 has an HO32 diff, for which there is essentially nothing. Having recently expired the 12-bolt in my '77 Silverado, I'm less inclined to use the other 12-bolt I have under my trailer.  So.... 9" truck axle with nodular iron center:

AND, because why not, a set of never-used GMT400 2" spindles.  I'll need to fabricate my own arms anyway, to match the width of the 9", which actually suits the 18" rim's deep backspacing well.

I also have a Fox-body steering rack somewhere, but I don't think I took a picture of that.

wheelsmithy
wheelsmithy SuperDork
5/21/19 7:36 p.m.

In for all, especially BAGS!

 

SkinnyG
SkinnyG UltraDork
5/26/19 8:34 p.m.

We got on the lift today. This is the first serious look underneath ever. And I bought the truck last year.

It -looks- like it could lay rocker easily, as the frame rails are a lot shorter on these X-Frame trucks. Pancake the front crossmember, sure. Do something about the bottom of the X, maybe. Will the Trailing Arms tuck in high enough at the back of the frame??

Keeping the torsion bars is nice and convenient and affordable, but a challenge.

 

Something in the front of the truck kept creaking as it sat on the lift.  That wasn't scary at all </sarcasm>.
 

 

759NRNG
759NRNG SuperDork
5/26/19 8:58 p.m.

Torsion bars on a 1961 Chevy PU????? who knew.....I most certainly did not.....and you're gonna try to lower this....oh I forgot Teacher likes a challenge wink

 

SkinnyG
SkinnyG UltraDork
5/26/19 9:08 p.m.

Torsion bars were 60-62, then they ditched the X frame and went coil springs.

Folks say the torsion bar rides way better, but I'd hazard a guess it's because the fully boxed X-frame is so much more rigid.

The center of the X hangs pretty low, but if I design the truck to -ride- low, I should be able to cap that off flush with the frame. Might have to raise the top depending on what I need to do with driveshaft.

AND I intend to shorten it, and shorten it properly.  I can't find any build anywhere where someone has properly shortened an X-Frame, they usually just cut the X out of it.  I got a Sawzall and a welder; I ain't scared.

759NRNG
759NRNG SuperDork
5/26/19 9:14 p.m.

Cousin Eddie might know a thing or two about this (shorten' frames)

 

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