Specs

[SPECIALGAGT]

Tell me WHERE to look for this stuff (in GAOC, please) and I won't keep bothering you::: for 3.1 V6 :: bore, stroke, valve-size. Thanks.

[doobiess]

bore and stroke for a 3100 v6 is 3.50 x 3.31 inches and stats on the valves are

valve face 45 degrees
valve seat angle 45 degrees
valve margin width intake.. .083 inch
exhaust .106 inch
valve stem guide to clearance .0010 to .0027 inch
valve spring free length 1.89 inches for both
installed height 1.710 inches

hope that answers everything

[SPECIALGAGT]

Wow, the info was fast !! I should have also asked whether the valves' seats can be replaced with larger. If so, is intake better to enlarge, or exhaust, or can both be reamed out? Will the block need / accept any relieving at the new valve/cyl. margins? Or is it better $$-economy to put on 3400 heads, which one thread says is possible, and not too risky. Anyone ever done it??
I'm looking for a 8.9 sec., 125 mph GA/GT. (Yah, right!!):lol: :eek:

[rixGAphx]

Originally posted by SPECIALGAGT I'm looking for a 8.9 sec., 125 mph GA/GT. (Yah, right!!) :lol: :eek:
That's imminently doable, 2 ways:

1. Hard Way.
Install a 50hp NOS.
Install a turbo.
Install a hot cam.
Install headers and free-flow exhaust.
Relocate the engine to the back seat, since the heavy GA will never allow enough fwd traction to use the power/torque necessary for 9.0/125.
Then junk it, 'cuz your first and only run will trash the tranny and the engine.

2. Easy way:
Push it over a 1440' high cliff.

Or is it better $$-economy to put on 3400 heads, which one thread says is possible, and not too risky. Anyone ever done it??

Haven't done it, but it seems doable.
Your 3100 heads would need significant shop time for the proposed mods, and still wouldn't flow that well since the intake runners were never intended for the larger valves (even if they are possible).
Why not get the 3400 heads, do minor improvements, relieve the bores for the valves, and slap 'em on?
Note, the quench bowl in the 3400 heads is sized for the proper compression ratio of 3400cc's of cylinder volumn; the compression ratio will go down significantly unless this is corrected, which could cost $$.
Prolly $100 -150 to pick up a pair of heads at the local yard.

Hell, pickup the entire 3400.
With TH700R4 from an early '90's Cambird, set it lengthwise like a proper drag car, and stuff a locked differential in the rear.

Seriously, you have a pretty good sporty car, but it's never going to be a dragstrip wonder no matter how much time, effort, and $$$ you throw at it.

There's a 'Performance' forum on this website if you'ld like to get more into that, and also specific engine forums for 3100 and 3400.

Good luck.
-Rick

[SPECIALGAGT]

Both steps 1 & 2 seem a bit drastic !! Would "step 3" be, "All the above"!! So, then, the 3.1 bottom-end will handle a significant (vs "large" ) boost in HP? I have the engine I'm building, on the shop floor. 120K mi., with (poss.) a spun main-bearing, which thanks to "check your hood-latch NOW" did not get really bad. And now I should remove and sell the 3.1 heads, and get 3.4 heads. This will be a $50 exchange, I have found out. Besides cleare / larger runners, will /does the 3.4 head need / take larger valves? I am planning .060-.080 - over pop-ups to maintain the compression, and will avoid going high enough to require 97+ fuel. Any favorite manufacturer? When the 3.4 heads are on the 3.1 block, will the 3.4 TB work?? That's my final question here; I didn't find the "performance" site until you mentioned it. Thanks. I will go there and bench-race. Does "Flatheads Forever" ring a bell with you, being an "Old Timer? Are you THAT old!!??" Thanks again.

[rixGAphx]

Originally posted by SPECIALGAGT
I am planning .060-.080 - over pop-ups to maintain the compression, and will avoid going high enough to require 97+ fuel. Any favorite manufacturer?
First, try the GM over-the-counter Performance Catalog, about ~$12 each year.
Second, try asking around on some Fiero websites. They're about the only ones doing performance upgrades to the 60*V-6's.


[/QUOTE]When the 3.4 heads are on the 3.1 block, will the 3.4 TB work? [/QUOTE]
It's my understanding that in stock form, ALL 60* intakes are interchangeable with ALL 60* heads, from 2.8 carb'd (as on my '85 Cherokee) thru 3.4 MFI early 90's Cambirds thru mid-90's 3.1 MFI thru present 3.4's.
This sounds really weird, I know, but GM seams to have maintained EXACT size and relationship of all intake-to-head passages.
That includes the early iron heads (as on my Cherokee) and aluminum.

The main difference in intake systems, physically, is between for-aft alignment (Cherokee, S-10, Cambird) which had inlet air coming at the nose of the engine (harmonic balancer end) and transverse which have inlet coming from the driver's side (flywheel end).

So, other than sensors which are different between TBI and MFI, your present intake should mate just fine to 3.4 heads.

BUT DON'T TAKE MY WORD FOR IT!!!
Do additional research before laying out 50 bones.

[/B][/QUOTE] Does "Flatheads Forever" ring a bell with you, being an "Old Timer? Are you THAT old!!??" Thanks again. [/B][/QUOTE]
:eek: :D :D

My dad had a '59 Studebaker with a flatty IIRC, probably one of the last ones manufactured. I observed while he and his buddy changed the timing gears.

The only flatties I've actually worked on are B&S lawn mower engines; the first in '67, the most recent in June of this year. I swear they both used the exact same parts!!

I don't know squat about your other questions regarding valves; tho the 60* V-6 is a sound block with lots of potential, it's never been put into a vehicle worth of the race track other than the Fiero. (Which met its demise because of insurance costs, relative to inexperienced/inept road drivers crashing the damned things because they couldn't adjust to the 'twitchiness' inherent in the handling of mid-engine cars.)
But old Fieros are highly sought-after as the basis for kit cars, and those builders are quite familiar with wringing every horse out of the V-6's.

Good luck.
-Rick