Dart 180 cc alloy head as cast

[econo racer]

I like those heads they make for good acceleration and torque. But for the extra hp would the sportsman II be easier?

[cv67]

platinum copy 2.02 1.6 valve mistprint on sheet
Under 205cc
No pipe sf 600 4.125 bore tfwiw
297/219@.500

[SpeierRacingHeads]

ATK built a 383 with as-cast Dart 200cc heads and HYD roller and it made 503/515hp.. Sent the heads to Eric and he ported them and put it back on the dyno and it made 515/551hp. Dyno is on youtube.

1) Your not making 540-550 with an ported head
2) Don't use my example of how to make 500+ ftlb of torque from a 3.48 stroke

[Elroy]

viewtopic.php?f=1&t=58354&start=75
check this build may give you some ideas////similar cubic inch and goal///318 CFM threw 205 cc volume///something to chew on

Is this a model to copy,... Or how not to do it ??

Randy

Not my place to say really///copy it?////do the opposite of?///use as a stepping stone?//just noticed the cowan build was similar so l linked it. 318 cfm at only 205 volume equals high pitot readings

[randy331]

viewtopic.php?f=1&t=58354&start=75
check this build may give you some ideas////similar cubic inch and goal///318 CFM threw 205 cc volume///something to chew on

Is this a model to copy,... Or how not to do it ??

Randy

Not my place to say really///copy it?////do the opposite of?///use as a stepping stone?//just noticed the cowan build was similar so l linked it. 318 cfm at only 205 volume equals high pitot readings

How about a little simpler way to get that kinda power.

viewtopic.php?f=1&t=42988&p=545684#p545684

Randy

[steve cowan]

i was looking at oil ring tension yesterday
standard oil ring 16 pounds with the fish scale
i have 4'' bore oil ring that went 5 pounds drag
i want to try a vacuum pump any way when i dyno engine
with low tension rings and vac pump on the street can there be other issues.
ring pack is 1.2 , 1.5 , 3mm , piston is 417gram short skirt

[randy331]

Steve, is that a SHP pro series piston ?

Is it steel top with a napier second ring ?

Randy

[CGT]

i was looking at oil ring tension yesterday
standard oil ring 16 pounds with the fish scale
i have 4'' bore oil ring that went 5 pounds drag
i want to try a vacuum pump any way when i dyno engine
with low tension rings and vac pump on the street can there be other issues.
ring pack is 1.2 , 1.5 , 3mm , piston is 417gram short skirt

Napier 2nd? My SN build had 4.005's in a 4.040 bore...also 3mm. It didnt smoke with no vacuum at all until it did lol.

Tore it apart and rehoned...put a higher tension expander in it....redynoed, still smoked. Thats when i found that the smoke was coming from my homemade intake gaskets not sealing correctly the whole time.

The shortblock was turning over at about 6 to 7lbs when I tore it down. 12 or so after putting torque plates back on , rehoning and putting a bigger expander in it.

I think you can get away with a lot less tension than what the ring people say, especially with a napier 2nd. Of course vacuum gives you some more safety.

[SpeierRacingHeads]

Steve, better sell your heads and buy Vortecs! Much easier!!

[steve cowan]

Steve, is that a SHP pro series piston ?

Is it steel top with a napier second ring ?

Randy

i ordered pistons 2 months ago lol and was looking at CP with 1.2,1.2,3mm but Summit did not have to suit a 5.7'' rod so i purchased the JE piston
SRP -SP40F
top ring 4.032'' x 1.2mm carbon steel nitrate bar back cut torsional
second ring 4.035'' x 1.5mm iron -napier
oil ring 4.030'' x 3mm std tension

JE pistons 1.2,1.5,3mm oil ring 001.JPG

JE pistons 1.2,1.5,3mm oil ring 002.JPG

JE pistons 1.2,1.5,3mm oil ring 003.JPG

JE pistons 1.2,1.5,3mm oil ring 004.JPG

[steve cowan]

i was looking at oil ring tension yesterday
standard oil ring 16 pounds with the fish scale
i have 4'' bore oil ring that went 5 pounds drag
i want to try a vacuum pump any way when i dyno engine
with low tension rings and vac pump on the street can there be other issues.
ring pack is 1.2 , 1.5 , 3mm , piston is 417gram short skirt

Napier 2nd? My SN build had 4.005's in a 4.040 bore...also 3mm. It didnt smoke with no vacuum at all until it did lol.

Tore it apart and rehoned...put a higher tension expander in it....redynoed, still smoked. Thats when i found that the smoke was coming from my homemade intake gaskets not sealing correctly the whole time.

The shortblock was turning over at about 6 to 7lbs when I tore it down. 12 or so after putting torque plates back on , rehoning and putting a bigger expander in it.

I think you can get away with a lot less tension than what the ring people say, especially with a napier 2nd. Of course vacuum gives you some more safety.

Chad,
i remember when that happened on SN,thanks for clarifying about the intake gaskets,makes me think i can make a low tension ring work in my application.
this is new territory for me hence the apprehension.
i have read there is a possibility the piston pins could get dry with vacuum in my application?? pin oilers via mains overkill??
the 4'' oil ring is a Wiseco single ring set i bought just to look at tension,it certainly feels nicer that a 16 pound oil ring

[steve cowan]

Steve, better sell your heads and buy Vortecs! Much easier!!

i have 4 x sets of Dart heads that i dont intend on selling
BUT i really like the look of the GM vortec 210 alloys
might have to get a set

[CGT]

i was looking at oil ring tension yesterday
standard oil ring 16 pounds with the fish scale
i have 4'' bore oil ring that went 5 pounds drag
i want to try a vacuum pump any way when i dyno engine
with low tension rings and vac pump on the street can there be other issues.
ring pack is 1.2 , 1.5 , 3mm , piston is 417gram short skirt

Napier 2nd? My SN build had 4.005's in a 4.040 bore...also 3mm. It didnt smoke with no vacuum at all until it did lol.

Tore it apart and rehoned...put a higher tension expander in it....redynoed, still smoked. Thats when i found that the smoke was coming from my homemade intake gaskets not sealing correctly the whole time.

The shortblock was turning over at about 6 to 7lbs when I tore it down. 12 or so after putting torque plates back on , rehoning and putting a bigger expander in it.

I think you can get away with a lot less tension than what the ring people say, especially with a napier 2nd. Of course vacuum gives you some more safety.

Chad,
i remember when that happened on SN,thanks for clarifying about the intake gaskets,makes me think i can make a low tension ring work in my application.
this is new territory for me hence the apprehension.
i have read there is a possibility the piston pins could get dry with vacuum in my application?? pin oilers via mains overkill??
the 4'' oil ring is a Wiseco single ring set i bought just to look at tension,it certainly feels nicer that a 16 pound oil ring

I wouldnt mess with pin oiling myself. You are unlikely to be running enough vacuum for that to become an issue.

As far as expander tension. I have a new formula now. On SN I had expanders in .005 or so increments. I just went down until the piston wouldnt hold itself in the bore. Lol. Now i would get to that point...then go up .005 lol.

Just kidding lol i think your stuff is gonna do really well. Anymore i think if your shortblock is rolling over at 10 to 15lbs, youve gotten most all the meat off the bone anyway. My LS3 project i kept kind of conservative on that also. 12lbs on it if i remember correctly.

[MadBill]

...
i have read there is a possibility the piston pins could get dry with vacuum in my application?? pin oilers via mains overkill??
the 4'' oil ring is a Wiseco single ring set i bought just to look at tension,it certainly feels nicer that a 16 pound oil ring

A 380" SBF dry sump road race engine I consult on runs a 2 ring low tension package with a vacuum break set to 12-14" H2O*. The consensus seems to be that that's enough to garner 90% of the potential gains without risking pin oiling problems etc. After 4 season the internals including pins look like new (*It starts to smoke under decel if it loses vacuum for any reason.)

I know some drag race apps use all they can get, 25"+...

[steve cowan]

thanks for the reply Bill,
i have read about that road race deal you are involved with ,pretty impressive.
i figured 12'' vac on a wet sump deal like i am doing would be about it.
moroso or GZ pumps not sure which way to go there.
one question i have is i am getting a re-balance of the rotating assembly,would this have to include the mandrel drive for vac pump.i do not have a vac pump set up as of yet.