Box Stock

Hemi predator gas build

Well I've got the long block pretty much complete now. New pics in the photobucket account in my first post.
A few notes, I use a piece of vacuum line on the valve stem to make it easy to turn and lift the valve when lapping them in.
The hemi rockers rubbed on the spring retainers slightly, I had to relieve them about .020" with the die grinder.
My piston wound up .025" in the hole, so I was able to use a single .009" head gasket to get my clearance nearly perfect.
Because I want to try one change at a time, I'm going to run the stock rockers 1st, then try a shortened/welded one on the intake valve to see how the on track performance is.
Next up, custom header and world formula style intake manifold.....
 
rkcarguy said:
Well I've got the long block pretty much complete now. New pics in the photobucket account in my first post.
A few notes, I use a piece of vacuum line on the valve stem to make it easy to turn and lift the valve when lapping them in.
The hemi rockers rubbed on the spring retainers slightly, I had to relieve them about .020" with the die grinder.
My piston wound up .025" in the hole, so I was able to use a single .009" head gasket to get my clearance nearly perfect.
Because I want to try one change at a time, I'm going to run the stock rockers 1st, then try a shortened/welded one on the intake valve to see how the on track performance is.
Next up, custom header and world formula style intake manifold.....
Click to expand...

making great progress. Its going to be fun.

I had mine in winter brackets this weekend. at 482 lbs going across the scale it was over second faster than the fastest lo206 and those guys were racing at 340-370 lbs
 
Wow that is a lot of weight! The 206's are the fastest packages on our track to date at 365#'s for light and 380#'s for heavy, 1:01.50 range for the fastest guy last weekend.
We had a couple guys come out to play/practice with some built alky big blocks though that ran 56 second laps though!
 
It was over 500 lbs with the other engine :D

The fastest 206 was around 44.9 and he weighed 362.
I was a second faster on my best lap.
The animalized 206s with different pipe, and unrestricted coil, usually run 43 flat at 375 lbs
 
Lol, I hear you but my track has always been the sealed 206 but in past years they allowed coil and pipe changes and also allowed carb jetting. Starting this year they are going full lo206.
 
That's great your keeping up at that weight! My track has a couple of very tight turns in the southern infield section that really kill the speed and they make weight/HP a huge factor. Our next race we're running super speedway layout where they remove that portion of the track and bypass it with a longer back straight.
 
I just built a SA carb for a customer.. its a stock, thinned butterfly, epoxy in the body.. on my old Hemi predator it made 20.96hp, and that's on gas.. that about 1hp less than it usually makes on meth... but the lower rpm is higher with meth.
 
youngengines said:
I just built a SA carb for a customer.. its a stock, thinned butterfly, epoxy in the body.. on my old Hemi predator it made 20.96hp, and that's on gas.. that about 1hp less than it usually makes on meth... but the lower rpm is higher with meth.
Click to expand...

What are you finding to be the best AFR for gas? In the low 13's?
That's pretty amazing your getting that kind of HP out of an SA carb, how big are you able to get the bore?
 
rkcarguy said:
What are you finding to be the best AFR for gas? In the low 13's?
That's pretty amazing your getting that kind of HP out of an SA carb, how big are you able to get the bore?
Click to expand...

I don't have a AFR gauge... I have to play the jetting game. The venture is right at .700..not round.
 
Not much of an update, got V2.0 of the nasty cold going around:(
Just got into the hardware store and grabbed a set of metric M8x1.25 x 60mm grade 10.9 flange head bolts to replace the stock head bolts.
They are a pretty gold irridited finish, should be gold plated because they were $2.60 each!
 
rkcarguy....do those bolts for the head reduce stretching? I snapped two stock head bolts last year on two different engines and went to studs, but I'm running a different class this year and need something other than the pot metal crap that china sends....
 
Mikey, yes they do. They are a much better grade and I don't feel that "streeeeeetch" when approaching torque like I do with the Chinese junk bolts. The only difference is the heads on them are usually 13mm and they are gold irridited, which I'm sure is a deal breaker for AKRA because things that don't break are a performance advantage.<end sarcasm>
 
rkcarguy said:
Mikey, yes they do. They are a much better grade and I don't feel that "streeeeeetch" when approaching torque like I do with the Chinese junk bolts. The only difference is the heads on them are usually 13mm and they are gold irridited, which I'm sure is a deal breaker for AKRA because things that don't break are a performance advantage.<end sarcasm>
Click to expand...
But real strict rules are needed. How else can you make it easy for the newbie to win? I sometimes think the rules are written to make sure the newbie has a better chance of winning. It seems there are a lot of people that will leave the sport if they're not immediately on the podium. The newbie has this strange idea that if we make the rules strict enough, it will make it easier for him to win. When in fact, the exact opposite is what is true.

Many times, newcomers make the assumption that the only reason they're not winning is because the winners have cheater engines. After all, this is such a simple sport, anybody should be able do it. What always surprises me is, they really think that it's all engine. So they go out and spend $150 on an engine and $2500 on a kart. Then they are surprised at how hard it is to win. Conclusion; those fast guys are all cheating!

I'm sorry if I hurt anybody's feelings, sometimes I just can't hold back.
 
thanks! looks like I'm making a visit to the local nuts and bolts store!! wouldn't happen to know the side cover size too? figger iffin I'm gonna replace the junk, then might as well replace all of them!! our rules for the econokarts (read that as stock predators) will let me change them out, so if it means a small performance advantage, oh well....
 
AL, that's partially true and partially not. My point is that "durability mods" such as billet rods and good fasteners that offer no performance advantage shouldn't have such strict rules against them.
 
Mikey, the side cover sizes are in my very first post. I could never find them anywhere online so I posted size, pitch, AND length for once!
Note that we have a pretty amazing local hardware store that stocks all kinds of off the wall fasteners, I doubt you'll find these in Home Depot or Lowes.
 
My ARC flywheel I mounted on this engine is set at 32*. I'm running premium pump gas and around 10:1 compression. Will this be ok or should I back that timing down?
 
You must log in or register to reply here.
Back
Top