Finally went and did it.... wife is not happy

[porsche4life]

Oil will make the mud stick less.

[Tim Hancock]

I can't tolerate a greasy grimy engine, suspension or frame. Every thing you touch in the front/middle of this car is a greasy grimy mess. Once I clean it up/repaint it and reseal the engine/trans/rear end, I will power wash it clean again after each race (just like I did when racing MX every weekend back "in the day").

[304065]

Tim, do you hear that sound?

The very faint, high frequency, way up around 10Khz. . . quitely at first, then louder, and louder, and louder.

It is the song of the Siren, luring you toward the rocks. It is the most beautiful music you have ever heard. I have heard her too these past seven years, and am familar with her language. Let's see if I can translate what she is singing. . .

"Now that the engine is out it is simple to disassemble the chassis. You know you want to anyway, to inspect every weld for cracks. Once you are certain of the mechanical condition, it is simple to fabricate a large powder coat oven out of some insulation board and a propane-powered IR heater. Imagine how easy a pure white chassis will be to keep clean and be sure there are no issues before each race. Just like a Super Cub, Tim. Fill the tubes with linseed oil. Pressurize the tubes and put a peanut gage up front so you can verify that there are no cracks, like a 917, or the wing spar of a Zlin. . . Tim it's simple. . . ."

Can you . . . resist? I . . . I could not resist her.

[Tim Hancock]

Originally Posted by 304065

Tim, do you hear that sound?

The very faint, high frequency, way up around 10Khz. . . quitely at first, then louder, and louder, and louder.

It is the song of the Siren, luring you toward the rocks. It is the most beautiful music you have ever heard. I have heard her too these past seven years, and am familar with her language. Let's see if I can translate what she is singing. . .





Can you . . . resist? I . . . I could not resist her.

To resist is futile.


Is this your cub project?

[Joeaksa]

Originally Posted by Tim Hancock

To resist is futile.


Is this your cub project?

Do not believe thats a Cub, looks more like a Champ or Citibria fuselage... with Cub style landing gear.

[Tim Hancock]

Originally Posted by Joeaksa

Do not believe thats a Cub, looks more like a Champ or Citibria fuselage... with Cub style landing gear.

Look at the door/window opening, the half oval rear window frame, the bird caging for the turtle deck..... gotta be a Piper Cub derivative.

[Joeaksa]

You are the piper guy so should know!

[MJHanna]

Looks like fun.

[Tim Hancock]

After experimenting with some Butyl Cellosolve from work (one of the degreasing ingredients in many household cleaners), I went back to good old Kerosine (essentially what is in most engine spray degreasers) and powerwashed a couple transmissions and the engine.

I checked the compression with an aircraft engine differential compression tester and got pretty good numbers, but the PO said it was spitting a good amount of blowby out of the valve cover vents. I guess I am going to tear it down to see if it needs bearings/rings/valve work. Plus the PO could not tell me with any certainty how this engine is built up. I intend to find out.

Pulled the valve covers before calling it quits last night and found it has 354434 heads which are/were only 305 heads I am guessing that they were reworked and have larger valves installed. It has Compcam roller tip rockers with half of them marked 1.52 ratio and the other half marked 1.6 ratio (intake/exhaust or vice versa). I am new to this oldskool SBC V8 business, so this will be interesting trying to figure out the ramnifications of what parts are installed.

Holley 2 barrel carb is marked 6R 3250 B 3D. Hopefully it will be sufficient to start with and it appears it will bolt up to the 2 barrel cast iron intake the PO gave me (track rules mandate a cast iron intake but any carb can be used).

I put a timing light on the engine prior to yanking it out and it was set at 25 degrees and did not seem to change with rpm. I will have to dig into the HEI distributor and figure out if has any sort of advance mechanism that is deactivated. Seems like I heard most dirt racers are running in the mid 30's for timing.

Still need to locate a set of 2 1/2" ramshorn exhaust manifolds as the headers are a no/go at my track.

[Zeke]

Well, Tim, as mentioned, you will not need a ton of HP over extremely good handling. Knowing you, I expect you will get the thing dialed in to the point that it drives itself through the corners with a little aid from your right foot. I know you will need to be able to respond to dry or wet tracks and compact vs. loose. But once you find the range, it will be magic.

What's fun is that each lap is different unless you've got the lead.

[Tim Hancock]

Engine is about completely tore down. Cam lobes look smooth but vary at least .020".... will likely buy a new cam and install new rings/bearings.



Need to install some tires that hold air so I can move the car around my shop.... Harbor Freight no longer carries their cheapo bead buster/manual tire changer so time to build one.

A little scrounging/welding/machining and it is coming together




Just about complete.... just need to get some concrete anchors and make some tire spoons then a quicky rattlecan paint job.

[Tim Hancock]

Spring is coming.... gotta quit scratching my head and start making some progress.

My car came with aftermarket racing upper control arms, weight jacks and non-stock mounting shocks..... Rules state no tubular upper front control arms so I found some rusty legal "stock" stamped ones on a Blazer at a local junk yard (thankfully S10 and Blazers up to around 2002 come with the same arms as older GM metric chassis cars that are no longer seen in junk yards).



I was going to cut off the aftermarket mounting ears welded to the frame, but then I realized if I swapped the left/right new control arms, they were close to being in an optimum geometry in regard to camber/caster. Only problem was that the ball joints angles would be extreme and the control arms need to be a tad longer to get me around 3-4 degrees neg camber FR and around 2 degrees FL.

I ended up doing some major surgery to re-angle the ball joint mounting area and then lengthened the arms at the other end near the pivot shaft. Once I am done welding/grinding, no one will ever be able to tell







Front suspension before




After with new control arms



Hopefully I will get chassis mods/repair/paint done within the next couple weeks so that I can concentrate on the engine rebuild.

[romad]

That shock is not in the best position in the middle of a tube. Also jacks in the front might not meet with bomber rules or really be necessary. You generally want to un complicate the set-up. Set the front roll center and adjust cross and weight tranfer in the rear. Place the shock back in the orginal position.

[FLYGEEZER]

Your havin' way too much fun!!! I started on dirt "flat trackin" a Harley in the 60's. I envoy your youth, enjoy!

[Tim Hancock]

Originally Posted by romad

That shock is not in the best position in the middle of a tube. Also jacks in the front might not meet with bomber rules or really be necessary. You generally want to un complicate the set-up. Set the front roll center and adjust cross and weight tranfer in the rear. Place the shock back in the orginal position.

Original "style" shocks are indeed ordered and will be installed in the "stock" location as the rules require. The white shocks in the pics were installed like that because the car had 1"-8 weight jack screws installed right down thrrough the center of where the stock shocks are normally. I removed the weight jack nut/plate from the frame and will fab a simple shock mount approximately where it is on a stock metric chassis.

My A-arms are now mounted so that their pivot axis is essentially parallel with the pivot axis of longer lower A-arms. I have taller Impala spindles which result in getting some angle in the upper control arms when the lower arms are at ride height (level). This raises my roll center a bit and will give me a bit of help with the camber change due to roll. I have eliminated most of the anti dive by lowering the front A-arm mounts but have the ability to crank in a bit of pro-dive on the LF if I desire to try it. I have a set of hidden weight jack shims ordered and once I get them, I will be able to install them to make sure I pick a good spot to weld the upper shock mounts so that they do not rub the inside of the weight jacks through full suspension travel.

Most cars in this class have the upper A-arms pivot axis mounted in-line with the frame rails.... this results in caster going the wrong way as the wheel goes up. IMO, my set-up while not "ideal", will provide me a bit better front end than most of the competition in this particular class.

I am fairly confident that I will be able to end up with at least a "decent" handling car compared to the majority of the other cars, but it will take some time to figure out as this dirt oval stuff is nothing like normal sports car set-up.

[romad]

How do you find the time for all this.......I race, fly, off road but never at the same time. You done your homework, but here a few other points that may help or not.

timing is off. Circle trackers lock out ign. advance, and I believe chevys run large ignition advance, something like 40 +. I'm a Ford guy so don't qoute me on that.

Degree the cam depending on the grind straight up is the safest with out a dyno, but 4deg advance will work on any track under a 1/2 mile.

If you have to run cast iron find a good high rise chevy Marine and corvette center dump exhaust. Just taken the headers off is going to tame that engine.

I have one word for you in chevy stock class racing ...Brezinski
Cast Iron Cylinder Heads | UnderCover Porting | Brzezinski Racing, Inc

In regards to breathers spitting oil: Left turning traps oil in the right side head........find out if the engine has upper oil restrictors installed. also consider a accusump

[Tim Hancock]

Romad,

I will look into the oil restrictors (is it something I can see on the block somewhere?). Rules state no "Bowtie" or high rise intake manifolds. Center dump exhaust manifolds is what I intend to use for the exhaust. Brezinski stuff is great from what I have read, but at this point with "this" motor, I do not plan on spending too much money.... that said, I do intend to match the ports on my heads and intake manifold as they are not even close right now. With the 8" "DOT" only tires and a 3/8 mile dirt track that goes dry slick most nights, I do not think I will need much more than about 300-350 horsepower starting out provided I can figure out a decent set-up.

Do you currently run dirt oval cars? If so, what type?

[romad]

Tim,

I ran a Ford factory stock on pavement and helped out on a few late models over the years, no dirt. I will be of no help in the fine tuning, dirt does demand a different experience. My expertise is mostly engines any how...... which started me thinking about the rocker ratios.....

I think you are going to have problems with the dual ratio rocker ratio if you swap cams. generally its considered a cheat if your cam is spec'ed symetrical . Many guys run a higher ratio on the exhaust side to correct flow problems, but swapping cams may change your valve /piston clearances. Its really impossible to determine if that setup is valid or not with out a dyno. Sometime guys hear its the thing to do without any real perfromance considerations. I'll talk to my chevy guru.

Oh and the oil restrictor should be a orific plug screwed into the lifter galley on the back of the engine( just below the dist. boss. Don't or will not be install with Hyd. lifters.

[Tim Hancock]

FWIW, here is what I got engine wise after tearing it down in case anyone has any input about how to procede with a budget 350 build.

3.48 stroke Scat cast crank, 5.7" Chevy rods, 4.000-4.001" diameter 350 block
305 heads that cc to around 53cc (large valve is around 1.94 ish diameter).
1.26" OD valve springs (1.7-1.8" assembled height)
Summit 17350 cast "racing" pistons 4 valve relief (6 cc equiv dish volume)
.041 thick felpro head gasket
.025" deck height
Isky hydraulic cam w/ with about .450 lift IIRC (I don't have the numbers in front of me)
1.52 and 1.6 stamped Compcams roller tipped rockers
Compcams 4130 push rods and guides


-Cam is worn and will need replaced - looking at Summit and Speedway catalogs at their similar value priced hydraulic cam/lifter kits
-Valve springs????
-Pistons look like new, but measure 3.995 in diameter..... looking at KB "claimer" cheap flattop pistons with 5cc valve relief.... .006"-.007" is too much clearance IMO... looking for about .003".
-Will need moly coated rings of some sort to go with above pistons.
-Will be re-using Holley 500 CFM 2 barrel on cast iron GM intake.
-Will be using cast iron 2.5" center dump exh manifolds.

Car has 6.00 gear, track is 3/8 mile clay medium banking, a guess at straight away speed would be about 70 mph. RPM's will likely be around 6000-6500 max but the engine should be capable of hitting 7000 on occasion just to be safe. Will be running at least 100 octane AVgas (or higher octane Racegas) assuming I will be around or higher than 11-1 compression.

[romad]

What tranny are you using manual or auto?
The 2 barrel and RV manifold is going to leave you a little short of breath by about 100-125 CFM. your max rpm is going to be under 6500 . You'll want to refer to your cam supplier, but the approx required cam for a 3/8 track and a 4 barrel(600-650CFM)carb would be 285-295 duration with 106-108 lobe centers. Being a budget engine be careful about to much lift. If you get into
spring bind you will need to do additional machine work. The dual ratio rockers is a guess at best. I would go straight up. More is better but not over 1.65, you will get into geometry problems. But if you do use the same rocker I would use the 1.5 on the exhaust side. Chevy's flow poor on the intake side and great on the exhaust side, be careful making the exhaust flow better.
Again check for interference, bind, and piston clearance. The cam supplier will give you the appropriate spring info.

Any money put into head work is worth it, but be careful with any extensive porting. A good three angle valve job, blended seats, good seal, and un shrouding the valves as best as you can with a hand grinding will go a long way.

Do you plan to rework the block? Kb cast hyper-tech work good but you will need tighter clearances. Again great cylinder work is worth the extra expense. torque plate boring and honing at least.