Friday, September 17, 2010

Powervalves and PCV Valves

My car was running pretty decent after bumping the timing back, rebuilding the carb, and swapping jets. Yet it still seemed to be running rich, burning the hell outta my eyes and leaving me smelling like I'd been pumping gas all day after just a short ride. Obviously, something wasn't quite right, and I had a couple of thoughts.

First off, to try and combat some of the fumes, I finally installed a PCV valve. I've seen more people out there running a breather in each valve cover than I have somebody running a PCV valve. Honestly, I think we all assumed the same thing, that the PCV was some sort of emissions equipment that had no place on a street/strip car. Well, come to find out, that's not the purpose of a PCV valve. I knew what a PCV was, it was Positive Crankcase Ventilation valve. I also knew that it operated off of the engine vacuum. What I didn't realize was that running two breathers simply allowed the crankcase pressure to vent, and no matter how good the valve cover baffle, that venting including an oil mist that covered the valve covers, which then ran down to the headers, and added to my engine bay fumes that make cruising somewhat unenjoyable. I went with a PCV valve for a 1970 Chevelle 454, since I figure the pentical of horsepower would be my best bet for my engine.

Next up was why my car was running so damn rich that it burned my eyes. I wasn't exactly sure how a powervalve worked, other than it added fuel during wide open throttle. After checking around online, then taking a vacuum measurement, I had my rich idle condition figured out. My carb was equipped with 6.5 powervalves, and my vacuum was 5 inches, which meant from idle through my powerband my powervalves were dumping fuel in the engine.

A call to Barry Grant's Tech line helped me get in the ballpark regarding which powervalve I needed. They recommended either a 2.5 or 3.5, and stated really it's a trial an error science. After checking my engine vacuum again at idle, this time with the car in drive as suggested by the Tech guy, I rolled the dice and went with the 2.5. My idle vacuum is about 5 inches, and most people seem to suggest dividing your vacuum number in half to determine your powervalve you need. Perhaps this is because there are two powervalves in the carb and the vacuum is divided between them, I'm not sure.

I fired up the engine after swapping in the new powervalves and was rewarded with popping through the carb, which was a sign of a lean condition. After some adjustments, now the engine was backfiring through the exhaust, signaling a lean condition. I need to use the vacuum gauge and an extra set of eyes/hands to get it fine tuned, but it's tons better than before! I took a ride for a bit and was rewarded with a much more pleasant ride. The fumes seemed to be non-existant, acceleration was even better, and throttle response was much more instantaneous! Who says a cam this big of a cam feel "bulky" on the street? This damn thing is a rocket ship with a quick blip of the throttle. Bulky ain't even in my vocabulary.

The car still isn't tuned in perfect, but are they ever? It's tuned in better than it's ever been, and now that I know a thing or two about tuning it, idle and streetability will only get better. Sadly, the car will likely return to my parents' for winter storage in a month or so, but I'll be ready to kick off the cruisin'/car show season as soon as spring is sprung!

Tuesday, September 14, 2010

Dave seems like one cool dude.

I was scanning through youtube videos and ran across this guy named Dave, who happens to own a 930 hp 69 Camaro. Dave and I would get along just fine I think. This is just one of many videos he has on youtube.

Dave's massive burnout

Thursday, September 09, 2010

New Plugs, Wires, and a Carb Rebuild.

I replaced the plugs and wires a few days ago, which work out much better than my previous wires, though still not perfect. While my clearance issue between the plug/wire and the primary header tube on the passenger side, the 90 degree wires aren't the best fit for the other 7 plugs. They'll work, though I hope the header flange doesn't cook any of the wires. I suppose ideally I need a 90 degree boot for my trouble plug, and the 135 degree wires for the other 7. The Accel plugs didn't appear as short as I had expected, though once installed, gained much more clearance than I anticipated. That being said, I still can't remove or install the plug without removing the passenger side header.

Yesterday I tackled the carb rebuild, which was actually MUCH easier than the intimidating bag of parts and gaskets had initially posed. As for the instructions Barry Grant sent with the rebuild kit, it sort of sucked in my opinion. Now I realize that kits are fairly universal and all, but a nice diagram, or even a list of parts that WILL be used for each individual carb would be nice. Some parts I didn't use because they obviously were for another model. Others I didn't use because there were only enough to do half of the carb, such as the accelerator pump spring and the brass needle atop the carb for the squirter/nozzles. I got the mission accomplished, I just felt a little more effort could have been made with the instructions.

I slapped the carb on and attempted to fire the engine up just prior to going to work yesterday. The engine fire, then stalled, never to fire up again. I pulled the air cleaner and discovered fuel being pumped out the vent tubes when I turned it over and gas leaking all over the intake. I was left wondering if I forgot a gasket, assembled something wrong, or perhaps installed the brass needle mentioned above upside down. With no time to trouble shoot the issue, I got ready for work and did a quick google. It seemed as though it was a float issue.

Today, I ventured out to the garage and immediately adjusted both floats lower. I was rewarded with an instant fire up, sputter, and stall. The stall was due to the idle screw being adjusted way to low. I gave the screw a couple of turns, fired it up, and she purred like a kitten....hmmm...or perhaps "roared like a lion" would be a better description. I checked for leaks, all looked well, and prepared for a drive.

The road test went well, as the car seems much better with a fresh tune. I still need to double check the timing, as I think it may be a tad bit high still, perhaps in the 36 degree range, when I'd like it in the 32-33 degree range. My last issue I believe is still a ground issue. A few days ago I attempted the start the car and it seemed dead. Then, after throwing some jumper cables on and turning the car over, the voltage seemed fine. Now I KNOW you can't charge a battery showing 5 volts up to 12 volts with a 20 second jump start. I'm thinking a ground wire running all the way from the battery in the trunk to the engine block will solve all my issues. I may add a couple more ground straps, as extras, between body, frame, and engine just for good measure. My voltmeter jumps all over the place from time to time, leading me to believe there is definately a ground issue going on somewhere.

I was really hoping to hit some cruise nights his season, yet they seem to be winding to a close. I checked on Baker's of Milford only to discover that their end of the year cruise happened last weekend. I know there has to be a good number that will be going through October, and I hope to hit one or two. That being said, simply having the car back on the road would have been plenty of reward for this season. Next year, after getting a 5 point baby racing seat, the Chesher family will be riding 3 deep! :)

Thursday, September 02, 2010

Craig's List Deals of the Day

Reading the Craigs List cars for sale, I came across a few killer deals.

First, a 1969 Firebird for $1,200. Yeah, it's just a shell, but since you can buy pretty much every part for these cars, it would give somebody looking to do a full frame up restoration a good starting point.

1969 Firebird 400

The next deal doesn't have a listed price, so how can it be a deal? Well, let's just say I have a soft spot for these old, square, big bodied Caprices. I have no desire to paint it loud colors and go ridin' on 24's either. Lowered, some nice 17-18 in rims, suspension upgrade, and updated motor and I think you'd have one sweet ride. Whatever the cost, a senior citizen car that is unmolested with just 12,000 miles is every gearheads dream car.

1989 Chevrolet Caprice

Here is a car that needs an engine, but if the car is solid and interior is decent, for $1,150 it would be a great car to transplant an LS engine into. Your money would basically be all tied up in the new powertrain, as you'd have a car for a song and dance, and have the luxury of paying V6 insurance.

1996 Camaro RS