Category ArchiveCars

Positive Ventilation Part 2

Well, really not part two, because I’m not changing anything, just reporting back.

I am happy to report that after this past Sunday’s KYSCCA Event at the Kentucky Fair and Exposition Center, my PCV solution works. The car did’t puke any oil out of the breathers. Victory!

Tensioner woes

The 1984-1987 (and 1989 Turbo Trans Am) engines had something that was relatively new to GM in the 1980s: A serpentine belt with a tensioner to drive the accessories. All the other G-Body powerplants (305 V8, 231 non-turbo V6, and the 4.3L V6) used multiple V-belts, with the tension set by feel.

The Grand National, with its fancy fuel injection and turbocharger, required something new. So, instead of a bunch of V-belts, it got an inch-wide serpentine with a tensioner to maintain tension on the belt instead of prying at accessories with a screwdriver.

This was all well and good, until my tensioner started making noise. Terrible noise. And it wasn’t the bearing in the tensioner pulley, no. the spring-loaded tension mechanism was popping and grinding and making a terrible racket. It needed to be replaced.

Problem: they don’t make it anymore. GM discontinued it. All the parts store no longer had them in stock. Turns out the tensioner assembly was unique to this engine, so it’s NLA. Thankfully, the good people at White Racing has created this new billet tensioner to replace the discontinued stock unit. It’s expensive considering the OE tensioner used to sell for $60, but this is an old, niche car. Gotta pay to play.

So I got one.

New tensioner on left, old and busted on the right

The first thing you notice is it’s shiny. The second is the massive amount of metal around the bolt holes compared to the stock unit. Where the stock unit has thin cast-in gussets, this new piece has been machined leaving as much material around the bolt holes as possible. This was done to alleviate a nasty habit the stock pieces used to have: they’d break. A popular thing to do with the Buick V6 was to put an eyebolt through the alternator, then hook that eyebolt to a ratchet strap that was attached to a hole in the frame. This kept the engine from rocking over to the passenger side and breaking the driver side motor mount. The problem came when people started making big power, all that force got transferred through the alternator case to the tensioner (which the alternator attaches to). The tensioner would then break. Not good. This tensioner is manufactured with a lot more metal hoping to avoid this situation.

Installation was pretty straightforward. Disconnect the battery, take the belt loose, get the intake tube that runs from the MAF to the turbocharger out of the way, unbolt the alternator and swing it out of the way, then remove the two remaining bolts to pull the old tensioner. Installation is reverse of assembly.

After installation, all of the undesirable noises and vibrations that had been coming from the front of my engine are gone. That includes not just the popping, but a persistent click that I had assumed to be a lifter. It was the tensioner all along.

Positive Ventilation

Turbocharged Buick V6 engines are famous for many things. One of them is puking oil out of every possible spot when the engine is under boost. They blow the dipstick tubes out. They force oil past the rear main seal. They spray oil out the valve cover breathers.  Mine even was forcing oil out of the PCV valve grommet under the intake plenum. They can be a huge mess. Even my newly rebuilt engine is doing this. It’s blowby. Gas getting past the rings when the engine is under boost. My first few autocross events, I was coming into the grid smoking after my third run from oil escaping the valve covers and pouring onto the exhaust. It was embarassing, it made a mess of the lots we race in (BAD), and made a mess of the engine compartment. I have been determined to fix it. After several attempts, I think I’ve nailed it. I’ve come up with a system using two catch cans and an industrial strength check valve. It goes a little something like this:

In this first picture, you see the passenger side of the intake manifold. Down underneath the plenum is an OEM PCV valve. The Goodyear hose runs to a catch can bolted to the side of the intercooler, then back up and through that brass check valve. The check valve is rated at 400psi, and is there to prevent manifold pressure from getting into the crankcase when under boost. Without that check valve, positive manifold pressure would easily overpower the OE PCV valve and pressurize the crankcase, which forces the oil out and makes a mess.

Now, the stock set up simply had a hose running from the PCV valve to the PCV inlet tube you saw the check valve attached to. The catch can keeps oil from making it to the check valve and gumming it up, as well as keeping the oil out of the intake tract.

But, there has to be another part. The stock PCV system had a vent in the passenger side valve cover that was connected to the turbocharger inlet. That set up mostly worked, but once you turn up the boost, that single vent simply isn’t enough. I’ve added a second vent.

Instead of one vent line, I ran two. Each valve cover has a Mr. Gasket breather cap on it and a 5/8″ line coming off of it. The lines go into a tee just behind the alternator, then run to another catch can.

From this catch can, we run out to a fitting that’s been screwed into the inlet pipe ahead of the turbo but behind the mass airflow sensor. This is important and I’ll explain.

PCV systems are basically a tuned leak. A port on the intake manifold provides a vacuum source, and a vent in the valve cover/intake tract provides a source of fresh air. Engine vacuum draws air into the vent, through the crankcase, and into the intake manifold where the crankcase vapors are burned in the cylinders.

In a computer controlled vehicle, this poses a problem. If you vent to atmosphere, say as if you’d used an open breather element on the valve covers instead of the closed ones I used, you would get extra oxygen in the cylinders that hadn’t been metered by the MAF. On a Buick using the stock computer, this extra oxygen is detected by the O2 sensor, and the computer adds fuel. In the Buick’s case, it adds WAY too much. So much that it washes out the rings, contaminates the oil, and eventually ruins the bearings. I didn’t want this to happen.

So, the vent is plumbed into the intake tract after the MAF. This ensures the air entering the crankcase through the vents has been metered, so when it shows up in the intake manifold via the PCV valve, the computer has already taken the air into account. It keeps the mixture correct, and doesn’t kill itself.

Under boost, the check valve on the manifold side closes, and the turbocharger inlet should draw out the crankcase gases via the breathers. In all cases, pressure should not build up inside the crankcase. It shouldn’t leak, and any atomized oil will condense in the catch cans and not foul up the turbocharger. All the air in the system goes through the MAF, and all should be happy. So is it?

Yes. In the screen capture below, you’ll see a grid on the right side. That is the Block Learn Multiplier (BLM) table. It’s basically a fuel trim table. If everything is absolutely perfect (70 degrees F, no leaks, perfect engine), all the numbers would be 128.  They’ll vary with conditions (temperature, whether the gasoline is RFG or not, etc.). If you have a vacuum leak to atmosphere, like you would with a PCV system vented on the valve cover to the air, you’ll see BLM numbers above 150, and that’s bad. These are all in the low 130s, which is pretty good.

The PCV system isn’t leaking in air from the atmosphere. I’ve already found a very slight amount of water/oil mix in the smaller catch can after a 20 mile drive, and I’ve got no leaking oil running down the valve covers or collecting under the intake plenum. Preliminary indications are positive, and I’ll report further after my next autocross event to see if this system stands up to competition.

New Seats!

So let’s talk about seats for a bit. Seats are important. Seats keep you in front of the steering wheel while you’re driving. When you turn, seats, combined with the seat belts, keep you from shifting around inside the car. In a crash, seats and seat belts keep you from getting crushed, either by slamming into the rear seat (or the passengers that might be there) or eating the steering wheel. They’re very, very important.

That said, the seats that came in GM products of the ’80s were designed to meet safety standards of the time as well as the desire of the typical ’80s customer for a smooshy, compliant seat. While the Grand National got a decent set of buckets for the period, the foam is still smooshy and the bolsters are set up for a person much wider than me. In a recent autocross, I was using my grip on the steering wheel to keep in place, and the tilt mechanism gave out. The wheel dropped into my lap, and I nearly spun the car out. Not good.

Not too long after that, an acquaintance of mine was racing his Malibu in Lexington, and his entire column failed, and he actually did spin the car. No bueno.

So I bought some seats. What I chose were some black buckets from NRG. I got the pair at Amazon for $299. They’re a ripoff of the Recaro bucket seat you could find in the 2000 Honda Integra Type-R. I picked them because I remember my friend’s Type-R and how well I fit in those seats. Honda made them to fit smaller Japanese customers, not fat Americans, and I fit in them perfectly.

Step one was removing the stock seat, and vacuuming up all the dog hair that was under them.

After removing them, I bolted down the brackets I sourced from Wedge Brackets. These things saved me gobs of time. Fabricating brackets would have taken me hours, and Wedge makes brackets and sliders for OEMs, so I have a bit more confidence in the safety of these in a collision that something I would have made myself.

Next step is getting the sliders bolted onto the seats. The NRG seats came with their own double-locking sliders, so I used those.

The NRG seats showed their Chinese-ness here. The bolt holes for the sliders were covered by fabric, I had to locate them by feel, then use an awl to punch holes in the fabric for the bolts to run through. Annoying.

After that, it was a matter of bolting the seat/slider assembly to the car.

Thoughts on these seats? They’re cheap. The fabric isn’t top-notch. The foam is very firm. In fact, I’ve gotten a new appreciation for how stiff my suspension actually is. The old seats sucked up a lot of the smaller bumps. The lack of squish in the cushions also means I’m sitting slightly higher in the car than I was. I may need to swap out for thinner sliders. The bolsters are fantastic. My skinny posterior fits perfectly and they upper bolsters seem to contain my shoulder and midsection pretty well. I’m able to take corners at speed with just fingertips on the wheel, and that’s using just the three point seat belt. Final verdict on how well they hold is reserved for the next autocross. I’m hopeful I can get away without a harness, because I need my back seat to remain usable.

These are also light compared to the stockers. With sliders, they’re 25 pounds each. The brackets are about 2-3 pounds. The stock power driver seat was over 50, and the passenger seat was close to 40.

But the best benefit? My irreplaceable stock seats are now wrapped in plastic and in the basement, safe from sweat and spilled drinks for the foreseeable future.

Wrapped for storage!

 

My fastest run from the CAM Challenge

Enjoy!

 

CAM Challenge East

I had the honor of participating in the first Speedway Motors CAM Challenge East, hosted by the SCCA at Grissom Air Base in Peru, Indiana, this past weekend.

To say it was a blast is an understatement. The course was fast, the cars were incredible, and the people were fantastic. The contrast between this event and the National Tour event I ran way back in 2003 was astounding. These CAM folks are fun to be around. Everybody enjoyed themselves. The “ringer” cars that whiney people said would show up and clean everybody’s clock showed up, and some clocks were cleaned, and NOBODY GOT UPSET. Because this crew appears to show up to have fun, not win. That is a novel concept for a national-level SCCA event.
The G-Force! from left to right: Andrew Scott, Lance Hamilton, Dave Nutting, James Bishir
One of the highlights was meeting up with some fellow G-Body owners. We had four: Myself, Lance Hamilton, Dave Nutting, and James Bishir. James is especially notable because this was his first ever autocross event. He was the perfect n00b. He asked questions, he talked to people, he listened, and he improved every single run. His first run, he was ten seconds off pace. By Sunday morning, he had beaten me by seven hundredths of a second.

Another treat was getting to watch Robby Unser and two-time Indy 500 winner Al Unser Jr. up close. They were both running in beautifully engineered machines built by Speedway Motors, and they were both blisteringly fast. But much to what should be the consertnation of the CAM doom and gloom crowd, the Unsers didn’t prevail in CAM-T on Saturday. Nope. They showed up with pit crew in professionally built race cars, and themselves were professional race car drivers with multi-decade careers. On Saturday they got beat by a kid – Cody Mason. And nobody was mad.

Takeaways for me? I need more tire. A lot more tire. I was running on 245mm tires, and was probably on the narrowest tire of any car at the event. Dave Nutting was also on 245s. James Bishir was running 275 in the front, 295 rear. Lance Hamilton had 275 all around, and everybody that beat all of us was on 305-315mm tires. Steamrollers. Thanks to being able to eyeball Lance and James’ cars, I can start planning on what I need to do to run similar sized rubber next year.

Here’s a link to my Google photo album from the weekend:
PICTURES!

So that Watts Link thing? Yeah, it works

So, there was an autocross yesterday. The day started quite rainy, resulting in a low turnout, but things cleared and we had a fantastic afternoon for an event. Seven runs, done by 3. Perfect.

Except on my second run, somebody came running up to my car to tell me I’d let loose of a large bolt on course. A quick peek under the car revealed I’d lost the bolt holding the propeller on my Watts Link.

Using a borrowed wrench and some scraped elbows, I disconnected the Watts bars from the axle clamps and removed it. Back to stock rear suspension, and right back out on course.

Observations? Well, oddly , I went fast. A lot faster. But I’d only run two runs so far with the Watts, and was still figuring out the course. It’s possible that gain was all Watts, but also possible it was all me being better.

What was stark was the car’s behavior. It was LOOSE. really loose, except when it wasn’t. There was very little consistency. In one corner it would push. In another it would try to step the rear out. When the rear did slide out, it didn’t gracefully slide back into line when I lifted the throttle or steered into the slide. Nope, it snapped back the opposite direction. Each run I found myself madly sawing at the wheel trying to get the car to go where I wanted it to go.

The takeaway for me was that I’m likely faster with a loose car, but the Watts adds a large level of predictability. I’ve ordered new parts to replace what fell off and will have the Watts back in place for the next event at the Corvette Museum. I’m going to raise the center link pivot one hole to see if I can keep the predictable handling while also loosening it up a bit.

We shall see.

Of hoses and coolant

Sooooo, yeah. I had to go to the dentist today. I thought I’d take the Buick. It ran fine on the way out, didn’t smell any oil burning off the exhaust, all good things.

When I came out of the office, there was a puddle of coolant under the car. Grrr.

A hose connecting the water pump to the heater lines had failed. It was an OE hose, 27+years old. Surprise, surprise. So, on this 89 degree day, I called AAA to get a tow home. Surprise! Five hour backlog.

I ended up walking to an Autozone that was a mile from the dentist and retrieved a replacement hose, some tools, and a bottle of coolant. Swapped it in the parking lot, drove it home. No more leaks. Yay.

How does this thing work now?

So, all this work, and no updates on how well it did… until now:

Driving impressions? Very good. The day before this event, I taught at the local drivers’ school. Aside from student that showed up with a bone stock Evo X, my car handles better than everything else I drove that day. A lot better.

Now, that said, I was still puking oil everywhere. Turns out I had a very slight head gasket leak. I’ve just replace the driver side head gasket and will be putting it through its paces this week in preparation for the next event on June 28th.

Buick Brakes, Part 2

Back in Part 1, I described some of the issues with braking on my 1987 Grand National. In this installment, I’m going to explain what I went through to convert my car to a manual brake setup.

The first thing I did was call Wilwood, who manufactured the front brake kit I already had on my vehicle. My kit is a now-obsoleted 10.75″ disc brake kit with Dynalite four piston calipers. While the rotor diameter is only slightly larger than stock, the rotor is much thicker and mated to an aluminum hub. The setup fits behind the stock 15″ wheels.

Wilwood took the information on the brake system, and recommended a 15/16″ master cylinder. The master cylinder size is based on the total piston diameter of the axle with the largest pistons. The weight of the vehicle has no bearing on master cylinder selection. I see that taken into consideration in internet discussions about master cylinders, so I’m putting it out there: it doesn’t matter. You need to know the piston area.

Wilwood 261 series master cylinder kit, I got mine in black

Knowing the proper master cylinder size, I hit Summit Racing and ordered a Wilwood master cylinder kit. It included a master cylinder and an adjustable proportioning valve. I also grabbed a 10psi residual pressure valve to go into the rear line.

 

Old and busted. Master cylinder, booster, and vacuum reservoir

Once I got it in hand, removed the existing components. This pile weighed 16.4 pounds. The replacement parts weigh just four pounds.

Now for the kicker: the Wilwood master, and just about any other will not bolt to the firewall. You need an adapter bracket. In my case, I was fortunate enough to still have my old PowerMaster. The PowerMaster used a 7:1 pedal ratio, so the bracket for it aimed the rod at the pedal at the proper angle for a manual pedal (6:1). I removed the bracket, cleaned it up, painted it, and sat it on the heater to cure the paint a bit faster.

PowerMaster brake bracket

Once the paint was dry, I bench bled the master and bolted it into the car.

New Master Cylinder!

Now came the hard part. Lines. This was a mess. The factory lines don’t have the proper ends to screw into the proportioning valve. They also connect to a combination proportioning/residual pressure valve/distribution block on the driver side frame rail. This block also serves as a mounting point for a bracket that’s involved in the transmission shifter linkage. This valve has to come out, or it will negate the fancy proportioning valve I just bought.

Factory proportioning valve is hidden behind that plate

Making things worse, the line coming out of this valve going to the rear brakes was a 1/4″ line, which all the other lines are 3/16″. The fitting on the rear line is also goofy metric fitting that you can’t get a union for. I had to cut the flare off the rear line, remove the line nut, and splice in a pre-flared section using a compression fitting.

Also, if you are running drum brakes in the rear, you must install a 10psi residual pressure valve inline between the rear drums and the proportioning valve. This residual pressure valve will keep the rear wheel cylinders pressurized at 10psi all the time. This will act against the return spring in the drum assembly and keep the shoes pressed against the drum. Without it, the shoes will pull off the drum, and you’ll waste your first pedal press pushing the shoes back against the drums, possibly crashing into somebody in the process.

Once other thing I learned: Harbor Freight’s tube flaring kit sucks. Don’t use it. Just get the pre-flared lines from the parts store and bend them to length. If you have to cut one, use a compression union to put it back together.

For the front brakes, you need two 3/16″ lines with 3/8″-24 tube nuts. I got two 30″ length sections, and two unions. Carefully bent

Unions joining lines coming from the new prop valve to the factory lines going to the calipers

up, they easily screwed into the bottom of the proportioning valve, and the unions allowed them to easily mate with the factory lines going to the front calipers.

Detail showing connections to the rear line: the compression union, 3/8″ inverted flare union, then the 3/8″ to 3/16″ adapter, then the 3/8″ nut on the 3/16″ tube going up to the residual valve.

After the lines were all hooked up, I used 1.5″ steel tubular spacers to replace the transmission linkage bracket that had been bolted to the old proportioning valve.

The next step was connecting to the pedal. The Wilwood master has a rod coming out of it that’s threaded for a 3/8″-24 rod end to use as a clevis. The brake pedal I swapped in when I converted to vacuum brakes also had a hole in it already in the exact spot needed. Sadly, I couldn’t find a rod end that would work, so I made my own Clevis out of a piece of bar stock and a steel tube. It’s ugly, but it works. Alternatively, it might be possible to remove the pushrod in the master and replace it with the pushrod from the master or booster you already have. I didn’t want to take apart my shiny new parts.

After all that, the brakes still sucked. I suspected air was trapped in the system somewhere and it needed to be power-bled, so I dropped the car off with my good friends at Grossman Tuning. Not only did they power bleed it, they re-adjusted the rear drums and dialed in the prop valve for me.That’s all! The brakes take a lot of effort, but they work great, and they work the same way every time, boost or not.

Parts List:

  • Wilwood 15/16″ master cylinder and prop valve kit, PN 261-13626-BK
  • 10psi Residual pressure valve, 260-1876
  • 2x 30″ long 3/16″ pre-flared brake line
  • 2x 3/8″ inverted flare unions
  • 1x 12″ long 1/4″ pre-flared brake line
  • 1x 1/4″ tube compression union
  • 1x 78/” inverted flare union
  • 1x 3/8″ to 3/16″ inverted flare adapter (to adapt rear brake lines to 3/16″ lines coming from master)
  • Brake Fluid
  • Hardware for making a clevis to mate the pedal to the master cylinder pushrod