427 engine (part 2) - RHS block

[Rich Z]

Haven't gotten a new tune lately, so I decided to pull off the airbridge to try to bulletproof that entire air path. Just as well I did, because the lower opening of the airbridge was partially collapsed where I couldn't see it while installed, so likely boost was leaking at that point. I've got some metal tubing, so I'm working on forming the airbridge openings around the tubing so I can clamp those T-bolt clamps TIGHT around it. I'm also seeing if I can lower that airbridge a little bit to give more hood clearance.

Had to order some more 3.5 inch diameter pipe and some extra couplers from Summit, so the car will be down for a couple of days.

Oh well, supposed to get rain tomorrow and Friday anyway....

 

[navy2kcoupe]

Oh well, supposed to get rain tomorrow and Friday anyway....

The forecast for Friday and Saturday up here calls for from 12 to 24 inches of snow. I'll be more than glad to swap with you! :rofl1::rofl1:
Andy :wavey:

 

[Rich Z]

The forecast for Friday and Saturday up here calls for from 12 to 24 inches of snow. I'll be more than glad to swap with you! :rofl1::rofl1:
Andy :wavey:

Thanks, but no thanks. I would be just as happy to go to my grave without EVER seeing snow in person again.

Highs are forecast to be in the low to mid 70s for the next several days.

Just sayin' .......... :hehehe:

 

[Rich Z]

Well, I will say one thing about these plastic airbridges. With the right sized metal pipe and a heat gun, you can pretty much form them however you want to. Wish my little lathe was big enough to handle 3.5" diameter pipe, as I've got a piece of aluminum tubing that I would like to remove some metal from the inside of. The only aluminum tubing I could find with 3.75" outside diameter has a quarter inch wall, which is really too much to be used in my intake. I've got a piece of mild steel with that outside diameter and about an eighth inch wall, which will do, but I just don't like to use anything that can rust anywhere on the car.

 

[Benjamin]

Well, I will say one thing about these plastic airbridges. With the right sized metal pipe and a heat gun, you can pretty much form them however you want to. Wish my little lathe was big enough to handle 3.5" diameter pipe, as I've got a piece of aluminum tubing that I would like to remove some metal from the inside of. The only aluminum tubing I could find with 3.75" outside diameter has a quarter inch wall, which is really too much to be used in my intake. I've got a piece of mild steel with that outside diameter and about an eighth inch wall, which will do, but I just don't like to use anything that can rust anywhere on the car.

the reduction in flow using the 1/4" wall pipe will be negated by being able to actually seal in all the boost.

I wouldn't worry about it a bit.

EDIT: I think you are saying it won't fit inside the bridge, if so, I am unsure what to suggest....

get the steel rings made to your liking and I will powdercoat them for you so they won't rust.

 

[Rich Z]

the reduction in flow using the 1/4" wall pipe will be negated by being able to actually seal in all the boost.

I wouldn't worry about it a bit.

EDIT: I think you are saying it won't fit inside the bridge, if so, I am unsure what to suggest....

get the steel rings made to your liking and I will powdercoat them for you so they won't rust.

Actually, both the steel and aluminum pipe (tube) are 3.75" outside diameter, so either will work in the bottom opening of the airbridge. And that seems to be pretty close to the outside diameter of the section of the MAF housing I need to attach the airbridge to. If attaching the airbridge directly to the MAF housing won't work for me, then I will have to use one or the other tube as a support ring inside the airbridge when I put a coupler between the bridge and the MAF housing.

Yeah, I hear what you are saying about boost but I would still feel better about having the air flow as unrestricted as possible. But truth be known, the MAF housing itself is actually a restriction in the airflow. Easy to see when you are trying to find the correct diameter couplings for everything. So you are probably right, it really doesn't matter much.

But in any event, the reason that attaching the airbridge to the MAF housing might not work is because I will have to move the airbridge more forward than it has been. So I'm not sure it will fit underneath the hood, since it was already pretty tight there, and the hood slopes downwards the closer it gets to the front of the car. But removing a coupler at the front also changes the angle of the airbridge, so I really won't know till I just try it. I may even have to cut out some of the radiator support itself, if need be.

But right now I can't tell for sure, as I have the upper radiator support out. The blue painted one I've had on the car has a crack in the cover, so I'm either going to fix it or put my stock black one back on. It never was on there right since I brought it back home as the fans and shroud have been sticking too far backwards and not fitting flush against the backside of the radiator like it should be. So I need to look it over closely to see why that is. Besides, I'm thinking about putting insulation on the underside of the support to try to shield the airbridge from the heat from the radiator a bit. So while the airbridge and couplers are out, this is the time to take a look at all that.

At the upper part of the airbridge I have a 3.5" polished aluminum pipe that I can either use as a support ring in the airbridge opening, or if I need some additional length, just don't cut is so short so it can run to the coupler on the throttle body. Lord knows I've got enough T-bolt clamps now. With all the couplers and pipes I've got, I'm sure I will be able to get something to work OK. And if not, well, there's enough stuff available from places I've stumbled upon looking for this airbridge pipe where I may just have to try my hand at fabricating something to just take the place of the airbridge completely. I'll probably wind up wishing I had kept my welder I gave away years ago. But not that I ever really learned to weld, anyway.

I even had my old aluminum BBK airbridge out to see if I was overlooking something about getting that to work properly, but doesn't look like it will unless I can take metal off of the bridge ends or the opening in the intercooler to bring it down so the hood isn't hitting it.

Thanks for the offer of the powder coating. I may take you up on it if it comes to my having to use that steel tube.

 

[Rich Z]

I wound up putting my old stock upper radiator support back in, as it just seemed to fit better than the blue one I had been using. Plus the paint on the blue finished one was getting kind of beat looking from what it has been though the last few years. I was able to get the radiator positioned better so that the fan shroud is now flush up against the radiator. I also lined the underside of the support with some adhesive backed insulation while I was at it to try to shield the airbridge a little bit from heat coming from the radiator beneath it.

Still got some minor snags, but the airbridge went in pretty well. Connie was helping me with this step of the process. She seems to get a kick out of helping me in the garage. I was able to slide the lower end of the airbridge over the end of the MAF housing, so I didn't need to use that steel tubing, and I cut off a section of the 3.5" aluminum tube to go into the upper section and mate that to a rubber coupler to the throttle body. That rubber coupler is a 4" to 3.5" adapter, needed to mate that throttle body to the airbridge. So the aluminum tube bridges the gap between the rubber coupler and the airbridge, allowing me to get a nice secure fit with the T-bolt clamps.

As for the snags, I didn't have exactly the sizes I needed for a couple of those T-bolt clamps. Apparently they are VERY specific to the application needed, with only about three tenths of an inch leeway between the lower and upper limit to the size of connection they will work with. So you pretty much have to measure for EXACTLY the size you need. On the lower section of the airbridge I had to put a piece of rubber coupler over top of the airbridge itself to allow that clamp to seal. Then on the rubber coupling between the throttle body and the aluminum tube coming from the airbridge, the clamp I used there on the aluminum tube is bottomed out. It's snug, but I'm just not comfortable that it is TIGHT. So that means another order for Summit Racing. While I was at it, I also ordered T-bolt clamps for as much of the rest of the STS plumbing that I could reach without taking anything apart to get to the connections. Hopefully I measured the diameters correctly. Like I said, there is very little room for guesstimating what you need with those T-bolt clamps.

Anyway, I snugged everything down, then started up the engine to allow the airbridge to get hot enough to be flexible, then cranked down the T-bolts to form the ends of the airbridge to the aluminum tube at the top, and the MAF housing on the bottom. I could FEEL the bolts tighten up, so obviously the plastic of the airbridge was pretty pliable then. When I installed the aluminum tube back into the bridge after cutting the tube to the size I needed (got to use my bandsaw, yay!), I already had to re-heat the airbridge just to get the tube back into it. So it should be pretty snug in there now, and hopefully be an airtight fit.

Also, I didn't realize how much thread would be showing on those T-bolt clamps, so I'm going to have to reposition them. Just looks goofy the way it is now with them sticking straight up into the air alongside the airbridge and couplers, but it's fixable. I figure I'll do that when I get the proper sized clamps in from Summit.

But one thing for sure, the airbridge fits a WHOLE lot better now like this. Lots of clearance between it and the hood now. I guess I can even put that hood liner in that I've had sitting in it's box for the last couple of years.

 

[shakedown067]

Yeah those t-bolt clamps are crazy. I have them on my silicone radiator hoses...one day I'll pull out the dremel and knock the bolts down a bit. They sure work well when you have the "prefect" size, as they are certainly limiting, but they seal so nice and look great when you hide those massive bolts.

On a side note, when it's time for a paint job, you should have that fast intake painted body color. Would look sharp with all the chrome wire loom. :thumbsup:

 

[Rich Z]

Looks like I won't be getting my Summit stuff till Monday. But yeah, I'm going to try to hide those bolts better I was looking closely at the pics last night and I'm wondering if I have the MAF connector sitting too high. I may have to adjust that as well if it's too close to the hood.

As for painting the intake manifold, yeah, that probably would look pretty sharp, but to be perfectly honest, once I've got everything running right, I'm not taking anything apart again unless I have no choice in the matter. Meaning, if the world won't end if I DON'T do it, then I'm not taking ANYTHING apart again.

 

[shakedown067]

Yeah, I certainly understand that one...but I figured since you've done it a couple of times now, thought it might be fairly easy. Hey it's a project car, so you'll need something to do to it down the road. LOL

 

[Rich Z]

Yeah, I certainly understand that one...but I figured since you've done it a couple of times now, thought it might be fairly easy. Hey it's a project car, so you'll need something to do to it down the road. LOL

Yeah, but at some point I would like to think that I could actually drive the car to California and back like Aaron Scott said I could do with it when I picked the car up from him.

But hopefully the day will come when I stand back and look at the car and think that I absolutely don't have anything else that NEEDS to be done with it, except maybe for routine maintenance here and there.

Anyway, today I just tightened down the bolts on the upper radiator support. I had left them loose in case I needed to take it off again to trim back any place on it that the airbridge might hit against. But such was not the case. And I loosened up a couple of the T-bolt clamps on the airbridge and rotated them a bit more underneath to be a bit more out of sight. I checked on the MAF connector and it seems to clear the hood just fine, so I don't need to move it.

I haven't gotten a new tune from Mike Carnahan this week, so I'm thinking I may play around with the tune myself over the weekend to see if I can make any headway with that low rpm surging I have. I'll just take baby steps with the changes and see what happens. Except for the above and sharpening the throttle response a little bit more at low pedal pressure, there really isn't that much that has to be done with the tuning. At least anything that doesn't need a dyno to work with.

 

[Rich Z]

Today I actually played around with the EFILive tuning program a bit. I looked over the log files, paying attention to the values of the areas where I was getting the engine surge and also the weak initial throttle response, and played around with the spark advance tables. I modified just the cells in the 800 to 1200 rpm range at the vacuum levels indicative of idle and initial throttle opening.

Then I flashed in the new tune and took the car out for a spin. I do have to say that the cold start was rougher then before, so apparently the changes I did didn't do that any good. But it did seem like throttle response was improved quite a bit. Of course, it just might have been a case of "the car runs much better since I washed it" syndrome. :hehehe:

It appears that the spark advance trace is more stable that it has been earlier. Not jumping around as much. But engine speed is still fluctuating as much as 100 rpm while just drifting down the dirt road with my foot off of the gas pedal, so there must be some other things that need to be tweaked. Hmm, maybe by changing the scale of the log display I will be able to see the variation in engine speed better to get a better idea of WHEN the changes take place in relation to everything else being logged.

When I first started the car, I got some error messages on the DIC, though. SERVICE TRACTION CONTROL, and REDUCED ENGINE POWER popped up. I just shut off the ignition and restarted it, and those all went away. Maybe something to do with my disconnecting the MAF sensor cable confused the PCM or something. I guess I'll see what happens next time I start it up. I didn't get anything strange showing up in the log file while test driving the car, so I hope it's just a hiccup from the above mentioned connector being disconnected. I guess I really should disconnect the battery when doing that sort of thing.

But I did get a persistent error tripping the CHECK ENGINE light. I scanned for codes and found a 99 - HVAC B0338 H C code. Nothing would reset it, so apparently it's indicating a REAL problem. I checked around and the most likely candidate is the Interior Temperature Sensor has gone bad on me. Either that or the connector has come loose. The error indicates and open circuit on this sensor. I've ordered a new sensor, and I guess I'll be taking a look at that sometime this up coming week.

Oh yeah, that drivetrain noise is back. I heard it several times today when pulling away from a dead stop. I even had the steering wheel straight a couple of times, so I'm not too sure about the probability of it being the serpentine belt. But I do have a new belt that I'm planning to put on the car sometime soon, just in case. No telling what sort of brand belt is on there now, but I wouldn't bet on it being top of the line. I ordered the Gatorback belt, since that appears to be pretty highly rated by many people.

 

[Rich Z]

Got in the assortment of T-bolt clamps from Summit today, so I replaced the ones on the airbridge that were too large and also repositioned them so they weren't quite so noticeable sticking straight up in the air like they were.

The engine compartment is starting to look pretty spiffy..

Also replaced all the wormgear hose clamps on the rest of the STS plumbing that I could get to without taking anything apart to get to them.

I know the input side of the turbo housings don't really need to have T-bolts for the coupler, but I figured that while I was doing the other ones....

I also did the clamps up front on the intercooler.

The ones right against the intercooler were a bit tricky to get to.

When it comes time for me to have to take off any panels that allow access to the other STS couplers, I'll replace those clamps with T-bolt clamps as well. Assuming I can. I recall that some of them might be visible and I might be able to touch them with my finger tips, but might not be quite so easy to replace those clamps without pulling the pipes out. If that is the case, then I'll just stick with what I've got.

I'll need to heat up the engine compartment again to get that airbridge hot so I can crank down the t-bolts on it to make sure it is sealed up OK. I repositioned both of the clamps on it today. But I'll leave that for another day.

 

[Rich Z]

Heated up the engine yesterday and tightened down the T-bolt clamps nice and snug on the airbridge. Hopefully they are sealed up good and solidly now.

I got a new tune from Mike Carnahan on Wednesday, but it wasn't till today that I took the car out to test drive and do some data logging. He says he's got the air/fuel as good as it's going to get, so time to work on the advance timing and driveability issues. I was surprised to see that he kept my earlier minor changes in place, so apparently at least I didn't make things worse with them.

Cold startup is still kind of rough. The engine idle speed seems OK, but the engine shakes quite a bit till it gets warmed up and the O2 sensors start working. So that is going to need more work. Obviously is something in the open loop tuning.

Idle speed while going down my dirt road is lower, but the surge seems a little worse to me when I put light pressure on the gas pedal. I can also really feel the surge when coming to a stop light when the rpm will drop down low. Actually with the car in any gear with the rpms dropping down close to 1,000 rpm when you really should down shift will get the engine to surging. I think an indication of the problem is that the rpm values being logged are jumping all over the place, with a swing of as much as 200 rpm in some instances. Also appears that the timing starts making abrupt swings too. But I'm not sure which is the chicken and which is the egg.

But on the plus side, I noticed that when coming to a stop light and I engage the clutch to take the transmission out of gear that the engine rpm doesn't jump up in rpm like it used to do, and stays pretty stable at a normal low speed. Before it would rise in speed and stay that way, out of gear, until the car came to a dead stop. Then the rpm would come down to a normal idle speed. So that is MUCH better now.

Throttle response feels pretty darn good. Might need a little bit more sharpening, but I could live with it like it is. And gas mileage is still pretty darn impressive, as well.

I didn't push the car into boost at all on this trip out. This was mostly just to take a look at the surge problem and throttle response on the low end of engine rpm and throttle pressure. So it was a pretty leisurely drive. I had the camcorder running just to make a record of anything that went awry during the drive, which didn't happen, so nothing worth posting here in video form.

Oh yeah, didn't hear a peep out of the drivetrain noise. I got in new Gatorback belts, so I'll likely change out at least the serpentine belt over the next couple of days in case that is contributing to the intermittent noise I've been hearing. I doubt the AC belt is making any noise, as I haven't had the AC running at all for quite a while now.

And that DIC error that was coming from the interior temperature sensor has gone away on it's own. Still haven't gotten the new sensor in, but I'll just set it on the shelf in case the error comes back sometime.

Washed down the car when I got back home with Dawn dish detergent, as I want to take a stab at fixing those rock chips in the paint sometime soon. So I wanted to strip any wax or polish off of the paint before starting on that.

 

[Rich Z]

Today I was going to pull off that insulation I had put on the lower part of the headers and use the same insulation I put onto the rest of the exhaust system. But looking it over, I decided to just leave it as it is. Those burn marks haven't gotten any worse, and I noticed that the clearance between the headers and the bell housing is REAL tight. Tight enough to where I might not be able to get that other insulation between them, as it is thicker. Then I would have been stuck likely having to buy more of that original insulation anyway. So maybe best to just leave well enough alone.

I put on the new "gatorback" serpentine belt. This one is definitely tighter than the one I pulled off. Took some grunt power to get it onto the pulleys. Maybe over the next day or so I'll take the car out to see if any noises crop up. I don't think the "drivetrain" noise could be caused by a slipping serpentine belt because I don't think you could feel that sort of thing through the gear shifter like I have when the noise takes place. But heck, can't hurt to put on a new belt anyway. And I've been surprised before.

And you know what? I can't think of anything else, mechanical wise, that I have to do to the car now. Well, maybe change the oil and filter, but otherwise, I think I've done everything that I know of that needed to be done. Unless that drivetrain noise is actually a premonition of something getting ready to break or that interior temperature sensor problem comes back, I think now I can play around with the paint finish to try my hand at fixing rock chips in the paint.

And play around with the tuning, of course. But heck, I've got my car back now. I feel like I can drive it when I want to, when the weather permits. But still going to be a while yet before I will feel comfortable driving it any distance. But it's getting there.....

 

[schpenxel]

And you know what? I can't think of anything else, mechanical wise, that I have to do to the car now.

And play around with the tuning, of course. But heck, I've got my car back now. I feel like I can drive it when I want to, when the weather permits. But still going to be a while yet before I will feel comfortable driving it any distance. But it's getting there.....

Now that's cool. I almost forgot about this project--really wish it could have stayed on the other forum, there were a lot of people watching it.

 

[Rich Z]

Now that's cool. I almost forgot about this project--really wish it could have stayed on the other forum, there were a lot of people watching it.

Yeah, it was closed by pewter99. CorvetteForum is pretty much owned by their sponsors.

 

[schpenxel]

Yeah, it was closed by pewter99. CorvetteForum is pretty much owned by their sponsors.

I've noticed. It's absolutely nuts when you see all the bad stuff posted about some of the vendors on other forums, then see all of the same stories get deleted off of corvetteforum.

I still say the guys who made the mistake on your driveshaft length (can't remember their name) could have gotten some great free publicity for helping you out. I hate to know how many people were following your thread there at the end.

edit: Also, those engine pics look nice!

 

[Rich Z]

I've noticed. It's absolutely nuts when you see all the bad stuff posted about some of the vendors on other forums, then see all of the same stories get deleted off of corvetteforum.

I still say the guys who made the mistake on your driveshaft length (can't remember their name) could have gotten some great free publicity for helping you out. I hate to know how many people were following your thread there at the end.

edit: Also, those engine pics look nice!

Yeah, that was Pfadt. I think they got pissed that I called them to the carpet for screwing up like they did. They sent the wrong sized shaft. No two ways about it. They want to blame the installer, but let's get real here. Chris Harwood installed it, Aaron Scott took it out of the torque tube and looked it over, and McGee's Auto pulled the engine and reinstalled it back onto the torque tube. None of them apparently saw any obvious signs that led them to believe they should measure to see if Pfadt screwed up. It wasn't till Shane at the local Chevy dealership pulled my drivetrain and saw the damages that he said, point blank, that the driveshaft was too long. So was everyone BUT Shane, who saw that driveshaft as incompetent as Pfadt infers? Or is Pfadt just grasping at straws trying to deflect blame from themselves?

I didn't ask Pfadt to pay for the damages. I actually couldn't PROVE the driveshaft caused all the damages, since when I got the car back from Aaron Scott there were bolts missing from the bell housing, which certainly couldn't have helped matters. But who really knows which problem caused what damages? I merely asked for a refund of the shaft as my car was already back together again, and they refused. And even then, it was obvious that sending me the correct driveshaft was done grudgingly.

As for CorvetteForum, well, the site was bought out by an advertising company that in my opinion is solely interested in making money off of their investment. It's no longer owned by people really interested in the topic matter there, so I guess their new focus on generating revenue is about all that can be expected. So the expectation now is that the moderators over there have to enforce the dictates of "protect the sponsors, at all costs". Right is right, and wrong is wrong. But apparently wrong can be bought off and whitewashed there at the cost of a sponsorship.

 

[Rich Z]

Well, the car is pretty much stuck inside for a few days. Heavy rains yesterday, more showing up here today, and even more predicted for Sunday. Our road is rutted pretty good right now, so will likely only get worse.

I decided to go ahead and change the oil, since I checked my record book and the last oil and filter change was back in June. Just 1,000 miles on the car since then, but I figured I should do it. Also put the Joe Gibbs 15w-50 oil that Brian at LME recommended that I use in the engine. Stuff is definitely thicker than the other oils I have been using. I put in a Fumoto oil change valve to replace the regular oil pan drain plug while I was at it. Had to fiddle around with extra gaskets to make it sit at the correct angle, though, and not have the valve handle hanging down exposed to road debris while driving.

When I started the car after the oil change, the new serpentine belt looked OK that I put on the other day.

I'm curious to see what that thicker oil will do for the oil pressure when I get to drive the car around and get it good and hot. The pressure was sitting at 48psi when I started the car up cold and let it idle. Seems to me that this is about 10 psi higher than I was getting with the thinner oils.