Preparing for a cross-country trip

[shotwell]

I've got an '80 Monte Carlo Turbo that I'm preparing to drive from Virginia to Washington State. I've been going over the car little by little making sure that everything is in shape for the haul.

Recently I did a tune up...replaced the cap, rotor, wires and plugs. I found a major discrepancy in the spark plug gap specification. Three parts stores gave me three different gaps, .035, .040 and .060. Furthermore, the Chilton I have says .060 while my old Clymer says .035! Confused, I took the advice of a parts clerk and bought Autolite AP26 plugs and gapped them to .040. The car seems to run fine, but I'm experiencing poor fuel mileage, I think. I've been averaging around 15 MPG with mostly freeway driving. Is that normal? I've only really stomped this car a few times and experienced some hesitation at the higher RPMs. Do these plugs really need to be .060?

I've got some other issues and questions, but this is the big one for the moment. Any help would be greatly appreciated.

 

[Ttype83]

My Hayes & Chiltons call for a ACDELCO plug R45TSX gaged @ .60 for a 80 Buick V6...should be the same for yours.
I'am runing ACDELCO CR43TS with a .35 gag and have been for some time now. Not sure what that equels to on Autolites...FC227 should I think he runs those....Fred?

I've done that drive a few times...last one with the buick, You taking the Northern or Southern route?
Jim

 

[fc227]

Hi

I run Autolite #24 gapped at .040”. The problem with running a wider gap is the possibility of the spark being blown out at high boost levels and causing a miss. (Even with a stock HEI system, which is a good system)

There is also a second side effect of running a wide plug gap. That is it wears the cap & rotor out quicker. (Burns the tips off.)

Has for your mileage 15 MPG sounds about right, But what where you getting before? Was it more? Have you pulled a couple plugs to see if it is running rich? And the air filter is it clean?

Where is the timing set at? If you have vacuum advance is it working along with the mech. advance in the HEI dist. (Unless this computer controlled, I don't think it is on the 1980, but I could be wrong.)

I’m looking for a 1980 Turbo Monte; if you run across another please let me know.

 

[shotwell]

Looks like I've got some cross-referencing to do on those plug types. I agree that .060 is a bit wide. As for everything else, the air filter is clean. I haven't pulled any of the plugs yet. My car isn't one of the California computer controlled ones. I'm running vacuum advance and not sure of what the timing is set at. Probably the next two things I'll do is change the plugs or gap, whichever is necessary, and set the timing. I've only had the car for a couple of months, so I don't really know how it was running last time it was tuned up. When I got it she was only hitting 5 cylinders and the plug wires were toast.

This leads into my next question. Is it possible to in effect disable the turbo to attain better gas mileage on the freeway? I figure that would involve keeping the wastegate open all of the time, but I don't know if that would be good for the wastegate either. Just a thought.

I'll be taking the northern route. I'll probably snake up to I-90 from here and hit I-94 out of Chicago. I've got a friend to go see in Billings. From there I'll probably cut through Idaho and work my way to I-84 into Portland. Should be a fun drive!

 

[pat83t]

I am running ACDelco R45tsx's and I gapped them at .045. As for gas mileage I have been getting awesome mileage the last couple of weeks since putting a bigger cone filter on my cold air intake. Most won't understand this but Jim and shotwell should. I filled up in Longview and drove to Boring Or. then to NW Portland (St. Johns) then back out to Boring then to Troutdale and back to Boring, then to Gresham and back to Boring, then to Troutdale to fill up. When I went to fill up I had 1/4 of a tank left. I filled up and drove back to Longview and then back and forth to work this whole week and it is sitting on 1/4 of a tank again.

Sounds Boring huh?

You live in Vancouver? A friend of mine that works at the Schucks on 4th Plain Blvd has a rolling '80 Monte chassis that he is giving away. It is up here in Longview. Has a 3.73 rearend under it.

 

[fc227]

The 1981's had a normally open wastegate. But that only lasted one year. IMO I do not think you will easy and big difference from leaving the wastegate open.

 

[fc227]

That should say, "I don't think you will see a big difference in mileage.”

 

[fc227]

DOH !

 

[shotwell]

OK, scratch the wastegate idea then. Thanks fc227.

I just called Pep Boys and asked what Autolite plug the AC Delco R45TSX crossed to. They told me Autolite 666. That's completely different from my Autolite 26's! They also listed a .060 gap on them, and this agrees with the Chilton manual. I know gapping the proper plugs too narrow will make the plugs run colder, so I don't want to do that. I also don't want to burn holes in my pistons! What to do, what to do.

pat83t, I'm not sure about the gas mileage you're getting. I tried to do the math and came up with 12MPG which can't be right. If you would in the next few days copy down the odometer and figure the mileage I would really appreciate it. As for the '80 Monte rolling chassis, tell your friend I'll take it. I always need extra Monte parts. Funny he works at Schucks on 4th Plain...I probably know him. I worked at Car Care Center for a time and am really good friends with Chris from there. I often picked up parts from Schucks when there wasn't anything else to do. Small world!

Thanks all,

Mike

 

[b4black]

Even Buick didn't seem sure at what to gap the plugs at. They changed it from year to year. For an unmodded car, I would run at 0.040 or 0.045 and go a heat range colder than stock (R44's). But for the highway journay, I might go R45's at 0.050. Truth is it proably won't make a huge difference either way.

Check the timing and then check ALL the vacuum hoses and sensors for leaks. The vacuum/emissions can kill MPG's.

 

[shotwell]

It looks like any way you slice it these Autolite 26 plugs are going to have to come out. I'm not looking forward to the three on the passenger side again, especially the back one, but I'll do anything for better gas mileage at this point. This is a 2800 mile haul!

I'll be checking for vacuum leaks and such this weekend. An interesting note, I took the belt off the smog pump and seem to have gained a bit of pep. I'm not exactly sure the ramifications of that, so if anyone knows please tell me.

As far as timing, the Chilton says to run 15 degrees BTDC. I can still barely read the sticker under the hood, and it probably says 15 degrees also, but doesn't the type and gap of spark plug affect timing? I time all of my V8's by ear, but with this spark retard system, whatever it's called, I fear this would be counter-productive. At any rate, if you guys have any other tips on how to get better fuel mileage other than keeping my foot out of the carb please let me know. Thanks again!

 

[fc227]

Want to tade that turbo Monte for a 1978 Monte (plain V6 buick)?

 

[shotwell]

Does it have a manual transmission?

 

[fc227]

No Automatic 3 speed (th200) I think.

 

[fc227]

I'm just kidding with you , You don't think you really want My Monte. It need a new front passager side fender, rocker panels. & tires.

 

[shotwell]

LOL, I figured that. I'd love to have a manual transmission setup for the '78 - '88 G Body though. That would be a blast with the 383 I plan to build for my '79 Monte. There is much to do before that though. I've got to get this '80 Monte home safe.

 

[pat83t]

Originally posted by shotwell


pat83t, I'm not sure about the gas mileage you're getting. I tried to do the math and came up with 12MPG which can't be right. If you would in the next few days copy down the odometer and figure the mileage I would really appreciate it. As for the '80 Monte rolling chassis, tell your friend I'll take it. I always need extra Monte parts. Funny he works at Schucks on 4th Plain...I probably know him. I worked at Car Care Center for a time and am really good friends with Chris from there. I often picked up parts from Schucks when there wasn't anything else to do. Small world!

I figured it out and it works out to about 18.5-20 MPG. That friend of mine's name is Pat also. He just got moved down there about 6 months ago. He was at my store before that up here in Longview.

 

[shotwell]

Well, the job I was on in Virginia ended ubruptly on Tuesday and they sent everyone home. I didn't have everything on the car done that I wanted to, especially the spark plug thing, but fate was on my side and I make it all the way back with no serious problems. My best tank of gas was about 18 MPG, the worst 11 MPG. I averaged around 14 or 15 MPG. Yikes! I'm going to be picking up some Autolite Platinum 666's tomorrow, gap them to .055 and see how it runs. I imagine I'll have to change this a few times before I am satisfied it is right...I'll keep you all posted.

One thing I noticed in the drive is that the engine would get really hot if I drove over 70 MPH. It was about 200 degrees most of the drive, but would go right up to 220 if I went 65-70. I pushed it to 85 for a while in Idaho and the temp was probably around 240 before I backed off. It never boiled over or anything, just got really warm. Is this a characteristic of this engine or do I need to look closely at my cooling system? I had a full trunk and some stuff in the back seat, but the car was by no means overloaded.

I only used 2 quarts of oil in the whole 3000 miles.

pat83t, let's get together sometime this weekend or early next week and talk about that '80 Monte rolling chassis. My email is shotwell@pugetsound.net and phone (360)574-5799.

Mike

 

[pat83t]

Well, I am off tomorrow (sunday the 3rd) and then I am off Wed, Thur, and Sun. next week. That sunday (the 10th) I am going to the all buick show in Brooks Or. (about 30 miles south of portland.)

 

[b4black]

I'd pass on platinum plugs. They are more for longevity, not better performers. Most V6 racers that tried different plugs stick with cheap ol' AC or Autolight lugs.


On the heat, it might be a bad EGR causing the engine to knock. Get a ~165° thermostat (same as a SBC, so they are easy to find) and maybe it's time for a new, 3-row radiator.