1985 V8-S10 Blazer
Moderators: MostMint, wxo, Fred32v, Basement Paul, ttamrettus
Re: 1985 V8-S10 Blazer
Just put a T in a vacuum line on another vehicle and use that as your pump. That will allow you to see if the vacuum advance is working.
I am not sure how that distributor advances timing. In a stock GM HEI the springs and weights are what controls centrifugal timing advance under power. The vacuum advance only advances timing during idle and part throttle conditions. Under WOT vacuum advance would be zero.
If it was mine I would take it apart or google the part # and find out how it works - maybe the centrifugal advance is inside.
I am not sure how that distributor advances timing. In a stock GM HEI the springs and weights are what controls centrifugal timing advance under power. The vacuum advance only advances timing during idle and part throttle conditions. Under WOT vacuum advance would be zero.
If it was mine I would take it apart or google the part # and find out how it works - maybe the centrifugal advance is inside.
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]
-BP[/quote]
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Re: 1985 V8-S10 Blazer
My suggestion with the distributor is to get the model number off of it and find the operator's manual online. I did this with my MSD from the TubStang with success and learned all about it. I 'spect you'll have the same results. Cool that it's electronic already.
New intake looks great.
-BP
New intake looks great.
-BP
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Re: 1985 V8-S10 Blazer
I had thought about using the Chevelle or Corvette to draw vacuum on it, but without knowing what to look at, I didn't try it. Tonight, I stopped at Autozone and they have a hand-held vacuum pump in the tool loaner program. Perfect.
And I was right -- vacuum advance canister is leaking. I can't get more than 5" and it bleeds down quick. I hooked up the pump to the distributor while the engine was running an no change. I tested on my HEI, which I can pull easily to 15". I did verify that the mechanical advance is working, though. For the time being, I put a golf tee in the vacuum advance line.
Here's the instructions I found online -- pretty awful quality. http://prestoliteperformance.com/media/ ... 41000E.pdf -- which states the vacuum canister is a non-cataloged part, and the phone number listed is disconnected. A quick search at Summit seemed to confirmed lack of availability. The drawing also confirmed my suspicion about a ballast resistor. Previous owner had one in there, but I removed it when I took everything apart (ok, I broke it) but was 99% certain it shouldn't be there anyway.
Not sure what the next step will be to remedy this. I guess I'd prefer to find a replacement vacuum can first. If not available, a small-body distributor keeps me from having to re-plumb oil pressure sender and re-wire an important ground. I have a few old points distributors in the basement, and for $80+ I could buy a Pertronix Ignitor conversion. Getting my large-body HEI in there would let me get rid of the external coil, giving me room for a larger, drop-base air cleaner and just be a better all-around solution, IMO.
-Dave
And I was right -- vacuum advance canister is leaking. I can't get more than 5" and it bleeds down quick. I hooked up the pump to the distributor while the engine was running an no change. I tested on my HEI, which I can pull easily to 15". I did verify that the mechanical advance is working, though. For the time being, I put a golf tee in the vacuum advance line.
Here's the instructions I found online -- pretty awful quality. http://prestoliteperformance.com/media/ ... 41000E.pdf -- which states the vacuum canister is a non-cataloged part, and the phone number listed is disconnected. A quick search at Summit seemed to confirmed lack of availability. The drawing also confirmed my suspicion about a ballast resistor. Previous owner had one in there, but I removed it when I took everything apart (ok, I broke it) but was 99% certain it shouldn't be there anyway.
Not sure what the next step will be to remedy this. I guess I'd prefer to find a replacement vacuum can first. If not available, a small-body distributor keeps me from having to re-plumb oil pressure sender and re-wire an important ground. I have a few old points distributors in the basement, and for $80+ I could buy a Pertronix Ignitor conversion. Getting my large-body HEI in there would let me get rid of the external coil, giving me room for a larger, drop-base air cleaner and just be a better all-around solution, IMO.
-Dave
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Re: 1985 V8-S10 Blazer
Love the hand drawing on the last page! Vintage. I like putting an HEI in it over the winter and the drop base filter. Yeah, K&N!
-BP
-BP
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Re: 1985 V8-S10 Blazer
Went to accel-igntion.com last night and was happy to see a 216 area code phone number and a Memphis Rd address. Fingers crossed, I called them this morning to see if they had a replacement vacuum can, but no joy. A quick search on ebay also yielded no results.
I guess I'll plan on getting the HEI in there sooner rather than later.
-Dave
I guess I'll plan on getting the HEI in there sooner rather than later.
-Dave
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Re: 1985 V8-S10 Blazer
Did you just call "no joy"......Maverick? 

Re: 1985 V8-S10 Blazer
Guess you're referring to the issues I had with the Maverick? I never figured out if the idle problems were ignition or my rebuilt Holley. Went with MSD ignition and coil and QuickFuel carb and things got better. Doug, of Prestige Motors in Charlotte, thought it was the cheap, Chinese no doubt, HEI distributor that was causing the problem.Blue_69_malibu wrote:Did you just call "no joy"......Maverick?
Ford guys HATE "big ugly" HEIs but I liked the one wire (two with tach) hook up and having a complete, single unit, spare ignition in the trunk. They do occupy a lot of real estate on the front of a Ford engine but it didn't bother me. (Posted a close up of the engine with the HEI looking huge in the foreground to antagonize them.

Maverick
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Re: 1985 V8-S10 Blazer
Believe it or not, that was not actually an automotive reference.
I was quoting the movie Top Gun......which is what came to mind when I read "no joy".
I've been known to quote movies from time to time.
I was quoting the movie Top Gun......which is what came to mind when I read "no joy".
I've been known to quote movies from time to time.

Maverick wrote:Guess you're referring to the issues I had with the Maverick?Blue_69_malibu wrote:Did you just call "no joy"......Maverick?)
Re: 1985 V8-S10 Blazer
DOH!!Blue_69_malibu wrote:Believe it or not, that was not actually an automotive reference.
I was quoting the movie Top Gun......which is what came to mind when I read "no joy".
I've been known to quote movies from time to time.![]()
Maverick wrote:Guess you're referring to the issues I had with the Maverick?Blue_69_malibu wrote:Did you just call "no joy"......Maverick?)
Maverick
Re: 1985 V8-S10 Blazer
Tony is like Rain Man when it comes to movie stuff..... He never forgets
a line. "Definitely Wapner"
GM
a line. "Definitely Wapner"
GM
- Blue_69_malibu
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Re: 1985 V8-S10 Blazer
If only I had been graced with a more practical...or marketable...."special skill".GMJohnny wrote:Tony is like Rain Man when it comes to movie stuff..... He never forgets
a line. "Definitely Wapner"
GM

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Re: 1985 V8-S10 Blazer
Since we've had some bonus weather these past couple weeks, I decided to set aside the radio project and have it drivable again. I took it out on Thanksgiving night with Gwen and Holley just to put a few miles on it. I also drove it to work today, co-worker and I drove it to lunch, drove it home.
While it ran decent, I decided it was time to install the HEI. I mean, this was a 0$ upgrade just requiring my time. This HEI has a fancy MSD module in it, it has a MSD curve kit in it with, I think, one light, one medium spring, a decent coil in the cap, and a good set of wires, which happen to be red, matching the stripes. Tony's car ran mid 13s with it this setup. I got the oil pressure sending unit in there, but I don't have quite enough room to get the wire on for the gauge to actually work. I'll get that later. I made the extension for the main ground for the vehicle harness (10 gauge wire). I tired putting my 14" drop base air cleaner on there, but the front hits the thermostat/upper radiator hose.
I have the timing at 8* right now, but getting a little bit of pinging on full throttle. I need to order a timing tape for the balancer. I've made all the little incremental changes -- a little carb tuning, torker-->performer, HEI w/working vacuum advance, it really runs a lot better than when I first got it. Carb needs more tuning, I bet it's a bit lean. But I really like driving it. I'm curious what kind of mileage I can get from this.


Tony stopped by and we made a few aesthetic changes in the garage. He's good at making this stuff look nice. It was an excellent night in the garage.


-Dave
While it ran decent, I decided it was time to install the HEI. I mean, this was a 0$ upgrade just requiring my time. This HEI has a fancy MSD module in it, it has a MSD curve kit in it with, I think, one light, one medium spring, a decent coil in the cap, and a good set of wires, which happen to be red, matching the stripes. Tony's car ran mid 13s with it this setup. I got the oil pressure sending unit in there, but I don't have quite enough room to get the wire on for the gauge to actually work. I'll get that later. I made the extension for the main ground for the vehicle harness (10 gauge wire). I tired putting my 14" drop base air cleaner on there, but the front hits the thermostat/upper radiator hose.
I have the timing at 8* right now, but getting a little bit of pinging on full throttle. I need to order a timing tape for the balancer. I've made all the little incremental changes -- a little carb tuning, torker-->performer, HEI w/working vacuum advance, it really runs a lot better than when I first got it. Carb needs more tuning, I bet it's a bit lean. But I really like driving it. I'm curious what kind of mileage I can get from this.


Tony stopped by and we made a few aesthetic changes in the garage. He's good at making this stuff look nice. It was an excellent night in the garage.


-Dave
Re: 1985 V8-S10 Blazer
Are you concerned about the bundled and closely parallel plug wires?
Maverick
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Re: 1985 V8-S10 Blazer
Not really, maybe only from an aesthetic point of view. I suppose some proper separators couldn't hurt. I had them zip-tied together like that when they were temporarily on the Chevelle. They are new enough that I would expect them to not have any cross-firing issues.Maverick wrote:Are you concerned about the bundled and closely parallel plug wires?
-Dave
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Re: 1985 V8-S10 Blazer
I put some miles on it today. It really runs much nicer now. The carb still needs some fine tuning, but I'm comfortable driving this thing anywhere now. I made a visit down to Andy's to drop off some race-related stuff, went over to Summit to pick up a few things, and then took a meandering drive home. I calculated 15.8 MPG (87 octane) of mixed driving, which is a decent start.
-Dave
-Dave