73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: srozell on May 08, 2017, 10:45:44 pm
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I tried searching to see if this was answered, but I couldn't find anything.
The previous owner of truck cut, broke, sliced and plugged the existing vaccuum hoses on the truck.
Many of the fittings/valves that hoses are supposed to be attached to are physically broken.
I am assuming this will have a huge impact on the cold-starting of my truck. Am I right?
Would it be possible to bypass most of these hoses with a different carburetor and would it make sense to do so?
My priorities are
1) Reliability,
2) Maintainability
3) Cost
4)Humiliating my father in his '56 Mercury P/U. :)
1980 k20, 350 w/ air and cruise control
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Somethin I've always kept in the back of my mind was: the hoses/lines,sensors,valves,etc...was put on a vehicle for a reason. Wheather it be for somethin minute or somethin youd definately tell a difference in,they all serve their own purpose. I can't remember what exactly my issue was,but I could tell a difference in the way my truck was acting and it turned out to be a simple vacuum hose that was detached. I hooked it back up and the issue was gone. Of course, seems like there's quite a bit of people out there who don't like all that stuff on their vehicles cause it steals some power,but myself,i don't care about that. My truck will still give me a speeding ticket if I want it to. I still have all my emissions stuff and hoses/lines attached. As far as the carb,I'd stick a the original,IF yours now is in fact the original or oem. Its more fine tuned to your truck. All of that's just my own opinion. Everyone's different.
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The carb is definitely original. I should probably post some pics of the rats-nest under the hood so subsequent posters get a feel for how bad it really is, but my daughter won't slow down long enough for me to pull the air filter off!
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Lol...myself,I'd either get your carb rebuilt or get a reman'd one...of the same as what you have now,of course. Seems like your #1 hurdle is your daughter though!lol
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The carb has been rebuilt, though I'm not dismissing it as a potential source for the rough-starting of this truck.
As I mentioned, things are broken, and vacuum hoses are not even close to being where they should be.
Here are some pictures:
(https://myuglytruck.files.wordpress.com/2017/05/20170509_151751.jpg)
(https://myuglytruck.files.wordpress.com/2017/05/20170509_151827.jpg)
I'd love to get some solid recommendations on the direction I should lean towards.
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Yeah....your setups different from mine or I'd offer you help. This is probably a stupid question,but have you tried lookin up a vacuum hose routing diagram for your truck? If nothin else,maybe for the valves,etc.. that aren't broken?
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R u going to have to pass emissions with this.
Factory service manuals are a Buffett of info.
Your not going to get much help without telling Year, make, model etc.
Rebuilt replacement or rebuilt original carb?
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I'll never have to pass emissions with this.
I have all the info for restoring it to factory, my question is primarily, should I, or would I be better serviced by a different carb/intake set up.
My bad, it's a 1980 Chev k20, air conditioning & cruise control. So far everything is stock.
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Myself...I'd stick to stock. Course,im partial to stock,but w that aside,the more youd change,the more $ you'll spend and adjusting/fine tuning youd have to do...unless that's what you really want (different carb,intake,etc..). I'd get the valves/fittings replaced,if possible, the hoses replaced and hooked up properly and the carb looked at. Once you have those solved,you'll notice a good difference.
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Sorry, I missed the question in there Blazer74.
It is a rebuilt original carb.
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I agree with NCOhio but its all what you want.
Dizzy vac is probably already rerouted directly to manifold vac.
Properly adjusted choke and carb for your cold start.
Most of those TVS valves are coolant temp controlled vac switches reducing vac until engine is warm
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With the TVS's broken, is it worth replacing them, or should I just plug them?
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I'm not sure how many tvs you have on your truck and how many vacuum ports are on ea one,but on mine, I have 2 that has 4 ports ea. With that bein said, that's up to 8 possible issues I could have w them bein plugged off..4 if I have one plugged off. I'd see bout gettin them replaced.
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Here is the diagram I am using to re-route the vacuum hoses. The only thing I can't seem to figure out is what the DVTR Valve/ A.I.R. pump is that is referred to on the right.
It is totally possible that the previous owner removed it, so a picture would be nice, if possible.
(https://myuglytruck.files.wordpress.com/2017/05/1980-k20-vacuum-routing.jpg)
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I'm not sure how to send a pic,unless it's through txt message,but I never tried either.lol. If youre lookin under your hood,it'll be JUST to the left of your alternator and under your air cleaner snorkel. Its not a big part and it has 2 big rubber hoses and a small vacuum line attached to it. If your set ups different, and if you want,pm me w your phone # and I'll send you a picture.
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I tried to figure out how to put a pic on here....I THINK I figured it out,but not sure.lol. The only thing i think I have figured out is the "Mona Lisa" icon... yep...that's it. How would I do it? Fyi,i didn't take the pic yet.
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I'll take a look tomorrow morning where you describe. I've got a feeling mine has been removed. Is it belt driven?
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No belts involved.
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Ok, thank you. I got distracted today putting a 4" lift on the truck and forgot to look!
I'll get there... eventually.
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I went out to my shop to check on something, and so I looked under the hood and I don't see anything where you describe it.
I'm sure the previous owner removed it.
I'd love to see a pic, but the closest thing I have to pictures on my phone is call-display. Old school I know.
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The only thing I can't seem to figure out is what the DVTR Valve/ A.I.R. pump is that is referred to on the right.
It is totally possible that the previous owner removed it, so a picture would be nice, if possible.
The AIR pump is just that, a mechanical pump that generates air flow to your exhaust manifolds, air cleaner, catalytic converter, etc. It's only necessary if you're concerned about emissions. This is a hose that could simply be plugged. The vacuum line is going to the Diverter Valve (DVTR) that determines where to send the air flow based on engine operation. Since you don't have any of this setup, just plug the line, no harm done.
I, too, am a big proponent of keeping everything under the hood as close to stock as possible, but there are a couple things that really don't do a whole heck of a lot towards performance and this is one of them.
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Thank you for that. The hose is currently plugged because I had no other choice, I guess I'll just shorten it and leave it plugged then.
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I know this is an old thread, but most of the opinions seem to be leaning one way, and I thought I would weigh in from the other side. I am also a proponent of keeping things original, but if value is not a factor, I am an even bigger proponent of keeping things simple. The owner has stated that he will never have to pass an emissions test. He has also stated that at least some amount of the of the equipment is already missing. It sounds like a candidate for removing all the plumbing that is not necessary for the engine to run effectively.
On my '85 C10 I was experiencing multiple vacuum leaks from the old vacuum hoses, lines, and connectors. I tried for a while to maintain all original connections, but it seemed as though every time I worked on the truck, I would accidentally break off another brittle, hard-to-find hose nipple. I finally decided to remove as many emissions related hoses and lines as I could. I also replaced the Quadrajet with the electrically controlled solenoid (passenger side front corner) with an Q-jet M4ME from a '77 small block pickup. I haven't regretted it. Yes, I have blocked of a number of ports on the carb and the manifold. Yes, I know that someone designed it to operate with all the hoses in place. No, I do not think I know more than the engineering team at GM. What I have gained from doing this is to assemble a reliable, efficient engine that allows me the access I want and the reliability that I need. Effectively, my setup is functionally similar to the setups produced before all the vacuum operated emissions equipment was introduced.
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Like anything, you should have a well thought out plan with an end goal. The path you take to get you there may involve straying far away from the factory if it's not conducive to your plan. In my opinion, if you have a system that has been butchered throughout the years, catalog pics, box everything up and get to work cleaning up the disaster area. If not for any other reason there may be others looking for those emissions parts that could use them so never trash them or save them in case you want to sell them with the truck some day.