inline 250 Vacuum/Emissions System

[bob77]

Is there a particular spot on the carb that I should connect the gauge?

[bob77]

Does anyone know what sort of compression reading I should get on my 250. Would this info be on the tag under the hood?

[Captkaos]

Vacuum would be connected with an port on Manifold vacuum.

The compression reading won't be on the underhood tag.

[Lt.Del]

the main thing with compression is they should all read similar.  If one reads way off, you have a problem with that one.

[bob77]

Cool. Thanks a bunch. I have been reading quite a bit on compression testing and am hoping to check it either tonight or tomorrow. (depending on when a buddy of mine brings me his compression tester). As I didn't see any evidence of oil on my plugs when I changed them out, I am more suspicious of a bad valve than of a ring issue. (It's more than 30 years old, I'm sure the rings aren't like new). I am actually more suspicious that something is amiss in the carb. When I do the compression test, I will post my findings and will be anxious to hear opinions.

Thanks as always.

[cb7501]

My '84 GMC has the rochester 2SE 2 barrel carb on the integral head 250. I'm not sure if this would bolt up to your head or not, I'm sure someone here would know.... The 2SE should be easy to find in a junkyard (they came on several different cars as well), and has an electric choke.  At the very least rebuild your carb. I went from 13mpg to 18 just rebuilding mine. Cheap and easy, can't hurt.

You can take off your EGR valve and plug the hoses, and fashion a block off plate-- or just plug it and leave it on. No backpressure issues.

You might also consider installing an electrical fan, they are cheap in the junkyards and could give some mpg gain. I put one on mine and felt a difference in engine response. I have done several different things to help gas mileage as a little project, but don't drive the truck enough to check all of them seperately, so I don't know the effects on mpg. My mileage lately is ~16-20mpg ,with a best ever of just over 21.

Jason

[bob77]

Well, tested for compression tonight. I was VERY pleasantly surprised.

Cyl 1 - 160
Cyl 2 - 160
Cyl 3 - 160
Cyl 4 - 160
Cyl 5 - 165
Cyl 6 - 165

I would call it a give or take 5 or so PSI on these readings as I did each Cylinder about 4 times and kind of tried to take a average. I have to say that I was quite shocked to find that not only did all cylinders compare very closely, but that they were still so high for a 77. I just picked the truck up a few weeks ago. The paint quite worn from the motor, but you can see that it had been painted once. (some parts blue and some red showing through.) I'm guessing that sometime in the last ten years or so the motor had been rebuilt. Other than the leaky valve cover gasket which I replaced, it doesn't seem to lose a drop of oil. The fella I bought the truck from said he picked it up in Nevada about 6 years ago and it had been a Nevada State owned vehicle. (Parks department or something). Some state of nevada tags and such still appear on the dashboard. I'm guessing that the State of Nevada kept up with maintenance on the rig whenever it needed it. I am very pleased.
Now, another development in the Fuel Consumption scenario I am dealing with. I decided to spend the three bucks and replace the fuel filter in the carb. (mildly suspicious that there wasn't even one installed). The gentleman I bought the truck from rebuilt the carb himself a few years ago and didn't exactly do a very good job. Throttle linkage made out of a coat-hanger...etc... Anyway, when I went to pull the old filter, there was no spring behind it and it certainly seemed to just lay very loose in the housing. I figured at the time that maybe that's just how they were....Until...
Tonight, after I installed a new fuel pump, I opened the box for the carb rebuild kit and began looking over what trouble I was going to get myself into this weekend. Low and behold, there on the diagram I see a spring that goes behind the fuel filtr and seats it in place.
Correct me if I am wrong, would missing this spring not allow fuel to bypass the filter and move through the carb at a higher rate than normal? Causing a rich running condition and poor fuel mileage?
I am going to try and locate a replacement spring tomorrow and test my theory (I may be completely wrong... It happens all the time). I still plan on rebuilding the carb this weekend. I'm sure it could use it. If someone would like to give me some feedback on my compression test results and my fuel filter spring theory, I would be most appreciative.

Thank a bunch!!!

[bob77]

cb7501
Any pointers you could give me on choosing an electric fan or installation would be great. It's something I had thought about but didn't want to pay too much for. I didn't really think about a junkyard item. I suppose just finding a newer chevy truck or some such with an electric fan would do the job.

[Skunksmash]

I dont know, man. I have always been scared of junkyard parts that are parts that have ever been under any strain. You might install a junkyard electric fan and have it fail in a couple weeks cause it was just used up. If it were me i would get a new one. There must be some company out there that offers an electric fan setup for our trucks?

[VileZambonie]

Yes there is a drop in for our trucks but it is expensive!

[Skunksmash]

Yes there is a drop in for our trucks but it is expensive!

you mean this one?

http://www2.partstrain.com/store/?Ntt=Cooling%20Fan&N=9959%201588%204294966976


Yeah thats way to expensive. Or maybe it is the average price of an electric fan. I dont know.

[Captkaos]

That isn't a "drop-in".  The drop in that uses factory mounting is the Perma-Cool.
http://store.summitracing.com/partdetail.asp?part=PRM-19513&view=32&N=700+4294908216+4294908213

BTW, $260 on the Flex-a-lite is a GOOD price!

[eventhorizon66]

Check again, Capt.  That said $360.

[Skunksmash]

Wonder if the drop in one would still work with that thicker, better radiator?

[cb7501]

Good luck with the carb rebuild, that little monojet will be a piece if cake, even if it's your first carb rebuild! Take pics and notes while you take off the linkage/s and disassemble, it'll save you some head scratching later.

I used a fan from a 98 V6 Mustang, $30 from the local yard, had to modify the plastic shroud a little. Lots of people use a ford taurus fan, do a google search (e-fan taurus) and you'll get lots of info & how to. I bought a fan controller at auto zone (part 733652) for $25, came with the rely and fuse, fixed (pre-set) thermostat.  Spent another $8 on wire, connectors, etc. I'm no mechanical genius, and this was an easy project. And for about $60, you can give it a try and see what you think without breaking the bank. You can always 'move up' to a high dollar fan if you want to later -- and have time to put some $ in the bank in the meantime. That's just my 2 cents . If anyone wants pics of my set up I'll post a few w/ an explanation of what I did.

I've been running mine since this May; mostly trips into town but also hauling. Even in 95 degree weather I had no issues. When I first set it all up I let the engine heat up to ~230 before I hooked the fan up...and watched the temp gauge drop in secods back to usual temp. This thing is impressive. It doesen't even run too often, mostly at stoplights. My stock alternator has been more than adequate, although my truck doesn't have a/c to run or electrical acessories besides a cheap radio...

If you're really worried about the reliability of the e-fan set up, throw your stock fan behind your seat-- you could pull off the e-fan and stick the stock one back on in 10 minutes on the roadside if something goes wrong. Do a little research and pick a good fan, use the correct gauge wire and big enough relay, and you won't be disappointed in this project.

Choosing used vs. new fan:
These fans are well engineered, long running pieces of equipment. The mustang, taurus, and sevaral others have a very good reputation for durability and excellent function even from the bone yard. There's really not too much you could do to 'abuse' an electric fan, so I don't have a problem buying one from the 'yard, as long as all of the wiring & connectors are OK. If it goes bad in 5 years put yer stock fan back on, run to any junkyard and for $30 and you're back in business. For my budget this is the way to go. Lots of people-- from dopes like me in old beaters to guys with highly modified 350's in drag cars--are doing this with good results. I don't have anything against buying a new fan, I just like a thrifty approach to my truck (and an excuse to go the junkyard!). If purchasing new is what gives you peace of mind go for it!

Jason