250CI I6 Problem

[ryhan87]

I have a 72 Pickup with the 250 in it. Its running a little rough. I have looked over the points style dist and the points are adjusted and nothing looks to worn or corroded, the rotor shaft is a little sloppy but not bad. The head has been redone and has all new gaskets. The motor is tough to start, when running it lacks power and backfires or misses when you try to rev it up a bit. It is only bad when cold though, it seems to fix itself up when the motor warms up but still coughs a bit every once in awhile. I think the carb needs a rebuild but not sure any suggestions? Also what year of HEI distributer would work on my motor? Im trying to find one at a junk yard.

[Shyguy]

I have what I think is a 1970 250 l6 with a mono-jet carb in my '67 short stepper. It has an automatic choke.

When I first start it the thing runs real rough until it warms up. Once it is warmed up it runs ok but stumbles some times when I give it the gas.

I think some of the problem with it is it set for a about a year with out being ran so I am putting a good carb cleaner in the tank hoping it will smooth out some after I drive it some.

I am not sure what Hei it has, but here is a picture of it.

[68lwb292]

I think the HEI out of any later inline 6 will work. They started in the cars first then the trucks later I think any car 76 and newer had HEI. One guy told me he found one in a camaro with a 250L6I think the novas and malibus had them too and any truck late 70s and newer with a straight six. It doesn't matter if it has the intregal head or not the blocks are all the same.

You can get a new one on ebay for about 80 bucks shipped including the coil.
http://cgi.ebay.com/ebaymotors/NEW-H...item45ee3f96e0
Or go to your parts store and price one for a 78 camaro with a 250 six. Another thing if you go HEI you'll have to change your plug wires too cause the caps are different.

Those carbs are easy to rebuild just take the numbers off it and go to your parts store they'll have a kit for 10 or 12 dollars, I soak my carbs overnight in clean tranny fluid then blow them all out with air, maybe a little soap and water if they are really greasy. They usually come out ok. I hope this helps you out some, good luck.

[Dark Knight]

The popping and sputtering sounds like a timing problem to me. I've got mine adjusted so well that I can crank it up without using the choke! Don't ask me how...all I can say is that it took hours of tinkering.

[PanelDeland]

http://67-72chevytrucks.com/vboard/s...d.php?t=148346

That link is the best HEI specific to a 250 6 there is.

You may need to rebuild the carb and replace the filter in the carb itself.You also should know the intake and exhuast manifolds are connected under the carb.The heat from the exhaust warms the intake.The 6 has an open design intake and the fuel can condense in the intake.This heat exchanger helps warm the mani to prevent(somewhat) the condensation of fuel.There is also a heat riser in the exhaust system,usually between the exhaust manifold and the exhaust pipe.It is a spring loaded damper which helps keep heat in the exhaust mani at start-up.It has a bi-metal spring which expands/contracts with temp change.As the engine warms the spring this heat riser opens allowing exhaust to flow more freely.Make sure the heat riser will open/close by hand(you are less likely to get burned if you check this while the engine is cold.Then warm the engine and make sure it is actually changing position as it warms.
After my HEI swap I haven't had this problem but then I did it in early spring so the temps did not affect the mani temp as much.