Should I just go HEI

[dave`12]

67 c10 250 engine. Hard to start, especially when cold (I have to use starter fluid). Just installed a rebuilt rocherster b carb from summit, only adjustment was to turn the mixture screw all the way in, then 2 turns out, and the idle. Engine stumbles when I try to accelerate. Low power.

Timing currently at 0, fixing to change that. Only vaccum line is base of carb, it goes to the dizzy. compresstion test, all 120 or just above except #5 is 90.

I just want to get this thing running ok so that I can enjoy it, does not have to be perfect. Trying not to sink a ton of money into it. Don't know condition of distributer, it looks ok. I cleaned it up, plugs look ok and gapped, cleaned them too. new wires and cap. rotor looks ok.

I admit I'm lost. lots of good, very technical advice in another thread. SO I'm tearing my hair out. Should I just go with an HEI? I think I could find a write up and get it installed correctly. I don't have a dwell meter, and am afraid that buying one will just be more money down the drain, cap does not even have a window.

Maybe someone could walk me though the steps to get it "in the ball park" so that I can drive it, then work on getting it better later? Would you guys just get an HEI?

Wish I had the abilities you guys have, but I do have one thing, I can follow directions and learn if they are not too technical.

thanx

[leddzepp]

Yes. I just installed HEI in my 68 a few weeks ago. It eliminated hard starts, rough idling, and every snap, crackle, and pop. By far the best upgrade I have done to this truck.

[72kool]

almost every time the question comes up to swap to HEI, the answer should be yes. the best upgrade you can do to almost any classic. only thing i would advise is to keep a spare coil in the truck. it is common for them to not start once in a life time, and 9 out of 10 its the coil.

[Big Kev-O]

I would go HEI, just avoid those cheap sloppy billet chinese units including the MSD Streetfire. They are all junk. 40k miles and the MSD Streetfire HEI neededcomplete rebuild. Remanufactured GM units are way more reliable.

[GRX]

Really depends on condition & wear of your components. Most people who see an improvement are replacing worn out point systems. So naturally it runs differently. Being that the system in your '67 is likely old and worn, you may as well change to HEI if you are going to have to replace everything anyway. Stock HEI set up (new) from a '75 truck will get you there cheaply.

[stomper]

Dwell angle / point gap is the first step. If that's not right all the rest is in vain. Check/adjust that first, then set the timing, then tune carb. HEI is better but you can make it run fine with the points.

Unfortunately the dwell angle on a 6 can be adjusted while it's running like a v8. On a 6 you have to remove the distributor cap, set the point gap (.019 I believe), then check the dwell angle while it's running. If you don't have a meter the best you can do is set the gap and you're in the ballpark.

[davepl]

If you can find AN ACTUAL ORIGINAL GM HEI, then do it. The cheap ones are garbage, at least I've have 2 bad ones out of the box before I learned it.

If looking stock matters, and even if it doesn't, I'd just use a Pertonix module in your original unit. You may have a point gap issue to check, and that'd eliminate it, but gap them before you throw parts at it. Dwell can cause hard cold starts.

But sounds like you're missing some stuff. Is your choke set? Is your choke pull-off door gapped correctly? Heat riser working? Heat stove and chimney in place? Thermac valve working properly?

All that stuff needs to be there in proper working order for it to run right cold.

[71meangreenc10]

Do not use the yellow wire from the coil as your hot wire. You must run a new wire from the fuse block or you will kill the coil. HEI will make that 6 perk up for sure. I am pretty sure you hook the wire up at "Ignition Unfused" on the block, but I can check for you.

Never had a HEI coil go out, but the Control Module under the cap....keep one of those in the box....

Smitty

[leftybass209]

Originally Posted by davepl

If you can find AN ACTUAL ORIGINAL GM HEI, then do it. The cheap ones are garbage, at least I've have 2 bad ones out of the box before I learned it.

If looking stock matters, and even if it doesn't, I'd just use a Pertonix module in your original unit. You may have a point gap issue to check, and that'd eliminate it, but gap them before you throw parts at it. Dwell can cause hard cold starts.

But sounds like you're missing some stuff. Is your choke set? Is your choke pull-off door gapped correctly? Heat riser working? Heat stove and chimney in place? Thermac valve working properly?

All that stuff needs to be there in proper working order for it to run right cold.

Pretty much. Get your engine running well WITH your points (or KNOW it's a distributor problem) before considering HEI, or you may fall into the pigeon hole some people do of cursing the HEI because they didn't know how to address the real issues. Pertronix is a great alternative. I shouldn't even say alternative, because it basically is an HEI setup that is used in place of stock points. The benefit of the Pertronix system is that, you already have a distributor that you can rebuild. There's nothing wrong with HEI, and some aftermarket companies supply a quality product, but a rebuilt stock HEI is an awesome proven performer, with plenty of customizable pieces to get your advance working exactly the way you want it. I'm using a GMPP HEI and it's beautiful in operation and far exceeds the Accel piece I swapped it with.

[dave`12]

Ok, so I'm working on it now. Seeing if I can get it with the original points. I got to assume the carb is ok, it's brand new from summit (rebuild).

setting the timing (i don't have a tach, so I'm ballparking the idle speed. The tag has an O and an A. I just set it to 3 lines north of the 0, towards the A. I'm guessing that's 6 btdc???

Another thing, my only vaccum port is from the carb to the dizzy. I hooked it up to a vacuum gauge and get 0 at idle. I can rev it some and get 15 pretty without going too high. This seems wrong, shouldn't I get some idle vacuum?

Hard to start, even warm, but seems to idle ok once running.

One other thing, compression test all just over 120, #5 is 90. same reading wet (with oil). Hoping that is livable.

advice appreciated.

[1972RedNeck]

Originally Posted by leddzepp

Yes. I just installed HEI in my 68 a few weeks ago. It eliminated hard starts, rough idling, and every snap, crackle, and pop. By far the best upgrade I have done to this truck.

I'll second that. I even run HEI's on my Fords.

[EARNHARDT#3]

'67 should have a manual choke

Originally Posted by davepl

If you can find AN ACTUAL ORIGINAL GM HEI, then do it. The cheap ones are garbage, at least I've have 2 bad ones out of the box before I learned it.

If looking stock matters, and even if it doesn't, I'd just use a Pertonix module in your original unit. You may have a point gap issue to check, and that'd eliminate it, but gap them before you throw parts at it. Dwell can cause hard cold starts.

But sounds like you're missing some stuff. Is your choke set? Is your choke pull-off door gapped correctly? Heat riser working? Heat stove and chimney in place? Thermac valve working properly?

All that stuff needs to be there in proper working order for it to run right cold.

[EARNHARDT#3]

Originally Posted by dave`12

Ok, so I'm working on it now. Seeing if I can get it with the original points. I got to assume the carb is ok, it's brand new from summit (rebuild).

setting the timing (i don't have a tach, so I'm ballparking the idle speed. The tag has an O and an A. I just set it to 3 lines north of the 0, towards the A. I'm guessing that's 6 btdc???

Another thing, my only vaccum port is from the carb to the dizzy. I hooked it up to a vacuum gauge and get 0 at idle. I can rev it some and get 15 pretty without going too high. This seems wrong, shouldn't I get some idle vacuum?

Hard to start, even warm, but seems to idle ok once running.

One other thing, compression test all just over 120, #5 is 90. same reading wet (with oil). Hoping that is livable.

advice appreciated.

Get a new intake/exhaust gasket and install it. I can all but garuantee you've got leaks. They're prone to it and it will never ever run properly with leaks. It will take you under an hour to get it all done. It looks a little more difficult than it really is.

[leftybass209]

Originally Posted by dave`12

Another thing, my only vaccum port is from the carb to the dizzy. I hooked it up to a vacuum gauge and get 0 at idle. I can rev it some and get 15 pretty without going too high. This seems wrong, shouldn't I get some idle vacuum?

Hard to start, even warm, but seems to idle ok once running.

One other thing, compression test all just over 120, #5 is 90. same reading wet (with oil). Hoping that is livable.

advice appreciated.

Compression tests should ideally be run with the engine warm, as that is when the rings are sealing the best. If you have that much difference, then you have a leak in that cylinder. Whenever you pull a vacuum line, make sure you plug whatever you pulled it from. In this case, plug the vacuum advance if you used that source. However, ported vacuum won't give you a good reading if you're trying to tune that carburetor, it really needs to be done with full manifold vacuum. Look over your instructions to find the full manifold vacuum source on that carb is so equipped with one.

About your vacuum. It could be some type of intake leak, OR, it could be that you're connecting to a ported vacuum source, in which there won't be any vacuum until you increase RPM, just as your claiming happens.

[EARNHARDT#3]

Oh...on a 250 there's a plug under the carburetor on the intake manifold. It's 1/4" NPT. Screw a hose barb in there for a vacuum signal. If you have power brakes that's where the hose is probably hooked up.

[dave`12]

Originally Posted by EARNHARDT#3

Get a new intake/exhaust gasket and install it. I can all but garuantee you've got leaks. They're prone to it and it will never ever run properly with leaks. It will take you under an hour to get it all done. It looks a little more difficult than it really is.

Man, I'm hoping that's not it, but I think you may be right. I tried to tighten a few of the bolts, very hard to get to, and I could not budge any of them. And I'm missing the first and the last.... (more intelligent people than I would probably say bingo, dummie).

Just about destroyed my rib cage trying to bend over the high fender and get to those puppies.

I sprayed carb cleaner all around the intake manifold and no idle change, so I'm REALLY hoping that mean no leaks. I also felt around the exhaust manifold for air coming out where it should not - again nothing.

I'm dreading the thought of trying to tear that apart...

And thanks, gonna look for the plug in the manifold that I can use to get vacuum.

[EARNHARDT#3]

I sprayed and sprayed until I was blue in the face and didn't find the vacuum leaks. But they were there. It's seriously an easy job to do. The bolts are easy to take on and off and the manifolds are bolted together so it all comes as one piece. If my 375 fat a** can bend over and do it anyone can LOL

Also, the first and last bolts are just alignment dowels. But a lot of guys thread them out and put bolts in to better fasten the manifold.

Originally Posted by dave`12

Man, I'm hoping that's not it, but I think you may be right. I tried to tighten a few of the bolts, very hard to get to, and I could not budge any of them. And I'm missing the first and the last.... (more intelligent people than I would probably say bingo, dummie).

Just about destroyed my rib cage trying to bend over the high fender and get to those puppies.

I sprayed carb cleaner all around the intake manifold and no idle change, so I'm REALLY hoping that mean no leaks. I also felt around the exhaust manifold for air coming out where it should not - again nothing.

I'm dreading the thought of trying to tear that apart...

And thanks, gonna look for the plug in the manifold that I can use to get vacuum.

[dave`12]

I'm replacing the points and condenser now. If, after resetting the timing, I still can't get it to run right, well I will tackle the job

And thanx for the info on the dowels, that makes me feel somewhat better.

[EARNHARDT#3]

When you do the intake/exhaust gasket...while out of the truck bolt the 2 manifolds together with the new gasket that goes between the exhaust flapper box and the intake manifold but let the bolts loose. After tightening the bolts to the head then go back and snug up the others. This way the manifolds are flat against the head.

[RichardJ]

>>my only vaccum port is from the carb to the dizzy. I hooked it up to a vacuum gauge and get 0 at idle. I can rev it some and get 15 <<

That is correct and it indicates that the carb is adjusted somewhere close to correctly. That vacuum port is called timed vacuum or ported vacuum. This vacuum is from a port above the throttle blades and should show little or no vacuum and will not advance the timing until you begin to open the throttle.

If you use manifold vacuum for the dist vacuum advance, it actually retards the timing above idle. It makes for a Band-Aid to solve off-idle pinging and isn't even close to the vacuum advance that Chevy designed.

Dwell must always be adjusted before the timing. Look for a used dwell meter at a garage sale or Craigslist and offer $20 no matter what the clown is asking for it. You are the only buyer he is going see, even if he hangs on to it for months.

Buy a new timing light, because they get beat up and you need one even with HEI.

Mechanics need tools, otherwise they're just cowboys.

>> only adjustment was to turn the mixture screw all the way in, then 2 turns out,<<

That's the bench adjustment, now you need to adjust the mixture to what your engine needs with the engine running.

[RichardJ]

>>Also, the first and last bolts are just alignment dowels. But a lot of guys thread them out and put bolts in to better fasten the manifold.<<

For a stock cast iron manifold, most agree to leave the pins alone so the manifold is free to expand as Chevy designed it. If you use aftermarket tube headers then you should remove the pins and replace with threaded studs. In fact, it is better to replace all the manifold bolts with threaded studs. There are already two threaded studs to start with.

[dave`12]

Thanx for the info, EARN, will take that advice (hopefully won't have to).

Thank you Richard. Nice to know that my carb is at least in the ball park. Not many adjustments I can make. I have a new timing light, got it at 6 b now, will retime after setting the points. Haven't had any luck with a dwell meter yet. I've never set points before, but the plan is to get on one of the high points on the lobe and use feeler gauges going for 019. Hopefully that will get me close.

Was going to use the vacuum gauge to fine tune it, someone mentioned a plug in the manifold that I can tap into, gonna check, otherwise that's a no go. Also happy that my vacuum is not wack, being 0 at idle was a shock. Never worked on a carb without a port for a vacuum gauge that I could use. I was looking forward to that, lots of things can be learned from the vacuum gauge.

My timing light is new, but it's a cheap harbor freight, so I got my fingers crossed.

[RichardJ]

When setting the point gap, depending on your vision, it is important to carefully observe that the points DO NOT move when you insert or remove the feeler gauge and that there is only the slightest drag. If the points move, you do not have .019" gap. An .018" feeler should drop through without resistance. Separate the feelers from the pack for best results.
I see more and more people having trouble getting the correct dwell reading after setting gap, because they forget the spring on the point arm has only about 12 oz. of tension.

You can always rig up a temporary "T" fitting on the manifold port for the PCV hose.
I would think you should be able to set the timing at 6 or 8 degrees without any pinging. I think when I still had the Rochester B, I just used the tach and adjusted for lean-roll and probably added 1/8 - 1/4 turn for good measure. I agree using a vacuum gauge with the tach is better.

[BCOWANWHEELS]

I like points personally, there trouble free and last a long time , bet your dist is worn badly,there known for it. remove cap and rotor and try to wiggle shaft. if any side to side movement its bad, get a reman point dist, it comes with all the guts, get new cap , rotor & plugs n wires and your done. time it to spec. also I,d check compression on all cyls to get condition of engine, front 2 cylinders are bad for wearing out faster than the rest. if there low best to install a sbc and be done with it.

[BCOWANWHEELS]

I like points personally, there trouble free and last a long time , bet your dist is worn badly,there known for it. remove cap and rotor and try to wiggle shaft. if any side to side movement its bad, get a reman point dist, it comes with all the guts, get new cap , rotor & plugs n wires and your done. time it to spec. also I,d check compression on all cyls to get condition of engine, front 2 cylinders are bad for wearing out faster than the rest. if there low best to install a sbc and be done with it. lastly make sure your intake manifold gasket isn't leaking (there known to ) , use starting fluid sprayed where gasket is. if it revs up gasket is bad.