Inliners International Forums General Discussion Engines 230ci speed issues!

I am a 17 year old with a '69 Nova. It is very pretty on the outside, but is not doin' too well on the inside. It has a 230ci engine. My dad and I put an offenhauser four barrel intake on it with a holley 450cfm carburator. We also put stovebolt castiron headers on it with dual exhaust all the back with dynomax mufflers. The problem is that when I try to floor the pedal, it bogs for a few seconds and then usually stalls. This is really annoying when I try to race a Civic. Very embarrassing...but at least it looks good right? I also encounter that when I downshift my th350 from third to second, it gives me relatively no speed gains. Also annoying! Can anyone tell me the answer to these speed problems. Thanx!

------------------
A little 230ci '69 Nova with a four barrel and headers!

Don't race Honda Civics.

I was just joking about racing honda civics. I actually do not race anybody, but I do at times need to step on the gas to get going. I would appreciate some 'helpful' responses. Thank You.

Assuming there are no internal motor problems, no leaks (vacuum) between the carb and manifold and manifold and head and the ignition including plugs and wires, points etc are in good shape it is likely carburetation. Check the plugs. If they are very black and or wet, it is too rich. If very light or if the plugs are showing wear or even metal splatter too lean.

Just a place to start. Diagnosis over the net is tough to do. Good luck!

I would definately look at the plugs to start with, and see if it's running rich. That seems like the most likely problem. What rear gears does your Nova have? Might also want to check your timing and make sure it's dead on. One last thing. Is your intake heated? Good luck. John.

I looked at the plugs and the electrode on all of them look pearly white with light grey on the tip. The center two plugs have a ton of black build-up on everything but the electrode, even the threads. The outside ones aren't as bad as the inside ones but there is still plenty of black build-up.
I know the engine isn't running rich becuase I took the original 59 jets and sequentually went down nine steps to 51's and realized it was losing significant power. I then put back on the 53's and decided it was running good again. This is why the problem I am experiencing is so strange. How would I be able to recognize a vacuum leak if there were one??
Our manifold is a heated manifold so that is not the problem either. Thank you for all of your help.

Also...I have the stock gearing in the differential which I believe is 3.08.

I've never messed with Holleys, so I can't help you much there. I do know that with those 3.08 gears you're launch is going to suck, but top speed will be great. Part of your bog could be that, but as far as stalling I think there is something else wrong also.

What type of ignition setup are you running? Also, what is your plug gap set to? How long has it been since the last rebuild, etc.? Did you have these problems before putting on the Offy manifold? I'm just trying to get as much info as possible. Hope this helps. John.

I have an iginitor electric distributor kit on my distributor with a fairly new vacuum advance. I have the stock coil.
I'm not sure exactly what the plug gap is set to but about 6 months ago I put on new plugs and I know I adjusted it to the correct gap amount.
I have no idea when the last rebuild was, I haven't rebuilt it since I have had it. I have done compression tests on all of the cylinders and they look fine.
This morning I did a vacuum test and the vacuum is absolutely normal. I also checked the timing and it was dead on. I am sooooo confused.
This same problem was prevelant when the stock manifolds were on it, but it was not as bad as it is now. Maybe it is just more noticable with the extra power of the four barrel.
A wierd thing is that when I put the transmission into 1st and manually shift the transmission up to third there is no bog whatsoever. It is only when the car is in drive and the transmission is shifting automatically that there is significant "bog". It does not go away when the engine is warm either. Thanx again for you help.

Hmmmm..I'm starting to think that this has something to do with the tranny now. There should be a vacuum modulator that controls shift points (I think). You said it doesn't bog when you shift it manually. BTW, anyone else feel free to jump in at anytime, since I don't know much about automatics. How's your tranny fluid? I don't know much about automatics, but if the bog doesn't occur when you shift it maually then I would look into the system controlling the shifts. Just a wild guess.

When you put in your Ignitor system, did you increase plug gap? I put that same system on my 250 and increased the gap to .055" I'm running an old Accel coil, but I'm going to switch it to a Pertronix coil and remove my resistor wire. The increased gap will help with mpg and give you a smoother idle. Hope this helps. John.

Novaboy, have you tried changing the accelerator pump outlet or adjusting the pump lever? The 230 is a small engine and doesn't need a whole lot of gas when stomping the throttle. The outlets are available with different sized holes to reduce or increase how much gas comes out when you squirt it. The lever travel adjustment changes how long the squirt lasts. Also, is that a vacuum secondary carb or manual? If you are only getting the bog when the secondaries open, then you've got a fuel calibration issue in the back end of the carb, and is especially critical on a manual unit. Too rich = bog city

------------------
David
newbie #4153

It sounds like your Holley may have a blown power valve, which will dump raw gas into the manifold and will cause the middle two cylinders to be extremely rich. Has the engine backfired? Holleys have fragile power valves which like to rupture if there is a back fire.

------------------
1950 Chevy pickup with '62 261, 4 speed.

Hey there Novaboy,

It is very cool to see a young person into muscle cars even though you are running a six. Trying to hang with your peers running all them cool rice rockets is kinda tough with you and your Nova. You gotta up them in uniqueness and coolness. Anyone can have a V-8.

I had a 62 Nova with a 250 Offy manifold and Holley 390 CFM. You said that the plugs are white colored, this means that you are not running rich. With a Holley there are so many adjustments to look at. I also had a "bog" on my Nova but I had a Power Glide 2 speed tranny. What helped me was to go to bigger accelerator pump nozzle and I installed a new pump cam. When you open the thorttle plate quickly, your vacuum goes away and it takes a 1/2 to 1 1/2 secs for the engine to start pulling air passed the venturies and drawing fuel. More gas. In your case with the TH350 you may also or first try to delay the opening of the secondaries. If they are opening to soon, this will also cause a "bog". I you can get yourself a Holley carb performance book if you want to learn about Hollies.

I still drive a inline 6 with a Holly 390. It is in a heavy 56 Chevy pickup. If I peg it at low rpms it will also "bog". So I just don't put my foot on it until I have some rpms built up thanks to the clutch. And I put my foot in it all the time.

Have fun.

Luis

Concerning Novaboys TH350 tranny, the throttle valve has to be positioned correctly no matter what the engine is or how it is set up..The TV has to know whats going on even while shifting manualy.The vacuum modulator is important also..It should be connected below the throttle plates as a rule..A replacement of quality that is adjustable is good for helping the shift points..Usually you st up the TV cable by holding the throttle wide open (not running of course) and have the TV cable extended all the way out so it just fits onto the carb linkage where it belongs..make sure the TV cable not kinked or broken..I remove them to be sure. The high ratio rear end will probably make the shift points different..