The Stovebolt Site Forums The Shop Area Engine Shop What's up with this???

My 235 powered 48 Chevy Pickup is giving me problems. This last week, the engine has been running erratic. Missing in high gear and not accelerating smoothly. The last couple of days, Its starts fine, but is slow to warm up. Once it warms up it idles ok, but I seem to have no middle. It idles and has good response at full throttle, but does not hardly have any throttle in the middle range. When it first started missing, I changed the plugs, and was going to change points, but they gave me the wrong ones at Carquest. I will do that today when I exchange for the correct ones. Last night I pulled the top off of my Rochester B and checked for debris in the float pin and flooded floats. The accelerator seems to be pumping ok and the fuel pump is supplying fuel. I had recently set the air/fuel mixture and the distributer is advancing properly. The only thing I have note done is check the timing. What would cause this? Thanks in advance for any help.
Ralph

First install new points & gap them. Than check
the timing. Look inside the dist. cap for any carbon tracks & check the plug wires with an
ohmeter. When you had the top off the carb did
you check the power valve. The rod should go up
& down freely & open the ball in jet.Also check
the float level.

Thanks for the response Wrenchbender. I did check to see that the power valve was free, but I didnt tear into it any more than that. The points that were there looked OK, but I change them regulary and keep the old ones on the glovebox for emergencies. I am not suspicious of the float being out of adjustment, cause this a new problem on a daily driver. If the points dont help, I may try one of my other carbs. I have several of these B's, but they are untested. Any other ideas?
Ralph

IMHP Slow to warm up.... sounds like rusted passages in the head . The hot spots in the head created by the blockage could be responsable for the bad performance after warm up.

water in the gas mayby

Update. New points did not help any. I am still chasing my brother down to get his timing lite. Dont think its timing, but will check it anyway. I may take the carb off my spare 216 and see if it helps. I hadnt thought about bad gas. Thats happened before on my 92. (Hmmmm, scratching my head). Thanks for the help.
Ralph

Had symtoms like this awhile back with the daily driver Toyota truck. Turned out to be a bad plug wire.

yep could be plug wires unless there soild core

Not checking the timing after you do anything to the points is not an option. If you checked the dwell on the old points before you pulled them and then set new points to the same dwell, the best you could be is CLOSE to the OLD timing.

Here's an update. I went to try one of my other carbs and hit a snag. I did not realize that the 216 carbs are different size than the 235 carbs. I took one off my spare 216 and the base holes are too narrow. My other carbs have been scavenged to where they were more work than repairing or replacing my carb. May try to borrow a known working carb from a buddy and see it that helps. Have not tested the individual plug wires. Will do that today. Adjusted the timing Saturday and did not notice the difference. I still believe that my fuel pump is ok, but I may try my spare. Since I have good response at full throttle, I think I am getting good fuel delivery. The only other thing I can think of might be the distributor. I have the one that ran in my previous engine. Will try that if the carb change doesn't work.

I have a new problem on a pickup I just traded for that is not stovebolt powered. I just traded my 92 Chevy 4x4 with 200K miles for a 99 Chevy crew cab, 4x4. The "new" truck runs out real well, but when I was almost home, the anti lock ABS brake light came on and has stayed on since then. This is the newest pickup that I have ever owned and I am not sure what to think about this. Several buddies have told me that they always come on. Some have told me that the sensors get dirt in them and trigger the light. Some have told me that their light always comes on when they engage the 4x4. Has anybody had any experience with this ABS stuff. Thanks!!
Ralph

Kind of funny about the carb fitting problem. I purchased a rebuilt rochester for my 216 and just tried to install it over the weekend and learned the same thing. The studs are too narrow. Now I have a nice rebuilt carb I can't use. It had a Rochester on it but they are just different enough I can't even make it work. I guess I'll end up selling it and buying a rebuilt W-1 going back to original.

OK , Here's my guess ......

Nothing in the mid range sounds like the power valve ....... or ...... manifold heat riser stuck .

Here is a long shot idea but it happened to me. Check the steel vaccum line between the carb and the distributor. I was suffering almost the same symptoms until I accidentally discovered a cracked and rusty end at the flare was causing an air leak. Changed the line and solved the problem.

Thanks for the ideas guys. I put a kit in the carb last night and it probably needed it. I also checked the plug wires as well. I drove it to work this morning and still the same problem.
Dusty. When I had the carb out last night I did notice that the power valve is a little worn, but still keeps the little rod on the bb. How worn is too worn? I checked the heat riser first thing and it is free and functioning. The truck runs better when warm, but is still lagging in the middle of the throttle. oldblu49. I wondered about the line, but the dist. is advancing under throttle. If it is leaking, it is a very small leak. I do have an extra to try and its an easy swap.

I am thinking distributor now. I have an extra from my previous running engine. I may swap them tonight. I even drained most of the gas and refilled on the way to work. Will add some gas treatment tonight (I forgot it at home). The engine needs an overhaul, at least new rings etc. I have a spare 235 and I need to get it to a machine shop, but I am having a hard time finding someone who knows 6's. I am going to check my compression tonight and possibly switch out the dist. Keep them ideas comming. MT suggested plugged water passages in the block and that is very possible as the block was very dirty when I installed it. It took several flushes to get the block to flow clear. I just dont know if it will cause the current problems. This is fustrating and I miss driving my truck every day. Thanks All.
Ralph

I still think your problem is in the carb.

My '48 had a sputtering miss in high gear going up a slight grade when I had the old 235 in it. I cleaned the hardened grease out of the distributor grease cup, filled it with fresh stuff and screwed it in. That solved my problem. Has anyone else found an unlubricated grease cup creating a miss?

This has been a great learning experience. Keep the ideas comming. When I drove home from work last night, it was running better. A lot of the work I have been doing was needed anyway, so all is not wasted. Wrenchbender. I am inclined to agree with you on the carb, but I havent been able to borrow a working carb to test in my engine. I did notice that I was getting a little "backfire" up the carb, so it may still be timing issues or electrical. The distributor needs to be cleaned and checked, so I may clean my spare and install by this weekend. We had a lot of lightnng last night so I didnt get to work on the truck last night. It is running better, but still not anywhere where it was three weeks ago. I went to fire it up this morning and I had a flat. Love those safety wheels. Anybody wnat to come air it up for me?
Ralph