The Stovebolt Site Forums The Shop Area Engine Shop OK At my wits end, tune up woes

Well, as background, I have a pretty good working knowledge around these 235's. Have a '54 235 I'm having trouble getting running right. Have done the points, plugs wires, timing, all the dwells and gaps,and the carb. Still having trouble in acceleration and steady power in the hills. Idles good. If I pull the choke a little it runs a little better. Haven't done a vacuum check yet but got a guage for christmas. What should I look for when checking vacuum. I have a feeling thats the problem but have checked the obvious places (manifold, wipers and vacuum advance)with no luck. Any tips or suggestions?
thanks in advance
Jim

check around the carb for air leaks - the base can get warped

Bill

Had a huge vacuum leak last year, truck would run only with choke pulled out. Vac. fitting at carb was loose. The vacuum gauge is a great tool, hook to intake, should have 16 to 18 reading, steady not bouncing needle. I like to adjust carb and set timinq via the vac gauge. You can spray Barrymans Chem tool around intake and carb with motor running, if speeds up you've found your leak. BE CAREFULLWITH THIS STUFF!!!

If all else fails go back and adjust valves, but not to tight.

I've tried the "Barrymans" trick with a torch. Probably not the best tool either but long story short, didn't show any difference. Will be checking with guage tomorrow. Will post back
Jim

my truck showed the same symptoms and it was the fuel filters. i replaced both with NAPA Gold filters and have had hassle free fuel flow since. i also sprayed a lot of carb cleaner on and in the card to make sure it was clean enough to work. i had a small air/fuel leak at the base of the carb in my 235 (61) but all i did was tighten it up. fuel filters my man...$6 well spent.

I don't know if it carries over to the 235 but it says in bold caps at the start of the "tune up" section of my 216 shop manual that it's impossible to tune up an engine if the valves are not adjusted correctly. I was having problems with driveability, checked the valve adjustment, all were a little tight, reset the valves, problem went away. Just a thought.

46,
when you did the carb, did you notice the hole in the base of the carb that must match up with the notch in the insulator?

46 Burb,

You say "trouble in acceleration and steady power in hills". What other symptoms accompany these problems, backfiring or popping..surging slowly.

Fuel things usually happen "softly and gradually" as opposed to "instant" glitches caused by electrical.

If you sit in the driveway and accelerate the engine, does it exhibit the same problems as it does under a load going up a hill?

If you do some more sleuthing, maybe something will show itself!

As a parent of two teenage boys, I can assure you that wits have no end.

Stuart

Definitely an "instant" problem. No other problems other than I said. I do have the carb and insulator holes lined up. I think I will start with the valves then the vacuum check.
Always good stuff on this site!!
Jim

Make shure the initial timing is correct. It can stand a few extra degrees before top dead center as the gas has more octane than they had back then. Check the power valve in the carb. It should spring up & down & move the ball off its seat. Also check the float level.

Did the valves, points, plugs, vacuum is ok, timing done,checked for leaks & still the same. Only things I may need to check are: the vacuum advance, should that be ok if the vacuum gauge has ok reading?
I will switch the carb from my 46 burb too which runs real well to see if that is it. May not get to it till the end of the week though.
thanks for all the help!
Jim

I started having exactly the same trouble on my 235. I tried changing carburetors and bought one of Tom Langdon's Holley/Webber 2 bbl carbs and converted it. It's never run so well.

My thought is that the Rochester 1 bbl carbs don't have an adequate accelerator pump, causing a lean condition when the engine demands more fuel. The fact that it runs better with the choke pulled out a little seems to support the assumption that maybe you're running lean all the time.
I guess you could rejet your Rochester, and have it rebuilt. I didn't try that with mine. I just replaced it because I never liked it anyway.

You think you might be running a bit lean?

Yeh, could be but like you said, only when it wants more. Did that carb bolt right up or was there something else we would need also?
JIm

Yeh, could be but like you said, only when it wants more. Did that carb bolt right up or was there something else we would need also?
JIm

I didn't replace the vacuum advance, How can I check that or do you just replace. It does move freely when throttle is applied, don't know if it is behaving properly on the road though.
Jim

Jim,

I am experiencing the same problem. I am going to test some of the things metioned on the posts. If I figure mine out I will let you know and if you get your fixed let me know what the problem is.

Thanks for asking the bolters, it has really helped me out too.

Dan

Jim,

If the distributor moves when the engine is brought off idle (in the driveway with hood up) then the vacuum advance unit is working. It has a diaphragm in it that can fail and leak. This usually means it won't move the distributor and it creates a vacuum leak.

If the vacuum advance is doing its thing in the driveway, its doing its thing on the road.

If you wanted to check it..for grins..you merely put it under vacuum and see if it holds. The easiest method is to suck on it and plug it with your tongue..you will feel it if it holds.

Stuart

How did you set your timing? A 1954 235 should be timed at 2 degrees after T.D.C. and a 216 is timed at 5 degrees before T.D.C. If you are using the original 216 bellhousing and flywheel the steel timing ball in the flywheel is in the wrong place. I never see this mentioned but it could screw somebody up if a newer engine has been installed. Just a thought.

Curt B.

well got it taken care of. I put the carb off my 46 burb on and it workes fine. Anybody know a number or brand/style of carb you can get over the counter that is an easy and cheap replacement? This isn't my truck and I don't want to spend a lot of money.
thanks
Jim