advice from any 235 chevy experts?

hey dudes, i got a little problem with my straight 6. it runs good, starts right up on a freezing morning, and i drive it everyday. it does everything it should, except it doesn't have any balls what so ever. i know these aren't huge horsepower engines but i mean this thing just putts along and you can lay into it and it'll just gradually rise in RPM. and if you floor it it'll wake up a bit, but then it'll act like its getting too much fuel and it starts to sputter and choke up. anybody know whats going on?

it's a 1961 235 inline six backed by a 3 speed column shift and it's in my 1958 chevy delray.

yeah it's a big car and little motor, but this engine is putting out very little torque and horsepower. but it runs very well. no ticks or knocks, it runs like a champ except for power... could it be carb problems? i really don't know

all advice would be appreciated!

 

maybe the carb or vacuum advance

 

had a 53 chevy with the same issue, really bogged down under load, carb checked out, replaced the vacuum advance and ran like a champ

 

vacuum leak put you hand over the carb to try to chock it to death if it does not die you have a vacuum leak

 

okay thanks guys i'll give it a shot!

 

I put Fenton 2 carb manifold and Fenton cast iron headers with dual exhaust on my 57 Chevrolet 150 6 cyl to get a bit more power. Made a good bump in power. Got the parts from Patrick's. Good luck with your car

 

Also check the mechanical advance in the dist. And if a stock type muffler I have seen them fall apart inside and restrict the exhaust to the point it would barely go down the road. Vacuum advance is not doing anything under acceleration,only part throttle cruise.

 

it's got a single glasspack on it right now, i'll be putting tube headers with small glasspacks on it soon. and i have been looking at the clifford performance 4 barrel intake. Grander, i would like to do a two or three carb offenhauser instead of the four barrel, but i've been told that tuning the multi carb set up is extremely difficult and is good for looks and power but suffers for traffic light to traffic light everyday use.

 

tested it with the "hand over the carb" method, and thats not it. so the search continues... haha

 

These things are notorious for the vacuum advance units seizing up

Could be a restricted fuel filter or weak pump

Acceleration pump in the carb not opening fully

Base timing could be off, these things are bad for the fibre timing gears wearing down to nubs

Centrifugle advance could be seized

To a compression test and a leak down test, you could have a worn out engine.

Could you clutch be slipping? It kind of sounds like this could be your problem also.


And the multi-carb set ups are not that bad to tune at all. 2 is easier then 3 but both work well, save fuel and drastically improve drivability.

The trick is carb choice either zeniths or Carter's are first choice but rochesters will work just as well just trickier to tune due to the vacuum power valves used in them. Holleys and other brands work just as well but are not as common as the 3 stated above

Good luck with your car and keep us posted

 

Timing gears valve timing off

 

What gears do you have in the rear end? They may be to high. My 60 SDL had 355's and it had good power with a 235

 

Check the heat chamber that is made into the intake manifold. The 235 will run better if there's heat going to the intake manifold. The coil spring/shaft may be locked up. There's no way to keep it lubricated very well.Make sure it works freely.

 

Yeah sounds like vacuum advance I had that problem once give it gas see if your distributor is advancing

 

thanks man i have been thinking it could be a possible timing issue as well so i'm going to look into it next. it's got good compression; before i dropped this engine in, (the original is locked up tight) we tested it and made sure everything checked out, it's got good compression, good oil pressure, stays at 160 all day even when it's hot out. but the thing could have gone a little out of whack seeing that it was about 4 months ago since the engine swap. it's also a rebuilt engine, although i don't know what specifically was done to it and it was a few years back. but i'm keeping on dinkin with it and it's all fun. just need er' to run to get me back and forth to school everyday haha. thanks for the ideas man

 

mine has 355's in it as well

 

i've been hearing about making sure the intake is warm, and i'll have to check this out as well. thanks dude

 

thanks man, i am definitely looking into this. once i do i'll post back here to let ya'll know how it's going!

 

Doesn't the vacuum advance on those things operate externally to the distributor? If so, you should be able to see if it works just by looking at the distributor and revving up the engine. Distributor should rotate!

 

maybe you just need to downshift it?

 

You already know the answer at least you danced all around it, it is a 6 cylinder in a boat.

Never the less here are some things to think about. How many miles on the old 6 cylinder? Last time it had a valve grind last time it was completely tunned up, points, plugs condensor, rotor and cap, plug wires, adjusted the valve lash. Condition of the distributer itself.

Now that you have done all that what condition is the carb in and the fuel system, is it dirty and cruddy or ???

 

There is another huge possibility that no one has mentioned. What about the valves? If you have them set to tight to control valve noise, you won't have much power at all. That 1961 engine probably has hydraulic valve lifters, but I've seen people take the cheap way out when rebuilding one and drop mechanical lifters in. I've recently seen a 235 Chevy and a 248 Straight 8 Buick that had the valves set with almost 0 clearance and both engines would run, not get hot ,and they had no power. I adjusted the valves and they woke up wig time.
Here is another valve related issue that is over looked. I check this before I crank ANY 235 that has been sitting. The rocker arm shafts often get so much gunk in them that they don't oil well. The rocker arms are babbitted just like and old connecting rod. The shaft that they rotate on has a tendency to wear groves in it that cause a huge amount of resistance and bog the engine way down. I always remove the entire rocker shaft assembly as one big unit. If the rocker arms don't spin all the way around super easily, you have problems. I remove each rocker arm and soak it in diesel fuel and clean out the oil passages in each arm after I remove them from the shaft. Make sure you put them back on in the exact order that they were removed in or you will have a big old mess. If the main shaft has scratches or deposits of babbit stuck to it, you can use emory cloth to sand it smooth, but I would buy a new rocker arm set. If it is deeply worn on the bottom side, throw it away and get another rocker arm set. This is probably one of the most common problems with the stovebolt engines that gets over looked. If your rocker arm passages aren't oiling, then your valve guides are running dry and robbing even more power!
The entire distributor rotating has already been mentioned, but I have had them not turn because there is so much grit and filth between them and the collar that holds them down. You should be able to turn the distributor about 10 degrees or so when the car isn't running with ease. Sometimes people get the collar jammed when they tighten it down and cause it not to rotate. They make HEI didtributors for these engines now and they make a vast improvement in timing and performance.

 

when i dropped this engine in we threw in new everything. new plugs, plug wires, distributer, everything. i had just rebuilt the carb prior to putting it on this engine. also flushed out the fuel lines. got a brand new fuel tank, sender, and filter. as far as valve grinds or mileage, i'm not too sure about that. all i can say is this engine sat for 15 years and started with some gas in the old carb. after that, we went through and freshened everything up and put er' in the car.

 

thanks thats very helpful!

 

Not to hi jack the thread, but has anyone raced a 235?
I took an old 57 Chevy stock car to Loring AFB last weekend and we got it up to 101 mph with a single barrel carb. We want to make some changes for next year. Are there any easy hop ups to get more power, besides carburation?
We used a Saginaw 4 speed and 308 gears.
Thanks guys

 

i've actually been wonder this myself. people have raced them, but i have no idea how they were built.

 

so did it get fixed?

 

it's gettin closer, just freshing everything up. everything helps. new spark plugs helped a bit as well.

 

Please post anything you find out. I have been following this thread for my own 235 problems. I have the same issues, runs like a dream, quiet as a church mouse, but no power at all...

 

One is a pre full pressure 235 with triple carburetion, HEI, full roller cam and headers plus a old power glide two speed. It runs in the 13.'s at the strip. The other is a Clifford/Weber 38 setup later 235 that is an 11.50 second car. Maybe your setup is in need of review or your gear and transmission ratios are not properly thought out? The potential for 2.2 HP per cubic inch is there but it has to be well thought out.
Normbc9