Technical I let someone else touch my 235, and now its upset with me

After bringing a '50 Chevy 3100, with what appears to be a 1958-1962 235 engine, back to life after sitting for 20 years, I had it running pretty well. It would drive and cruise with no issue for the couple times I took it out. After converting the front brakes to discs, and upgrading the master cylinder, I took it to a shop. Told them to re-bleed it, and look everything over for safety's sake. The shop had good reviews, and I didn't think that an old engine was out of the woods for them. When I got it back, it barely wanted to start, and ran terrible once it did. Now, all I get is a giant whooshing sound when I step on the gas until I get into higher RPM's. I just moved so I don't have a buddy handy so I can't stick my head under the hood and pinpoint the issue. I can hear a big whooshing or sucking though when I depress the pedal. The truck doesn't want to stay running unless I get past that whooshing sound and take it to a high idle.

Now, I have combed the forums here and elsewhere and done my best to read up on potential issues and figure it out. Before the issue happened I took care of cap, plugs, wires, points, coil, fuel tank, lines and filter.

Since I have had the issue, I rebuilt the carburetor, taking note of the vacuum hole at the bottom that goes to the intake. I checked the accelerator pump, I replaced that cowhide piece that was old. I checked the bolts again for tightness to the intake. I checked all the screws that hold the carb together. I pulled the vacuum line to the vacuum advance, sucked on it and got some resistance and it wanted to turn the distributor. I have not yet replaced the vacuum advance but thats about the only thing I haven't done yet.

If anyone has any suggestions, or has had a similar issue, I'd greatly appreciate any assistance.

 

It sounds like the intake/exhaust gasket is leaking. Get the engine running and spray some starting fluid around the intake part of the gasket and see if the motor RPMs change (indicating a leak).

 

bleeding the brakes should not effect the running of the truck. what else did they do?

 

That’s my first thought,,,,
For sure find out where they did anything.

But then again it’s only recently been resurrected so something could have said fuckit I’m going back to bed.

And until it happens to you, you really can’t express how hard it is to explain weird stuff just going wrong. I’m not saying this is his problem but I get a dropped off car here for an oil change,,,pull it in change oil and now it won’t start. Damn timing chain went right then. Not my fault but explain that against the “what did you do? “ barrage of crap.

 

yep! I was burned, fixing problems I didn't even touch that went bad, only to have something else brake not long after. stop payment on the check, I suck etc.......

 

Sounds like you have a vacuum hose off or cracked. Look around the engine and see that all the hoses have both ends connected to something. If it has a pcv check to see that both ends are connected. Does it have a power brake booster? If so check the vacuum line to it also. Report back when you figure it out.

 

Yes check for vacuum leaks....
Check the base of the carb too...I sent my carb out before I tried to run mine and I got a new base gasket and spacer too...
Good luck with your project...
MikeC

 

This is exactly what I was thinking.

 

That's sometimes why shops will hesitate to work on the older stuff, it's bad enough with late model cars. Sometimes, stuff just breaks and the customer will never be persuaded it ain't the shops fault.

 

The more you do and the more you lay hand on this stuff the more wired stuff you’re gonna see with your own eyes.

 

Did you add a brake booster?

 

First of all, I appreciate all the replies. I'm still learning on these old motors. Sorry for the late reply I was out of town for a bit.

I had a friend come over and keep the throttle going while I stuck my head under the hood. The truck refuses to stay idling and the "whooshing" noise is coming directly from the carburetor. I checked all the usual areas (carb base, carb housing, vac. adv.) for leaks using starter fluid and got nothing. I'm wondering/thinking if it's time to pull the valve cover to see if I have a stuck valve or two. That will be my next step on all this, and I'll report back when I get a chance.

Thanks again.

 

Like has been asked, did you put a power brake booster on it when you perverted to discs?

 

They could of collapsed or smashed the exhaust....

 

Good call!

 

Any chance it has had modern oil put in during the getting it going effort? If you didnt add Zinc it may have a flat tappet now.

 

If it has a brake booster, I would disconnect it and see how it runs then. Have you given the shop a chance to look at it?

 

Does it have a ''heat riser'' ?? (exhaust heat/gas circulated around a cast port in the inlet manifold)
I've seen some rot/corrode thru into the inlet side of the manifold..

 

Most carb problems turn out to be ignition. So start with the basics. compression test. point gap. swap condenser with a known good one. adjust valves. Are you certain you have good clean fuel. A carb full of water acts the same way. I color my gas for my tractors. I add some out board engine oil. and that way I can see what's gas and what is water in the glass settlement bowl. and I often have to remove a bulb full of water. No matter where you buy fuel the tanks condensate and you can get some water. most newer fuel injected vehicles mix the water with ethanol and will have no problems. And some carbs have a power valve or vacuum operated metering rod that can give trouble.

 

I would have to believe that with the addition of disc brakes,there is an power booster and if it was mounted below the floor board there is a disconnected vacuum hose. the one going to the dist or wipers is not big enough to cause the symptoms but the manifold to booster would

 

Conclusion jumping
Kinda like a good old frog jump

 

Step 1
Compression test. No amount of tuning and fiddle farting will fix internal engine problems.
Read up on how to do it properly, what the results mean.

I wouldn’t do anything else or spend any time or any money until it passed the compression test.

 

Or crank it over with the ignition disabled and carb held open. If you have a bad intake valve it'll be obvious.

Sent from my LG-TP450 using The H.A.M.B. mobile app

 

KISS---slap a vacuum gauge on it. Stock engine should pull at least 17 inches and if not trace the problem down.

 

Hook up a vacuum gauge and see what it says

Compression test as well

To me it sounds like an ignition issue thinking it’s retarted somehow.

 

Bull shit!

Ben

 

I almost said that but bit my tongue instead.

 

How's the exhaust sound? Should be a good
'putt-putt-putt' with the 235.

Reason I ask is when I brought a slumbering (35+ years) '59 w/235 back to life, ran fine for starting it up now and then, then wet the bed on me, similar to yours. The old muffler crumbled up, pretty much plugging the exhaust up.

No place to check for exhaust backpressure w/o drilling/etc...but vacuum will tell you. You should easily have 19-20 in/hg at idle.

 

Got tired of mine bleeding.

Ben

 

Some of the very best tune up guys started out with one cyl engines. They learned the lesson of Spark Compression Fuel. they only had one cyl so there was no having other good hitting cyls covering up weak ones. any thing wrong with the three necessary componets and it would not run. There aint a piece of cast iron in the world that can fool you. if you don't let it.