Losing Power

[72FJoy]

My SBC 350 has lost some considerable power since I have put on the hardtop and doors. I don't think this extra weight would affect the HP but what could it be? A little history...

-Replacing my valve cover gaskets and #7 cyl rocker arms were both knocked off the springs.
-Had to replace the lifter and rods because lifter was stuck and rods were bent...therefore I had to take off the intake manifold.
-Noticed a huge HP decrease before all of this replacing. It seemed the more I pressed the gas the Flowmasters would sound good but wouldn't accelerate for s***. I feel it struggle for all hell when going up hills.

Could this have to do with taking the dizzy out and not timing it. I don't have the capabilities to time anything yet. I will soon. Also, could it be my carb? It's an old Rochester 4bbl.

What good is a Chevy 350 if you can't feel the power?

 

[Mark W]

You removed the distributor and replaced it without chrcking the timing? High on the list of likley reasons why you don't have power.

Two rocker arms were "knocked off the springs? How? Why? Lifter and pusrods damaged... what about the cam? Another likely source of power loss too.
Have you checked for vacuum leaks? With intake R+R'd that is a possibility also.


Mark...

 

[oldIron]

I'm with MArk, you really need to look at the timimg. That you pulled the Distributor and not sure when you put it back is a good possibility. I am actually suprised it runs at all. I would also want to know why there were failures to beging with.

Pete

 

[72FJoy]

Timing is top on my list...i'm waiting for a buddy with a light to hook me up. Looong story...I originally took my Cruiser down to the local coin wash to clean the engine. I didn't let it cool down....a little steamy. When I left the wash I drove out to make a green light and when I slowed down the engine started to knock pretty heavily. I stopped and opened the hood. The chatter sounded as if was coming from under the DR side valve cover. Before I could shut the motor the knocking stopped. I was shipping it out the next day and I was only a mile or so from my place so I drove with no problems. When it reached the destination two days later(Georgia) I started it up and drove about 2-3 miles. That's when I realized I had an oil leak somewhere that was dripping all over the exhaust. Didn't like the smoke screen so I decided to drive back home and park it.

I had a buddy take a look and he assumed that the leak was coming from my rear main seal. He then noticed I didn't have vaccum out of my PCV valve. He said I should plug the carb side and put a breather on the valve cover. He recommended that I should use the high mileage oil instead of the conventional stuff I was using to stop the leak. I then switched up the oil and started it. I noticed I had oil leaking from the oil pan. I replaced the gasket there and said I might as well change out the valve cover gaskets being that they were leaking as well. When I took off the Driver's side valve cover is when I discovered the rocker arms were off of #7. It looked as if the aft rod on #7 stopped on the stuck lifter, bent, and didn't have anywhere else to go but over to the other rocker arm which knocked it off it's spring.

The springs moved fine except on #7, of course. I removed the carb, dist, and intake manifold. I replaced the gasket, pushrods, lifter on #7. Put back the dist, and carb. Starting is a little groggy (timing...I know I know) but it finally starts after a bit. When I drove it afterward it felt like it had no power.

Sorry for the extremely detailed story but I didn't want to miss a thing.

 

[Mark W]

Timing still sounds lke the most likely reason for a new feeling of no power.

Your theory about how the rocker arms wound up off can not be correct. The lifter will not stick on the way down (or up with the cam pushing it). If it could, the valve would just stay open. If the valve spring could bend the pushrod, then it would do so as soon as the engine was started and the cam trying to push the vavle upen against the spring via the lifter, pushrod and rocker arm. I would also be very surprised if one pushrod/rockerarm could dislocate another.

Had you adjusted the valves/had the rocker arms or even the head off in the recent past?


Mark...

 

[72FJoy]

Timing is easy...thank God. Well, I hadn't touched the valves nor anything remotely close to that area. I also have an oil leak out of that stupid oil pressure sending unit area. I have the sender in place with high temp thread sealer.

 

[mdjohnsen]

...

 

[Pin_Head]

Gotta wonder why the push rods were bent. This doesn't just happen randomly. A compression test might reveal the problem.

 

[72FJoy]

Stuck lifter was the culprit. Replaced it on #7 aft valve. The springs do what their supposed to now. After I replaced the rod and before I replaced the lifter the rocker arm and spring just sat there and did a funky chatter without movement.

I swear that's what it looked like when I took the valve covers off....that the last rocker arm was knocked off by its rod because of the stuck lifter, it had nowhere else to go except the path of least resistance which was probably toward its neighbor. Its neighboring pushrod was bent too...not as much but it wasn't straight. Its lifter was fine because when I replaced its rod it moved fine. It think the forward #7 valve rod/rocker arm was a casualty of #7 aft valve stuck lifter.

Oh, I don't have the capability of a comp test.

 

[grant5127]

A stuck hydraulic lifter is due to sludge, varnish, crud, crap, dirt, or other contaminates blocking the internal works (relief valve) resulting in valves hitting piston causing bent push rods.... I would replace them all, after a good clean up... when 1 fails the remainder will follow suite...

 

[72FJoy]

I thought about it but at the time I suppose I was thinking bandaid....so, yes, I should have replaced them all.

 

[72FJoy]

Update: I finally had the distributor installed and timed (deployment to Iraq) Installed a new Holley carb and I feel the increase in power, however, when i open it up it still sort of chokes like there is that lack of power present. Still don't have the capapbility to perform compression test. Thinking about taking it into a mechanic....how much should I expect to pay?

 

[inkpot]

Update: I finally had the distributor installed and timed (deployment to Iraq) Installed a new Holley carb and I feel the increase in power, however, when i open it up it still sort of chokes like there is that lack of power present. Still don't have the capapbility to perform compression test. Thinking about taking it into a mechanic....how much should I expect to pay?

Howdy! I'm guessing you might be military? If so, don't you have an auto hobby shop on base? I used to nearly live in one of those. John

 

[72FJoy]

Oh yah...when I had my Heep I used to live in one too. This was at Marine Corps Base 29 Palms, CA and in Keflavik, Iceland. Of course they had guys that were willing to sit there with you and work on stuff to help. Where i'm stationed now...they have contractors that get annoyed every time you need help. It's a pain. I guess what i'm getting at is that i've never done a compression test either so I would be like a 12 year old with a penis pump.

 

[72FJoy]

Update. Had to replace my battery (three times) and my alternator (less than a year old) once. Getting a pretty bad drain when left hooked up overnight. It seems the cruiser will run smoother when a new battery is installed. Then over time it'll have a slow turn to start. I have an EZ Wiring harness that I installed a year ago and followed the instructions. Could this be the culprit to the loss of power?

 

[inkpot]

Howdy! I don't know what all years were the same design, but delco alternators from the 70's had a chance of doing a slow bleed especially if you are using the "one wire" setup. BTDT. Alternator charged OK, but had a slow bleed that took days to create a serious problem with the battery. John

 

[72FJoy]

Hmmmmm....I had replaced the initial one when I bought the cruiser. I had gotten a 100 amp cranker from Summit. Worked fine although I think the shop I took it to wired it strange. I say that because when the engine was cold the alt was warm. I haven't had a battery issue until recently though. Now I just unhook it when I park. Kinda ghey after a while.

However, I did just replace the dash and all the gauges. Speedo(used), tach(used), fuel, oil press(non-elec), temp(non-elec), and voltmeter. All VDO.

Now for the fun stuff...I bought the VDO speedo and VDO tach on eBay from a guy who wasn't sure which hook ups went where on the back of the tach but each side had a diff marking, i.e. +, -, and B+. The battery issue started after I did this "fix what wasn't broken" manuever. I'm sure it's probably the gauges. I need to check each fuse to see.

I was having distributor issues until I installed it correctly and it still sputters like it's choking or something. It almost reminds me of that commercial where the guy is driving a convertible Mustang with his woman. He goes to pass a chicken truck that's spitting feathers all over the place but his car chokes. I beleive it's a spark plug commercial. I just replaced all of my spark plugs not too long ago. I seriously hope it's not a bad ring. Fuel maybe? Brand new carb though.