430 out of the frying pan into the fire

Well I fixed the headgasket that was pressurizing my crankcase.

Threw a headgasket kit and an intake kit with valleypan at it.

Started right up, it did.......then while it was running on the choke for warmup it suddenly bogged down and started knocking.

I checked to be sure that water wasnt somehow getting into a cylinder....system holds 16lbs all day.

From a cold start today I pulled the 12V off the HEI and cranked it to see if I got oil pressure. I did.

So I tried starting it again. It runs real rough, wont keep going. I am getting 40 oil psi with it running like crap and stalling out.

I am running out of patience with this sheet and the cold weather. :af:

Ideas?

If it were a rod knock from a spun bearing it would run well but knock right?

collapsed/malfunctioning lifter? that might explain the poor running all of a sudden....

throw the thoughts out there. Any ideas welcome

maybe its simple as fouled plugs?

 

Pull n check your plugs first. Compression test second.

 

For a left field easy to check suggestion, make sure the float didn't stick on the Q-jet, could be flooding it. There will be obvious fuel smell though, and likely fuel coming out of the vent on the top of the carb.

A rod bearing can create enough drag to cause bad running. It won't run long if that's the case though. Pull dip stick and look at the oil on it for metal if its severely eating a bearing it'll show there.

---------- Post added at 02:43 PM ---------- Previous post was at 01:27 PM ----------

Follow up question. Are they the same heads you removed or are they another set you said in another thread were ready to be installed? I asked because I wonder if the valve guides are squeezing in on the valves causing them to hang. This would result in horrible running, funny noises and bent pushrods.

 

Same heads. I had thought the guides were shot, causing the pressure in the case but I was wrong. It was the blown headgasket.

I can do the pull a plug wire thing and try to isolate a certain cylinder thats knocking

I am thinking I will pull the plugs and have a look. Do a compression check.

While I do that I will pull the valvecovers and see if I can detect and "funny" movement of the rocker arms.

Dam thing was running great excepting the head gasket. Now headgasket is fixed and it runs like crapola.

sometimes they like to kick you

I havent seen metal in the oil....yet. I just have a baaad feeling it spun a bearing.

 

Open up the oil filter to see if the crank is in there...

 

I would suspect a collasped lifter or something with a rocker or pushrod.

 

this is a good idea too. thank you.

 

Put a 350 in it!

 

thats very probable if this 430 is chewing itself to pieces.

 

Hey,I was going to say "just put a 350 in it"!!

You beat me to it Sean!!

 

Stick a Mopar in it :idea2:ou:

 

At least the 440 block has some strength LOL

 

What kind of head gasket you use? Oil journal feeding rockiers isn't blocked off or restricted is it? Oil hemmoraging past cam bearing as a result? Maybe starving lifters?

 

good thought. Ive got victors on there now. has the appropriate holes.

getting good oil to and thru the rockers

 

Well I don't know the history behind this engine, I read somewhere someone said something about something else going on in some other thread. Anyway, you say the engine was running tip top before the head gasket change, correct?

So anything that's happening now must be a result of that action, whether directly or indirectly, OR the slim chance that something just happened to go bad while you were doing this head gasket change, and that the occurence of both simultaneously is purely coincidence.

If we were to roll ye ole dice-aroo, I'd go with the former and not the latter. So let's focus on that first.

Think about what all is involved in the head gasket change, all the parts that are touched, and imagine a worst case scenario. Was a tool or bolt or some foreign object dropped into anything anywhere? Like in the cylinder, down the valley pan, or on the head near a valve spring?
Were the heads torqued down using the proper sequence?
When you say it's knocking, what sort of knocking sound does it make? Does it sound like a loud heavy clank, like a bearing or wrist pin or something rattling around inside a cylinder smacking up against the head? Or is it a lighter, tapping type sound? Can you somewhat isolate the sound in a general direction? Like from the bottom or top of engine, front or back, etc. Was the knocking sound and engine running rough a sudden thing, or did it happen slowly as it warmed up?

The more details you can give, the better. Don't leave anything out no matter how insignificant it might seem (other than you picking your nose in the middle of tightening a bolt or something)

There might be something you forgot and won't remember until something triggers it in your mind. Could be talking here or going through the sequence of events in your mind.

You have to look at this through the eyes of a total stranger who doesn't know anything about your engine or setup other than it is a Buick 430 that just had a head gasket changed, ran fine before, and now it's knocking and running rough. This is all we know as of now.

 

after a couple days off to get my "bearings" (hehhehheh) I dropped the oil and cut the filter to look for debris.

A half dozen flakes in the oil pan, nothin suspended in the oil.

The filter had no flakes in the pleats nor in the bottom of the "can"

It doesnt look to me like I shredded a bearing.


I started it up again and noticed that the tapping is quick, like a tak-a-tak-a-tak-a-tak-a-tak sound, even at 850rpm. It does not have the low tok----tok----tok----tok----tok sound of a rod bearing.

The tapping is higher in the engine and towards thefront. And quite loud.

I believe it is valvetrain related although without the intake removed I have found nothing to indicate what the problem might be.

I am going to remove the intake and have a real good look at the lifters and pushrods.

 

Look real good at your rocker arms and pushrods and the valve stem ends...

 

Has the engine been rebuilt, and if so, were the cam bearings changed? If they were, did you use grooved bearings? Are the valve springs stock or have they been shimmed or Stage 1 springs or? Have the heads been disassembled?

When you pull it apart, look closely at the lobes on the cam where you heard the noise. Inspect the lifters and roll the pushrods around in their positions to see if any are bent, etc. Check the rockers for wobble or cracks. Has the timing chain cover been removed? anything done to the timing chain or gear? what about the fuel pump?

It's definitely valve train related, and appears to be coming from the area of the engine where the classic oiling issues from BBB's arised. That is, excessive pressures against stock parts with increased pressure on the front cam bearing either by the oil pump or the valve springs can cause the front cam bearing to 'melt' and debris will clog the bearing oil hole, starving the driver side lifters. If the whole driver side seems affected, this may be worth looking into, if it's only a few or less, then it's more specific, likely trauma damage as a result of misalignment of a valve train component, or factory defect in material.

 

/shrug?

I pulled the intake and valley pan.

All the pushrods are straight.

Rocker arms show no unusual problems.

All of the lifters stayed pumped up when I pushed against them while still in their bore. with oil in them i could not depress them at all.

I removed and disassembled each just to have a look inside them and be thorough. No problems at all.

The one thing I found, which I cannot imagine would cause the noise I have, is a small area of pitting on the very tip of one cam lobe. It has barely even marked the bottom of its lifter.

All the lifters have nice circular patterns, no evidence of straight contact.
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HISTORY:

The stock engine was a barn find that I ran in my 72 last year after a plain regasket. It ran great. I had looked at the cylinder walls and bearings and they all were super. I also : heads disassembled and cleaned. stock valvesprings no shims. new timing set. new fuel pump

This past winter I put in a comp 268 camshaft only.

It ran great this spring for the break in of the cam and for several trips around the block, excepting a blown headgasket. Ends up I had blown it last fall but it took time for me to diagnose it. anyhow it ran great with the 268 cam


I replaced the drivers side headgasket a couple weeks ago and started the car up. It started and ran well as it warmed up until......the knocking started and the engine bogged down, started running like junk - see beginning of this post.
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I have to believe it is bottom end now. I have found just nothing in the valetrain that would cause the noise. It would have had to have been a bent pushrod or collapsed lifterm which I do not have.

I do not believe there is an oiling problem because I get good oil flow from the rockers, the lifters are all pumped up, and there is no debris in them.

EDIT: cracked/flexing rocker is something I havent checked for....good idea I will check it oout

 

Before you rip the bottom end apart, put a stethoscope or a wood dowel against the fuel pump. Listen through the dowel, see if the noise is coming from the pump.

Not uncommon for engine-driven fuel pumps to knock as they begin to fail.