Diagnose This

[wallytoo]

The over rev condition may have damaged the head gasket between a pair of cylinders. That would have no effect on coolant or oil,

i disagree. blowing the headgasket can lead to coolant loss. picture is from the last head gasket failure in my truck. broke between #3 and #4, right next to the coolant passage, as opposed to the head bolt. coolant DID leak, right into the cylinders, out the exhaust and down into the pan.

may not always happen (coolant lass with gasket failure), but it has happened all three times that i've had it fail - all prior to rebuild.

however, from the info hank posted just above, about compression, he probably doesn't have to worry about head gasket failure. rod bearings? could be.

[HanksB3B]

Check your oil and coolant level first.   Then crack the drain plug loose enough to get a few drips out of it.  Any coolant should have settled over night and would be the first to come out..  Just oil, then do your compression test.  If that checks out, drop the pan and start checking brgs.  You could pull the tappet covers and check for broken springs too.  A burnt valve shouldn't make any knocking noises.  A scored or broken piston, wrist pin bushing or bearing going out will.

 

Today' marching orders:

 

1. Crack the drain plug to check for coolant.

 

2. Pull the tappet covers. Visibly inspect the valve/springs  (if nothing is visibly obvious, with no spark plugs and oil still in the engine, turn the engine over and observe the valve operation. 

Am I correct in assuming: If I find a broken spring I will have to remove the head to withdraw the valve.  If I remove the head I’ll have to replace the head gasket (thinking about what I’ll have to order from Napa)

 

3. Drop the oil pan and start checking bearings.

 I don’t know much about this or what to look for other than scoring and slop I guess.  (will read up on it though) 

 

Thanks (and have a great day),

 

hank 

Edited October 16, 2013 by HanksB3B

[Dave72dt]

You may be able to see a broken spring by the misalignment of the coils and yes , head off would be the easiest method of replacing it and depending on where it is, removal of the manifold may help.

For brgs, you may find some shavings in the bottom of the pan or material hanging out the sides of a main cap or rod cap, possibly some bluing on a rod cap, maybe some movement up and down on a rod along with the scoring and material transfer. Check the pistons when they are all the way down for cracks on the skirts or excess movement of the wrist pin bushing, all the way up check the cyl walls for scratches.

Lets hope it's a broken valve spring(s). Pay particular attn. to the cyl with the wet plug.

[wallytoo]

if you lost a rod bearing, look for a lot of silvery flakes (they'll be fairly easy to see, not like silt). it sucks to lose one, because you are looking at pulling the engine apart (very likely to need to redo crankshaft).

hope it isn't a rod or main bearing.

[Jeff Balazs]

Hank;

I was going to suggest that you pull the head and inspect. It is really not that big a job. Plus being able to see the condition of the cylinders and valves will go a long way towards assessment and ultimately your overall sense of what shape things are actually in. I know if it were me I would want to see in there.

 

Hopefully this all turns out to be something you won't have too bad a time dealing with.

 

Jeff

[HanksB3B]

Today's Progress: 

 

I think I got Luckier: (until I read Wallyhoo’s post)

 

1. No coolant in the oil.

 

2. No piston rings in oil pan (kinda wasn’t expecting any after yesterdays compression test all cylinders between 100-115psi.

 

3. Just some fine filings like you'd expect from a sub 1,000 mike rebuild. (Wallyhoo, I sure hope you’re wrong)

 

 

4. When I removed the valve covers they looked cherry to me.  No broken springs.

 

 

So now what ? (don't have to eat my Vegemite sandwich hey eh, if ya come from the land down under)

 

Jeff I'm with you on the removing the head and I don't see as that I have a choice.  

 

Could it just be a STUCK VALVE ?  or still be a head gasket (even though the compression test didn't indicate that)

 

Thanks, 

 

hank 

Edited October 17, 2013 by HanksB3B

[Plymouthy Adams]

continue to prove what is NOT wrong...

[Dave72dt]

run  your tappet gauges through the valves .. A stuck  valve would be noticably loser than the rest

[HanksB3B]

Anyone remember the head bolts that I think were a match to our Mopar ones but the may have been Fords ?  There was a good and very reasonable purchase someone mentioned a while back.

 

Dave I will “Run the tappet gauges through the valves”

Plymouthy I did feel like todays progress was “Continue to prove what is not wrong”.

 

If it is a stuck valve do you have to remove the head ?

 

Thanks,

 

hank  

Edited October 17, 2013 by HanksB3B

[Dave72dt]

Chevy SB head bolts, the short ones

[HanksB3B]

Chevy SB head bolts, the short ones

 Rather a Cheby than a Ferd..

 

So you guys are telling me to pull the head It's a must.

 

Thanks,

 

hank 

Edited October 17, 2013 by HanksB3B

[48Dodger]

"During the initial startup of a rebuilt spare carburetor the engine over-revved for about 10-15 seconds before I could shut it off"

 

 

What RPM did it over rev to, or what do you think it did? 

 

48D 

[HanksB3B]

"During the initial startup of a rebuilt spare carburetor the engine over-revved for about 10-15 seconds before I could shut it off"

 

 

What RPM did it over rev to, or what do you think it did? 

 

48D 

 

Do you mean on a WAG or a SWAG estimate scale? 

 

hint:

 

WAG = Wild Ass Guess

SWAG= Scientific Wild Ass Guess

Edited October 17, 2013 by HanksB3B

[NiftyFifty]

Hank did you pull the pan off! Or just check the drain plug magnet? You could have a bearing going and no real filings showing, make sure you check your rods and mains as putting back together before you find your knock could lead to doing the job twice. A this stage pulling the head is also a must just to check condition.

[HanksB3B]

4mula,

 

I removed the whole pan after draining just a little oil to see if there was coolant.  There wasn't.  Then I drained the pan and removed it in order to fix an ongoing leak. I botched the last oil pan gasket and the pan has an issue where the dipstick goes. Does anyone have one Tim in really good shape ?  Both left and right gaskets were oil soaked the entire length of the gasket. (that's not good) 

 

Looks like I'll be doing a bunch of things:

 

Verify if my head-bolts are new or re-used at the last rebuild and order the Chevy SB shorts ones. ARP bolts are costly and probably more than what is required.

 

Checking the valve clearances.

 

Removing the head: Can I still have a blown head gasket and have gotten a reading between 100-115 psi. (I forget the actual strokes of a 4 cycle engine does that matter)

Edited October 17, 2013 by HanksB3B

[48Dodger]

Just trying to get an idea of what happened.

 

Did it sound out of control, was it above 3500-4500, did it sound labored as it climbed, did it back fire through the manifold or exhaust,....that sort of thing.

 

48D

 

    just for fun:  https://www.youtube.com/watch?v=3NRaqgab0_w

Edited October 17, 2013 by 48dodger

[HanksB3B]

If I had to guess it was maybe 3500-4500.  It did not sound labored as it climbed. I was able to shut it off real fast.  No backfire, just a faster than usual 20 second surge I'd guess. Nothing unusual in the way of smoke. The power loss was not evident immediately after than. It seemed to happen gradually and became weaker during it's last ride with 3 people weighing it down.

 

Thanks Tim,

 

Hank

Edited October 17, 2013 by HanksB3B

[ggdad1951]

VPW also has head bolts, not "correct" but they are new, inexpensive and work.

[Merle Coggins]

I went back to the begining and reread everything again. Based on the information available, here are my thoughts. (Your quotes in Red)

 

"A few weeks ago my truck was not running right.  I discovered that the carburetor had become fouled"

 

Are you absolutely sure that the teflon bits in the carburator were your only problem? If they were only in the idle circuit it would only effect the idle. Did the engine run fine above idle?

 

"During the initial startup of a rebuilt spare carburetor the engine over-revved for about 10-15 seconds before I could shut it off"

 

What caused this? Was the throttle linkage misadjusted and the throttle plate was wide open? What did you have to do to correct this problem before the next start?

 

"Ever since that time I’ve noticed a loss of power as if the truck was running on 5 cylinders.  It seemed for lack of a better description to be “chugging”.  I thought about the timing being too retarded or maybe a loose ignition wire or a fouled plug"

 

What steps did you use to rule out a spark plug or ignition system problem?

 

Compression test Results:

1. 100 psi
2. 110 psi
3. 115 psi (this was the only "wet" plug.  The other five were very consistent)
4. 110 psi
5. 110 psi
6. 110 psi

 

This would sort of confirm your initial theory that there was an ignition issue. If #3 plug was wet, that would indicate that it wasn't firing properly.

 

"Under load the power loss seemed to become progressively worse during the ride and after running up a long incline I heard a distinct knocking noise"

 

This could be from a couple of different things. If the ignition timing was too far advanced from damage to the advance weights, during the brief high speed rev, that could have caused Detonation under load. Or, if there is still a carburator problem it could be running too lean, leading to your loss of power and Detonation under load.

 

"The truck will start and run easily as if nothing is the matter, but I know better"

 

This would indicate that there was no physical damage done to the engine. This is confirmed by the good compression test results. #3 being higher can be a result of the wet plug. If there was fuel or oil already in the clylinder to make the plug wet, this could have also provided a better seal for the rings resulting in higher pressures.

 

"1. No coolant in the oil.

 

2. No piston rings in oil pan (kinda wasn’t expecting any after yesterdays compression test all cylinders between 100-115psi."

 

Both very good things. Once again, proof that there is no physical damage.

 

"3. Just some fine filings like you'd expect from a sub 1,000 mike (mile  ) rebuild."

 

I also agree that this is likely from break-in after a rebuild. Not from this recent event.

 

"4. When I removed the valve covers they looked cherry to me.  No broken springs."

 

Once again, you have confirmed that there is no physical damage.

 

"Could it just be a STUCK VALVE ?  or still be a head gasket (even though the compression test didn't indicate that)"

 

I don't believe so. Your compression test results would tell us that all is well with those pieces.

 

"If I had to guess it was maybe 3500-4500.  It did not sound labored as it climbed. I was able to shut it off real fast.  No backfire, just a faster than usual 20 second surge I'd guess. Nothing unusual in the way of smoke. The power loss was not evident immediately after than. It seemed to happen gradually and became weaker during it's last ride with 3 people weighing it down."

 

 

Based on all of this information I would recommend that you go back to the beginning. The carburator work is what started all of this, so go back and recheck the carburator again. You may have some more debris in there that was missed, or a new piece has blocked, or partially blocked, the main jet circuit. I would also test the ignition system more thouroughly before condeming the engine. Verify the ignition timing and the advance curve of the distributor. The "wet" plug tells me that there was an issue. Maybe it was just that one plug that failed and it was a coincidence that it failed at that moment, just after doing carburator work.

 

Me advice to you would be to replace your pan gasket and get the bottom end back together, then check the carb and ignition systems again before wasting more time tearing apart a perfectly good engine.

 

Merle

[Don Coatney]

I dont know of any way a broken piston ring would find its way into the oil pan unless the piston shattered. A broken top ring will find its way into the exhaust pipe but not the oil pan. And of course the compression in the cylinder with the broken ring would be much lower.

 

How is the oil pressure on this engine?

[Dave72dt]

Checking the brgs while the pan is off  will cost nothing if they are fine and will be reassuring a problem does not exist in that area

 

 

The carb could well be the cause of the problem since that is all that was changed.  What we're looking for is the damage it caused.  Knowing what's right narrows down what isn't.

Edited October 17, 2013 by Dave72dt

[48Dodger]

Full tune up to get to square one means, checking the fluids, testing the components, checking the valves and the induction.....not just throwing cap and rotor at it. So you're doing the right thing Hank. And I agree with Dave, since you're there, check out your bearings.

 

I'm wondering if you replaced your gummed up carb with a carb that has its own problems from sittin' around waiting to be used again. Stuck butterfly (over-revving) and a stuck power piston (no power underload). But it is hard to guess from this far away. Hope all this chatter is helping out Hank.

 

48D  

[41/53dodges]

"Ever since that time I’ve noticed a loss of power as if the truck was running on 5 cylinders.  It seemed for lack of a better description to be “chugging”.  I thought about the timing being too retarded or maybe a loose ignition wire or a fouled plug"

Now that I think about it, I had this exact same issue! going about 60 to menards and lost a cylinder, started needing more and more throttle to keep up and the truck was shaking bad. By the time I got to a good place to pull off it was floored to keep up to traffic! come to find out, the ignition coil fell out of it's little clamp and knocked the #4 spark plug wire out of the distributor, causing a heck of a miss. Put it back and all was well!

 

"Under load the power loss seemed to become progressively worse during the ride and after running up a long incline I heard a distinct knocking noise"

Same with mine, I didn't get any knocking though. When a cylinder is misfiring constantly, it is just washing the cylinder walls down with fuel, which is not very lubricative. This is where the damage could be done, does the oil smell funny at all? someone on here awhile back did some serious damage to the bottom end from a faulty fuel pump dumping gas in the oil.

 

Good luck!

-Josh

[Jeff Balazs]

Hank;

Just a couple of thoughts. If you are going to order anything from VPW they have a really nice magnetic drain plug. I am no expert on these engines but that seems like quite a bit of metal you have collected with the magnet. I personally have never seen that much come out of a fresh engine but I suppose it could be normal for one of these considering how the filtration works. If nothing else a magnetic drain plug will help keep quite a bit of this out of places you don't want it.

 

What actually caused the throttle to stick open? Was this a assembly goof up on your part or was it caused by wear in the carb you had just fitted?

One thing you might consider is going back to the carb you had been running before this all started. Why not clean and rebuild it and see if runs like it used to? I am a bit unclear as to whether you have tried that and you have mentioned two different carb numbers.

 

One last thing. Is there any chance your timing is way off or that your vacuum advance has quit working ? Maybe the diaphram at the distributor failed ?

 

I hope something here helps and that this isn't as serious as it originally sounded.  As you know I am just about ready to put mine on the road for the first time in god knows how long. I was hoping we could have a little drag race It would be fun to see how these two old trucks stack up.

 

Jeff

[HanksB3B]

Today October 17, 2013:

Based on the following, I’m going to go back to square one.

 

Tim: Post #14

Full tune up first.....bring everything to square one, if all goes well, power tune the carb/ignition for optium vacum and timing. I always double check the last thing I rebuilt or replaced. With the egine running, do the valve lash for the best results. The carb can "make" you believe other things are wrong with the truck by not fully atomizing the fuel or pulling the right vacum.

 

It makes sense to go back to square one

 

Reading back through this thread,  I can’t seem to find where I mentioned that the rebuilt carburetor I’m running is not the original E7T1 but rather another carburetor a CO-1 that seemed to be a better candidate for a rebuild. The reason for the carburetor re-build was because due to a lack of a fuel filter, my next door motor head neighbor noticed my fuel pump bowl looked like a snow globe. It turned out to be Teflon bits floating around and they had worked there way and clogged the idle orifice tube.

 

 

From the get go I now realize that the result of rebuilding and installing a different carburetor may be the cause of what seemed to be Fuel Starvation.  Even though the carburetors looked identical from the outside in form and function there may be a difference.  I’m very curious to know if there is a difference in the main metering jet. Just for sh*ts and giggles I’m going to look at both under a microscope (figuratively) and after I put the oil pan and valve covers back might try to run the CO-1 with the E7T1 main metering jet. Before I do that I’ll call Then & Now to confirm my belief that the only difference between the two is the main metering jet. 

 

CO-1 (also marked E9-G1)

 

 

If you look closely in the photo above, you can see the idle orifice tube coated in white.  This substance totally clogged to tube itself.   

 

In the meantime, I’m going to rebuild my E7T1 especially since Keven was nice enough to send me a throttle body in much better shape than mine (shown below).  I’ll get busy bead blasting and cleaning up my tired old E7T1

 

 

Merle: Post #44

Thanks Merle for today’s in dept analysis. I appreciate the time and good advice everyone has offered me.  I’m now on the wave length that fuel starvation coupled with timing could possibly have led to what seemed like a very underpowered drive. 

 

Are you absolutely sure that the teflon bits in the carburator were your only problem? If they were only in the idle circuit it would only effect the idle. Did the engine run fine above idle?

 

No.  The engine ran poorly and I had to find a sweet-spot and hand hold the “cruise control” to nurse it home.

 

What caused this? Was the throttle linkage misadjusted and the throttle plate was wide open? What did you have to do to correct this problem before the next start?

 

The idle adjustment screw was set too high and the spring to the side fender was not attached.

 

What steps did you use to rule out a spark plug or ignition system problem?

 

Should’ve Could’ve Would’ve checked to see that each plug was sparking. Will revisit that at startup. (any methods I don’t know about other than holding the spark plug wire an 1/8” away from the plug ?)

 

"Under load the power loss seemed to become progressively worse during the ride and after running up a long incline I heard a distinct knocking noise"

 

This could be from a couple of different things. If the ignition timing was too far advanced from damage to the advance weights, during the brief high speed rev, that could have caused Detonation under load. Or, if there is still a carburator problem it could be running too lean, leading to your loss of power and Detonation under load.

 

I agree that this is the impasse I have to go back to.

 

Based on all of this information I would recommend that you go back to the beginning. The carburator work is what started all of this, so go back and recheck the carburator again. You may have some more debris in there that was missed, or a new piece has blocked, or partially blocked, the main jet circuit. I would also test the ignition system more thouroughly before condeming the engine. Verify the ignition timing and the advance curve of the distributor. The "wet" plug tells me that there was an issue. Maybe it was just that one plug that failed and it was a coincidence that it failed at that moment, just after doing carburator work.

 

Me advice to you would be to replace your pan gasket and get the bottom end back together, then check the carb and ignition systems again before wasting more time tearing apart a perfectly good engine.

 

This seems to be the least intrusive and labor intensive way to go.  Based on the observations and advice made so far.  I vote for resolving the carburetor, spark and timing issues.  I’m very thankful for all your guys help.

1. Get that oil pan back on and fill the engine with oil.  (based on the condition of the valves I’m opting to not pull any bearings, bearing in mind I may have to re-pull the oil pan later.
2. Check the tolerances of the valve tappets, then turn over the engine with no plugs and observe that each valve is doing it’s thing and not stuck.
3. Rebuild my E7T1 carburetor but for kicks if I find a difference in the metering jet of  the E7T1 and CO-1 carburetor, I’ll put the main metering jet from the E7T1 into the CO-1 and start the engine.  The CO-1 idles nice at about 500rpm it’s just when gas pedal pressure is applied there’s a chugging (fuel starvation).

My main question is this:

Before the last ride the only problem was lack of power from what appeared to be fuel starvation.  The last ride with two passengers was when bad seemed to go to worse to the point of being very happy to get the truck home?  

 

Tim: Post #47

Full tune up to get to square one means, checking the fluids, testing the components, checking the valves and the induction.....not just throwing cap and rotor at it. So you're doing the right thing Hank. And I agree with Dave, since you're there, check out your bearings.

 

I'm wondering if you replaced your gummed up carb with a carb that has its own problems from sittin' around waiting to be used again. Stuck butterfly (over-revving) and a stuck power piston (no power underload). But it is hard to guess from this far away. Hope all this chatter is helping out Hank

 

The CO-1 

 

Before I fight about pulling the bearings please tell me what is involved.  You are talking about the connecting rod bearings right ? How many do I have to remove, what am I to look for ? etc. ?

 

 

41/53dodges: Post #48

Thanks for your input (misery loves company doesn’t it) The oil looked a little dark but was not thinned out and looked almost good enough to put in my BMW beater

.

Jeff: Post #49

I’ve been wanting one of those magnetic drain plugs for a while now and will get one after this fiasco is over for sure.  The cause of the over-rev and the why not rebuild the original is covered above in this post.

 

I’ll catch up with you guys later I have to go get my wife’s truck SMOGGED (or what fun) and then a trip to AAA (glad it’s not DMV)

 

Thanks for everything guys,

 

Hank 

Edited October 17, 2013 by HanksB3B