Chuck’s engine build thread!

[ChuckN]

“Wisdom comes from experience. Great Wisdom comes from really ****** experience.”

This and also “good judgment comes from experience and experience comes from bad judgement “.

 

[ChuckN]

Well, I give up. I’ve tried so hard to no avail today. It fires right up, but I have a miss that I cannot get rid of.

It cracked off first crank but had the miss from the get go. We stopped and checked compression, even 190 on every one, no low spots. We found a cracked plug wire, so I ran to town and replaced them all, and I had a distributor cap so I threw that on at the same time. Timing is well advanced but I bumped it forward a bit more and no change (not that I thought that it would be the issue.

I’ll check the rockers and lash, but I don’t think it would be the case if I have the same exact compression on each cylinder. I have a hard time thinking that I fouled a plug, they all looked pretty good and it had a miss from the very first revolution.

I’m done for now, I need to step away and get out of the garage for a while.

 

[Radiohead]

Well, I give up. I’ve tried so hard to no avail today. It fires right up, but I have a miss that I cannot get rid of.

It cracked off first crank but had the miss from the get go. We stopped and checked compression, even 190 on every one, no low spots. We found a cracked plug wire, so I ran to town and replaced them all, and I had a distributor cap so I threw that on at the same time. Timing is well advanced but I bumped it forward a bit more and no change (not that I thought that it would be the issue.

I’ll check the rockers and lash, but I don’t think it would be the case if I have the same exact compression on each cylinder. I have a hard time thinking that I fouled a plug, they all looked pretty good and it had a miss from the very first revolution.

I’m done for now, I need to step away and get out of the garage for a while.

Probably a doa spark plug. New doesn't mean good anymore. Isolate the dead hole and replace that plug. Or play whack a mole and see if the miss changes holes.

My money (with everything else being right) is a bad plug.

 

[ChuckN]

Probably a doa spark plug. New doesn't mean good anymore. Isolate the dead hole and replace that plug. Or play whack a mole and see if the miss changes holes.

My money (with everything else being right) is a bad plug.

Well, too early to tell, but after a little research, I’m my own worst enemy.

I’d read that aluminum heads need anti-seize for the plug threads. But first of all I didn’t know that you’re not supposed to use copper anti-seize. And if you use anything at all, it’s supposed to be a pinhead sized drop on the 3rd thread, no more. Well, in my usual “more is better “ line of thinking which is something I constantly battle against, I smeared it all over the threads.

But worst of all, NGK plugs have a trivalent coating for anti-seize properties and are specifically designed to be used dry. So that wasn’t helping either. (Of course that’s not readily available information and I didn’t know any of that).

So, I marked all the spark plug wires, pulled them off and pulled out the spark plugs this morning. Then I took one of the old plugs, and use it to clean all the threads out by running it in and out of the threads in the head until it came out clean.

I’m going for a bike ride with my friend this morning, I have new plugs on order that I’ll pick up after that. I’m not saying that’s the actual problem I have, but for now I’m going to plug my ears with bees wax and pretend that it was for my own sanity until I find out otherwise.

 

[legopnuematic]

I’d pull the valve covers and give the valve train a once over.

When I put the engine back in my 76 and the first fire one of the pushrods dislodged itself, either #4 or #6. Didn’t bend the pushrod or damage anything, put it back in and relashed the valve and double checked everything and then proceeded with cam break in etc.

That was at the end of 2018 and that was the last time I’ve had the valve covers off of the truck and lot of miles since.

 

[ChuckN]

I’d pull the valve covers and give the valve train a once over.

When I put the engine back in my 76 and the first fire one of the pushrods dislodged itself, either #4 or #6. Didn’t bend the pushrod or damage anything, put it back in and relashed the valve and double checked everything and then proceeded with cam break in etc.

That was at the end of 2018 and that was the last time I’ve had the valve covers off of the truck and lot of miles since.

Maybe you’re right- engine is dead solid quiet though, and I’ve got even compression everywhere- if that were the case and I had something off with the valvetrain, wouldn’t that show up on the compression? Not against checking anything though.

 

[legopnuematic]

In my scenario above, no noise other than the miss.

If it was an exhaust pushrod, the intake is still opening and able to fill the cylinder with an air charge, still creating compression.

Also put a vacuum gauge on it, that will provide some insight too. Could even be an intake gasket leak.

 

[ChuckN]

In my scenario above, no noise other than the miss.

If it was an exhaust pushrod, the intake is still opening and able to fill the cylinder with an air charge, still creating compression.

Also put a vacuum gauge on it, that will provide some insight too. Could even be an intake gasket leak.

Really! That’s interesting. I’d have thought that it would be popping out the intake. I’ll take a look today.

 

[ChuckN]

Well, all the rockers are absolutely fine. I rotated the engine and checked each one. Since I’d ordered them and picked them up, I put in the new plugs as well.

It still has a miss, but it’s struggling less. When I am revving it 1500-2500 and when I do steady RPM, I can hear and feel a cylinder going in and out of having power.

I wonder if the coil or module is giving me problems now.

If anyone wants to walk me through a tutorial to diagnose HEI, I’d be all for it.

 

[ChuckN]

Well, I just took a reading from the black ground wire to the back of the coil where the button goes- I don’t even get a reading- it sits on OL. The yellow and red wire read 0.8.

 

[82SquareBurb]

Flaky module? I don't know a test for those other than to swap a "tested" one in as a check. Used to be cheap if you have a spare?

 

[ChuckN]

Maybe- I’ll see if I can test that too @82SquareBurb

Coil seems to be fine now- I thought my meter defaults to “auto” mode but it doesn’t . I now get 0.8 ohms on primary, 7K on secondary.

 

[Rustisbest]

It still has a miss, but it’s struggling less. When I am revving it 1500-2500 and when I do steady RPM, I can hear and feel a cylinder going in and out of having power.

Possible some critters got in the carb through the bowl vent? Or maybe gummed up from sitting? Maybe add some fresh gas to see if it clears up any. Just throwing a few things out there

 

[legopnuematic]

My one experience with an HEI module dying was I went to a gas station to get a soda, truck was running fine, park, shut it off, come back and go to restart and nothing. Replaced module (in the parking lot) and all was well again.

Is the vacuum advance hooked up? I had the wires for the pickup get fatigued and under certain conditions with the vacuum advance moving it would start missing/cutting out. If I kept a super light foot it would be ok, but try to give it any more throttle vacuum would drop and begin cutting out. Also check the connections at the cap, both the connector from the base of the distributor, and the terminals in the cap. I’ve had them either get pushed up into the cap and make poor/bad connection or the female terminals in the pigtail fall out of the connector body and make poor connection.

I’ve come to find that I should never discount or write off any possibilities with this type of stuff. Numerous times the problem was something I wouldn’t have believed had I not dealt with it myself. One of my favorites (to tell now that’s dealt with) was after I did a dingle ball rebuild on the slant six in my Dart. Get it back in and running, had some issues with intake and exhaust leaks, got those sorted, I had noticed that when it was hot the vacuum gauge would bounce like crazy, when it was cold it was steady or at rpm’s off idle it would steady out. Readjust the valves a few times (solid lifters), keep checking for intake leaks, carb adjustments, etc. Finally worked my way to thinking valve springs, sure enough I could open a valve with one finger, while running I could push lightly and make it hang open, or pull up carefully and vacuum was steady again.

Replaced them with “340” replacement springs and low and behold, the issue went away for good. There was a few contributing factors to this, one is I had the head cut for compression and a valve job, which would raise the valves height, lowering spring pressure, I reused the stock springs which ones used in production were weaker than what was ever offered as a replacement (replacement springs are the same as 318 springs) from Chrysler or aftermarket, and I did put a slightly bigger cam in it. So yeah, valve float at 700rpm