292 Questions

[May70]

And cyl 6....

[May70]

I also uploaded a video of it at idle and smoking

https://youtu.be/z3IX2LqhiMQ

[jfnar]

I'm not an expert but have you looked for vacuum leaks?

[Steeveedee]

Hand over the snorkel doesn't change anything because the air will then go in through the choke stove port further back. It looks like your pistons are pretty coked up. That engine is really noisy, too. In any event, if you take it out and put a load on it, that will burn all the crap off the pistons. I think that that is where most of the smoke is coming from. Those compression numbers aren't stellar, but they're good enough. Those scratches on the cylinder walls only have one solution, though, and that's bore and/or sleeve.

['68OrangeSunshine]

Apparently the PO put a lot of miles on your 292. Or the long vacation allowed gum and varnish to harden up in your valve train.
I used a valve-cleaning spraycan of foamy stuff -- shot thru the carb -- on a sluggish 350 V8 in my '71 GMC. Can't recall the product name or maker, but it worked pretty good - followed by a long drive. I would try that first before getting down to a rebuild. Or try any other shadetree magic: Marvel Mystery Oil, Rislone, warm diet CocaCola?

If your rings are somewhat worn, you can try getting better compression by increasing the viscosity of your engine oil. I use straight 30 weight Valvoline Racing oil [VR1 p/n223] in a normally good 292. As mileage racks up, I run 40 weight, then SAE 50. [But before I get to filling the crankcase with SAE 90 gear oil, I rebuild. ]
So maybe 10W-30 is too light for you. Try 20W-50 or SAE 40, and see if it runs better.
I once got a 25 year run out of a 292 L6 I built in 1977. Only variance from stock was a .030 overbore. It went for 250,000 miles in my little Orange Stepside. Towards the end it was blowing blue smoke rings of pure 50 weight, but it still started right up and ran.
In 2002, I started rebuilding the original L6, that I had put up in a crate, and rebuilt that with a more aggressive profile. That's the L6 that's in there now.

[RichardJ]

I have had a hard time deciding where to start.

>>Dwell is reading 39.
15.4V @ idle <<

Dwell should be 31*, which is to say your point gap is way too small. FIX. NOW.

15.4 volts @ idle ? That's a real problem. An original 10Dn externally regulated Alt will seldom generate more than 13.0 V at 600 rpm idle. You have a bad voltage regulator or bad volt regulator ground.

That is a noisy video. Either use a stethoscope or a long wood dowel and listen to the water pump and the alternator bearings. The high Alt voltage will contribute to alternator noise.
You could also just remove that single fan belt and run the engine, to see if some of that noise goes away. With engine off, spin the water pump and Alt by hand.

While you have the belt off, remove that ridiculous fan spacer. Without a full fan shroud, the only thing that fan spacer could ever do is reduce the life of the water pump bearing.

You are right about using two manifold-to-head gaskets as being a bad idea. You should have listened to yourself. Loosen the intake-to-exhaust bolts to just snug. Then with 1 manifold-to-head gasket installed, tighten those nuts/bolts first. Then tighten up the intake-to-exhaust bolts.

Has the coolant level been going down?

Has the engine oil level been going up?

[Steeveedee]

The 15.4V could be from the battery being low and getting brought back up. If I read this thread right, he's been doing a bit of cranking which could lower the battery voltage. I was taught that minimum charging system voltage is 13.5V to overcome system resistance with enough voltage to charge the battery.

[May70]

Apparently I went with my first thought and didn't put two gaskets on there. Checked it earlier and was scratching my head, definitely just one gasket there.

I cranked on it a lot just before checking voltage, I was doing the compression test. However I did check the ground on the voltage regulator and it needed some cleaning up. Will check that again once I get things back together.

Carb is apart and in the ultrasonic cleaner now, it had a thick layer of gunk in it. I have a kit, new float and in-line filter ready to go. The barrel filter and spring weren't in the carb so gonna have to order those. Do these years use the paper or the bronze/ceramic (?) filter in the carb?

The alternator was caked inside and out with oil gunk, bearings were going on it that's what most of the noise was. Decided to just go grab a refurb. By the time I ordered bearings and took the time to clean it out im money ahead.

Water pump/fan spins freely no issues and no noise. I need a new belt so I will pick one of those up tomorrow, wow they are proud of that little belt.... Napa B151 premium xl 25-10035 with notches on the inside is what was on there. Not sure if I need the notches, I dont see one on napas website with the notches but the one i see is about 45$... Anyone have advise on that?

New plugs are in.

Used some seafoam in oil/gas. Will check to make sure all goes well with carb before adding too many variables at once. I have a feeling the smoke is coming from the valve seals but we will see. Once I get this all back together and it runs I will put new points/condenser and probably a cap on it. Recheck dwell after that.

Once all that is done I am going to attempt to get 75-100 miles driven over a few days. Then see where we are at. Probably at night so they will think im a mosquito truck haha.

I was told that a few squirts of oil and another compression test will show drastic increase if the rings are bad (made sense to me) but not really sure what would be drastic vs rings are good. Will probably try that after the drive.

Once the seafoam has run its course ill probably bump it up from 10w-40 to 20w-50 as mentioned before. And re-evaluate from there.

Thanks for the inputs. This forum is invaluable.

[Steeveedee]

Either the short paper filter or the sintered bronze filter will work. The sintered bronze filter stops water, but once it's clogged the spring lets whatever is in the fuel system by, anyway.

Take the cap off and see what the points look like. You can do that without upsetting the timing, since there is an indexing lump on the cap that fits the slot in the distributor. If the points are all pitted, it'll be obvious.

That belt price is ridiculous! Check around. They should be about 1/4th that price.

[May70]

I did a carb kit and put it all back together. When I went to clean the old gasket on the intake manifold I saw there was oil sitting in the bottom of the intake manifold.

The pcv on the valve cover appeared to be letting oil past it. Im not sure if that amount of oil could have passed up through the hose and into the manifold via the nipple. Anyone have that experience? I picked up a new pcv today. Belt was a special order for 30$ at Advance so I wont get that for a few days. Im not too confident that failed pcv is 100% source of the oil.

[geezer#99]

Temporarily replace the black pcv hose with a clear hose to see if that’s the oil source.
Clear hose is available at Home Depot plumbing section.

[Steeveedee]

That's probably the source of all your smoke. Take a look into the valve cover and make sure that the baffle is in there. If it has that much blow-by it needs rebuilding.

[May70]

Originally Posted by Steeveedee

That's probably the source of all your smoke. Take a look into the valve cover and make sure that the baffle is in there. If it has that much blow-by it needs rebuilding.

Are you referring to the pcv or the oil in the intake manifold? Id say its a good bet the oil being in the manifold is the reason its smoking but im not sure about the how it got there part.

As for the baffles in the valve cover I am not sure what you are talking about, do you have a picture? Mine doesn't have one of those breather things it has the regular fill cap (if thats what youre talking about).

[Steeveedee]

I'm referring to the oil in the manifold. Looking into the valve cover where the PCV valve goes, there should be some sheet metal that interferes with the splashing oil to keep it out of the PCV system. You should not be able to see valves or push rods when looking in. I don't have a pic, sorry.

[May70]

Oh ok I follow you.. I dont believe my valve cover has that. I had it off and cleaned/painted it and am not recalling. Will check tomorrow. Thanks

[geezer#99]

They look like these that are for a sbc.
Bolt in or are welded in under the pcv hole inside the cover.

https://www.summitracing.com/int/par...6962/overview/

['68OrangeSunshine]

The stock L6 valve cover has them. One forward under the oil cap, and one rear under the PCV valve. Don't know why anyone would go to the trouble to cut them out.
Freah air intake for the PCV system is in the air cleaner, thru the 1-1/8'' hose that comes off the air cleaner [collar?] and goes into the side grommet on the forward of the valve cover. In later models, there was a fiber filter to prevent oil vapor ingestion. Could this be what's malfunctioning?

[May70]

There is no mesh or baffles on the hose to the manifold or the one to the breather. You can see right down to the rockers etc.......

I recall the only thing around the oil cap is a small square (ill draw a picture). But its open at the bottom.

[geezer#99]

If you have no baffle for the pcv you can install a baffle/grommet like this.

https://www.amazon.com/Moroso-68773-.../dp/B001G97Y6C

They make different sizes. Measure yours to be sure.

[Steeveedee]

Looks like the oil fill cap baffle is in place, so that's one good thing.

[RichardJ]

This picture was surprisingly hard to find on the internet. Without the PCV baffle, oil splashing on the PCV Valve would be sucked into the intake manifold.
The other baffle keeps oil from being splashed out when you remove the fill cap. It also keeps oil from entering the hose to the air cleaner.

[Motorfist]

I have been watching this thread keenly as I am trying to get a 68 with a 292 I6, Rochester Monojet, with sm465 back on the road right now. Would it be ok to ask questions that are very relevant to this conversation or shall I start a new thread? I do not want to hijack this thread or step on toes...

[May70]

Had a hard time today trying to take the grommet off to measure the hole. Looks like ill have to remove the valve cover and cut the top off of the grommet, then pull it through the hole.... hopefully i can find a replacement...

Went up to parts store today, the only grommet with a baffle they had was too big. Looks like ill have to order it online somewhere and I will need the exact hole size. It doesn't seem like that is a common part to order.

Alternator that I picked up was supposed to be 'an exact fit' and wasn't.. The shaft is not long enough to put a spacer on to line it up with the other pulleys. I asked if they stocked any double groove pulleys, I got a confused look and a "whats the year make and model".. Im going to go pick my old one up tomorrow and rebuilt it i suppose.

Carb went back together smoothly. I got one of the 1" filters for the carb (carquest part number in pics was like 1$) and a spring from the hardware store. It seemed like the spring was too strong and it actually crushed the filter preventing any gas flow and caused gas to leak out around the fuel inlet. I removed that filter and will test it tomorrow to see if it still leaks.

[Steeveedee]

Originally Posted by Motorfist

I have been watching this thread keenly as I am trying to get a 68 with a 292 I6, Rochester Monojet, with sm465 back on the road right now. Would it be ok to ask questions that are very relevant to this conversation or shall I start a new thread? I do not want to hijack this thread or step on toes...

I'm not the law around here, but I'd suggest a different thread because people are going to get confused on which one is which.

['68OrangeSunshine]

That sidesaddle valve cover grommet used to be a dealer part. Back when GM dealers had Chevy L6 parts. The grommet was closed on the end you put in the valve cover. You had to cut it open to make the hose work.

Have you tried the usual suspects? Classic Industries, Car and Truck Shop of Orange Cal, LMC, even?