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GWallace · 02-08-2016, 07:43 AM

Todd,
I have a had a 77 since it was one year old with a federal emission set up. It is still configured like it was when it left the factory. The coach was built in May 1977 and the chassis was built in October 1976.

I understand that the CA setup had an AIr Injection Pump that is not on my unit. With the AiR setup there are tubes that attach to the exhaust manifold at each cylinder. For the federal set up the original exhaust manifolds from the factory did not have holes for the tubes but any replacement manifolds do have the holes. The original manifolds were bad about warping, leaking, and cracking. My replacements (one in the 1980's and one last summer) both have plugs in the holes. The replacements have a design change to reduce the chance of warping and cracking.

The vacuum hose connection for the air cleaner valve connects to a vacuum tube protruding out of the carburetor on the passenger side toward the carb front. The tube extends out from the cast carb body through the choke mechanism on the pass side of the carb. The rubber vacuum hose from the air cleaner just pushes onto the tube.

On setting the timing and the dog house. While you can open the dog house and use the regular timing mark visible from above, there is a second timing mark visible from underneath (if someone has not removed it). Since the second mark is at different location use the No 5 cyclinder for the timing light instead of the normal No 1 cylinder. As stated above the setting for 1977 ( Federal or Ca) is 8 degrees BTC at 700 RPM with the vacuum advance disconnected. The marks on the pointer ar in 4 degree increments. From your picture it does look that the distributed is rotated differently from mine as mine came from the factory. The timing is the critical part what ever the position.

On my carb it has done well all of these years until last summer. The ethanol gas attacked the plastic float and started flooding the engine. Fortunately the local parts store had a metal float available and now all is well. Also according to the Chevy service manuals the carb part number for the CA setup is a different part number than Federal set up carb part number. I do not know the difference.

Good Luck,
Gregg W

calais66 · 02-08-2016, 08:26 PM

Looks like my info was dated. Sorry!

'Models from 1975 or earlier. Previous laws stated that a car that was 30 years old or older was exempt. However this has been recently changed to any car made before 1975.'

Keyair · 02-08-2016, 09:58 PM

Your info was correct up until 2005.
When 1975 vehicles aged in, then as they were the first year that had a Catalyst, the State decided that was the line. All vehicle(except Diesels), have to pass Smog based on their original spec. Same applies to Diesels for 1998 and newer.
This is why I own 2x '73's, 2x 74's and a '84 Diesel!

Sadly, I didnt know this when I bought my MH... I misread the rules and thought 14,000lb and up was exempt...

Todd C · 02-09-2016, 09:41 PM

Today was a very bad day. I drove it to the smog shop hoping he could tune it up prior to attempting a smog check. However, it is not going to happen. He says I have two dead cylinders--#3 and #5. And he thinks it may have a bottom end knock.

I knew it had a miss which is why I did the plugs, rotor, cap, wires and carburetor rebuild.

So what say you all? I'm afraid I didn't sign on for this part of the deal. I really thought with less than 50,000 miles and looking so bone stock, it would be just a matter of bringing it back to life with normal maintenance items.

At this point, I'm not even wanting to pull the valve covers or heads off. When I was younger, I might have jumped in to do the engine swap. Not now. Love the RV, but I'm afraid someone else is going to have to take it and move it in the right direction.

bkahler · 02-10-2016, 05:38 AM

Todd, don't get discouraged just yet. At a minimum you should get a second opinion. Everyone makes mistakes and that could be the case with the mechanic.

There are various things you can try such as running a few cans of Seafoam through the carburetor while running the engine and there are probably some snake oil potions out there that could help as well. Pulling the heads with the engine still in the chassis isn't a show stopper. Pain in the behind yes, but very doable regardless.

The low end knock is a different issue. I don't remember if you changed your oil or not but if you haven't then I would do so before making any more decisions on what to do. Save the old oil and have it analyzed as that could tell you a lot about the condition of the bearings.

Since yours is a 77 model you probably have two headlights per side. If so the front of the motorhome is a lot easier to dismantle than the earlier 74-76 models. That change alone makes it a LOT easier to get access to the motor. Also there are enough of us on Airforums that have pulled the engines out of the chassis that we can walk you through the work that needs to be done.

Brad

Keyair · 02-10-2016, 10:24 AM

That sucks, but all is not lost.
A compression and/or leakdown test will tell you what is going on and where...
A knock may well be caused by #3 and#5 NOT firing... or burning into an intake or exhaust port if the valve is stuck or burned. The very fact that 2 adjacent cylinder on the same bank are suspect would make me wonder if that is connected... blown headgasket between those 2 cylinders maybe? If so, you could pull that head to know for sure...

I have done rod and main bearing on engines "In Situ", but I am not sure if that is possible on a BBC and a P30 chassis.
Big Blocks in this chassis dont last 100k plus... the weight/heat takes a toll on them. My 345 motor expired at about 70k miles by my record of bills, and was replaced with a Jasper Remanufactured motor. There are plenty of people here and in the classic section who have replaced bad motors... I am not sure what the bills looked like.

If I could offer advice it would be this...
Take a good hard look at your rig, and see what it needs... how good is the body/chassis/systems/interior? Putting a replacement engine is not cheap, but its not insane either. I firmly believe that we are at the bottom value of these Motorhomes, and they will only rise from here... A nice example with a fresh engine is worth the investment of time and some money.

chunga · 02-19-2016, 12:37 PM

Also make sure you drive the unit for some time before testing since a colder engine temp will give false readings.

hhendrix · 02-19-2016, 02:19 PM

I'm not sure what "two dead cylinders" means by your statement. Does it mean they are not firing or does it mean they don't have any compression.

Let's start with the easy assumption that they don't have spark. Simple test if you have an ohm meter. Disconnect the plug wire at both ends and simply measure the resistance in the wire. Many engines of that vintage came with carbon filament plug wires. This was done to prevent static interference with electronics, but mostly the radio. But they break down over time and tested for resistance they should be flexed because cracks occur in the carbon and can appear to fine until moved. Anything over 5K ohms is suspect. If they are copper wire filaments, there should be no resistance. As I stated in my earlier post, all wires should be checked before moving on.

Second scenario, if your lucky you may have a couple of stuck hydraulic valve lifters. Not uncommon in an engine that has been sitting a long time. We used to STP oil treatment to unstick the lifters. I was always amazed when such a simple solution worked but it often did.

However, before I would try the STP, as I stated earlier with bad compression in any cylinder, I would do a leak down test. You do each cylinder one at a time. You remove the plug and bring the piston to Top Dead Center so both the intake and exhaust valves are closed. A hose from the tester screws into the plug opening and then the tester is connected to an air compressor. There is a special set of gauges on the tester that measures the air going in and leaking out. Opinions vary but if the reading is less than 85-90%, you may have a problem. The beauty of the leak down test is it immediately tells you where the problem is. If you put your ear by the exhaust outlet and can hear or feel air, then you know it's an exhaust valve problem. Open the carb and again if you hear of feel air it's a good guess an intake valve is the problem. Lastly, remove the oil filler cap or PCV cap off a valve cover and can sense the air, then the cylinder rings are suspect.

Any good shop will have a leak down tester but you're looking at a 1-2 hours labor. Remember a stuck lifter will be stuck in the open position which is why you don't have compression in that cylinder. So another way to investigate if you don't have a test is to pull the valve covers and watch the rocker arms as you rotate the engine. It could be obvious without rotating but often not because it doesn't take much opening to lose compression. Leak down testers are not too expensive and some auto parts stores rent them but you need an air source. There are videos on YouTube that show how it's done.

So the question for you is: Was the discovery of the "dead cylinders" done by a compression test or by pulling plug wires? If was done by a compression test than any good shop would have done a leak down test, since half the work was already done. If it was done by pulling plug wires, that really doesn't tell you much.

No offense, but when I had my shop in CA, I found that most "smog testers" and gas stations had limited skills and equipment. I think you need to investigate further. Good luck.

cdufault · 04-23-2016, 08:39 PM

I'm interested in your CA smog test results. I registered mine in AZ since I split time there and CA. I figured my 77 originally purchased in Illinois wouldn't pass smog test in CA.

Todd C · 04-24-2016, 07:37 AM

Quote:

Originally Posted by cdufault

I'm interested in your CA smog test results. I registered mine in AZ since I split time there and CA. I figured my 77 originally purchased in Illinois wouldn't pass smog test in CA.

I got NO results because of the two dead cylinders. He couldn't even do the test.

However, I did learn that my vehicle falls under the Federal guidelines for what smog equipment is required on it. It's very simple according to the smog guy. All that is needed is the PCV and the thermostatic air cleaner. The air injection pump and the other California specific stuff isn't required since the vehicle was originally sold outside of California.

I'm stuck on what to do next with this coach. I thought I might figure out what's wrong with the engine by removing the left head (#5 and #7 are the dead cylinders). However, I found nothing obvious, so the project is dead in the water. I'm trying to sell "as is, where is" for practically nothing, but no one is willing to buy and put money into the engine. I hope it doesn't come down to selling it to the recycling yard.

cdufault · 05-01-2016, 09:29 PM

Yeah, don't know what I'd do if in the same situation. Might look for a used engine from car-parts.com and find someone on Craigslist to install. Only thing I keep thinking is this is one of the few classic motorhome that won't rust, rot or develop the saggy roof syndrome; which is why people trick them out. It's also a very convenient mid-size rig that is is meant to be driven. Good luck which ever way you go.

NevadaGeo · 05-02-2016, 01:11 AM

I suspect there's a plot of land available for not a lot of investment in Mineral County or White Pine county that would have very nice view from your vehicle's new home. Only a few counties in Nevada require smog tests. But Nevada does have property tax on vehicles. You'd be surprised how short the wait time is in those DMV offices too. Don't you want to take a nice drive to the country?