Hi there - I have a slant six in a chipper, I believe from the early to mid 80's. I appreciated this forum's help 5 years ago when I got it running - here is that thread.

As an update, I did get it running. It has never run well, but it was serviceable. There were a whole series of small, irritating to find, electrical issues - shorts due to cracked insulators. I do not know if I got them all. The temp gauge reads hot all the time now (even when off), and the oil light seems to be on more than off, even when the dipstick reads full. When I last used it, it tended to run full throttle, or it would die slowly. That is not terrible when chipping, but not great. Over time the power seemed to decline, it would take longer to recover from a large tree. I don't think I used it at all last summer, so it has been sitting.

Now I am trying to get it running, and I would really like to get it running well. I got it started, but it does not run. There seems to be a bad exhaust leak - black smoke coming from the exhaust manifold at the fan end. What comes out of the muffler is black, then white. I don't see anything in the coolant. The oil on the dipstick smells of gas and seems thin. The coolant had drained out over the year or so since it last ran, I am still not sure where it is going.

The compression is still good - more variation than five years ago, but still between 120 and 150.

I don't know if it is typical, but the exhaust seems to be very intense - it comes out with a lot of force. The muffler points towards the ground and when I run it to chip I kill the grass in a 2 foot area - it burns it, then blows away the chaff. Starting it in the driveway blew away all the sand.

Where should I start? Five years ago SlantSixDan said the carb (Holley 1904) looked done. That would explain the less than great performance. Does anyone have any recommendations for a replacement?

I could imagine that the white smoke is just condensation from having sat. I am not sure what to say about the fuel in the oil. The fuel pump is new in the last few years and seems to work. Could it just be that I flooded it getting it started, and the mix is way off? The plugs are all black and smell of gas, so clearly the mix is off.

I have not checked the timing, or looked at the points yet. I did set the timing a few years ago, and replaced the plugs, points, wires, coil. All cylinders do seem to be getting spark. Would it be worth doing a leak down test (I would have to buy the tester)?

I look forward to hearing your thoughts!

Thanks in advance,

Bart

Well I would imagine that a replacement carb would be available or possibly a rebuild kit if you wanted to do that. These folks rebuild automotive carbs as well as other things so maybe they can help. http://www.then-now-auto.com/ I purchased a rebuild from Rock auto for my 80 Volare a couple of months ago and it was not too bad in price. What you describe certainly sounds like a fuel issue. As far as the coolant, check for obvious leaks. Sitting for a long time can allow even a slow minor leak to empty a cooling system. When you say you got it started do you mean running or just start and die or running rough? You can do a leak down test. Maybe if you have a local parts house they will have a loaner?

Have you pulled-off the valve cover and performed a valve lash adjustment?
If not, start there and re-touque the head as the first step.
Here is some additional info from the Slant 6 "How-to book:
DD

If a Slant Six engine stays running, has oil pressure, does not make loud knocking noises and does not quickly overheat at idle, you should fix any obvious leaks or problems then pull off the valve cover then check and adjust the valve clearances, as the next step in your evaluation process.

If the engine runs fine but has excessive blue tailpipe smoke, oil consumption, bad oil leakage, or loud knocking noises, check the following items before deciding to pull the engine for rebuilding:

Excessive blue tailpipe smoke:
• Crankcase oil level is too high—is the dipstick the correct length?
• Clogged or incorrect PCV valve.
• Incorrect carburetor base to intake manifold gasket.
• Carburetor base gasket is reversed and blocking the PCV port.
• Intake manifold PCV port or hosed clogged.

High oil consumption:
• Crankcase oil level is too high.
• Clogged or incorrect PCV valve.
• Oil pressure sending unit is leaking.
• Plugged or sticky piston oil control rings.

Excess oil leakage:
• Crankcase oil level is too high.
• Oil pressure sending unit is leaking.
• Old / split spark plug tube O rings and/or damaged spark plug tubes.
• Loose oil pan or valve cover bolts.
• Loose oil pan drain plug.

Loud knocking noises:
• Loose torque converter flex plate bolts (automatic transmission only)
• Worn or failing accessories (water pump, alternator, power steering or fuel pump)
Tip: Remove the fan belts and momentarily run the engine to test for accessory noises

Mechanical Lifter Valve Lash Adjustment

Slant Six engines produced up to 1981 used solid lifters and adjustable rocker arms to open & close the valves. There is a small amount of clearance called "lash" designed into this system and those settings (different clearances for intake valves vs exhaust valves) must be initially set, then periodically checked and adjusted during the life of the engine. Correct valve lash adjustment ensures smooth, quiet and trouble-free operation. Engine performance declines and the valve train becomes noisy as the valve clearances become wider with wear. The engine misses, or the idle becomes rough and you risk burning the exhaust valves if the lash is insufficient. Valve seat recession will reduce valve lash clearance.

The valve lash clearances are crucial to solid lifter engine performance and smooth operation, so it should be the first thing checked and adjusted when troubleshooting or tuning up a pre-1981 Slant Six. The job of lashing valves sounds intimidating, especially to the novice mechanic, but it is a straightforward process that uses common hand tools and can easily be performed in a couple of hours. The end results will be:

• Improved engine performance and economy.
• Smooth idle and better throttle response.
• Quiet valve train operation.
• Improved engine vacuum readings.
• Less chance of burning an exhaust valve or ejecting a push rod.

Doing the adjustment activity also gives you a chance to inspect and improve other items which affect overall engine performance and helps you decide if the engine needs additional work. The solid-lifter valve clearance adjustment activities reviewed here will do more then quiet down a ticking tappet or smooth out a rough idle. The job also includes:

• General inspection of the engine's top end. Is it clean or caked with sludge? Any broken valve springs?
• Inspect the pushrods. Have any jumped out of place? Are they all spinning as the engine runs? Are any bent?
• Inspect the valve stem seals. Are they hard and crumbly or soft and doing their job?
• Check cylinder head and rocker arm shaft bolt torque. Are all the head & rocker shaft bolts at the correct tightness?
• Inspect the rocker arm assembly for oiling. Is each rocker arm feeding oil to the valve and push rod?
• Clean and inspect the PCV valve & breather cap. Are they clogged? Are the hoses in good condition?
• Straighten and reseal the valve cover. Insure that engine oil is not getting past the valve cover gasket.

[Begin Tech Tip]
You will need the following items and tools to do a lash adjustment on a Slant Six:
• New valve cover gasket.
• Socket Set.
• Feeler gauges, .006" to .025" range minimum
• Torque wrench, pound-foot type
• Spray carburetor cleaner
• Solvent or engine cleaner
• Spray paint for the valve cover (optional).
[End Tech Tip]

Perform the lash adjustment on a hot, running engine. It can also be done cold, on a non-running engine. To do a running-engine valve lash adjustment, run/drive the vehicle so it is at normal temperature. Remove the valve cover and place a piece of cardboard or a drip pan under the engine, if you are worried about oil drops. You may need to disconnect some hoses and wires to get the cover off...

Thank you for your responses!

I believe the lifters are hydraulic, so I don't think I can adjust the valves. I had not thought to re-torque the head - I will try that.

I have not yet had it really running - just started, and it would go for a bit, then fade away. I feel like the mix is mostly to blame, combined with having sat for so long. There is definitely an exhaust leak at the manifold. Should I expect a fight to get the manifold off?

Thank you for the link, I will give them a call and see what they say. I did rebuild the carb a few years ago, but I am not sure the body is within tolerances anymore, so I am not sure a rebuild kit is enough. I have been reluctant to buy a new carb as I have read that they are likely to not be much better than what I have.

Where could I find a quality rebuilt carb?

Thanks again!

Bart

It depends...
Generally speaking you won't find a rebuilt carb, that is a quality unit if done by a commercial shop. You are better off rebuilding the one you have by yourself. AT the very least, if you must buy a commercial rebuild, it is wise to keep the old carb, so once you discover that the new one is junk, you have a good core to rebuild yourself.

I say this because there are plenty of stories about how the "commercial" rebuilding process is an assembly line process where all the same carbs are batched together, media blasted, and reassembled to a one-size-fits-all process. Such a process removes the corrosion protection from the inside and outside of the carb. It makes the carb look appealing but does not help you in the long run.

This may be an option depending upon what is on the engine right now. I personally would go this route over a commercial rebuild, and-but-umm, I would do everything I can to address the present carb's issues first...

https://www.carburetor-parts.com/Replac ... _3860.html

For help finding a suitable carb, remove the air cleaner and show us some clear, sharp photos, from multiple angles, of the carb you have now. Try to show us the front, back, left and right sides as well as a top view.

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Too many people who were born on third base actually believe they've hit a triple.

Thank you for your help. I will try to get some good pictures tomorrow.

I believe what is there is a Holley 1904, and it looks a lot like the one you linked to. I did rebuild it, which helped, but it is not great. That makes me wonder if I screwed up or the core is worn out. Because this is not in a car, the throttle is connected to a governor, and the vacuum is sealed off (it is sealed off on the distributor as well). I don't really care what goes back on, as long as it works!

Pictures tomorrow,

Bart

Not to be any more argumentative than absolutely necessary as I mentioned I got mine through Rock Auto and this outfit did the work:
https://www.uremcoinc.com/
They also sell direct but their direct price was higher than Rock Auto's. I have it on my Volare and the difference is dramatic. Runs very well, hot or cold and very responsive. i too have rebuilt carbs with mostly good results. Although it took a couple of tries for the Quadrajet. I would look into it as like me you probably have no way to measure and test all the places that leakage could occur. Not to mention possible blocked or partly blocked passages. However if you do decide to do it your self these folks are also an excellent resource. Willing to talk and answer questions.
http://www.thecarburetorshop.com/

Hi there - It took a little longer than expected to get the images, but here they are. The wetness you may see is WD-40 from getting the air filter off.

Hopefully I got useful angles. Let me know if there is something else you'd like to see. I really appreciate your help with this as I have little experience with carbs in general, and little success when I do mess with them. The choke shaft seems like it has a fair amount of end to end play, but I do not know what is appropriate. The throttle shaft has less end to end, but still is looser than I might expect. Neither has much side to side "wiggle" (perpendicular to the shaft) - it does not feel like the bores are super oversized, just that they are not tight at all.

Maybe these numbers mean something? 1984 seems like the manufacture date. Here are some overview shots: I will put more in the next post.

Thanks for your help

Bart

Here are some more images going around the carb body.

Some more, starting to look down the throat.

OK - The last of the photos. I wonder if the linkage between the governor and throttle should be adjusted. There is quite a lot of slack in it, so the throttle can bounce through about 1/2 of its movement. In other words, at fully open the plate is at 90°, and at fully closed it is at 0°. But when the throttle control to the governor is at low idle, the throttle plate has no restraint from swinging between 0° and 45°. Maybe the dynamics of a running motor make this irrelevant?

I can see how to adjust the linkages, but not really sure what my goal should be in adjusting them.

Thanks again for your help

Bart

plymouthcranbrook - I would be happy to buy a decent remanufactured carb. One of the problems I have is trying to figure out which one. Because this is not from a car, I can't search a place like rock auto very easily. Sometimes I can cheat by using a car I know has a slant six, but for the carb it seems like there were a lot of options and I do not know what is likely to work or not.

As I recall, I used a rebuild kit from http://www.thecarburetorshop.com when I did it a few years ago.

Thanks again

Bart

Looks like that Holley 1904 carb was actually original equipment; if you'll search here for "6873" (the carb list number) you'll find it.

Don't know that this helps you any, but it's interesting.

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Too many people who were born on third base actually believe they've hit a triple.

I would suggest calling and speaking to Jon at the Carb shop. He knows all and share it. Always ready to assist on the AACA site with carb questions. If there is a way to get one he will know it.

Also just did a google search and this is it. Don't know quality but if a 1904 is what you need they seem to be out there.

https://www.google.com/search?q=holley+ ... e&ie=UTF-8

UREMCO specifically mentions Industrial applications on their first page if you read it all as well