The Stovebolt Site Forums The Shop Area Engine Shop engine vacuum question -updated with pictures

I have a 265 v8 that has been sitting for 30 years. I am trying to get is started. So far it has not fired even one time. My question is how much vacuum should it generate while cranking with the starter?

I think I have covered all the basics but any other suggestions and comments are welcome. Thanks.

Not very much cranking. Do you have spark at the plugs? Might try just a little fuel down the carb throat. Does it sound like it has compression or like it free wheels when turning?

Gotta have spark, fuel and at the right time for it to start.

Check to see if the rotor turns in the distributor when the engine cranks. If it does, see if the rotor points to #1 when the piston comes up to the top.

What all have you done to get it ready to start? New spark plugs, new points, condenser, distributor cap and rotor? What gap did you set the points at? What gap for the plugs?

I have spark at the plugs. All new tune up parts. Timing is set with slight advance with cap #1 just to the right of rotor when at TDC. The rotor is turning. Points and plugs set to MFG spec but off the top of my head I cannot remember. All new fuel lines, tank, fuel pump. Fuel bowl in carb is full when the top of carb is removed. Accelerator pump is working when the throttle is opened. I could not get it to fire even with ether. That is why the vacuum question. Could a huge intake leak cause similar symptorm?

No. If you tried starting fluid and it didn't fire then for some reason the plugs aren't firing under compression. Should belch, back fire, do something if the wires are in the wrong order when you send some ether down the carbs throat.

Only reason I can think of that starting fluid won't create some kind of response is if no spark is actually reaching the plugs. Or if there is not enough compression. Might run a compression test, and make sure all the valves are moving and not stuck.

I will do a compression test in the morning and update. Thanks Roy.

Compression test results below. Also, while turning the engine over at one point I got a little bit of what I think was lifter tapping. Is it possible the low compression could all be due to the valves or is it more likely a problem with the rings as well? Does anyone know what kind of compression readings I should be seeing?

1 = 37
2 = 30
3 = 25
4 = 30
5 = 20
6 = 10
7 = 40
8 = 45

Either is not a good judge to go off of. I have seen good running engines not fire on. Try turning the distributor while cranking, get it to backfire or buck or do anything. If it still won't hit, hold the throttle wide open and crank for a bit incase its flooded.

How did you get the compression readings?

was the throttle wide open?
all the plugs out?
each cylinder had four or five revolutions with starter?
dry or wet cylinders?

If all the above were met, you are way low on compression. Have you soaked the cylinders with penetrant oil to loosen the rings?

Joe

When I did the compression test, the throttle was closed and all plugs were in accept the one being tested at the time, I did do several revolutions until the gauge stopped climbing. We have been spraying penetrant intermittenly into the cylendars for a few months now.

Do you think it will change the readings very much with the throttle open and all plugs out?

remohbill, Over the years I have enjoyed the challenge of reviving a long stored engine and had a lot of opportunities to do so on tractor and automobile,stationary,marine and even 1 little aircraft.
Engines that have rested,exposed to our humid air here will have the carbon deposits that are on comb chamber and valve surfaces changed to many times a corrosive material that will pit the areas in contact.The ones that hurt most in a case like yours, I think, is the sealing surfaces of the valves and seats, plus any residue prevents proper sealing resulting in leakage and lowered compression at cranking speed.
The greatest aid in starting an engine that has been stored like this is an increase in cranking speed,which effectively raises the compression by reducing the time available for leakage.
If the vehicle can safely be moved/driven the easiest way is to push start in a lower gear.Less than 15 MPH in 2 nd gear is usually sufficient.When started this way the slow starter is not used so it doesn't lower the voltage available for ignition.
If push starting is not an option, I have don a temporary rewiring of the starter to provide 24 volts to the STARTER ONLY.Easily done by lifting the wire on bat post at the starter solenoid that feeds the vehicle and with a jumper make sure it sees only one battery while a battery is added to provide 24 v for the starter.Lift the starter pull in wire at the solenoid and actuate the starter with a screwdriver or a jumper on this terminal when ready to crank.
Probably when the engine starts and runs for 5 minutes sometimes less, it will be able to start as normal as the running will clear the seat sealing areas and the engine will be freer to turn also.
Be aware-non gasoline additives dumped in a cyl can kill the spark plugs and our modern oils will do it.You should consider new cheap plugs to get started or use your torch to clean the old ones by heating the insulator nose to incandescence when it will be naturally cleaned.Small torch and great care please and don't forget the anti seize.
I think your comp test tells us the valves are moving and sealing some--not stuck open. They won't stick closed unless something bends or breaks.Lifters that have leaked down while stored will cause wrong valve timing, reduced compression, reduced valve opening and the click you hear.When it runs things will change.
Starting fluid lights easily but I have seen weak engines that would do little until fed some gasoline through the carb throat.
Good luck and keep us posted

I would invest in a gasket set and open that baby up, if only for inspection and cleaning. It might be rare/valuable enough to freshen up: hone, rings, bearings, valve job, etc.
How many miles on it?
Double-check your timing of #1 at TDC of compression stroke.

cm

How much do you know about the history of this engine? Are you absolutely sure that the distributor is in correctly? Usually as the process goes, you will hear the odd explosion and then it will start to speed up when turning over. This is becuase some cylinders are partially firing.

I would check to make sure that when #1 Cylinder and valves are ready to fire, the points are about to open and the rotor is pointing to #1. There are no big mysteries here. When all that is checked I would dump a couple of ounces of gas down the carb and give it a shot. Personally I would stay away from the starter fluid.

Those compression readings are wayyyy low even if the throttle plates are closed. I doubt you'll get it to fire on compression like that even if pushing it.

Buckle down and open that engine up. Get ready to put some new rings in, clean the cylinders good, most likely the valves are carboned up to the point they aren't closing good.

May even have some broken rings in it if it was stuck a little before turning. You can do a cylinder leak down test to see if the engine is leaking compression by the rings, or through the valves.

I am told I can check the timing with a timing lite with just the starter turning the engine - if so I will verify again. After that, we are going to try and start the engine again and if still no luck, off come the heads. Thanks, some really good advice from everyone. I will be watching throughout the evening if others have additional comments. Thanks again.

If your distributor is installed 180 deg off, the timing check will show it as being correct. If this is the case you could just re-install the wires on the cap to correct it. With the valve cover off on the #1 side, you should see that as you rotate through where #1 should fire, the valves on that cylinder should remain absolutely still. If they move, it is not set up correctly.

If your timing was 180 off, 1 rotation of the crankshaft, I don't think I would rewire the dist cap to match. Seems to me I remember doing that on my first rebuild back in 72 and something about the dist not being right blocked oil to the Mains.

It's not that involved to check and recheck the timing and if it is off pull the dist and rotate the crank on turn and put it right. Just one of those lessons I learned the hard way. If I'm wrong someone correct me, I'm a big boy I can take it.
Larryw

The way that distributor position could affect oiling was only with the 55 and 56 265 engines.The groove for oil in the lower part of the dist housing extended only part way around then ended with a blanked space that stopped the groove.57 and later the groove was extended all way around the dist so it passed oil no matter where it was located-rotation wise.
The correct positioning for the 55 and 56 was with the vacuum advance unit pointing over the outer front corner of the right valve cover.If deviated from this a lot oil supply would be blocked to the right bank lifters and rockers.Also these 2 year engines required a short(part way around) groove in the rear cam journal.Solid lifter cams had a shallow groove and hyd had one about 5 or 6 times deeper.For a while the low HP engines were supplied with solid lifters from the factory.

Today I checked the timing again by removing the valve cover and verifying valve positions of #1 while at TDC. Then while turning over I set the timing to aout 4' BTDC with an inductive timing light. Previously it had been at about 4' ATDC. While turning over, we did notice the valve operation was a little erratic. Sometimes the rods would spin and sometimes not. Also, the valves seemed to not close the same amount each time. I was turning the engine over at app. 106 rpm and poured gas down the carb and still nothing. We put a generous amount of oil down in cylendar 1 and did compression test again. It went from 45 yesterday to just about 50 today. Bob Taylor above knows his old distrubutors. My engine is a 55 265 and the oil groove he mentioned above is exactly like what I have. The groove only goes part way around. Any way, we got one head off today. We got hung up drilling our an exhaust manifold bolt. Pictures of the valves are linked below.

http://s1178.photobucket.com/albums/x376/remohbill/

Remohbill, The heavy carbon we see says much oil burning but these early engines were notorious for oil consumption as built with 1 quart in 1000 mi being considered good.
They didn't use a positive seal on the stem and the earliest had shorter valve guides than later in the year 55.This combined with lots of oil in the valve covers made for high oil consumption.
We learned early on that a must when doing valve work was to install Perfect Circle type seals---the exact type that GM finally went to in about 1968.Your heads require cutting the guide tops to install them but is a 30 second per guide job with the appropriate tool in a 1/2 inch drill.
55 V8 blocks are getting scarce as they were different than any other year having no boss on the block for an oil filter.
A clue as to whether this oil is being passed by the rings can be had by observing the piston crown --if much oil is being allowed up by the rings the piston will be washed clean of carbon in the area nearby.This is nearly always found around the periphery of the piston top and it will be juicy with oil.