Today's Conundrum

[Bayless]

Also, you should always remove all the sparkplugs for a compression test and be sure to block the carb throats fully open.

 

[SaxMan]

Well, to add further insult to injury, the gasoline smell returned. When I went to drive the car around to burn off some gas, I found that the taillights and tag light wouldn't illuminate when the headlights came on. Brake lights are fine. Turn signals are fine. Hazards were a bit nutty. If I didn't twiddle with the switch, only the right signal would come on. I was able to get both lights to go on flash. I was able to drone around the neighborhood with the hazards on....hopefully long enough to get rid of the gasoline smell. Of course when I got home and check the gas cap, it wasn't completely secured :sour:

Do you guys suggest wood or concrete walls to bang your head into?

 

[AN5Sprite]

Do you guys suggest wood or concrete walls to bang your head into?

I only use the finest tone-woods, Bosnian maple and Italian spruce for noggin-knocking.

 

[SaxMan]

The leakdown tester finally came in today. As I'm reading through the instructions, it indicates that to test the cylinder properly, you need to have the piston at top dead center (TDC). How do I turn the engine manually so that I can do this? They also indicate that the engine should be run at least 10 minutes before doing the test. I really don't want to risk doing any more damage by running the motor, though.

In the instructions, it says if you have compression loss in adjacent cylinders, it is a head gasket issue. We already know from the compression test that my problem is with significant loss of compression in the number 2 and 3 cylinders. It says if you have multiple problems, only the most prevalent one may show up on the test. I'm guessing that I have some valvetrain issues as well. I figure it can't hurt to see if any other symptoms come to the fore with the leakdown test.

 

[JPSmit]

Take a screwdriver, or a longer piece of something. remove the first spark plug. (closest to rad) insert the screwdriver end so that it touches the top of the piston. rotate the engine by hand until the screwdriver just <just!> starts back down. If you go too far, rotate it all the way around again - if you turn it back it will take up the slack in the timing chain and won't be quite right.

 

[SaxMan]

Take a screwdriver, or a longer piece of something. remove the first spark plug. (closest to rad) insert the screwdriver end so that it touches the top of the piston. rotate the engine by hand until the screwdriver just <just!> starts back down. If you go too far, rotate it all the way around again - if you turn it back it will take up the slack in the timing chain and won't be quite right.

Okay...so where do you rotate the engine by hand? from the water pump pulley?

 

[AN5Sprite]

Pulling on the belt should do it...

 

[nomad]

Easy way is to put the car in 4th gear and roll it using the front tire. Car is light and with plugs out it will roll very easily. When you run out of rolling room, take it out of gear and roll back to starting point. The reason the leak down tester says to run the engine is to get oil up in the rings which would give you a better and more accurate reading. I'm betting that the problem will be evident as soon as you put air to the two middle cylinders though.

Take heart, its a long winter...I'm sure it will run again!!

Kurt.

 

[SaxMan]

So, I got the leakdown tester out, took out the plugs, used the 4th gear trick to get TDC on the cylinder (thanks, Nomad!), because I couldn't turn the engine any other way, go to hook up the leakdown tester to my compressor and...I have the wrong connector. The leakdown tester has a male connector, and the end of my compressor has as 1/2" threaded connector. I needed a female connector or a threaded-to-female connector. Man, I hate when you get into something and find out it has the wrong connector on it. Reminds me of this one crazy weekend...

I did pull off the valve cover. The valvetrain looks to be in pretty decent shape. I'll post up pics soon.

 

[SaxMan]

A trip to Home Depot solved my problem of having the wrong type of connector. Here's the results:

Cylinder 1: When compressed air was applied with the cylinder at TDC, compressed air escaped from Cylinder 3
Cylinder 2: Compressed air applied caused air to escape from cylinder #4
Cylinder 3: Compressed air applied caused air to escape from cylinder #1
Cylinder 4: Curiously, this cylinder had no problems when air was applied

With the valve cover gasket off, I was able to see when both valves were in the closed position and I confirmed the TDC position of the cylinder with a screwdriver. Wouldn't the results with a head gasket break mean that air should escape from consecutive cylinders and not alternating ones?

 

[JPSmit]

is there air escaping through the valves in which case it would follow the firing order?

 

[SaxMan]

That's a possibility. I'm going to redo the leakdown test today, since I didn't do it properly to get an accurate readout on how much loss I'm having. Whether it's valves or the head gasket, I'm thinking the head needs to pulled to see what's going on.

 

[Trevor Jessie]

When you say the valves were closed ... you mean that the rockers were exerting NO pressure on the valves at all. I hope I'm not insulting your intelligence, but since this is your first time I thought it'd be prudent to double check.

 

[Jim_Gruber]

You do need to rotate the engine to TDC for each cylinder you test.TDC for each cylinder IIRC.

 

[SaxMan]

Yes -- I had each cylinder at TDC with the individual valves for each cylinder in the "closed" position (both valves at the top of their travel).

Considering I'm still a relative newbie to the mysteries of auto repair, and with as many questions as I ask around here, I never take offense or insult to any follow up questions.

For instance, if I posted that my car wouldn't start, I would not take offense if someone asked me if I had put the keys in the ignition.

 

[SaxMan]

Update: I discovered the value of re-reading the instructions. I misinterpreted one of the instructions (which were rather sparse) concerning how to set the gauge for your baseline reading. Result: Values that were consistent with the compression test I ran and consistent with a head gasket leak.

Cylinder 1: 30% loss (still in the good range on the gauge) and no apparent leakage to other cylinders
Cylinder 2: 70% loss and definitely leakage into Cylinder 3
Cylinder 3: 60% loss and leakage into Cylinder 2
Cylinder 4: 40% loss (borderline good to moderate) and some leakage from the valvetrain, possible leakage into cylinder 3

I think my problem last night was I was pumping too much air into the cylinder head and it was going wherever it could.

I also learned that if you are going to do the 4th Gear trick to turn the engine, make sure you take the car back out of gear if you are going to increase the psi to hear for leaks. I didn't know you could run a Spridget on compressed air!

To me, these results confirm what we've been kicking around since the start of the thread: Head Gasket with some additional valve adjustments (replacements?) needed.

 

[Trevor Jessie]

You may be able to replace just the head gasket and valve seals and get by. However, I'd go ahead and have the head rebuilt complete with exhaust seats and new guides. Oh ... and check that the brass plug in the head has not recessed.

 

[Jim_Gruber]

Trevor isn't the brass plug between # 2 & 3?

 

[Trevor Jessie]

Yes, between 2&3. I have a head here on the shelf with that issue. When I pulled it from the parts car it was obvious that the previous owner was trying all sorts of head gasket goop to keep the head gasket from blowing.

 

[Jim_Gruber]

IIRC the 1275 that will go into Bugsy II when I leak tested appeared to have low conpression between 2 & 3. Also started losing oil going to a qt every 200 but not losing it out the back end of the engine. I need to repeat the test when the time comes and will at least get head skinned and new seals and valves done. It's a '69 hi compression that was a great runner before PO had opportunity to acquire a 1380 and a 5 speed.