Blown head gasket?

[Engr_Jim]

I own a '65 convertible t-bird with a stock 390 and no, I'm not a mechanic. Lately the car has started to overheat more and I've got some two badly fouled plugs. I see no signs of antifreeze/oil cross-contamination. I've flushed the radiator. I also have poor power and slow acceleration.

My question is partly about the current problem and partly deciding how far I should go with the engine - that has never been rebuilt.

I can certainly run some compression checks but will that isolate a blown head gasket vs something more serious in the head? I also wondered what happens if I go to the trouble of replacing the head gaskets with the engine in place and still have poor compreesion because of either a head crack or simply worn out rings - and then need to pull the engine for a rebuild? I think I'd be up for tearing into the head but not pulling the engine (just not sure) as I'd need to then get it to a shop for rebuilding, etc.

Advice?
Recommendations?
Just wanna poke fun at my extensive knowledge?

All welcome,
tbirdjim in Denver

 

[4-5-6-birdman]

Lots of possibilities...let's start here..

First off when you say fouled I assume they are badly oil fouled to the point of not firing anymore? The compression test is the easiest and first test you should run. Check all eight cylinders and record the results, you should not see more than about 10-15% variance across the board. Post the results if you can.

Is the Bird consuming oil or having excessive blowby or pushing oil out anywhere? It is possible you just dealing with a flat worn out engine, if that's the case doing the head or valve seals will be a waste of time and effort.

There is one other diagnostic test that will tell more than the compression test and that is the leak down test. You can do a search for leak down on the web and it will show you the principal and how to make your own. It does require you have an air compressor however.

Probably at this point run the compression test and post the results and I can advise you from there. Good Luck

 

[boaterbob]

I would make sure i was getting good spark to the two plugs. Corroded cap or bad wires would also make plugs foul.

 

[Engr_Jim]

First off when you say fouled I assume they are badly oil fouled to the point of not firing anymore? The compression test is the easiest and first test you should run. Check all eight cylinders and record the results, you should not see more than about 10-15% variance across the board. Post the results if you can.

Is the Bird consuming oil or having excessive blowby or pushing oil out anywhere? It is possible you just dealing with a flat worn out engine, if that's the case doing the head or valve seals will be a waste of time and effort.

There is one other diagnostic test that will tell more than the compression test and that is the leak down test. You can do a search for leak down on the web and it will show you the principal and how to make your own. It does require you have an air compressor however.

Probably at this point run the compression test and post the results and I can advise you from there. Good Luck

Thanks for the advice. Finally got around to running the compression test and the results were all 140-150 psi. The manual indicates 170-210 at sea level is appropriate. I'm in Denver, still those seem very low. The plugs are oil-fouled and the engine leaks oil (from where I'm not sure). It doesn't generate much power at all. Sounds like a 'flat worn out engine' doesn't it?

If so, that leads me to the next step - the overhaul. I'm not sure how much I can handle in the rebuild. Do most folks pull the engines themselves with a rented crane and somehow get it to a shop for rework? Is that too big a job for a handy mechanic but one who usually just does moderate repairs?

Thanks in advance!

Jim
'65 T-Bird Convertible in Denver

 

[4-5-6-birdman]

Thanks for the advice. Finally got around to running the compression test and the results were all 140-150 psi. The manual indicates 170-210 at sea level is appropriate. I'm in Denver, still those seem very low. The plugs are oil-fouled and the engine leaks oil (from where I'm not sure). It doesn't generate much power at all. Sounds like a 'flat worn out engine' doesn't it?

If so, that leads me to the next step - the overhaul. I'm not sure how much I can handle in the rebuild. Do most folks pull the engines themselves with a rented crane and somehow get it to a shop for rework? Is that too big a job for a handy mechanic but one who usually just does moderate repairs?

Thanks in advance!

Jim
'65 T-Bird Convertible in Denver

Your compression numbers are not that bad. The most important thing is +/- 10% across the board aside from totally low numbers of which you have neither. BoaterBob may be onto something, especially with 2 fouled plugs and the readings were good on both of those cylinders? It is also possible that you have lost or really bad intake valve seals on those 2 cylinders. Pretty unlikely since valve seal failure or fatigue is generally global. In your earlier post you said 2 fouled plugs and now you state the plugs are oil fouled, is that all the plugs? How much oil is it burning and does it smoke on free revving or only when you first start it? If you have never pulled an engine and don't have a friend or someone that can help you with knowledge or experience you might want to look at a shop to do it. Before you get that far you should ensure you know what you have. Good Luck!

 

[Engr_Jim]

Your compression numbers are not that bad. The most important thing is +/- 10% across the board aside from totally low numbers of which you have neither. BoaterBob may be onto something, especially with 2 fouled plugs and the readings were good on both of those cylinders? It is also possible that you have lost or really bad intake valve seals on those 2 cylinders. Pretty unlikely since valve seal failure or fatigue is generally global. In your earlier post you said 2 fouled plugs and now you state the plugs are oil fouled, is that all the plugs? How much oil is it burning and does it smoke on free revving or only when you first start it? If you have never pulled an engine and don't have a friend or someone that can help you with knowledge or experience you might want to look at a shop to do it. Before you get that far you should ensure you know what you have. Good Luck!

Thanks for the analysis (you and BoaterBob)!
Two plugs are fouled the worst and even seem wet with oil. The rest are also very dark. It blows black smoke and when first started or reved up, I'll can turn the concrete under the pipes black. As for how much oil it's burning it's hard to know because it is also leaking oil. I put it up on jacks this weekend and it seemed as if every fluid (except antifreeze was leaking - PS, Tranny, Oil everywhere).

I've never pulled an engine, so it sounds like it may be beyond me. I was also thinking of getting involved with the local T-Bird club - perhaps another source of advice (or assistance .

Thanks
Jim

 

[Joe Vandatta]

390

I have a 390 in a 66 Bird and my compression runs the same as yours (cold engine) runs fine on regular gas and uses very little oil at 110,000 miles. I went to a little hotter plug as I do a lot of local driving and the plugs stay clean.
I have the stock Ford 4100 carb which continues to do a good job. I recently installed the Pertronix ign. system and is doing well also.
As 4-5-6 says, I would take a good look at your ign. system and carb. --black smoke means too rich.

 

[Engr_Jim]

I have a 390 in a 66 Bird and my compression runs the same as yours (cold engine) runs fine on regular gas and uses very little oil at 110,000 miles. I went to a little hotter plug as I do a lot of local driving and the plugs stay clean.
I have the stock Ford 4100 carb which continues to do a good job. I recently installed the Pertronix ign. system and is doing well also.
As 4-5-6 says, I would take a good look at your ign. system and carb. --black smoke means too rich.

Thanks Joe, your message gives me hope! Before I commit to an overhaul I did want to try a number of things and the list is now longer with your suggestions:
1) Consider the Pertronix system or at least a hotter plug.
2) Take it to the car wash and clean off the engine top and bottom and the tranny and find the source of all those darn leaks - its not good when the oil pan and the tranny pan are actually wet with their respective fluids.
3) Check the timing and mixture settings - it does run through the gas.
4) Need to put in a new steering column bushing and shift lever cause I have the 'hold the shift level to start' it problem.

Joe - is your engine original or rebuilt? Mine indicates 99K miles and I have no way of knowing but it could have turned over though the rest of the car shows only moderate wear and is all original - it just continues to amaze me how much survives after 40 years!

Jim
'65 T-Bird Convertible, Lt. Blue

 

[Engr_Jim]

I have a 390 in a 66 Bird and my compression runs the same as yours (cold engine) runs fine on regular gas and uses very little oil at 110,000 miles. I went to a little hotter plug as I do a lot of local driving and the plugs stay clean.
I have the stock Ford 4100 carb which continues to do a good job. I recently installed the Pertronix ign. system and is doing well also.
As 4-5-6 says, I would take a good look at your ign. system and carb. --black smoke means too rich.

Joe,

Forgot to ask: how do I select a 'hotter' plug? Do I just ask for a hotter one at the Auto Parts store and will they even know for a '65?

Thanks in Advance

Jim
'65 T-Bird

 

[Joe Vandatta]

390

Jim,
First of all, it is a good idea to steam clean the engine to make it easier to find the leaks. Strong suspects on the engine are rear main, fuel pump mounting gasket, seal in timing chain cover --- that is if your pan gasket is okay.
As for my engine, it is original, I bought the car new and have maintained it myself.

The spark plugs I am using are Champion RF11YC. You can get them at any parts house.
You can also get a repair kit for the 4100 at Napa, I think you have problems there.

I would also install new pug wires and ck. the dist. cap, including the sockets that the wires go in, I have found a problem there.

The comp. figures sound okay and the engine sounds like it can be saved.

Good luck,
Joe

 

[Joe Vandatta]

390

I forgot to ask how much oil pressure you have. You should have at least 30 lbs hot at 2000 rpm.
Joe