Blown Head Gasket Between Cylinders... I Think

[Guest Mike]

STATS: SBC 350 with Edelbrock Performer RPM heads and approximately 10.5:1 CR.

 

I think I've blown a head gasket between at least two cylinders. I threw a belt a few days ago and the engine heated to 250 F, but only for a few moments. Of course, I shut it down immediately and let it cool. I'm hoping the heads aren't warped!! Anyway... this problem followed the thrown belt.

 

It definitely feels like pressure is leaking between cylinders. I once drove an old 302 CID Maverick with this problem and it feels just like that one did. No water is in the oil and no exhaust gasses are in the crank case or in the coolant. It's not overheating... just has half the power it should have.

 

Here's my question: Since I'm currently out of funds... can I safely drive the car for a week until I get my next paycheck?

 

BTW, the old Maverick was my fathers' and he drove it with the leaking head gaskets for years... really. When he passed away, I helped my mother find a buyer for the car. This kid replaced the head gaskets and it ran just fine.

[LeeMS]

Mike not sure what you mean by "feels like pressure is leaking between cylinders" it should feel like a couple of dead cylinders, rough at idle, vacuum signal bouncing a few inches. Would not recomend driving .I've see block damage resulting, tourching or melting away the metal between clyinders.

Do some checking and find out whats going on first. Comp test, leakdown,at least a vac gauge test.

[Guest Mike]

Mike not sure what you mean by "feels like pressure is leaking between cylinders" it should feel like a couple of dead cylinders' date=' rough at idle, vacuum signal bouncing a few inches. Would not recomend driving .I've see block damage resulting, tourching or melting away the metal between clyinders.

Do some checking and find out whats going on first. Comp test, leakdown,at least a vac gauge test.[/quote']

 

Thanks LeeMS. Yes... this is exactly what it feels like. I currently don't have a vacuum guage or a compression gauge for any testing.

 

I just bought this car a few days ago. Since I haven't worked on my own cars for years, I have no gauges and few tools. I can't afford to buy anything at the moment, or spend $$$ having someone else test the engine, or continue paying for a rental car.

 

I just spent $250 on car rental and $700 on emergency surgery for my dog. Before all this, I spent about $400 on tools so I can do some basic auto work. I've lost about $1500 income due to caring for a sick family member and I'm completely $broke$. To top it all off... my daily driver quit on me last week. If I call my boss and tell him I can't come to work for a week, he'll go completely insane. I was hoping this car could get me to work until I can repair my daily driver... then finish the updates on this one.

 

Damn... I think I'm ranting... or is it whining? Not sure... but the bottom line is, if I can't drive this car, I'm screwed.

[A. G. Olphart]

If you have no mixing of fluids, you can drive the car. Perhaps not a great idea, but which is more important, that engine, or your job?

 

If you pull all the plugs and they all look to be about the same color, you should be good to go. If two adjacent plugs are fouled/ quite a bit darker than the others, odds are good the gasket is gone between those cylinders. You may be able to baby it along for quite a while (remember the Maverick?); No long hills, no high speeds, no quick starts. With minimal throttle, you will get minimal cylinder pressures and drag it along as long as possible, hopefully untill you can afford repairs/new engine.

 

Car pool?

 

Overheating is one of the primary symptoms of a blown head gasket; with luck, you may just have ignition troubles.

 

 

.

[Pop N Wood]

You need to worry about getting water in the oil and oil in the water.

[Guest Mike]

If you have no mixing of fluids' date=' you can drive the car. Perhaps not a great idea, but which is more important, that engine, or your job?

 

If you pull all the plugs and they all look to be about the same color, you should be good to go. If two adjacent plugs are fouled/ quite a bit darker than the others, odds are good the gasket is gone between those cylinders. You may be able to baby it along for quite a while (remember the Maverick?); No long hills, no high speeds, no quick starts. With minimal throttle, you will get minimal cylinder pressures and drag it along as long as possible, hopefully untill you can afford repairs/new engine.

 

Car pool?

 

Overheating is one of the primary symptoms of a blown head gasket; with luck, you may just have ignition troubles.

 

 

.[/quote']

 

Without a job, I'm more screwed than if I damage these heads. I did check the plugs and they're all a nice light beige color with no oil or water residue and no appearance of washing or oddball burning.

 

I was intending on taking all side streets and avoid highway speeds... just keep it under 40 and easy on the throttle. Of course, watch the oil and water gauges while constantly listening for any aural anomolies. Also check the fluids before I start it each time.

 

The main difference between this car and my fathers' Maverick is his had iron heads while this has aluminum. I'm hoping this won't matter.

 

I'm not aware of any car pools, but I can check Monday. Maybe I'll get lucky and won't have to drive it after that.

 

It's not really overheating... just running a bit warmer than I like in about the 200 degree range. It only overheated that once because it threw the water pump belt. Too, the guy that sold me the car had 100 percent antifreeze in the cooling system. After adding 1.5 galons of distilled water and a better flex fan, it now runs about 10 degrees cooler. I intend to install a Griffin radiator or other brand of like design to further enhance cooling. With the new radiator, a new 160 degree thermostat with by-pass, and a better fan shroud, I think it'll be okay. This car seems to run better before it reaches peak temperature... at about 160-170 degrees. In fact, every "old school" performance car I've owned has run better at cooler temperatures after tuning the carb(s).

 

I suppose it could be ignition, but I don't think so. It has an HEI and if the... what's it called... controller thingy is bad, won't the engine just die? The wires seem okay but I haven't tested them yet. You're right though. I could be misdiagnosing the problem. Like I said earlier, I haven't worked on my own cars in a long time.

 

Thanks for your help A.G.!!!

[Guest Mike]

You need to worry about getting water in the oil and oil in the water.

 

Hi Pop N Wood,

 

Yes, you're right. I must be very cautious. I've checked the oil and radiator. There's no exchange of fluids noted. There are no exhaust gasses entering the crank case or the radiator. All the plugs are an evenly colored light beige with no oiling, washing, or weird burning. I think it's okay for now.

 

Of course, if I can find another way to work, that's the better/safer solution. The problem is I'm just in a bind at the moment. My funds are exhausted from multiple unplanned issues and my daily driver quit. I didn't want to sink any more $$$ into the old green bomb... a '91 Mazda 626 with a fender dent, bad paint, and cracked dash... a car so ugly Kermit the Frog wouldn't be caught dead in it. It seems now I have no choice but to repair the thing. Oh well...

[jbk240z]

What's wrong with the 626?

[Ansel Marrow]

This sounds like some similar problems Ive been having with my 305. A pal of mine thought the head gasket was blown, or worse yet, a cracked cylinder head. Making about half the power since I got it, very dissapointing first drive.

 

Whats a good coolant/water mixture to use in high-temp environments? Ive been leaning towards 70/30.

[Paz8]

You should never go more than a 50/50 mix, most car manufacturers go with 40% antifreeze, 60% water.

[Guest Mike]

What's wrong with the 626?

 

I started it the other day and ran for a couple seconds. It made a loud pop, then died. It turns over and tries to start, but it won't. It's not making any odd noises. I need to have it towed and looked at... but I'll have no $$$ available for a few days... too many things hit me at once recently.

[A. G. Olphart]

"This car seems to run better before it reaches peak temperature... at about 160-170 degrees. "

 

Mike, you don't have the worst/solid symptoms of a blown gasket; the rougher running when hot might just be too much advance for the extra temperature (any sound of preignitioon/detonation?).

 

Do you think that you might have trapped an air bubble in the cooling system when it had the original problem? That can cause overheating too.

 

 

.

[Guest Mike]

This sounds like some similar problems Ive been having with my 305. A pal of mine thought the head gasket was blown' date=' or worse yet, a cracked cylinder head. Making about half the power since I got it, very dissapointing first drive.

 

Whats a good coolant/water mixture to use in high-temp environments? Ive been leaning towards 70/30.[/quote']

 

I hope your heads are okay. Depending on what's on there, it could be an expensive repair. I wish you the best of luck.

 

On the outside chance that my heads are bad, I'll probably just buy some iron Vortec heads. They're about 40 pounds heavier than aluminum, but I can buy a new set for about $400 and they'll perfrom better than my current heads. I'm expecting to replace my carbs/intake and exhaust system soon so the added cost of those is moot.

 

I think a 70/30 mix is about right. I would add another lubricant/corosion preventive though. There's another product available that's suppose to run much cooler than any antifreeze mix... even cooler than 100 percent water. I can't remember the brand but I'll post that later. I saw it at one of the large auto parts stores and asked about it but no one had used it. The down side is that it has no antifreeze properties so it must be drained and replaced with an antifreeze mix every winter. This stuff costs $20 per galon but, if it really works, I guess it's worth the cost. Again, I'll do some research on this stuff and post the brand later.

[Guest Mike]

You should never go more than a 50/50 mix, most car manufacturers go with 40% antifreeze, 60% water.

 

Yeah... it really surpised me when I saw what was coming from the radiator overflow... pure oily yellow antifreeze. After adding 1.5 galons of distilled H2O and a better flex fan, this thing runs at least 10 degrees cooler.

[A. G. Olphart]

Mike- I forgot to mention that with a leaky head gasket, the harder a person works the engine, the hotter it gets. (Higher compression pressures shove more exhaust gasses into the water jacket). So if your car is stable at a somewhat higher temperature than you are used to, probably not the gaskets.

 

 

.

[Guest Mike]

"This car seems to run better before it reaches peak temperature... at about 160-170 degrees. "

 

Mike' date=' you don't have the worst/solid symptoms of a blown gasket; the rougher running when hot might just be too much advance for the extra temperature (any sound of preignitioon/detonation?).

 

Do you think that you might have trapped an air bubble in the cooling system when it had the original problem? That can cause overheating too.

 

 

.[/quote']

 

There is just a tiny bit of pre-ignition... just barely noticeable and only at WOT when it doesn't kick down a gear. It's so faint that it took awhile to ascertain that it's really happening. I've been adding a gallon of Xylene per tank of fuel and this helps. Given that it doesn't seem to have enough torque at upper RPMs and with the faint pinging, I assumed too much CR for 93 octane and too little timing advance... a quick fix by some mechanic trying to put a band aid on the pinging created by pump gas and high CR. If I must back the timing advance down even more, I'm afraid it'll run like dog poo. It's just not set up right. I really need to run a full diagnostic on this motor before doing anything... starting with a compression test. If my suspicions are correct, I'll be increasing timing advance and using a lot of tetraethyl lead.

 

I don't think it has a trapped air bubble... at least not now. When I added the water, the coolant seemed to be flowing quite well. BTW, has anyone considered removing the thermostat and installing a variable speed control for an electric water pump? It could come on at preset speeds... maybe 10,25,50,75 and 100 percent depending on water temp. It could come on at 10 percent at 140 degrees, 25 percent at 145 and increase every 5 degrees until you reach 100 percent speed at 160 degrees.

[Guest Mike]

Mike- I forgot to mention that with a leaky head gasket' date=' the harder a person works the engine, the hotter it gets. (Higher compression pressures shove more exhaust gasses into the water jacket). So if your car is stable at a somewhat higher temperature than you are used to, probably not the gaskets.

 

 

.[/quote']

 

Thanks A.G.

 

This car is "new" to me... only had it a few days. So I've been hitting the throttle pretty hard:mrgreen: I haven't seen any evidence of exhaust gasses entering the coolant. It does run better when it's cooler though. But then... every "old school" carbureted performance engine I've owned runs better cooler.

[A. G. Olphart]

You're welcome, Mike. Good luck sorting out your new toy/ daily driver:mrgreen: .

 

 

.

[Guest Mike]

You're welcome' date=' Mike. Good luck sorting out your new toy/ daily driver:mrgreen: .

 

 

.[/quote']

 

Thanks again, A.G. I truly did buy this new toy because I'm tired of driving the old POS. I've been denying selfish purchases for so long that I'm truly sick of it. I do want this car to be my daily driver and I'll keep the old POS as a backup.

 

It'll take some diagnostics, fiddling, and some time... but this little hybrid will soon be happily zooming at its very best and shaming nearly all 'stangs that are foolish enough to challenge it:-D

[eec564]

BTW, has anyone considered removing the thermostat and installing a variable speed control for an electric water pump? It could come on at preset speeds... maybe 10,25,50,75 and 100 percent depending on water temp. It could come on at 10 percent at 140 degrees, 25 percent at 145 and increase every 5 degrees until you reach 100 percent speed at 160 degrees.

 

I don't think that would work very well, as you'd need a closed-loop system to measure flow. 50% voltage on an electric pump won't equal 50% flow, and a lot of 12v pump motors won't run under load at less then 9 volts, and 70% flow or so, depending on pressure.