the engine diagnosis game!

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68 A

68 A

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Who wants to play?!

So I took the dart to a friends house Friday night (100 mile round trip), returned Saturday at 1, then headed out to a wedding 35 miles away at 1:30. 10 Miles into the trip as a car ahead of me was slowing down to turn right, I passed and opened it up, and instantly the cab was full of smoke. Stopped at a gas station, looked under the car, didn't see any oil leaking.

Back on the road. When ever I got on the throttle it would smoke alot more than if I was just cruising. Decided that I needed to stop again and look under the hood. I could see that there was an oil leak, as there was oil on the timing chain cover. Figured it was leaking out, fan was blowing it on the header making it smoke, and blowing it through a hole in the firewall. However, I also heard something that I hadn't heard when I had oil leaks before, sounded like a valve opening or closing was my thought.

Anyway, didn't think it was too serious, drove it to the wedding, then parked it and brought it back home Sunday. Same symptoms as before.

I got into it tonight taking it apart, and now I know what is wrong as it is all apart in the garage.

But who else knows what happened?

And possibly why? (I'm not sure why)

I will follow up with the answer and lots more questions tomorrow.

Thanks,

Steve
 
If it's chattering sound and you have smoke out the pipe=broken rings

Are you sure it's oil and not atf?
atf leaking under rpm/pressure from the radiator trans cooler blown byt the fan?

rear main leak can piss and catch the header, but you say the front cover was oily.

so I'll guess front seal.
 
the question is where on the cover, top or bottom? if it's on the top I would guess intake end seal caused by too much crankcase pressure. since you said you got on it ring seal could be a problem. same possible thing if you blew out the front crank seal. run a leakdown test to see if the rings are sealing.
 
Harmonic balancer came a part and rubbed a hole in the front seal casing?
 
and the answer everyone has been waiting for!!




I thought it was the intake manifold leaking from the oil sitting on the top of the timing chain cover, so I took it off and I couldn't see a leak. So I got the trouble light out and started looking:

Dart 014.JPG


Dart 015.JPG
 
One more good reason to use steel shim gaskets. Mopar LA engines only have 4 bolts around every cylinder.
 
I'm missing something here. That is a blown head gasket right?

Then how did oil get on the timing chain cover?
 
Crankcase pressure goes thru the roof so oil will get pushed out.

On the gasket.. the only reason it would pop there is either it pinged/detonated when you got on it, or the head or block isnt flat enough, or it wasnt torqed properly. If you look, number 7 also looks close to breaking and was pushing gasses into the crankcase too. Looking at it, I'd say it's not flat. I would use a machinist's straight edge to carefully inspect them both before you reassemble it. So did it ever ping? Carefully clean the carbon off the pistons... are there any tiny pits visible in the surface? Use a strong light and magnifying glass... look a tthe ceramic on the spark plugs.. any flecks of metal or tiny blueish/black spheres stuck to it? Most blown head gaskets are symptoms... not causes.
 
ramcharger said:
One more good reason to use steel shim gaskets. Mopar LA engines only have 4 bolts around every cylinder.
Click to expand...

So do fords in nascar and if you use a high quality gasket this problem go's away.

If you have more than 10.1 you need to step to a race felpro or something.

The gasket in the pic looks like a mr gasket or victor reinz, not good.

yeah moper, he should check the decks out with a straight edge.
 
mullinax95 said:
I'm missing something here. That is a blown head gasket right?

Then how did oil get on the timing chain cover?
Click to expand...

I think (hoping) that it blew it out the breather on the valve cover, since there was also oil on the valve cover.
 
moper said:
Crankcase pressure goes thru the roof so oil will get pushed out.

On the gasket.. the only reason it would pop there is either it pinged/detonated when you got on it, or the head or block isnt flat enough, or it wasnt torqed properly. If you look, number 7 also looks close to breaking and was pushing gasses into the crankcase too. Looking at it, I'd say it's not flat. I would use a machinist's straight edge to carefully inspect them both before you reassemble it. So did it ever ping? Carefully clean the carbon off the pistons... are there any tiny pits visible in the surface? Use a strong light and magnifying glass... look a tthe ceramic on the spark plugs.. any flecks of metal or tiny blueish/black spheres stuck to it? Most blown head gaskets are symptoms... not causes.
Click to expand...


I just checked the deck on the head and block. The smallest feeler gauge I have is 0.002, and I could not get it under the straight edge anywhere.

As far as torquing, I followed the procedure in my rebuild manual. However, I do not know how many times the bolts have been used, and plan on purchasing new for reassembly.

The compression is running around 9:1, and I have been using 89 octane. I have not heard it pinging. This is my first engine project, I'm sure it was not tuned as well as someone with experience could, but I felt that the timing was good. I do not remember what the timing was set at, But I marked the distributor with a marker before I removed it.

I think it was running rich as well. I had not rejetted yet, but felt like I needed too.

The plugs have white on the ground strap, and the internet tells me that I am running a plug with too high of a heat range (Autolite 3923). However, this is how the plugs look after driving it easily for 50 plus miles with the blown head gasket, so it probably isn't an accurate reading. There is no aluminum on the plugs.

As far as cleaning the carbon off the pistons, what is the best way to do it? Is there a solvent to use, or a brillo pad? I'm assuming no sandpaper.

The gasket that I used is a mopar performance gasket, it crushes down to .024-.028 to help with the compression. they advertise that they are good to 12.5:1 . I was thinking about using these again since I have a pair.

I also plan on taking off the other head to inspect, change the gasket and install new head bolts.

Thanks for the help!

Steve
 
I would run a bottoming tap down the head bolt holes. It sounds like they are flat enough. But you may want to shorten the bolts gently (dont let them get too hot) by about 1 thread. They may be bottoming in a hole or two due to milling. I've only seen that once, but something looks fishy. Does the intake fit well? The bolt holes are centered in the holes?
 
moper said:
I would run a bottoming tap down the head bolt holes. It sounds like they are flat enough. But you may want to shorten the bolts gently (dont let them get too hot) by about 1 thread. They may be bottoming in a hole or two due to milling. I've only seen that once, but something looks fishy. Does the intake fit well? The bolt holes are centered in the holes?
Click to expand...

You need to use a thread chaser, not a tap. A thread chaser cleans the threads without cutting metal like a tap will.
You can make a chaser out of an old head bolt. Get a dremel tool with a thin flat wheel and cut three or four grooves, length-ways, around the diameter of the bolt. Then, clean the bolt threads with a wire brush to knock off any burrs. The grooves collect any gunk that is on the threads of the holes.
After that, spray a little WD-40 on your new thread chaser and run it down each bolt hole.
 
moper said:
I would run a bottoming tap down the head bolt holes. It sounds like they are flat enough. But you may want to shorten the bolts gently (dont let them get too hot) by about 1 thread. They may be bottoming in a hole or two due to milling. I've only seen that once, but something looks fishy. Does the intake fit well? The bolt holes are centered in the holes?
Click to expand...

now that you ask about the intake, I did put a new intake on it and it did not fit correctly, I had the machine shop that did my heads mill some off to get it to sit down far enough, and I also drilled the holes out a little bigger. ( I can't remember if I drilled the holes before I had it milled or not).

I was looking for head bolts online last night and I saw washers with some of them. Could I use washers instead of cutting a thread off? Since I will be buying new head bolts I could buy the washers as well.


I did chase the threads before I put the heads on last time. It was just with a bolt to check the threads, I did not have grooves in it to help clean them out. It wouldn't surprise me if they were a bit dirty. The block sat for 5 years after the machine work and cleaning before I assembled it. Its very possible that there is dirt in the threads causing incorrect torque.

Thanks for the thoughts and Ideas, something I don't think I would have ever thought of!

Steve
 
1wild&crazyguy said:
So do fords in nascar and if you use a high quality gasket this problem go's away.

If you have more than 10.1 you need to step to a race felpro or something.

The gasket in the pic looks like a mr gasket or victor reinz, not good.

yeah moper, he should check the decks out with a straight edge.
Click to expand...

And so did the Fords in mustang (302), my cougar (351C) and my torino (400M). They all blew head gaskets too, lol. :read2:

I use Cometic gaskets exclusively now.
 
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