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Discussion Starter #1
Hi all, I bought my first vintage Mustang a month, a 1965 Coupe with what I believe is the original 289. The previous owner stated the engine stopped running suddenly ~6 months ago and was the reason he sold it. I bought it knowing it didn't run. I tried a couple of simple fixes such as recharging the battery, changing out the in-line fuel filter, and making sure the fuel pump worked, which it did. When I turned it on, the car would fire but would die immediately and would not run or come close to idling.

Today, I performed a compression test which showed the following:
1- 180
2- 0
3-120
4- 170
5- 0
6- 160
7- 165
8- 0

I repeated the test on the cylinders with 0 reading and got the same values twice. I was very surprised to see a 0 psi for 3 chambers and would expect at least a small amount of compression. I plan to pull the valve covers off tomorrow to inspect the rockers. I don't have an air compressor to perform a leak down test. I suspect its a problem with the cam or the valves but am unsure. I am certainly a novice with automotive work, and wanted to get guidance for the next steps. I think I am going to have to rebuild the engine but wanted to exhaust all possibilities before doing this. Thanks.

-Patrick
 

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The intake valve in those 0 cylinders may be stuck open or the exhaust valve may be severely burned.
 

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First, assuming you followed best practices for performing a compression test, did you at any point squirt oil into the "0" cylinders, to check for any degree of change? The ones that had compression look reasonable in terms of PSI.
 

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Discussion Starter #5
I didn't squirt any oil into the 0 cylinders. If it were a worn or busted ring, I would expect that at least some compression pressure would be generated, or could it produce 0 psi?

What would be the best way to assess if a valve is stuck open or burned? Would that be with a borescope?
 

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When you pull the VCs, and have have a "dead blow", if you don't see any action on cylinders 2, 5 & 8, move the rockers aside and give the valves a "smack" to determine if they are stuck. But then, your observation when cranking will be an indication too. If all fails, might as well plan for a head removal. I'm not sure a Borescope is going to be much help in this one. Good Luck! (if you give them a "smack" be gentle if the pistons are near TDC.)
 

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Can't smacking a valve with a dead blow hammer result in flying keepers?
Not if you smack the end of the valve stem and not the retainer.

Just turn the engine over with the valve covers removed. You'll quickly notice any valves that aren't moving. Burned exhaust valves will require a little more investigation.
 

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Can't smacking a valve with a dead blow hammer result in flying keepers?
Not really, as more often than not, the reaction of the spring is too fast. You'll simply get a bounce. In reality, many of us have complained of how tough it is to remove keepers when using spring compressor. However, it is always important to be vigilant and wear eye protection.
 

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Burnt valve seats from using unleaded gas.
 

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Just turn the engine over with the valve covers removed. You'll quickly notice any valves that aren't moving. Burned exhaust valves will require a little more investigation.
As mentioned, I would first verify that the valves are moving up and down properly. Could be improperly adjusted valves staying open, bent pushrods, or some of the other stuff mentioned above.
 
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Honestly, all of the advice everyone has give is sound and accurate, but I really wouldn't waste my time trying to diagnose and fix an engine with 3 dead cylinders and a fourth (#3) on it's way out. Obviously something is catastrophically wrong and the engine is going to need a complete rebuild. Pull it and either rebuild or replace it.
 

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Discussion Starter #14
Thank you for the replies. Pulled the VCs, looks like all the valves are moving and I didn't see any broken rockers. I think I'm going to pull the engine and try to rebuild it. Seems like a perfect opportunity to learn more about my car and make some upgrades while I'm at it. If anyone is in the Austin area and is available for an engine pull, let me know. I have cold beer and a grill out back.
 

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You stated that the PO said the engine died suddenly. Check your timing set before you pull the engine. Valves in multiple cylinders don't just burn away suddenly.
 

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Discussion Starter #16
Pulled the engine last weekend and started taking it apart today. Below is a pic of the 2nd cylinder which had a zero compression. The piston is completely cracked and actually had part of it chip off. Obviously not good. It was difficult to get the lifters out from that cylinder position as well.

773633


When I first got the car and tried to get it running, I had to pour a ton of coolant into the radiator and I wonder if the PO let it run dry which led to the engine severely overheating. Is this block even worth taking to the machine shop to reuse or should I assume its going to be trashed?
 

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Wondering if somebody tried to fire it up with too "liberal" a dose of ether....
 

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Wow! How the valves in the head look, are they beaten up like they smacked the pistons? The block maybe good if it has not been bored before, may need to rebore and new pistons depending on what else they find. Are the cylinder walls gouged up or not? I would take it to a machine shop and have them check the block out to see if it can be saved or not.
 

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The top of the piston looks clean with not much carbon build up. Not much of a ridge at the top of the cylinder either. Maybe the engine is a recent rebuild gone.
 

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What do the other "0" compression cylinders look like? Multiple sudden unrelated catastrophic failures are not likely. Rather, if the failure was indeed sudden, my guess is that something like a sudden prolonged significnt over-revving event caused a cascading failure that can be described as the engine eating itself. Approach this engine as if you are doing an autopsy and see what turns up.
 
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