96 GTX motor locked up! Help!!!

[ape1972]

Okay thank you

 

[mikidymac]

No reason not to bore to the next size. Group K will bore and piston match each cylinder and trim both RAVE valves for $120 total.

 

[R-u-n2it]

Listen to Miki, Group K knows what they are doing, and a resleeve still needs clearance checked on the piston going into it, if you never rebuilt a 785 get a service manual, example normal engines you put Loctite on the head bolt threads and grease the bolt shoulder base (for torque readings), not the 785, synthetic grease on threads (bolt is stainless and hole is cast iron/aluminum, dissimilar metals and will corrode) and blue Loctite on the shoulder. Here's 1 for you, all the exhaust flange bolts get synthetic grease except 1, which 1 and what does it get instead, and why? Tic Toc...... {;o). Lee

 

[ape1972]

Thank you all for the great and much appreciated info.
Quick update!!! Culprit was found in the pan.

 

[R-u-n2it]

Where did it come from? Was it getting wedged between crank counter weight and case? If it was wedged between anything and case check it close for cracks, The smallest of cracks can let air in. And to make sure nothing else can ruin a new rebuild pressure test your engine, especially if you recently had a problem that seized your engine and you aren't 100% sure it was NOT an air leak. You can't actually FIX an engine with a rebuild unless you also know what caused it and fix that also. Don't treat the symptom, treat the cause. Seen it happen way too many times. Good luck (not needed it if do it right). Lee

 

[JRB]

Pull the spark plugs and see if it turns over.

Agree 100%, I got that also, pull the plugs and see if it turns, will likely see lots of oil !!!

I don’t see anything you did wrong that would cause it to lock up unless a bolt fell down the intake.

 

[JRB]

Hello all,
I have very Odd problem!
I had recently pulled the motor on my 96 GTX for some maintenance. When I put the motor back in is when the problem occurred. I connected the oil lines but I had not connected the carbs yet. I turned th motor over to do a compression check. It turned over fine but when I tried again the motor locked up! Like I can’t even move it with a pipe wrench (lightly of course). I took off the pump, starter and rotary valve and still the same problem. It never fired up and I literally turned the motor over for three seconds max and no strange sounds or anything. Could it be hydrolocked? It haven’t been in water but I could really use some help!

Thank you all in advance!

Pull the plugs, and turn it, likely full of oil, leaky read valve.

 

[Chester]

Pull the plugs, and turn it, likely full of oil, leaky read valve.

It's not oil, read post #29. There are no reed valves.

Chester

 

[ape1972]

I will go through this motor inside and out... I split the case and checked for marks, nicks and gouges and it looked really good. I check all other parts as well and all good. I will have it checked for cracks (pressure tested) as soon as I can.
I guess I was lucky that I never fired up the motor. All of this damage happened just by turning it over for three seconds max.

Crazy!!!

 

[ape1972]

Where did it come from? Was it getting wedged between crank counter weight and case? If it was wedged between anything and case check it close for cracks, The smallest of cracks can let air in. And to make sure nothing else can ruin a new rebuild pressure test your engine, especially if you recently had a problem that seized your engine and you aren't 100% sure it was NOT an air leak. You can't actually FIX an engine with a rebuild unless you also know what caused it and fix that also. Don't treat the symptom, treat the cause. Seen it happen way too many times. Good luck (not needed it if do it right). Lee

Not sure where it came from but it had to have come from me by accident. Lesson learned.

 

[R-u-n2it]

You could have used a stainless magnet..... {;o)

 

[ape1972]

You could have used a stainless magnet..... {;o)

Good point!