I picked up a really rough 1972 914 a couple weeks ago. No idea when it last ran. I want to try to get the 1.7L running again. I’ve been putting Marvel Mystery Oil in through the spark plug holes. I’ve used a couple quarts in the last 7 days, rocking the car back and forth in 5th gear. I’ve tried jacking up one side and turning the rear wheel by hand, but can’t get the leverage to get the engine to turn over. Are there any other tips or tricks to unseizing this thing? I looked through some older threads, but wanted get all my options in front of me before dropping the engine and try to turn it over by hand.
Links to previous discussion or discussion outside this forum are welcome.

MMO is good stuff but if you seek the ultimate in penetrating agents, mix yourself up an 50/50 blend of acetone and ATF. Do the same as you already did, let it sit a few days. Amazing how well it works.

I 5th geared Dads car after sitting 10 years. Got it rolling and then popped it. It literally popped. Ran fine after that.

I ran into the exact same issue with my 73 914 1.7 that sat for 10-15 years. Spent some time rocking and rocking while putting mystery oil in the spark plugs but to no avail. Now planning on removing engine for a rebuild. Oh well and now I get to learn about engines.

Rookie here so am intimidated.

-Brett

Strip it, pull the heads.
Place case in a large bucket.
Drown in purple power cleaner, keep checking because overnight can eat aluminum.

You can also use plain coca cola

Well, here goes. This Honda CL 90 may have been submerged. I've used MMO and PB Blaster and things are still locked up. And since the clutch and gearbox share engine oil I can't even drop it into gear. It may be hopeless.

BTW the acetone and ATF don't mix. I had to homogenize it by hand


Click to view attachment

Put the engine in a fast moving cold water creek.
Check it every couple of weeks.
It'll free right up.
I actually had an old timer tell me to do that.
I've heard some crazy things but this is way up there.

48 volts to the starter

I also have a 73-914 the engine also stuck and wouldn't turn,,ive used marvel oil a long time..after a day or so of soak in cylinders I broke mine loose just bumping the starter. ive done it twice before.a few times a day bump the starter.be patient,i think it will come to u JT

https://www.youtube.com/watch?v=YJDT04DOalI


Frozen engine?
Rust in the cylinders,broken valve head,piston.
Nowadays,the tech exists to look inside,non-destructively to determine the cause.
Save yourself the hassle of an attempted resurrection of a blown engine.
'Forcing' an aircooled 4 or 6 would result in more damage.
A methodical approach,the right way the first time,this no time to experiment.
Buy the camera,toss it in your toolbox and live happier.

Remove the starter.
Use a big screwdriver to lever the flywheel. One direction then the other.
Roll the car, pop the clutch ? Only if you want to repair far more than a stuck engine.
Click the starter repeatedly ? Only if you want to torture test your starter. And wiring.
If it won't turn using a the flywheel / screwdriver take the engine apart.
You could have one stuck piston and maybe loosen it up. But if it's more than one or a variety of other things you are delaying the inevitable.
MMO and time are a good start.
My 2 cents.

He's right. After popping mine loose in 5th gear, it only ran perfectly for years up to 86K miles on it..... then I tore the engine down because of the heads leaking oil, and decided to build a 2056 for fun.

After taking the engine apart, I could clearly see the carbon deposits on the pistons that gummed things up.

It will either work or it will not. Better than stuck motor.

Marvel Mystery Oil

Freed up a hibernating Citroën DS that was given to me. It sat in a locked yard for 16 years outside. Pour some down the spark plug holes, let soak for a few days then turn the crank by hand just a bit....then turn some more a little bit each day until you think you can start it. Be patient!!

In college my buddy cut a Chrysler 440 out of a car in the back of someone's land and literally cut the engine mounts away from car and moved it out on a front loader. A few months of MMO and he was able to pull it apart. He ended up boring and sleeving the cylinders but got it apart.

I just went through this with my 74 1.8 derelict. Sat for at least 13 years, unknown everything. Motor was stuck, one of the plugs showed a bit of rust when pulled. I picked up one of the cheap USB borescopes and checked all combustion chambers for existing carnage and found none other than moderate rust. Oil drained and looked very good, no moisture. I overfilled the engine with the lightest weight cheap stuff I could find along with some Marvel Mystery Oil. I then added a 50/50 mix of MMO and ATF to each cylinder and let it all sit for about a week before I started trying to rotate it. Little by little it freed up, kept working it daily for a while - it is now rotating freely. It is going to sit in the pickle juice for a while - I am concentrating more on rust repair than the powertrain right now, but was curious if I could get the engine freed up.

Some of you guys with the marvel mystery oil recommendation are missing the fact that the engine could have had a catastrophic failure. I bought a 944 once that was reported to be seized. I knew full well it was seized when I bought it.

A borescope did not reveal anything serious. When I stripped the motor down, #3 piston was buried in the wall of its own cylinder. Was apparent from the bottom, but not so much from the top because it was almost at TDC. Was a bad rod bearing.

No amount of marvel mystery oil was going to free that up :-)

A conrod will tend to thrash around,making horrible noises on it's way out.Coolant in the oil is a bad sign.
Rust in the bore of an aircooled engine,or any engine,is a sure sign of re+re at minimum.
Not removing the cylinders and pistons on seeing rust in the holes is a sure way to waste time and money.
May as well hit the cases with a 20lb sledgehammer and finish it off painlessly.
I'm sure,at some point an F-head Ford ran fine with such treatment,but then,you could bore them out 3/8".
Finely machined,lightweight and delicate engines are these.Only when you have confirmed the tolerances can you stand on them.
They will surprise you how sensitive they can be when things are plain wrong.

Maybe we got lucky!!!