rx74u2nv

I have an 87 Base. I cannot get the engine to turn over. Tried turning the main pulley bolt clockwise, nothing. Tried push starting, tires just skidded. Any other ideas before I get a new rebuild??? Thanks.

ifryrice

It depends on what caused it to seize. If it's carbon or someting similar, you can try ATF or other dissolving agents in the plug holes to see if it'll work on freeing it up. You could also try an impact on the pully bolt after letting it soak to see if it'll spin.

rx74u2nv

oh yeah the engine is an Atkins rebuild streetported with about 65K miles

ifryrice

I'm not a fan of Atkins, so I'll leave my comments on them out of here. How did it come to be seized? Did it happen from sitting/locked while driving/after parking?

rx74u2nv

well its a long story actually. someone backed into me and my car ended up in the body shop. I got a call from them one day saying it had flooded a few days earlier and they tried to unflood it, couldnt get it started, then ended up sending it to a "mechanic" who said it was locked up. I might have sat about a week at the body shop. The "mechanic" told me he was using a pry bar on the flywheel and it would not turn. So basically i have no idea what happened. Of course nobody called me until it was at the "mechanic". But I did get $2K towards a new engine from them.

ifryrice

Interesting. My guess is either something fell in the block or they hydrolocked it and broke something. Either way, under those conditions trying to unbreak it like this will likely just damage more.

rx74u2nv

u mean by hydrolock that water entered the engine? Nobody drove the car, i recorded the mileage when i brought it in and it was the same after this happened. The body shop did say they stuck a camera in the plug holes and could see lots of carbon build up.

ifryrice

I was referring more-so to gas, but it could be carbon after all. If you can afford it a tear down is always better than ATF'ing it.

calpatriot

I have been through this once, also with an Atkins rebuild, but with many fewer miles. In my case the lock was cleared by TriPoint Engineering. They used some form of a penetrating oil (I do not know which), let it soak for a day or two, and then were able to turn it with a breaker bar on the pully nut. That was at least 3 yrs ago, and it has run very well ever since.

The presumptive cause was carbon lock. I was advised to 'drive the car harder', which I have happily done.

Since then I discovered that the ECU was not seeing the O2 sensor, and the car was running in open loop (rich) all the time.

The lock up occurred after a long trip (320 mi). My working theory is that the car was building excess carbon deposits due to running rich at cruise, and the 5hr trip put the amount of deposits 'over the top.'

I would find someone with expertise in clearing a carbon lock in rotaries, and let them do it rather than experimenting.

If you get that cleared, I would immediately check to see if the car is going into closed loop mode during cruise, or are there other reasons why it may be running too rich.

Turbo II Rotor

iTrader: (2)

Sounds like a foreign object in the engine.

stevensimon

iTrader: (11)

agreed with t2r. i bet you open it up and find a nut or some other chunk of foreign in there. either way.. 2k buys a happy turbo motor

Amur_

ATF is not a dissolving agent and contributes nothing to breaking up carbon.

A post in here from an engine rebuilder made years ago stated thought he believed that actual carbon lock was a rarity and that what was actually happening more often than not was an apex seal would 'fall' partway out of its groove and wedge between the housing and the rotor. How to free it? ATF or other lightweight oil and if you're lucky you'll get the rotor moving again without destroying the seal. I think that is what happened to calpatriot.

Hydro-locking a rotary is similarly unlikely.

Putting an impact wrench on it is to take an extraordinary risk.

I'd put money on either a dropped seal or a foreign object. In either case I sure as hell wouldn't try to force the rotors to turn - I'd be petrified of damaging the seal (s) or a housing. I think this calls for a light touch.

ifryrice

The chemicals thrown into ATF most certainly penetrate and help break up/loosen carbon. Just stick a rotor in it for a few days and come back with a wire brush, it kind of proves itself.
True, but it's been done before when someone fubars injector wiring or some other issue that fills the chamber with gas.

Forcing the engine to turn in any condition without knowing why is pretty much the same risk, especially after they've already prybar'd it a bunch. Either way it's never ideal if it can be avoided by just taking it apart.


Agreed, the damage that it can cause especially if you've got money for a new engine and can pull this one apart/rebuild really outweighs the reward. At the very least pull the exhaust manifold off and take a peak and try to see what you can find.

Have you tried going counter clockwise?

mbonner

A friend advised me to use a 50/50 ATF Varsol mix for freeing some stuck motors and to put into spark plug holes when preparing to lay the car up for winter as we do in the Great White North, Canada. I squirt somw mix into the plug holes, spin the motor for 10 seconds, put the plugs back in. The blue smoke cloud is amazing when the car is started up in the spring.
This makes total sense to me.
Mike

Amur_

Well, the thread I was going to link to is gone. It had several first-hand stories from members who had done things like leaving a carbon-caked rotor sitting in pail of ATF for a week or more and returned to find it had done nothing to soften, loosen or otherwise remove the carbon build-up. ATF itself has no corrosive properties until you heat it right up. Out of the bottle it is not a solvent any more than any other oil is.

What I have seen promoted in this section for dealing with carbon effectively is Seafoam...

Terrh

iTrader: (7)

diesel penetrates carbon instantly.

if it was mine

I'd pour a bunch in, wait, and then try and spin the engine backwards.

Get some down the intake manifold and some into the spark plug holes.

Wait a day or two.

Then tow the car BACKWARDS with the trans in 4th or 5th.

ifryrice

My experience was the opposite, let a rotor sit for bout 5 days came back with a wire brush and it was considerably easier to remove than the other parts of the rotor. Nowhere near as good as regular parts cleaner/other crap I had laying around but i figured i'd check just to see.

I didn't even think of Seafoam, that stuff's fun!

levelzero

iTrader: (1)

I agree with the using diesel trick, but I don't know if I'd be towing my car backwards.

If the shop hasn't have the engine apart then it's not likly a foreign object. It could be a dropped seal but I'd personally lean towards carbon lock.

rx74u2nv

Thanks for all the replies. I think Im gonna try seafoam and let it sit for a couple of days. It sure would be sweet to get it running again and get a free $2K!!!

WonkoTheSane

iTrader: (2)

Did you pull out the lower spark plugs and try to rotate it (by hand with a 19mm socket on a ratchet)? As someone above said, it IS possible to hydrolock a rotary engine if 1 or more of the injectors jam open...

I just did it a few weeks ago when I was troubleshooting my Megasquirt install

It's a crazy long shot, but all it requires is taking the plugs out to check.

gxl90rx7

iTrader: (1)

I helped him troubleshoot it when he got it back from teh garage. All spark plugs and acc belts were removed. We tried turning it over with a wrench on the front pulley bolt, both forward and reverse, nothing. We also tried push starting it in reverse and 1st gears (car moving forward) and it would jsut lock up the wheels

MKnA's dad

How much ATF or SeaFoam should be added, and to all 4 holes? Which should I try first?

Ryan123

iTrader: (3)

For one thing if you use ATF with car car locked and it was carbon build up as soon as it runs it will have low compression.... Atf is tranny fluid for TRANY only or it would say other wise. The ATF will eat at the the oil seals in the engine... dont use ATF

Proof:
http://www.aaroncake.net/rx-7/atftrick.htm

Aaron Cake

iTrader: (1)

Don't waste your time with ATF. It won't do much for the carbon (I have done the rotor in ATF experiment to prove this) and may attack some of the rubber used (depends on the brand of ATF, but some oil rings I left in ATF for a week turned to jelly).

Use carb cleaner that is described as "sensor safe" or use EFI throttle body cleaner. It is designed to dissolve carbon while staying fairly safe to rubbers used in engines.

Pull the lower intake and spray it into the intake ports, then pull the spark plugs and using a long tube, spray thoroughly the inside of the engine. Let it sit for a while, respray, and repeat this process over several days. SLOWLY try to rock the engine back and forth with a breaker bar. Compressed air can help blow carb cleaner into the engine...

MKnA's dad

Would that be better than trying SeaFoam? Would SeaFoam do any damage?