Wanted to check with the experts here before I take the darned thing apart again! Spent a bunch of time on research on this site and believe I have no choice but to start again, but wanted to check assumptions before I break the news to my kid that owns the car and is working on me on the rebuild. At the point where the irons and casings are back together, through-bolts torqued and end plate and oil pump on. When we try to turn the engine by hand using the flywheel nut on the end of the eccentric shaft clockwise (looking from rear of engine) we can get maybe 1/8 turn at moderate force but then the rotation meets a hard stop. Same thing when the we reverse the rotation, 1/8 of a turn with more drag than I would expect, than a hard stop. The stop feels like a 'klunk' (feels, no sound) rather than something binding up.

Quick recap. 1981 FB. Very much an amateur, first engine rebuild, have the Atkins video and taking it slow. Engine was running well prior to rebuild but multiple oil and coolant leaks. Rebuilt using Atkins Rotary kit. New edge and apex seals and springs. New O rings. New water jacket rings (if thats the right word). Did not replace bearings. During rotor assembly carefully checked that all seals depressed and returned when pressed with a finger so don't think any seals are jamming. Torqued the through-bolts 26 foot pounds, following order in Haynes manual. Tested coolant pressure using the Pineapple Racing tool and holds pressure so dont think a water jacket ring has moved and is herniating into the casing and jamming rotor.

I believe we have no choice now but to start taking the engine apart again and see at what point it starts to turn freely again. Have not checked end play yet, but am I right in thinking if I remove the oil pump, end plate and bearing that I have taken the end plate spacer thickness out of the equation? Have this wishful hope that everything will free up and turn nicely when I take off the end plate, but that hard stop feel seems to indicate something jamming against something else rather than something being too tight in its bearing. My head is saying that the hard stop feel indicates a seal came loose as we stacked up the engine and is caught between rotor and port... but again, total amateur here so checking with the folks that have done this before.

Please tell me what what I fear I already know!

 

Are the spark plugs out? If so, you are correct. The only way to fix this is to tear it down again. Take your time and inspect everything carefully as it comes apart one piece at a time. RAD Potential on YouTube had a similar issue recently. Whatever you do, do not try a turn the engine by hand at this time. It should turn freely with just turning the flywheel by hand with just a little pressure.

 

Can't offer advice, but certainly Kudos for your attempt!! I also did a First-Timer amateur rebuild, and mercifully, it turned out fine.You sound like you were careful, and did your diligence here. Sorry for the Ag, and hope the solution is a clean, easy fix.
DO let us know what happened!! We all learn here...

Stu A
80GS
AZ

 

you might as well try taking off the oil pump/front cover stuff and see if that does anything. also its ok to look in the ports and see if you can see anything

 

The two videos that helped me through two rebuilds is Arron Cake and Blake Marteniez. both on YouTube

As an aside, I also got Pineapple racings' HD water seals. which they claim are reusable.

 

When I had a shop build mine, it wouldn't turn. Turns out something small got wedged in the oil pump gear. Easy fix

Definitely pull the front cover off and take off what you can. If it still doesn't turn after that, it's internal and you'll need to tear it down again

 

Don't take it apart just yet . Two things that I have learned years ago :
Is the front cover on and oil metering pump installed?
Without the OMP engaged the drive gear walks out a bit when turning by hand and low and behold , stops the assembly turning . That was a Duh ? for me once or twice 😄
Also , if so , is the front pulley on and correct endfloat acheived ? If not , depending how the engine is sitting , the e-shaft can bind up internally (probably against the center iron ?) Just happened to me a few weeks ago on my last assembly . Once pulley was on and endfloat calibrated , everything turned nicely .
Just my 2 cents , having built 35-40 engines over thd years .🙂

 

Fixed. Thanks for all the advice. As you guys suggested, slowly worked our way back through the oil pump and into the engine piece by piece, testing to see if rotation freed up as we went. got as far as the rearmost rotor and engine still only rotating the same 15 degrees or so. Pulled out the rearmost rotor and bingo! Tested a turn by hand and observed a nice smooth 360 degree rotation with just a small amount of drag. Picked apart and reassembled the rear rotor, reinstalled in the casing... and now it turns smoothly and evenly. Working theory is a corner seal or apex seal/spring was not installed correctly or was hung up, but cant be definitive as some of the seals fell out as rotor was removed. Anyhow... going to put everything back together tomorrow. Happy days... for now.

 

Mix 4 oz of 2 stroke oil with 4 oz of atf pour it threw the primarys and secondarys leave for day or 2 then try to aoin it . My 12as apex seals where locked snd motor was locked the oil i guess did the job bbut it smoked like a chimeney when it started.