Aircooled CJ engine refitting after long time.

[geordie skydiver]

I'm currently going through the process of fitting a 2.0L CJ engine to my T25, in replacement for the CU one that blew up, and its a pain in the a***.

Anyway, I have the engine stripped of tinware, shroud, new heat exchangers fitted and I was turning it over by hand, when I found that it sticks, part way round.

I looked inside the intake ports and two of the vavles have rust spots on them, and don't seem to move (unike the other two) when i turn over the engine. Is this what is stopping me from fully rotating the crank by hand?

I've sprayed WD40 in the ports to see if that will unstick them, but is it nessecary to rip the heads off and clean up the valves, then put it back together?

As far as I'm aware this engine was running fine when it was removed.

[geordie skydiver]

Any advice anyone?

[cumbriankeith]

If the valves are possibly rusted shut might you be able to free them by just removing the rockers and "whacking" the offending ones with a soft hammer? - Worth a try to avoid removing the heads?

If you've got the gearbox off as well you good connect it up and spin the engine to do a compression test and see if the valves really do need a service...

[geordie skydiver]

Thanks Keith, I wish I had know this a few hours ago.

I ripped one of the heads off at lunch time, I'm gonna whip both off, pull the valves out and clean em up. Then get the heads sandblasted, and reassemble.

Thanks again.

[cumbriankeith]

Hey Lee, console yourself that the time you've spent doing the heads is an investment in the efficiency of the engine - and your peace of mind knowing they will be good for a load of miles to come. Don't forget to check the valve clearances - does it have solid or hydraulic lifters?

[geordie skydiver]

Hey Lee, console yourself that the time you've spent doing the heads is an investment in the efficiency of the engine - and your peace of mind knowing they will be good for a load of miles to come. Don't forget to check the valve clearances - does it have solid or hydraulic lifters?

Yeah, I know its an investment to sort the heads out, plus it isn't costing me anything but time and the price of new gaskets.

I'll have to check the lifters, not sure on type.

[geordie skydiver]

I've pulled the heads off and its lucky I did, one of the pots must of gotten water in it at some point and it is full of rust and "pooh".

The heads are going to be sand blasted, and I'll have to clean up the pot the best I can by hand.

*sigh. Why is nothing ever easy?

[cumbriankeith]

What's the thinking behind having the heads blasted? Won't it be difficult to keep all the grit away from where it's better not going?

[geordie skydiver]

There's not that many places it can go is there? The heads are fairly straight forward, not that many nooks and crannys I thought.

I just want to get them good and clean. Inside and out. Especially after this rust scenario.

I'm having the rocker covers and push rod tubes done at the same time.

[cumbriankeith]

I thought that the rings where the barrels seal to the heads would need to be looked after - they are best lapped to achieve a good seal or so I believe. Also the valve seats - or maybe you're leaving the valves in during the blasting?

[geordie skydiver]

No, valves are out.

After speaking to my mate who was gonna do the blasting, he's gonna get them chemically cleaned instead.