How to clean head exposed to elements

[ddrum]

Good evening, I've had a question for a while and have searched on Ratsun and still haven't found an answer. So I have this w58 peanut head that I would like to put on a L16, the thing is that it's been out for like 12 years and exposed a bit to elements, mostly dust from the Southwest desert here in El Paso Texas. So would it be better to disassemble all of it and clean with gasoline/ degreasers. Or don't disassemble and just rinse and scrub until clean? I also want to change out the valve stem seals, because of this should I lap the valves? Or can I just leave it as is, change valve stems scrub clean and install?

 

Thank you, Erick

 

https://imgur.com/a/UH0QeyZ

Edited October 3, 2024 by ddrum

[datzenmike]

All closed chamber heads came here on import engines as they were low mileage and cheaper than doing repairs or valve jobs on the original engines.

 

If changing the valve seals, a good idea BTW, then the spring has to come off anyway so I would get some valve grinding compound and an electric drill and lap them. Combustion chamber can be cleaned with a light or brass wire wheel but keep valves closed to protect the seats and stay away from the head surface as it's soft aluminum. While rockers are out, keep in order so they go back in order, spin the cam. It should spin freely. Inspect the rockers for scuffing. Best to use an oil that has a similar ZDDP content as when these engines were new. Today's oils are half what they used to be. I use Shell Rotella T4 10w30, it's a diesel oil with 1,200 ppm ZDDP. Oils today are 500-600 PPM. If the rockers show any scuffing then 400 wet emery paper on a piece of glass in the sink will usually refresh them. The L20B cam is a little better than the stock L16 cam. While valves are out you could remove the exhaust liners by slitting them lengthwise with a chisel and pry them out. Not totally necessary. I would keep and use the L16 exhaust manifold, it will fit and work on the round exhaust ports using an L16 gasket. The L20B exhaust manifold isn't that great.  

 

Looks like the lower right head bolt hole still has the alignment dowel in place, can't see the lower left one. Hang onto those.

 

Head surface looks ok but place a straight edge across the length in an X pattern and try to slip a feeler gauge under it. If warped, the limit is 0.004" about two thicknesses of newsprint. Wouldn't hurt to have the head surface milled as this head has a larger combustion chamber than the stock L16 and will lower the compression to 8.24 from stock 8.59.

 

I had one of these once but it had been out in the weather for decades. Did remove the liners though but couldn't save it.

 

 

 

 

 

 

[ddrum]

DatzenMike thank you so much for the detailed explanation. Ok I will do that. On that note, if I take the head to get resurfaced, should I take off the cam and valves? O take it as is completely assembled. I've read different things about how not to take off the cam towers and such, because L-series heads are more complicated than other engines. So basically the less disassembly the better?

[datzenmike]

Ask whoever you get to resurface what they want. You don't want them doing that and losing things, better you take it off and keep them all in order. properly. Better to keep the cam towers on but if you have to, mark so they can go back in original position and don't over tighten the bolts when you assemble them. About 5 ft. lbs max or the WILL STRIP!!!. One side has head bolts at 60 ft. lbs. through them, so they are not going to move anyway. Once installed put the cam in and it should spin freely.

[ddrum]

Thank you so much for the advice Datzenmike. I really appreciate it! Now I can move forward and get my 510 back on the road!