mainer311 Posted November 13, 2020 Author Report Share Posted November 13, 2020 Well, this W58 head just showed up. The steel exhaust liners were previously removed. It also looks like some work was done on the intake runners because they’re very smooth. Does anyone know what the cam markings mean? There’s a “B,” “DC 93,” and “280” stamped into the end of it. 1 Quote Link to comment
bilzbobaggins Posted November 14, 2020 Report Share Posted November 14, 2020 Have a pic of the exhaust liners removed? I am curious to see how it looks. 1 Quote Link to comment
mainer311 Posted November 14, 2020 Author Report Share Posted November 14, 2020 39 minutes ago, bilzbobaggins said: Have a pic of the exhaust liners removed? I am curious to see how it looks. Sure 2 Quote Link to comment
datzenmike Posted November 14, 2020 Report Share Posted November 14, 2020 I've removed liners before and ground away the bumps. These bumps support the liner in place and hold them away from the wall so they cannot transfer any heat. This way they glow red or yellow hot and with a working air pump pushing oxygen into the exhaust flow it self ignites and burns away any unused hydrocarbons. 2 Quote Link to comment
mainer311 Posted November 14, 2020 Author Report Share Posted November 14, 2020 (edited) Ports are measuring 1-5/8 for exhaust and 1-1/2 for intake. The head definitely has work done on it. Also, this looks different? Edited November 14, 2020 by mainer311 1 Quote Link to comment
mainer311 Posted November 14, 2020 Author Report Share Posted November 14, 2020 Just measured the cam. I get 1.524-1.223 x 1.48 = .445 1 Quote Link to comment
datzenmike Posted November 14, 2020 Report Share Posted November 14, 2020 Stock L20B is 0.413" 1 Quote Link to comment
mainer311 Posted November 17, 2020 Author Report Share Posted November 17, 2020 I cleaned the hell out of this head, then put a little ATF down the runners while the valves were still installed. I guess I know why this head came off. #4: 1 Quote Link to comment
mainer311 Posted November 19, 2020 Author Report Share Posted November 19, 2020 Have any of you guys had luck removing the valve guides on one of these aluminum heads? Quote Link to comment
Rat-a-tat-Dat Posted November 19, 2020 Report Share Posted November 19, 2020 Other options, instead of replacing valve guides, are knurling or valve guide liners. Quote Link to comment
Rat-a-tat-Dat Posted November 19, 2020 Report Share Posted November 19, 2020 Sorry, didn't answer your question. Aluminum heads need to be heated up first, usually a propane torch will do, but just heat the area slightly. With the right size hammer, guides generally come out in 15~25 strong, steady blows. Make note of any guides that come out looser than others and if you find a stubborn one, not much movement, try using an air hammer. Take measurements of the guides bore I.D. by using a snap gauge, dial bore gauge or a micrometer. Not sure of the actual tolerance here but I think you can buy oversized guides if required. Quote Link to comment
datzenmike Posted November 19, 2020 Report Share Posted November 19, 2020 Usually the head is set with the combustion chambers up and filled with kerosene and left over night. In the morning any empty combustion chambers need a valve job. 2 hours ago, mainer311 said: Have any of you guys had luck removing the valve guides on one of these aluminum heads? With the valve in the head and on it's seat but without the spring, the tip should not rock back and forth more than 0.2mm or 0.0079" in a direction parallel with the rocker arm.This is approved in the FSM for a quick indication of valve guide wear. There's a tool like a valve stem that's inserted from the combustion chamber side and you hammer them out or use a 2 ton press. Warming the head in your oven to 300F will make it easier. Quote Link to comment
mainer311 Posted November 19, 2020 Author Report Share Posted November 19, 2020 I definitely need a valve job. I soaked the head in gasoline to clean it, and upon filling the inlets, both intake and exhaust on #4 leaked out. I then filled the inlets with ATF (since it's red and easy to see) and had red leaks coming out the combustion chamber side. See my picture above. The head is hodge-podged together. It has all different valves and valve guides in it: some brass, some cast iron. I want to strip it all apart and put all new in. It looks like Riley (datnissparts) has 35 and 42mm stainless valves in stock. Quote Link to comment
Charlie69 Posted November 19, 2020 Report Share Posted November 19, 2020 On 11/12/2020 at 12:33 PM, datzenmike said: That's odd because all '78 and up engines had the W58 head with coolant flow intakes unless someone swapped them. If it had the married intake to exhaust this was from a '75-'77 L20B . The co-joined ones would get hot because of exhaust but also because they are bolted together. The W58 intakes have a heat shield to reduce radiant heat. These 80s 720s were California emissions trucks. Quote Link to comment
datzenmike Posted November 19, 2020 Report Share Posted November 19, 2020 Not all 720s I think. There were Federal and California carburetors and EGR systems. 1 Quote Link to comment
mainer311 Posted November 23, 2020 Author Report Share Posted November 23, 2020 I love buying used stuff and discovering PO BS. I just bagged all of my valvetrain components and then filled each one with oven cleaner to let it sit for a couple days. Washed everything off tonight and the wipe pattern on the rockers is off to one side. Whoever rebuilt this head was using a mild cam with stock lash pads. 😧 1 Quote Link to comment
datzenmike Posted November 23, 2020 Report Share Posted November 23, 2020 Not the end of the world as long as it isn't over the edge. Does no harm and it's correctable. 1 Quote Link to comment
mainer311 Posted November 28, 2020 Author Report Share Posted November 28, 2020 (edited) Still waiting for my pistons to show up before I can send the block off to get tanked, decked, and bored...so in the meantime I’ve been fitting these stainless valves from SI. Intakes are oversized to 43mm, and exhaust is stock 35mm. Debating on opening up the seats myself with one of those DIY cutters and an 8mm guide. I’m also waiting on my 8mm guide tool to show up so that I can finish replacing those. 2 of the valves have a ton of play, so I’m replacing all 8. Edited November 28, 2020 by mainer311 2 Quote Link to comment
mainer311 Posted December 1, 2020 Author Report Share Posted December 1, 2020 Just won a NOS valve cover on eBay for $25! 1 Quote Link to comment
datzenmike Posted December 1, 2020 Report Share Posted December 1, 2020 DATSUN 1600 OHC with fins over the sprocket hump ??? 1 Quote Link to comment
mainer311 Posted December 2, 2020 Author Report Share Posted December 2, 2020 26 minutes ago, datzenmike said: DATSUN 1600 OHC with fins over the sprocket hump ??? Sadly, no. It’s a “NISSAN OHC” cover. 1 Quote Link to comment
datzenmike Posted December 2, 2020 Report Share Posted December 2, 2020 NISSAN OHC......Used on '76 an on L20Bs DATSUN OHC.... L16s after '70, '74 and '75 L20Bs. L18s on '73 610, '74 710 and '74 620 DATSUN 1600 OHC Fins over cam sprocket or stop at cam sprocket before '71 on 510 and 521. I think fins over sprocket the earliest. Had them on my '68 510 and put them on the L20B I transplanted into my '71 521 which had fins stop at cam Quote Link to comment
mainer311 Posted December 2, 2020 Author Report Share Posted December 2, 2020 Well, it’s going on this L20b, so I guess it makes sense. Not sure what year it’s from. 1 Quote Link to comment
datzenmike Posted December 2, 2020 Report Share Posted December 2, 2020 I had the 1600 one on my 521 L20B just... because. 1 Quote Link to comment
mainer311 Posted December 2, 2020 Author Report Share Posted December 2, 2020 Man, air hammers are awesome. I bought a special 8mm tool for it, heated up the head a little bit, and had all the old guides out in 10 minutes. 1 Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.