datsunaholic Posted May 8, 2007 Report Share Posted May 8, 2007 Ever since I put the Z24 in my '81 Wagon it ran great but it puts down a James-Bond-esque smokescreen when starting cold (not always, but more than half the time). The stem seal change itself was less than pleasant. I've done stem seal changes before- on a 1960s Ford. Of course, the valve spring compressors they sell at parts stores are for 1960s American V-8s. Way too big, and meant for single valve spring setups. Well, I made it work, but what a pain in the rear. To do a seal replacement in-car, you have to keep the valves closed. I used my trusty air compressor with the hose off my compression gauge (with the check valve removed). Now, when I did this job on my Mom's '64 Falcon I had no problem with bleedoff. Oh, boy, is this engine leaky. I had to work through oil fumes, since the comprerssed air blew right by the rings. Maybe 120PSI was a little high, but I didn't want to drop a valve. Worse, #3 and #4 pressurized the radiator. I had to pull the radiator cap- the gurgling out the overflow was annoying. This is REALLY a bad sign. Of course, using the ons-size doesn't fit all spring compressor had it's share of fun. The puller arms would only grab the outer spring, so I had to force it into the inner spring which usually ripped the stem seal retainers off. That's OK on the removal stage, but not optimal on the install. This meant readjusting the spring compressor before install. Not always easy- a couple times the thing slipped off while backing it off, and one time the springs shot off into the distance (or so I feared). The outer spring rolled under the car- that was easy. The "top hat" landed between the ignition coils, which I found after a couple minutes search. The inner spring... took 10 minutes to find. It landed on top of the heater hose up against the block on the opposite side of the engine from everything else (had hit the hood and bounced, which stopped it from achieving low-earth orbit I guess). The stem seals themselves were hard as rocks and weren't sealing a dang thing. I drove the car after replacement and didn't get any smoke Monday, so I thought MAYBE that had solved it, but this morning it laid down a smokescreen that a WWII destroyer would have been proud of. So I guess it's the rings. They must seal up when everything heats up. The plugs aren't fouled at all- in fact, they look REALLY good, and very even. It's not like my B210 which fouled out #2 just black with oil, until it wouldn't even fire. The engine runs great, it just smokes something fierce on startup. Quote Link to comment
Icehouse Posted May 8, 2007 Report Share Posted May 8, 2007 That's a great story :D well to read hehe My 1200 does the same thing. Its not bad at my shop, its kinda funny when I start it up in the morning in downtown Seattle though :D I've been driving her for the last couple days so I feal your pain buddy :D Quote Link to comment
datsunaholic Posted May 8, 2007 Author Report Share Posted May 8, 2007 Well, one thing it's made me do is change the plans on the B210 engine. I have a second A14- I was just going to clean it up, replace the gaskets. But it's been sitting so long I think I'll pull the crank and pistons and check tolerances AND re-ring if the bores are good (they still have crosshatching so they can't be that bad, but maybe the rings are stuck). This on top of trying to build 2 L20Bs for my pair of '78 510s. Well, all 3 need engines actually. Problem is that '78 510s use a car block and all my bare blocks are truck blocks which means drilling out a new dipstick hole. I have one car block, but it needs an 010 overbore- it reads .007 over in places, out of round. Quote Link to comment
datzenmike Posted May 9, 2007 Report Share Posted May 9, 2007 Doug, I take the spark plug out and push a couple of feet of 3/8 yellow nylon rope down the cylinder and turn the crank on the compression stroke until firmly seated. The rope is squished against the valves and holds them in place and you can leave it over night and finish up the next day even. When done just reverse the crank a few inches and pull the rope out and on to the next. Quote Link to comment
datsunaholic Posted May 9, 2007 Author Report Share Posted May 9, 2007 Yeah, but I have the compressor, and the fitting for the compression tester has a air hose fitting so it works. It's worked fine on both my Mom's Falcon and now my Datsun. I'm more concerned about the amount of leakage past the rings, and I'm pretty sure the oil rings are stuck and inflexible. Quote Link to comment
Icehouse Posted May 9, 2007 Report Share Posted May 9, 2007 Dang Doug you got more projects than me!! I want to fix my a14 but I'd rather get a hyabusa engine :D haha At the price I will fix my a14 instead though. Quote Link to comment
Guest DatsuNoob Posted May 10, 2007 Report Share Posted May 10, 2007 What's the purpose of stuffing the rope in the spark plug opening? Quote Link to comment
Bleach Posted May 10, 2007 Report Share Posted May 10, 2007 What's the purpose of stuffing the rope in the spark plug opening? the bunch of rope fills the combustion chamber enough that when you release the springs on the valves, the valves don't fall all the way into the cylinder. They rest on the bundled rope inside. Also makes a nice rats nest if you decide to just abandon the project. Quote Link to comment
hang_510 Posted May 11, 2007 Report Share Posted May 11, 2007 Also makes a nice rats nest if you decide to just abandon the project. or a wick to draw in moisture, if its only a 'temporary' abandonment :P Quote Link to comment
Icehouse Posted May 13, 2007 Report Share Posted May 13, 2007 I thought the rope was to hold the L motor together :D Quote Link to comment
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