zgeezer Posted March 28, 2012 Share Posted March 28, 2012 My stock strut tubes had a small amount of oil that "submerged" the shock insert. The Datsun Service Manual states that when replacing the shock insert, one should also add 299cc of "damping"oil to fill up the space between the insert and the strut tube. I thought this was to transfer heat from the insert to the outer strut tube. However, I have my new shock inserts ready for installation and the instructions that come with the new inserts does not even mention adding oil. What is the "best", oops, sorry, "preferred" process: put them in dry and move on or measure that 299cc of shock oil and pour it in to fill up the void between insert and strut tube. If oil is the way to go, then: 1. what oil do you recommend and 2. how do you measure 299cc of oil without a graduated decanter? I found one thread that mentioned "submerged" shock inserts, but did not really address the question of whether it is necessary. G Quote Link to comment Share on other sites More sharing options...
johnc Posted March 28, 2012 Share Posted March 28, 2012 Remember that the OEM Datsun inserts were not inserts per se. They were double tube shocks that used the strut tube itself as the outer tube of the shock. 299cc is 10 ounces of fluid. If you pour that much into the strut tube and then slide in a full shock you'll make a giant mess. Spray a little rust penetrant on the inside of the strut tube and then grease the shock body. That will prevent any future corrosion and let the shock come out easily a few years from now. And ignore the posts that follow this that discuss the need for oil to allow heat transfer. If you're working the shocks hard enough to fade the modern synthetic shock oils then you're got other issues. Quote Link to comment Share on other sites More sharing options...
zgeezer Posted March 29, 2012 Author Share Posted March 29, 2012 Remember that the OEM Datsun inserts were not inserts per se. They were double tube shocks that used the strut tube itself as the outer tube of the shock. 299cc is 10 ounces of fluid. If you pour that much into the strut tube and then slide in a full shock you'll make a giant mess. Spray a little rust penetrant on the inside of the strut tube and then grease the shock body. That will prevent any future corrosion and let the shock come out easily a few years from now. And ignore the posts that follow this that discuss the need for oil to allow heat transfer. If you're working the shocks hard enough to fade the modern synthetic shock oils then you're got other issues. Thanks, John, I didn't know that Datsun originals were double tube. I just got back from assembling the strut by adding about 3 tablespoons of 30wt detergent oil. used the insert as a dipstick to gauge the oil level. My question, now, is do I leave well enough alone or disassemble, clean up, grease up, and re-assemble. I'm inclined to leave it alone. G Quote Link to comment Share on other sites More sharing options...
kaito Posted March 29, 2012 Share Posted March 29, 2012 Just leave it alone. You will be fine. Either way is ok. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted March 29, 2012 Share Posted March 29, 2012 Grease 'em like johnc says. I have had them rust in place and that turns an easy project into a really difficult one. I have been using a little oil since that experience and I always overfill and make a big mess. Grease makes good sense. That's what I am doing next time. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted April 4, 2012 Share Posted April 4, 2012 I usually fill the space with something that will best conduct the heat generated by the shock to the surface of the strut housing so it has a better chance of not overheating during hard use. Quote Link to comment Share on other sites More sharing options...
Leon Posted April 4, 2012 Share Posted April 4, 2012 I usually fill the space with something that will best conduct the heat generated by the shock to the surface of the strut housing so it has a better chance of not overheating during hard use. Remember that the OEM Datsun inserts were not inserts per se. They were double tube shocks that used the strut tube itself as the outer tube of the shock. 299cc is 10 ounces of fluid. If you pour that much into the strut tube and then slide in a full shock you'll make a giant mess. Spray a little rust penetrant on the inside of the strut tube and then grease the shock body. That will prevent any future corrosion and let the shock come out easily a few years from now. And ignore the posts that follow this that discuss the need for oil to allow heat transfer. If you're working the shocks hard enough to fade the modern synthetic shock oils then you're got other issues. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted April 4, 2012 Share Posted April 4, 2012 It only takes one ride down a washboard dirt road here in west palm beach to heat them to unbelievable temperatures. Some of us have no choice but to drive them. Quote Link to comment Share on other sites More sharing options...
Leon Posted April 4, 2012 Share Posted April 4, 2012 It only takes one ride down a washboard dirt road here in west palm beach to heat them to unbelievable temperatures. Some of us have no choice but to drive them. Out of curiosity, what's the highest temperature you've measured? Quote Link to comment Share on other sites More sharing options...
johnc Posted April 4, 2012 Share Posted April 4, 2012 The shocks can overhead (very rare nowa-a-days), but what most likely happens on washboard roads is oil foaming. It can occur even with gas pressurized shocks. Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted April 4, 2012 Share Posted April 4, 2012 Howlermonkey, I totally agree with those damn dirt roads. All the autox events have led me through one of those to the playing field. I hate it. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted April 5, 2012 Share Posted April 5, 2012 (edited) These roads here will have 5 inches or more from trough to peak on a washboard surface one day and be dead smooth the next. I'm sure grumpyvette knows what I am talking about and that the amount of energy that the shocks are being asked to absorb is pretty intense. It's an extreme situation but I endure it every day and I would rather my shocks not be insulated by an air gap from any cooling I can get. I'll try to measure the heat next time I have to endure it. Edited April 5, 2012 by HowlerMonkey Quote Link to comment Share on other sites More sharing options...
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