redtop Posted August 21, 2011 Report Share Posted August 21, 2011 I would like to purchase a set of 38mm 510SSS or 510 SSS round top dual carburetors for my 1978 620. These carburetors are sometimes referred to as Hitachi dual SU carbs because they are similar in appearance to their British-built counterparts. I would prefer to purchase a set of these side draft carburetors that that are in mint or in near mint condition. I would prefer that the carbs be complete: to include the the linkage, the manifold, and the aircleaners. I will consider purchasing a set of SU carbs that have been freshly or recently rebuilt and that are in usable (good to excellent) condition. Also, I will consider purchasing cores that I could send to Z Therapy to be rebuilt. Moreover, I will consider offers to sell to me parts for the carburetors, such as a manifold, the linkage, the aircleaners or an airbox, the choke cable aka the throttle cable, and/or the carbs alone. These carbs are known as 510 SSS or 510SSS carburetors. I understand that the carburetors are fitted to an SSS manifold and my be used on a l20b motor. The price I will pay will depend on the condition of the carbs and/or parts that you have for sale. I am looking for other parts for my 620, as well. I have posted pictures of my truck under the 620 section: Redtop's 1978 620. If you have an original air box for these carbs for sale, please contact me. Also, if you have velocity stacks and/or aftermarket or custom-made air cleaners for sale, please contact me. I understand that at least one member on this site has designed air cleaners to work with these carbs. Link to comment
the510keeper Posted August 22, 2011 Report Share Posted August 22, 2011 I have a set of 4 bolt roadster dome top S.U.s mounted to a 2 bolt 510 sss manifold. Totally rebuilt and ready. No aircleaners $350 + shipping. I can get you pics by the end of the week Link to comment
redtop Posted August 22, 2011 Author Report Share Posted August 22, 2011 I have a set of 4 bolt roadster dome top S.U.s mounted to a 2 bolt 510 sss manifold. Totally rebuilt and ready. No aircleaners $350 + shipping. I can get you pics by the end of the week Thank you for responding to this thread. I am interested in purchasing your carbs, and I look forward to viewing the pics. I do have a couple of questions: Who rebuilt the carbs? Did you? How long ago were they rebuilt? What kit, if any, was used? Is the linkage attached? Do you have the throttle/choke cable? Did you use the carbs after they were rebuilt? Do you know what the difference in performance will be between the 4 bolt dome top SU's and the 38 mm Hitachi SU's? Will a "2bolt 510 sss manifold" directly bolt on to my l20b? I am uncertain whether a 2 bolt 510 sss manifold will bolt on to my engine without any modification. If you know, please let me know. Perhaps a call to Z therapy is in order. I know that I have asked a lot of questions Thank you, in advance, for answering them. Link to comment
ggzilla Posted August 22, 2011 Report Share Posted August 22, 2011 The Datsun Roadsters used Hitachi carbs, not SUs, so the performance should be exactly the same per jetting. Before 1973 they were all dome-tops. The 2-liter Roadster made 135HP, and the optional 40mm carbs to make 150HP. But the 38s will be fine for stock-like performance. Link to comment
redtop Posted August 22, 2011 Author Report Share Posted August 22, 2011 The Datsun Roadsters used Hitachi carbs, not SUs, so the performance should be exactly the same per jetting. Before 1973 they were all dome-tops. The 2-liter Roadster made 135HP, and the optional 40mm carbs to make 150HP. But the 38s will be fine for stock-like performance. Thank you for your input, ggzilla. I spoke with Bruce at Z therapy a couple of minutes ago. Bruce told me that I could lose power in the low end should I use dual carburetors that are larger than 38 mm. I believe that I would prefer 38 mm carbs to the larger Roadster carbs which have been offered for sale to me by the510keeper, who, I assume, is very knowledgeable about his carbs. I would like to see pictures of his carbs and do more research before I decide whether or not to purchase them. The carbs may be just fine for my application. Bruce told me that the SSS manifold is a two bolt manifold and that it should work with my 1978 620 and its l20b motor. You appear to be correct about the term "SU" when used to describe Hitachi dual carbs. The term is a misnomer. The term is not used to confuse. The term is used to describe the similarity of dual Hitachi carbs to their British counterparts - the SU carburetors made by Skinners Union. According to Wikipedia, SU carberetors were originally designed and patented by George Herbert Skinner in 1905. There are a large number of British car enthusiasts out there, and I am one of them. In general, British car lovers are familiar with the look of SU carbs. These carbs appear in MG's, Austin Healeys, Jaguars, etc. British SU's have distictively shaped float bowls. I believe they are called "domes" by Z Therapy. I am a newbie to Ratsun. I am not that familiar with all of the terms used to describe Datsuns nowadays. Last month If the owner of a 510 told me, "I have a dime with dual Hitachis.", I would have been confused. Had the owner of the dime told me last month, "I have a Datsun 510 with dual SU's." I would have been able to picture his car in my mind. I read somewhere that dual Hitachi carbs are superior to British-made SU carbs. I don't know about that. I liked the dual SU's on my 1962 Mk II Sprite. The SU's on my Sprite had a small pump. I could could prime the carbs if I hadn't started the engine for a couple of days. I liked that. I do not believe that the dual Hitachi's have a priming pump. Link to comment
ggzilla Posted August 22, 2011 Report Share Posted August 22, 2011 Bruce told me that I could lose power in the low end should I use dual carburetors that are larger than 38 mm That sounds right. If you don't often rev the engine over 5k, go with the 38s. The Hitachis HJE/HJB 38s are most likely a licensed version of S.U. carburetors. They look like the SU Type H but have some differences. They are very well made, but so were the SUs. When you get into the emissions era then people have badmouthed both the SUs and the Hitachis, but I think there is nothing wrong with the newer ones. They have a better mixture circuit, and are a bit more complex, but work well if you adjust them correctly. They did make some 4-bolt Hitachi sidedrafts, for example the HJL series, that have a bad reputation. These were used on 260Z and 76-78 other Datsuns. Link to comment
MikeRL411 Posted August 23, 2011 Report Share Posted August 23, 2011 The SU's on my Sprite had a small pump. I could could prime the carbs if I hadn't started the engine for a couple of days. I liked that. I do not believe that the dual Hitachi's have a priming pump. The Hitachis have a "jiggle" pin to free up the input to the main body if the float output needle gets clogged by crud. "It's not supposed to work that way!" but if you reach under the inlet, pump the "jiggle" a few times it bounces the float and splashes some fuel into the main body. It may not be a "priming pump" but it sure works like one. I have left my RL411 for 2 weeks at a LAX parking lot, jiggled the floats and started on the first crank. Give it a try! Link to comment
redtop Posted August 23, 2011 Author Report Share Posted August 23, 2011 The Hitachis have a "jiggle" pin to free up the input to the main body if the float output needle gets clogged by crud. "It's not supposed to work that way!" but if you reach under the inlet, pump the "jiggle" a few times it bounces the float and splashes some fuel into the main body. It may not be a "priming pump" but it sure works like one. I have left my RL411 for 2 weeks at a LAX parking lot, jiggled the floats and started on the first crank. Give it a try! Thanks for the tip. I'll try it. Link to comment
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