| Performance Mods There are really a lot of options when trying to upgrade a first generation civic motor. If you would like to stay with the same motor you've already got. Check out this stuff: Block: EB1, EB2, and EB3 are more or less the same block, the EB1 (73-74, 1169cc) had a factory 70mm bore and cannot be taken out as much as the EB2 and EB3. The EB2 (75-77, 1237cc) and EB3 (78-79, 1237cc) are pretty much the same block, they had 72mm bores. They just had a different head and pistons. Standard block/stroke, find a set of Honda Goldwing GL1000 pistons. These pistons have the same pin as the 1200, and come in 72mm oversizable up to 73mm. These pistons are still availabe new and yield 1272cc's (w/73mm pistons). They'll bump your CR substantially and are a great performance mod. 2nd Generation 1300cvcc crank/rods with 74mm pistons (any really). I'm using 1975cvcc flattop pistons on my buildup, yielding 1410cc's. From what I've gathered people also like to use the EB3 domed pistons in an EB1 or EB2 to bump C.R. a bit. It's a pretty easy swap, though there might be clearance issues with the smaller combustion chamber, don't recall. There's also the option of the Goldwing pistons (73mm), and the stroker crankshaft. People have done this with good results, very quick actually. This would yield 1372cc's. Also, there has been brief discussion about using the 1500cvcc crankshaft in one of these little beasts. And apparently somebody's done it before, but I think it requires either custom rods, or welding a bit more material to the top of the block and having it resleeved, I'm definitely going to build one someday.... whee. ARP Rod Bolts: #207-6001 ARP Head Studs: #207-4001 Total Seal Rings: I ordered a set for $35, but was advised against them unless I planned on running alcohol. You can also spend upward of $150 on Total-Seal rings. These are prices for 74mm rings. EB1,2,3 Stroke: 76mm 1300cvcc/EN1 Stroke: 82mm Carburetion: First off you can use your stock two-barrel. Or you can bolt on (with adaptor plate) a 32/36 Weber DGV. Some people may tell you it's not right for the engine, but the masses say otherwise. There is the dual Keihin option which was standard issue on the 73-75 RS Civic. There is a quad-carb Mugen (?) setup that will wind quite well.... if you can find it. There's also the single and dual sidedraft option. Cannon, and others I believe, made an intake that will fit a single Weber DCOE/DCOM, Dellorto DHLA/DHLB, or Mikuni PHH carburetor. There are also a few DUAL sidedraft manifolds floating about the globe. If you can find one... your honda will FLY, the only drawback is that some require a 90degree conversion for your distributor. Exhaust: There's the option of the RS 4-2-1 manifold. This seems to be a good mod if you're not trying to go off the deep end with your motor. It will improve a stock motor or mildly built motor substantially. If you're luck you can find a Jackson Racing, King Motorsports, or Mugen style 4-1 exhaust header. Most of these I've seen come out the front grill and sweep back under the car. Exhaust diameter... from the information I've gathered, a good size for these cars would probably be 1-7/8" if you desire a good bottom end, 2" for a happy medium, and 2.25" for minimal bottom, good top end and a really nice exhaust note. If you're boosting your civic, don't go below 2", personally I wouldn't go below 2.25". I'll probably use 2.25" since I'm going for a 9500+ shift point, and eventual boost, excep that I just read that the rod/stroke ratio for the 1200 with the stroker crank limits it to about 8K... sad, I'll figure something out. Most people seem to run a glasspack in place of the factory resonator, and some generic turbo muffler out the back. I've also seen quite a few people fit a supertrapp muffler or other expensive exhaust options. Head: The most common heads are the EB2 and the EB3. The EB2 is a smaller valve head than the EB3. The EB2 valve sizes are 34mm intake and 31mm exhaust. The EB3 head has a 36mm intake and a 32mm exhaust valve. The EB3 also has a larger combustion chamber than the EB2, and different runners if I recall correctly. The EB3 is typically the head of choice. A heavily worked EB2 can flow better than a stock EB3, but then you work an EB3, you get the idea. I'm planning on using an EB3 head, with custom small-diameter-stem stainless-steel valves ($25 each from Manley). I'll have 37mm intake valves, and 32mm exhaust valves. I'll need to have custom valveguides cut for this, big deal. One kicker is that I'll need to get the valve heads ceramic coated because otherwise they'll heat up too much and fail. The stem helps dissipate about 24% of the heat absorbed by the valve during combustion. Cutting down the diameter also cuts down the surface area, making the valves not cool as efficiently. There are several companies that will still make a cam for the 1200. Web Cams has several grinds for the 1200, I believe Colt Cams does also, and Shadbolt also made cams (they still may). Most people go with Web Cam and get the Street setup. I've seen people with adjustable camgears, but I don't know where they come from. Though I'll be making my own soon, as I have three of the cast ones to play with. Tranaxle: There are quite a few transaxles that will work with the 1200. The stock 4 speed has a 4.93 final drive, any first generation transmission will bolt up to the 1200. I believe the best transmission for these cars is the 5speed from the 2nd gen. 1300cvcc. This transmission has a 4.93 final drive, lower 1st, 2nd & 3rd gears with a taller 4th and 5th gear. Recently some people were trying to mate the 1200 to the early accord transaxle. I believe it can be done, but requires an awful lot of work for what you get. A 5spd that you could have hunted around for and got from a later model first gen. |