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Tom1200

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About Tom1200

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  • Location
    Las Vegas
  • Cars
    Datsun 1200 coupe
  • Interests
    Vintage racing, rally , vintage motocross, riding my Beta 520RS

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  1. Ok late to the party but as one of the few guys on here racing an A-serIes powered car I will chime in. First, I too am a fan of bike carbs. I was lucky enough to score a set of flat slide carbs and custom manifolds about 10 years ago. Mine are non CV which do not have the restriction of the throttle plate like CV carbs do. CV carbs are still perfectly fine they just flow less. The bike carbs like R1 or Keihin flat slides like I use are essentially downdraft (45 degree angle) and so they clear the brake master cylinders. The classics dual DCOE style require the master cylinders to be moved. As as for cylinder heads; the A15 motor commonly used shrouded ports. Datsun1200.com has pictures that show the obstruction. No one has tried hogging out the port for fear of hitting a water jacket. The heads you want are either the H89 or the GX head. GX heads are pricey. A race ported one one will set you back as much as $2000, I paid $600 for an umodified GX head several months ago and then put about 20 hours in the head. As for porting the biggest gain is in the valve seat valve bowl area; the seats are narrow then the port and protrude into the port by near 2mm. Cutting back this step with a dremel and then taking material from around the valve guid to open up the port will net the most gains. Then of course match the manifold gasket to the head and manifold. You can go few ways here: A. Install a weber DGEV 32/36, port whatever head you have, use a Delta 278 cam (moderate street cam), Isky valve springs, header and 2" exhaust. This will net you around 12-15 horsepower. B. Get an H89 or GX head port it and fabricate a manifold for bike carbs, use SI tapered stem valves , Delta 278 cam and 2" exhaust. This will net you 25-30 horsepower. C. Add a set of flat top pistons to B. and you get 99hp at th wheels (this is the set up in my car) D. Use .30 over Mazda Miata pistons which will take the motor out to 1600cc. You will have mill 2mm of the top of the Miata pistons and have the small end of the connecting rods from 19mm to 20mm. This will necessitate the use of premium as well as being consecutive on the timing becuase the motor will now be at 12-1 compression. This will get the car up to 112-115hp at the weeks but you'll now have ventured into the less street friendly zone. E. Order 77mm pistons from SW Motorsports in Australia ($170 US including rings) these have an 8cc dish and keep the compression to 9.5-1 with a standard head gasket and 10-1 with the .6 race gasket. With all that said cost wise I'd go with A. as for the cost of building up an A-series you could swap over to a L20 or KA24.
  2. 1200 Utes are still a unibody/monoqueue same as a coupe & sedan. Along with the other guys it looks to me like you are probably hitting the bumps stops with as low as the car sits. When I first raced my coupe, we used lower blocks and I ended up cutting the bump stops quite a bit. Stock 1200 springs come with material in between the leaves to cut down on stiction but even if they are totally gone they are not going to cause severe harshness. They will contribute to it but it's not a pogo stick to Cadillac difference. Part of the issue with radically lowering the car is the damper/shocks are not operating in their optimum range. Here is what I would do: 1. Put a big smear of grease on the bump stop and see if it's hitting the axle in normal driving. If it is cut the stop until it stops hitting. 2. If the bump stop isn't hitting the axle tube put a 150lb load in the bed and see if the ride improves (you need to check the bumps stops aren't hitting after adding the load). If the ride does improve then take the small leaf out of the spring pack (see datsun1200.com and look for the race suspension manual it talks about this) 3. Go to the aforementioned suspension manual and see the modification for lower/extending the shock mount stud in the mounting plate. This will get the shocks in the proper range of travel. 4. If all else fails just raise it back up. If you currently have the rear lower than the front, get it back to the standard rake (read front and rear near level)
  3. One thing to add. The brake balance is going to be off after installing the ZX strut/caliper. Probably not an issue for most street cars but it's going to put more front bias into the system. You can restore some of the balance by using larger wheel cylinders on the rear brakes. I run a H190 on my car so it's better than the original rear drums but I am going to the 240Z wheels cylinders as I prefer more rear bias on the race car.
  4. So in 2014 I had an A12 in my car that had been in the car for something like 60 race weekends. The last 3 laps of it's last race motor dropped 100 rpm ever lap. When I got it home it had 80psi across the board. While the valves weren't bad the rings were shot and the bores weren't great. If it were a street car I'd have slapped some rings in it (possibly some bearings) and called it a day. A basic leak down test will give you an idea of what's going on. You can do a basic hillbilly rebuild (as noted above) or do a basic rebuild. You could probably get a piston set from Rockauto for around $125 and your local machine shop likely charges $150-$175 range to bore the block. Add in the cost of bearings, gaskets and possibly a valve job and you may be all in for $600. I'm of the same mindset as Stoffregen; take it apart inspect it, replace what needs replacing and leave the rest.
  5. Bike carbs can be perfectly streetable; like any carb they just need to be set up. Besides a custom manifold; you'll need a custom throttle cable; we modified one by soldering on the proper fitting for the bike carbs. A place like Terrycable could make one for you. You'll need a good fuel pressure regulator as bike carbs will need to be regulated below 2 psi, I run 1 psi on my regulator. I got the flat slides on my car running 80% in the garage, then went out to an abandoned mining road (mine is not a street car) and got the car probably 98% there. The final 2% was had with about an hour of dyno time, which cost me $100. For what you are doing you could also go with a single Weber DCOE. First thing you need to do is find out what head is on there; if it is the H95 and you want to get anything out of it you'll need a different head before you do anything else. Adding 20 horsepower really does make a huge difference; the car is never going to be fast relative to new cars. these things did 20 second 1/4 miles in stock trim and my heavily modded A15 powered car is/was (I have an A12 back in it) probably in the low to mid 15s. This is Mazda Miata level acceleration. With the A15 my car would slightly out accelerate stock NA Miatas. Now the news is not all bad think total package; Get another 15-20hp out of the motor (possible with the DGEV). When I say 15-20 I mean over stock, your car already has a header and larger exhaust. Upgrade the brakes (Datsun1200.com has several cheap upgrades for B210s), add a decent set of shocks/slash dampers, a set of Addco anti-sway bars, some slightly wider wheels and tires (175/70-13 or 185/60-13s). The 5 speed is a big plus; if you can find a 4:11 ring and pinion for the rear end that will also help the acceleration and the 5th gear overdrive means it won't be revving it's guts out on the freeway. Do all of the above and it will be a fun old car. By virtue of instructing at track days I get to drive a lot of really cool cars, I even have a fairly rapid single seat formula car but I still find moderately modified Datsuns to be a lot of fun. Just don't expect them to be fast. A perfect example is a $35,000.00 heavily modded 510 turns the same lap times as a $10,000 moderately modded Miata.
  6. First and foremost the dual DCOEs will not fit because the master cylinder on left hand drive cars is in the way. The DCOE kits are available because Japan & Australia have right hand drive cars and so it's not an issue. Additionally on race cars most people move the master cylinders anyway. You choices are move the master cylinders( you may be able to fit remote reservoirs to the master cylinders to gain the needed clearance) or you can run a single DCOE set up. You do have another choice and this is the route I went on my 1200; I use motorcycle carbs, the Keihin flat slides I use, as well as others, are downdraft (they are in a 45 degree angle) and they will clear the master cylinder. One of the 1200 members is selling a set of custom intakes for these type of carbs. For street use I would use CV style carbs as they are cheaper than the Keihin FCR carbs. So back to the A15 on your fathers B210; what head is on there? round port oval port? The DCOE carbs dependent on engine tune may add nothing or minimal power. As with most motors all the power is in the head. If the A15 you have has the H95 shrouded port head, the DCOEs will add nothing. You'll want to find a different head, an H89 head works well for the street (the number is stamped on the head, you'll need to remove the valve cover to see it). As B210s came with A14s, if you're using the A14 head then webers may be worth it. Here is what I would do; install a moderate cam, clean up the ports (especially around the valve seat as the seat protrudes into the port by 2-3mm), add a weber DGEV downdraft (it bolts onto the stock manifold) dual valve springs, SI valves (the stems are narrowed near the valve head for more flow) the and use the .8mm GX head gasket to up the compression (it will still run on pump gas). All of that would add around 15-18hp. While that doesn't seem like a lot it will likely take a full second off the 0-60 time. Note the motorcycle carb set up (provided you have a decent cylinder head) would be good for another 7-8hp. The current motor is probably making all of 45-50hp at the wheels, so we're talking about a 20% power increase with the above mods. The A15 that was in the 1200 I race made 99.8hp at the wheels at 8000 rpm, while it would be perfectly streetable it was all high RPM power. At 6500 it made 95hp, at 6000 it was down to 88hp, at 5300 it was down to 78hp and by 4300 it was down to 64hp. Finally give us more detail on the car, year of the car year of the A15 etc.
  7. I'm assuming the vacuum pump is for the brake booster? Note the 1200s don't have power brakes, so the loss of the vacuum port wasn't an issue when I installed the Flat Slides.
  8. Yes I seem to recall L16-L20s being between 60-70hp at the wheels, 510s are light but you'd need around 90whp just to keep with a Miata.
  9. Since you mentioned fabrication skills I'm going to reply based on parts being your only cost. Take the existing head you have now, clean up the ports and install a more aggressive cam. Fabricate a manifold so that you can install motorcycle carbs (carbs on ebay are stupid cheap) For a two liter motor 41-42mm bike carbs will do for the power level we're taking about. After that install a header and appropriate size exhaust. Realistically this will add around 15-20hp but it will be well under your $1200 budget. As for a turbo L-series, I generally concur that in otherwise stock trim it's likely to go kablamo. You can keep the motor together if you run really low boost but then the horsepower isn't going to be all that much of an increase so you might as well play with the option I mentioned above. As a fabricator you could also find a Nissan V6 and install that, I think those are around 160-175hp range but don't quote me on the exact figure. You should be able to find a wrecked truck for $1200. The reality is even 140hp in a 510 will make it scoot nicely...……..it won't qualify as "stupid fast" but you'll no longer be out dragged by some guy in is Prius as one tends to be in a stock/stockish 510.
  10. I'll assume the good L series heads, much like the A series, are getting scarce as well as expensive.
  11. A friend allegedly has a line on a twin carb L16 (SSS?) that can be had stupid cheap..........if it pans out I'll likely stop being lazy and do the swap. Otherwise I'll eventually get off my duff and build a 1600cc A-series motor. In the meantime I've been redoing the engine cowl/tail section on my 87 Novakar Formula 500..........so I'm not completely lazy. 110Hp In a Sprite would make it scoot nicely...........those darn Minis are sub 1400lbs and making something like 115-120hp at the wheels. Now wouldn't that Sprite be even fast with an L23 in it??
  12. Under 10 mph I will assume this is in first gear; what RPM and what throttle setting? 1200 rpms 1/2 throttle etc.? We'll need to no exact conditions to tune it via the internet. It could be excessive drivetrain lash, something like a severely worn ring and pinion but that would likely do it at other speeds to some degree. Go through this methodically; with the clutch fully engaged at 5 mph try gently rolling into the throttle, repeat this process but roll into the throttle more quickly each time. Next what kind of shape are the dampers/shocks in, if they are sacked it might make the car feel jerky. As someone who has owned and A-series powered car for 35 years I can tell you they like revs when you take off, they don't particularly like it if you trying to roll off a light with less than 2000rpm.
  13. The Datsun A-series is a great motor, the problem is the cars I have to run against in C-sedan or vintage GTL (under 2 liter). C-sedan is full of vintage Minis that are turning the same lap times as the SCCA GT-L lap record Fortech Mini. I'm to cheap and don't want those kind of maintenance intervals (refreshing the engine every other race). In GTL I'm up against 2 liter cars (I could actually run an SR20 or CA18 but right now I'm a bit burnt out on projects) so even with the largest overbore I'd still be at 1608cc. Given the level I run them at the best I can expect is around 115whp. My 1204cc A12 is currently belting out 78 rwhp and the 1508cc motor with 37/33 valves made 98rwhp. The car is currently 1672lbs with me in it (I weigh 145lbs). There is also no making it up from the driving standpoint as I've already been told by most of the people I race against that I'm driving the wheels of the thing....including a friend who is a professional driving coach. I need to be around 135-150rwhp to be competitive in vintage GTL; Dave Patten's all out A15 managed this but he was changing head gaskets as a regular maintenance item. An L16/18/20 would achieve these number much more easily than the A series would. I often think an L16 would be the way to go as people will practically give them to you and it would only add about 40-50lbs to the car. Full Disclosure: OK so the real problem is I'm cheap and lazy.
  14. Not installing one in your 1200 even though the rules for the vintage group you race with would allow it for your class. Continuing to build A-series engines when you know the same effort put into an L series engine would net 20% more power. OK so I have nothing real to contribute to this thread
  15. Tom1200

    280zx struts

    The top hat will likely fit up in the strut tower; the B210 as Mike noted is using a 2" outer diameter tube. Most of using these also use the camber plates as well and those are much more compact then the standard rubber donut style top hat. There are place that can do a complete kit $$$ or you can piece it together yourself $, just scroll though the pages to see what you need.
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