Blitzed

Ok. here's some pics. The rebuilt steering rack (assumed reassembled with assembly lube) and shipped ungreased. Pics shows a zerk fitting below the steering shaft spline. Does the stock rack not have this zerk fitting in this location? When gunning grease into the zerk fitting, How much is enough (original question) where should I see it ooze to know it's fully greased? Re small bolt: read in the thread someone installed a second zerk fitting in the factory breather hole, passenger side. See pic. Sorry, not a ton of info in the FSM. Thanks, Andrew

Ok searched greasing the steering rack on the site, here we are. 73 240z, purchased a rebuilt steering rack ungreased. What is the procedure? how do you know it's greased enough? Single grease fitting under the steering shaft spline. Do I need to add a second grease fitting on the passenger side small bolt? Thanks.

Thanks all, Confirmed blown head gasket over multiple cylinders. All piston tops steam cleaned on the intake side of the head. First pic is piston #6 how the piston top should look on a high mileage engine, covered in carbon deposits. Second pic is piston #3 nice and clean with drops of coolant on top. #3 was also the lowest compression reading at 150 PSI. It gets worst #4 and #2 have small portion of the piston top cleaned as well, all on the intake side. So the entire center section of the gasket failed. Confusing how all the test I ran where negative to coolant in the oil, carbon dioxide in the coolant. So where did the milky foam go? In my catch can venting the valve cover and block, the dreaded milky foam was present when I opened the valve :(. The engine starts and runs fine, not smoking???????????? Open the wallet and rebuild.

Thanks all, These engines can send you down a trail. Will report back on the head bolt retorque and the new valve stem seal maintenance. Will check the seal on the radiator cap but I've put to bed any external coolant leaks with the cooling system with all previous testing preformed. Another internal coolant leak test preform. Parked the car on my driveway incline (engine elevated) with a large coolant bleeder sealed in the cap neck and the bleeder tank full let the engine idle for 20 mins, opening the heater core valve. After the thermostat opened (140) rev'd the engine and idled for another 10 mins (160) closed the heater valve and rev'd again, zero bubbles or air escaping into the bleeder tank.

This started with loss of radiator fluid. Not running a closed system or overflow tank so not sure if it's just evaporating or steaming out the cap tube. Not a lot but I'm topping off more than usual. Nothing visible on the block, water pump, hoses or floor. So I'm checking for a blown head gasket. Engine runs fine. Next question is it steaming or white smoke out the exhaust, yes, cold starts only for a few minutes. once up to temp gone and restarts at temp no white smoke. California climate, it's not very cold, 50's. I've run every test on the radiator, pressure test, holds 15lbs for 24 hours. Chemical carbon dioxide test at the radiator cap, negative, stayed blue. Put the pressure tester back on and put 10lbs in the system, rev'd the engine to 6K rpm, no change in fluid pressure. Even checked the oil with the sizzle test. Heated a piece of tin and dropped engine oil from the dip stick on the tin, just smoked like oil should, if it's sizzles and crackles there is coolant present. All negative. No milky substance in the radiator fluid or oil, all is clean. So moved to compression testing, could be chasing my tail. The valve cover will come off to inspect and change the valve stem seals. I know, not a fun job. Will inspect all other components while preforming the service and retorque the head bolts.

Thanks Zed, N42 head, the pistons look dished from what I can see from the spark plug hole. Will borrow a engine video scope to confirm. It's a high mileage engine so the compression number should be low. With dished piston what should the PSI numbers look like? I've seen 155-170 range range 8.3.1. First test was a warm engine. Was going to run through a cool engine comp test. The compression tester is a OEM with a 15" hose, rental from Autozone. So not sure how accurate? ITB's so when I use a airflow synchrometer (in the horn), cylinder # 4 highest comp, lowest airflow reading.

Need some data. Purchased 73 240Z with a transplanted L28 N42 NA engine, from the mid 80's (high mileage engine). Have zero history of the parts used in the engine. What PSI compression ratio's should I expect on an old rebuild not knowing dome or flat piston. How can I verify the piston config? All seam to be in the 155 psi range # 4 cylinder is the highest at 162 psi . Interesting that # 4 with highest compression pulls the lowest vacuum number on the airflow meter at the intake? Thanks.

Read my post from 5/1/2023. Tried everything vibration would not go away. The stock (I said stock) Z suspension control arms with rubber bushing were designed for max 28lbs -30lbs tire air pressure on narrow tires. You're probably running a wider tire with a manufacturer suggested air pressure of 32lbs or 36lbs. I don't race but have been told most car drivers will reduce air pressure on the track. So just reduce your air pressure to 24lbs in the fronts and 24lbs in the rear and see if the vibration goes away. If so, begin to add pressure 2lbs at a time to find the tipping point with the tire pressure / suspension and the vibration. I'm running 25lbs fronts and 26lbs in rears on the street (15 60 205), no vibration. Is the car harder to steer at low speeds, yes but the steering wheel is much more enjoyable at driving speeds. Took it a step further and had the wheels (rim), tire, hub and rotor dynamically balanced (single wheel dyno) on the car. Downside, wheel must remain in the same position on the car, mark on the hub and no rotation. Good luck.

Very cool, congrats.

I agree "crap" I did remove it but I met a freak who's going totally original/ stock with his engine. I'm selling the tube, emission components are a must for the buyer. so need to return the component's the way I removed them. That's the challenge. My engine is EFI :). California is not requiring smog on exempted vehicles, the way they're going to get us is huge annual registration cost to drive the mass polluters, it's coming soon.

Hi All, Happy 2024, Hope all is well. Another DA who took apart a stock balance tube with pics and still can't figure out where everything mounts. N33 tube L28 .Even with the FSM manual, I seem to have a couple valves not sure where / how they mount to the tube? First image What this? Fast Idle for Air con? Where does it mount? Second image , have two valves very similar one mounts on the tube where does the other mount? Both have the same two hole mount bracket? Thank you,

As a new owner of a 240Z (2018) it amazes me when I meet a original owner of a Z purchased new and beloved for 50+ years. Several owners at ZCON had similar stories. Hagerty posted a story of a 240Z owner, check it out on Hagerty site, weekend road trips. https://www.hagerty.com/media/car-profiles/original-owner-a-navy-sailor-returns-home-to-a-new-datsun-240z/?

ZCON produced some incredibly Z builds, can you say 240Z GTR AWD. Not for the purest but pushing the envelope on what's possible with our beloved Z's. The event was assume great people, great events and great Z's. The hosting club and affiliates put together a assume week long event.

Kit includes the rail? I'm in. Running single coil sequential now but the EFI distributor allows conversion to COP or batch. Let me know when the kits are available.

Hi All, Trying to correct the vibration feedback in the Z's steering wheel is one of those problems you can chase down a rabbit trail and add additional dollars redoing services, unless you find the correct service / shop. Drove the Z to Solvang, CA this past weekend for the Datsun Roadster Classic (they include Z in the show), 340 mile round trip drive and the steering wheel vibration at 60+ drove me crazy the entire 300 + mile drive. Below 60 MPH puts you in the slow lane/ truck lane on the highway's which is also the roughest lane on the highway which compounded the issue. Took the Z to Nate Jones Tire in Signal Hill CA today. Wow, what an eye opener. Nate is an 80 years old, racer, builder and great resource. The service included truing the wheel (rim and tire) on the car. Frist tire pressure, Nate knew the Z's stock suspension was designed with a tire pressure rated at 28lbs max. I was running 36lbs on 205. Tires have too pressure for the suppression. He knocked the fronts down to 26 and rears to 28. Suggested with the mass of the tire, could run as low as 24 in the fronts and 26 in the rears for (dry) highway travel, track add 4lbs front and back. Next removed and rotated all tires with the valve steam to line up over a stud location. This became the static mounting location for the wheel, on and off, must mount in this location ,no future rotation. until the tire is shot Jacked the front up and rolled a custom machine (looked like a lawnmower base) and attached to front tire. Hit the inside edge of the rim lip with a small grinding blade, knocked down any shimmy / wobble imperfection in the wheel (rim) during rotation. Next trued the tires. We all let our cars sit for extended periods, this can create flat spots that will cure it self over time and miles. The equipment shaved grooves in the tread (top not side wall) and trued or rounded the tire. Next rolled another unit to the tire and applied a counter weight ring on the outside of the rim. Than rotated the tire and wheel (on the car) at high rpm. With a several feelers hitting the rim edge inside and outside and a strobe light he picked up the balance position of the wheel and tire at high RPM. Applied weights. The end result, vibration in steering wheel gone, vibration in car gone and a quieter cockpit. Great experience with I fear is dying expertise.

Thanks for all the suggestions. The issue is defiantly rotational, as above 70mph it begins to fade, still there but not as strong. Just have to drive 80mph all the time :). Found the shop to fix the issue. Lucked out and found two guys running a shop who came from the aerospace industry. Designed wheels and tires for NASA vehicle's and speed record cars in Bonneville. Walk into the shop (tiny old building) and they just finished a week at the Long Beach grand prix truing wheels and tires. https://www.natejonestire.com/ They listen to my story and said you're battling unsprung tension? The service is cheaper than new tires, will report back after.

Yeah, the rabbit trial has been long and expensive redoing parts/service twice in two years, new wheel bearings, nope, new tie rods, nope, reset the tension rod preload, nope, rebalanced the wheels and tires (counter), nope. realigned front end, nope. Every suspension bushing was replaced 2020 (rubber). took the car to Mike's Z shop, owner drove the car on the freeway, inspected the front end on a rack for a week, could not find a issue that would cause the shimmy. Only part untouched, the rack. Will check the hub trueness.

Hi All, Done everything I can, shimmy is still there at 55mph+ . Had wheels and tire counter balanced and now have weights on the inside and outside dia of the wheel, not good. Suggestion was replace the tires with a softer compound. Currently running 205 60 R15 BFGoodrich Advantage T/A Sports. For those who's shimmy went away with new tires, what brand and model did you go with? Don't need the size, just the tire brand and model. Sucks to waste the dollars on a new set of shoe's after only 700 miles. Thanks for the info.

this maybe the same question but does the front edge of the seal sit up against the inner bearing or is there a slight gap between the bearing back and the front lip of the seal? Inner hub has a lip above the bearing race and seal stops at this point. With the seal at this point the inner bearing can still wobble. Is this correct?

Hi All, 73 240Z 5 speed WR, R200 and ZCG CV axles (no U joints on the shafts) Experiencing thumping / vibration sound from mid to rear of the car at 45+ MPH and the thumping/ vibration sound gets more rapid as speed increases. Leaning towards the drive shaft U joints? under the car for inspection, rotating the drive shaft there appears to be play/slop not sure if this is normal? Any other test to determined if the DS U joints are compromised? Both joints have zerk fittings and are well greased. All other components in the rear have been replaced in the past two years, suspension bushings, wheel bearings and seals, R200 rebuilt, new diff mount, mustache bar bushing, springs, struts, brakes, wheels and tires. Thank you.

Also wondering if the type of bushing replacements adds to the overall (what if?) with larger wheels and tires. I went all new rubber bushing with stock suspension components as opposed to Polly. check the center hub opening on your aftermarket wheels. Make sure your wheel is seating flush on the hub plate. The stock hub has a 1/8" lip at the lug mount plate. you may have to grind the inside edge of the hub wheel opening to clear the lip on the stock hub for a flush wheel to hub mount.

Siteunseen, Did you have the steering wheel shimmy? If so did these lugs help with the shimmy?

Chasincats, Can you buy a lug nut for Konig rewinds that have a straight shaft (non accorn) with a beveled washer? Do not want to drill out the wheel opening.

Wheel has the same countersunk bevell and the lug nut. Sold with the wheels.

Ownallday, Where are you with the vibration? Did you find and solution? My 73 240Z with the entire front and rear suspension replaced all new rubber bushings, new tie rods, new wheel bearings ,ball joints, new shocks and springs, new polly bushing on the rack and steering coupler, Konig Rewinds 15 x 7 and new BF Goodrich TA 205/60/15. Rebalanced and re-aligned, twice. Steering wheels vibrates at 45- 50 MPH. The only part untouched is the rack, original to the car, no play in the steering. Prepping the car for a 300 mile highway drive, it may shake apart along the route 🙂 I'm going to throw more money and time at it and replace the wheel bearings, again. How many folks on the site did wheel bearings fixed the shimmy problem? Thanks