Miles
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Posts posted by Miles
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SBC 350 crate engine with mild cam, Holley Street Avenger carburetor (575 cfm), MSD Street Fire HEI distributor and wires, mild cam, new plugs gapped at .45. No vacuum leaks found. Engine installed in a 72 240z in 2009. Engine ran perfect for over ten years, but started surging at low speed cruise recently. Blocked all vacuum ports and connected vac. gauge to manifold vacuum on carburetor. Reading taken at warm idle.
In the video the engine can be heard speeding up and slowing down (surging) as needle moves on the vac. gauge.
Other: adjusting idle screws has no effect. Replaced needle valve/seat. Float level adjusted per specs. Went up two sizes on primary jets, but no change. Power valve OK. No vacuum leaks.
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See picture. Red circles indicate components that could contribute to the problem you are experiencing.
Note that these cars are about 50 years old and we can expect that the suspension bushings, springs and shocks will need to be replaced.
- Check that the mounting holes in the differential carrier bar (mustache bar) have not been hogged out.
- Check the torque on all mounting bolts/nuts.
Suggest that you replace all of the old rubber bushings with polyurethane bushings on both the front and rear suspension. Also, replace the rubber front differential mount with a solid mount. And no, the solid mount does not cause a lot of road noise. There are several options for a solid front differential mount. Search Hybridz for details on the Ron Tyler mount and the the solid mount sold by Motorsports Auto (MSA). The Ron Taylor mount is designed for racing and high horsepower applications. The MSA mount is more suited for stock daily driver. I have used the the solid MSA mount on two SBC V8 240z projects (built 2001 and 2009) and have had no problems.
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I bought the Modern Motor Sports 240SX rear disk conversion about 15 years ago. I didn't like the placement of the brake lines or the how the parking brake cable attached to the caliper.
- Relocated the brake lines and converted them to -3 AN lines using metric to AN adaptors
- Made one long hard line to go from the T connector to the driver side.
- Cut the hard line mounting tabs off.
- Made a hybrid parking cable bracket by cutting off the 240SX cable attachment and welding the 240z cable attachment in its' place.
See pictures
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I'll go to Tognotti's in Sacramento and pay about $50 more than Summit.
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I buy a lot of parts from Summit Racing. For the first time they will not ship a Holley Street Avenger 80570 carburetor due to California rules. California Air Resources Board won't allow the carburetor to be shipped. I can get the carb locally, but it costs about $50 dollars more.
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24 minutes ago, NewZed said:
They're still working as the wheel drops in to depressions or one side of the car lifts. That's how progressive rate springs work, the weaker end will collapse faster than the stronger end. The problem people have is that the rates are wrong between front and back.
With PU bushings there is no lifting effect from the bushing. So, it doesn't matter when you tighten the bolts and nuts.
I think it's just a bad product. I don't know why people keep buying them. That's why MSA keeps selling them, because people keep buying.
But the coils are collapsed and touching with the car just sitting! Can't imagine that they offer any resistance at all when the car is moving dynamically over dips and bumps or when cornering.
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1 hour ago, adivin said:
001 in front. 002 in rear
As I expected the top (soft) section of progressive springs collapse as soon as the car is on the ground. The collapsed section of the springs is doing nothing. This is why I rejected those springs on my first V8 240Z built 20 years ago. I used non-progressive springs rated at 180 lb/in front and 280 lb/in rear. My car is at stock ride height and is a very comfortable daily driver.
MSA should be ashamed to still be selling those progressive springs.
You can find springs for you car, but it will take some homework on your part. Note: stiffer springs can be shorter than stock springs because the stiffer springs don't compress as much when the car is on the ground. I can install my springs without a spring compressor because they are shorter, but stiffer than stock.
Arizona Z Cars used to sell "heavy duty" springs for 240Z/280Z cars, but no longer sells them. You could call Dave and see if he could give the specs or lead you to a vendor.
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On 12/25/2020 at 10:15 AM, adivin said:
Rather than start a new thread, I'll revive this one. I am having the same issue with the front being higher than the rear after installing the Eibachs. I am using the new Konis made for the 240z from MSA. If my measurement is good, the fronts seems to be about 1/2" higher than rear measured from the rocker. I don't have a hood or radiator on at the moment. Some say it will settle over time. Some say it never did for them. I have 6305.001 in front and 6305.202 in rear. I wonder how the issue finally resolved for PCressey?
Examine the gaps between the coils on the front and rear springs. What do you see?
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Buy this book:
"How to Restore Your Datsun Z Car" by Wick Humble
Try Amazon for source.
The book has detailed instructions on how to disassemble, repair and reassemble the steering column and everything else on a Z car!
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The switch has been NLA for years and the piston inside was frozen. So I replaced the brake switch on my 72 240z with a three way connector. See picture.
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2 hours ago, Witchboard said:
Of course! Have you already tried the larger clips? I went to Ace Hardware and picked up a couple with a thicker diameter wire than the original. Fixed the passenger side, but no dice on the driver's.
The shaft on my driver's side lock is warn down too far.
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33 minutes ago, Witchboard said:
I thought of that too. Thank you for the part numbers.
New floor mounted dimmer switches for vintage cars are available from several sources.
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Old school floor mounted dimmer switch:
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I have the same problem. Please post if you come up with a fix.
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Your cap may be threaded like the attached picture.
Apply heat around the outside and unscrew the cap with channel lock pliers? Propane torch would do it.
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Is the cap threaded? Perhaps it will unscrew.
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Your new MC will have the part you now need. So problem will go away.
The threaded part of the "plug" has a standard thread. The part you are asking about is interchangeable for the the 240Z, 260, 280Z and up to the 1979 280ZX.
Parts wanted: What you want to buy is an old 240Z, 260Z or 280z MC which will give you two plugs and cones.
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The 240z uses a tandem MC. It doesn't make any difference which line goes where. As far as the tanks go, the front circuit has a larger tank. Just switch position of the tanks.
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47 minutes ago, SH4DY said:
Fan is off and it's that cold. Has nothing to do with the fan.
Stopping the coolant from flowing through the heater core via the heater controls seems to keep it in the 160-170 range which I'm OK with.
This is interesting. Please remove the thermostat, take the car for a drive and report back what the temperature is.
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Too cold?
- Remove thermostat and install a flow restrictor. Try Moroso flow restrictor. Start with the mid size (blue) restrictor.
- Install a thermal switch that turns on fan at a higher temperature. Or turn your fan off with a switch.
With the components I listed in my earlier post, once my engine temp a reaches steady state of 185 deg (center of temp gauge) on cold 65 deg days or hot 110 deg days the needle just stays dead center.
You just need to tweak things a bit.
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SBC 350 carbed 240z
Arizona Z Car aluminum radiator + shroud + 3000 cfm Volvo fan + 185 Degrees On/170 off thermal switch + 70 amp fan relay + no thermostat = 185 deg indicated temperature during long idles in California central valley heat (100 to 110 deg).
Volvo fan is two speed, but is wired to run on high speed at all times.
Other: high volume water pump
Works. 185 deg all day
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This is the cooling system I came up with for my SBC 350 240z. It keeps the temp gauge exactly centered (approx 185 deg F) on hot (109 deg) California days even during long stops. The shroud plus the Volvo fan did the trick.
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Buy this book it will save you hours and hours researching 240z restoration issues.
How to Restore Your Datsun Z-Car: How to Restore Datsun 240Z, 260Z and 280Z by Wick Humble
https://www.amazon.com/How-Restore-Your-Datsun-Z-Car/dp/1931128022
SBC 350 Surging at Low Speed Cruise - Vacuum Gauge Reading Interpretation?
in Trouble Shooting / General Engine
Posted
Test done with PCV valve disconnected and hose plugged. Also, replaced PCV valve.
Thanks