Mark Maras
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Everything posted by Mark Maras
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An assumptions here. The engine doesn't cut out, it just runs out of power under load. I had a similar thing happen years ago. While driving my 240 down the freeway my speed dropped to 45 mph. Kicked in the clutch and revved it to 6 grand. Put it back into third accelerated at full throttle. It wouldn't go past 45 mph. Second gear, same thing. 45 mph was the limit. My Dad knew immediately what it was. Lack of fuel. Mine was corrected (temporarily) by blowing thru the firewall filter in reverse direction. Then a new fuel filter. Hope yours is that easy.
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Stumbling 240Z with Arizona Z car intake and Holly 390
Mark Maras replied to Zaspen's topic in Carburetor Central
The fact that #1 looks good and others are carboned up makes me think the problem is electrical. Probably somewhere in the cap, rotor, plug wires, plug wire connections. New plugs, resistance check on the plug wires, double check the plug wire connections and a good quality cap and rotor should clear it up. Jalex in Panama had a problem similar to this. #4 plug was always a little darker than the rest. He had good NGK plug wires, at the time. He replaced the plugs, and bought a Bosch cap and rotor. His #4 gremlin disappeared with those changes. -
Stumbling 240Z with Arizona Z car intake and Holly 390
Mark Maras replied to Zaspen's topic in Carburetor Central
IMO, the first thing to check is the accelerator pump in the Holley. With the engine off and the air filter removed look down into the carb. and operate the throttle linkage. There should be a visible squirt of fuel. I'd also verify the float level is correct. -
The only info I had at the time (1973) was from the parts guy. I did a quick search and there are bakelite VW wire boots still available but I failed to find one with a resistor. I'd go with either of the ones from Summit. They both have resistors in them. You will have to unscrew the caps from the plugs to use these connectors. Hopefully your plugs have removable caps.
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When I got my first Z, I swapped the plug wires to copper core wires. AM (71 Z) radio static was unbearable. My local parts supplier suggested using VW (I think) connectors that had a resister in them. They were a Bakelite (?) piece that replaced the rubber boot and connector that slips onto the plug. I cut the plug connection off the new plug wires, screwed the new connector on and voila no more static. I ran them for years with no noticeable change in performance.
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@Ryans280z, @DamonR
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As I recall, you're starting it on half choke now. You only need enough choke to keep it idling smooth. When it's idling you can blip the throttle to check the engine response. If the mixture is too lean (cold engine, not enough choke) the engine will stumble a bit before picking up revs.
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Wow, Those are great numbers. Thanks for sharing.
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I've used a lot of Permatex products over the years and had no problems. Either one will do the job but I'd use the 3M adhesive.
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You'll be pleased to know that the slow wiper speed isn't an issue at higher mph. The wipers will lift off the windshield.
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Hello from across the pond! Searching for a 240z
Mark Maras replied to Woody928's topic in Open Chit Chat
I've experienced a transmission whine and a prop shaft vibration. Fortunately at different times. The trans. whine was audible and sounded like a bearing going bad but didn't transmit any vibration to the shifter or the chassis. It was a bearing as suspected. The prop. shaft vibration in mine occurred above 80 mph and was horrendous. Sounded and felt like there was a 600 lb. bumble bee in the back. I replaced the u-joints but there was no change. Took the prop shaft to our local drive line shop to check the balance. They discovered a tiny dent in one side that screwed up the balance. They re-tubed and balanced it. No more problems. I'm not suggesting your tube is bent but it is possible to bend them. Check the u-joints first. Especially the front one. -
Thanks Cap'n. I was hoping you'd respond. I had that nagging thought that it sounded too darned easy and logical. Anyone else want to chime in? @jalexquijano Ignore my last post to you. Leave the floats alone. (Everyone can breathe a sigh of relief) If you want to lean it out a bit (1/4 -1/2 turn) to see how it runs, try it. Most of learned by trial and error. Remember, your plugs looked nice and clean at the current settings and it runs good.
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@jalexquijano A few more thoughts about adjusting your SUs. Make one adjustment at a time. It's fine to adjust both carbs at the same time but don't do anything else until you've driven it for a few days. If you really want to try adjusting the nozzles to 2 1/2 turns, consider this. One turn of the nozzle adjustment screw is 1 mm. Theoretically. if your nozzles are at 3 1/2 turns down you could raise them to 2 1/2 turns down and raise your floats 1 mm to compensate. Anyone out there have any thoughts on my theory? I'm still curious about that last compression test.
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@jalexquijano If you're curious, go ahead and turn the nozzles up about a quarter turn. easy enough to do and undo. However, the previous compression test is still troubling. If the valves are too tight there could be an expensive repair bill in the near future. I would find the reason for the low compression first. Personally I think it was a botched test but maybe that's just wishful thinking on my part.
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I find it hard to believe that's a factory part. The one in grannyknot's pic isn't lead. Lead doesn't rust. That looks like someone? bolted a thick steel plate to the car and started welding on more plate until they got the desired effect or gave up. That thing in the pic looks crude at best. Do they all look that bad?
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I built a good over-sized box from corrugated cardboard first. Cut extra pieces of cardboard to slip inside doubling all sides.Then lots of bubble wrap to pad the enclosed treasure. The two largest items so far are rear glass (extra cardboard on the edges) to Denver and a sizeable non odoriferous tank (that shall remain description-less for obvious reasons) to New York. Both shipments were under $70.00. My thought is the package gets handled less using Greyhound than other shippers. The only negative may be delivering and picking it up from a Greyhound Station.
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L28 Stroker Build - I need your advice :-)
Mark Maras replied to german240's topic in Engine & Drivetrain
That's weird. I'd have to guess dieseling too. Does the engine rotation reverse in that last split second when it dies?? If it doesn't, I'd grab my 4' garden hose stethoscope and start probing. It's a great tool for finding noise sources in hard to reach locations. -
L28 Stroker Build - I need your advice :-)
Mark Maras replied to german240's topic in Engine & Drivetrain
I twisted the little flat bar linkage piece that pulls the nozzle down to ensure the linkage mating surfaces were exactly parallel to the attachment points. That allowed the nozzle to return from the choke position easily. Carb. was removed at the time. I doubt that it can be done with the carb installed. -
The oil will give a lot of resistance which is normal when trying to raise the piston but it should rise (and fall) smoothly.
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I've used Greyhound Package Express to ship large Z parts. Price was affordable and everything has always arrived in good shape, even glass.
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I've never worked on three screw SUs but I recall that the float cover must be rotated to remove it. If you're referring to the float pivot pin, it should just push out of the float cover bosses with finger pressure. Fuel running out of the stacks would indicate that a float is stuck, needle and seat are leaking or the float level is set too high. I think the markings on the butterfly are from ZTherapy. Premier SU rebuilders in Salem Or. Is the piston pin you referred to, the brass jet needle? If so the needle may be bent or the nozzle may need to be re-centered. Try screwing the mixture adjustment 2 1/2 turns down from the top and see if the piston is still dragging on something.
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@maximus35 Jai's 76 is an early one. As I understand it there was a change in the bumpers mid year. She does need both end pieces and the long center rubber strip. BTW. She lives in Chatsworth, Geo.
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@Patcon Jai needs both side pieces and the long rubber? center strip.
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Sounds like the carbs are out of balance. Any early Z shop manual will tell you how to balance them. It's not difficult. I'd start with resetting the nozzles 2 1/2 turns down and then going thru the balance procedure. Dist. is usually set at around 10 degrees advance. There is a good thread about SU tuning. Google "Quick and dirty SU tuning.
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Using crude measurements, I think it will come out. The restriction seems to be the rolled bead at the end. Might have to open up the end a bit. The bead was probably formed after assembly. If the rubber gets hung up in the bead, I'd cut a piece of beer can to use as an inner sleeve to ease it past that spot.
