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oil in coolant but no coolant in oil.???!!


illestmatic

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Let's understand something here about the Z series engines, it's not just a bolt it in, or a route a couple wires here and this thing will run and drive, the later Z24 has an ECU of sorts, it's more like converting to a EFI engine.

The very early Z series engine like the Z20 might not need that ECU.

 

On California trucks, starting Nov '82 and on  Z24s and '85 and on Z20s used a feedback carb with a variable solenoid jet to adjust the mixture. The rudimentary ECU used an 02 sensor for feedback control. This was a carburetor.

 

From April '85 till the end of the 720 mid '86 a true throttle body fuel injection  with ECU and O2 sensor wa used on the Z24. This was fuel injection with a high pressure fuel pump and two injectors.

 

The Z20 was a Mileage Option engine from '84 on. It was a two liter, 9 to one compression engine with a 3.364 differential. It had a knock sensor and timing retard.... no shit!

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So its currantly 2a.m where I'm at and I'm excited for tomorrow. I will get my U67 head from the shop milled 25 thousands of an inch. The shop guy (tom) mentioned that my cam might get some time advanced because the cam will seat lower/closer to the crankshaft. TOM, being a Datsun 510 racer himself back the days, suggested I get camshaft shims the raise the cam .020 higher to reduce the chances of time advancement. Which I will get and have located a shop who has them. Though one thing I did do is remove the camshaft and rocker arms myself so that tom wouldnt charge me extra. I'm here thinking of how ill install everything tomorrow and am worried that I will have trouble putting the cam back together properly. I'm worried that the rocker arms well have to much tension on the valve springs and not let me tighten the cam down the spec.

 

Is there a propper way to install a camshaft and rocker arms with the valve springs still on the head?

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Hopefully yo will have kept track of the arms and they are going back into their original positions, same with the cam towers.

 

The cam will slide right in without the rocker arms in the way. Give it a spin by hand first to prove there is no binding from the added shims. To instal the arms, just get a pry bar and slip under the cam and between the lobes. Bear down on the valve spring retainer and compress the spring and slip the arm into place.

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UPDATE: okay so I received the head today from the shop and it looks great. Tom milled 24 thousands of an inch which is close enough for me. He did mention the bigger lash caps but quickly stated they'll be hard to find. But that I should be fine with the ones I have..

I plan to clean up the cams, and arms tomorrow and re-install them. Though one torque spec I couldnt find was the cam towers... What is it?

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Hey ratsun I have an issue with the installation of my cam and cam towers. I used the original cam and cam tower of the U67 head but when I put in the cam and tighten the cam towers the cam doesn't spin at all.

 

I was wondering of I can use the cam and cam tower of my a87 head.? Are the cams and cam towers the same for both the a87 and U67 head?

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The head is not straight anymore, you are going to have to shim the towers accordingly to make the cam barrel straight, there are others on here that will likely take you through the steps to fix this issue, if you force it to fit, eventually the cam will break.

I always have the machine shop set mine up, then I know it is right/correct. 

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I am talking about something else, take it back to the shop with the cam and cam towers, they will know what to do, it might need line bored, or they might be able to fix it with shims, take it back to the shop, it is not something they did wrong, it's all about time, time takes it's toll on everything.

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Who knows if those are the original cam towers.  I would take the head and "all" of the related valve train parts to a machine shop.  Have them go through the head again checking and repairing as needed. Have them line hone/bore the cam towers.  Have the head fully assembled.  If head was shaved too much the cam towers have to be shimmed accordingly.  You need a machine shop that knows Datsun L motor Heads.  Have the machine shop assemble the head.  Ask about warranty?

 

One of my pet peeves is people that do not know what they are doing separate L motor head parts.  The cam towers are machined to each head, line bored,  if they are removed from the head and re installed on the same head in a different position the cam will likely be tight or not go in at all..

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