Hatch alignment

[qz16]

CS,

I Think you have a great point about the glass.  I have been concerned about the effect of its weight, and form.  Also, the hatch frame may benefit (not very likely I suppose) from being locked in place against the weatherstrip.  Because the hatch is so much easier to handle without the glass and because the glass is 40+ years old and therefore fragile I wanted to at least get to the point where the hatch would open and close before installing it.  I’ve already got the second strut parts ordered.  They will be here in a few days.  You have helped me a lot in the years that I have been working on the bucket and I respect your experience,  but I have come this far and would like to see the impact of the second strut.  I don’t need a great deal of vertical help to clear the roof line, and the weight of the glass may negate the vertical lift gained by the strut.  You know as well as I that the 2^nd strut is not the final solution even if it works.  If it works I am going to have to get the hinge higher in its mounting.  I don’t want to risk damage to the roof line or even the paint if the strut gets old and fails.  Once the hatch can open and close freely I will install the glass before going any further.

As always, thanks for your advice and experience.

Regards,

q

[Racer X]

I disagree that the glass needs to be installed to facilitate adjustment of the hatch.

I also feel that the original strut  being connected is causing fitment issues, and should not be connected until the hatch is fitted properly.

Also, like I mentioned, it is a good idea to eliminate the new hinges as a culprit in the fitment. 

 

 

Edited September 23, 2021 by Racer X

[Roberts280Z]

I finally tried to mount my hatch yesterday.  I was relieved not to see this type of clearance issue.  I do see that the hatch contour matches the roof contour fairly closely:

I was concerned because I had done a fair amount of patching across the top of the hatch (as well as the bottom). I had fitted the hatch after the bodywork, but that was over a year ago.

In your photos, your hatch does seem to be 'flatter' than the roof?

Of course with new weatherstripping, I cannot close the hatch all the way, but that's another matter.

[qz16]

2nd Strut
It took a while to get the parts for the 2^nd strut .  I did not realize that the body mount was spot welded and the strut bracket was screwed to it.  CS was able to source the body mount – thank you.  Installation of the 2^nd strut confirmed that the strut forces the hatch vertically upward, and provided the extra clearance that was required to protect the body.  The image below shows the 2nd strut loosely installed.

 

vertical rise hatch corner
Earlier in this post I had a similar picture.  In it I had lifted the hatch right corner by hand to show the maximum vertical rise that I thought would be possible.  I did not move the paper with the lines on it.  This latest image below, shows where the hatch  right corner sits in its open resting position with the 2^nd strut installed.  

 

 

 

Patcon - I was wrong about there being vertical movement in the hatch hinge.  My comment made it seem as if there was slop in the hinge.  My hinges are new, and they have little to no slop in the hinge.  As you know, on a 240z there was originally only one strut to help raise the hatch.  As you press upon the bottom of the hatch to close it you begin to overcome the 88 lbs. of force of the strut. As you push down on the bottom of the hatch; the top of the hatch, at the roofline reacts, in the opposite direction.  The left side has nowhere to move as the strut is already forcing the hatch up, the length of the strut being the limiting factor.  The harder you push the hatch to close it the higher the force becomes at the top of the hatch on the right side.  This force causes the right side of the hatch to appear to rise, but it is actually causing the hinge to rotate on its hinge pin and in fact it creates vertical movement at the right corner.  Eventually I think you create enough downward force on the bottom of the hatch to overwhelm the left side strut and the hatch rotates downward to the closed position.  For whatever reason I need a little more clearance (probably earlier in the cycle) to clear the roofline.  Putting the 2^nd strut in on the right side seems to provide that extra lift.

 

Below are the results after installation of the 2^nd strut and aligning the hatch.

 

Left Top Corner                                                                                                                                                       Right Top corner

                                

          

Right Middle Gap                                                                                                                                                   Left Middle Gap

                             

 

Right Bottom Corner                                                                                                                                           Left Bottom Corner

                             

 

Hatch Top Left Gap  Hatch Top Right Gap

   

 

Hatch Roofline

 

Hatch Lip Corners

I am not satisfied with my work on the quarter edge corner or the hatch edge corners.  I guess it just got past me at the time.  I'll do better next time.  As far as the the body line not matching.  I think I will be able to address this with a striker adjustment and hopefully some help from installation of the glass compressing the new weather stripping.

 

 

[qz16]

Someone asked: What do you think caused the issue that required the addition of the 2^nd strut to obtain the necessary clearance?

 

In thinking about this I believe that you need to understand this car’s starting point.  My son, and I bought the car for one reason and that was to have the fun of restoring it.  Our intention was to keep it, so every decision was based on what was best for the car.  I believe that we did not knowingly sacrifice quality in any area.  We bought the best and did our best, if for no other reason than we intend to keep the car forever.  We started deconstruction immediately after purchasing the car.  This is an important point.  We had no history with this car.  I don’t know if the hatch closed properly before we took it apart.  It closed, so the real question is how uniform were the gaps, was the paint at the roofline scuffed/chipped.  The answer on the gaps is that they did not impress me as being particularly bad, or indicative of a body issue.  That’s not a very definitive answer, but it is all that I have.  The paint was in miserable condition.  There was zero clear coat and some rust in the typical spots, right dog leg, right fender near the door, right rocker, lower hatch, and lower right quarter panel.  I don’t  believe that I would have noticed a scuff or chip given the condition of the paint.  None of this really mattered to us because we were going to restore every nut and bolt anyway.  We were changing the color so we were taking it to bare metal and everything had to be removed from the frame.  I am sure that the hatch is twisted/warped.  Not so badly that it would not close, but bad enough that it was perceptible when laid out on something flat.  Now, did it twist because it was forced at some point during its life?  Did it twist over time because of the single strut?  Did it warp because the glass was removed and it was stored for a few years?  Was it warped because I live in Arizona and we get huge swings in temperature?  Whatever the reason and whenever it happened (most probably before we purchased the car) the result is that it has some amount of twist in it.  When the glass is installed will the weight take some of the twist out?  When it is closed against the new weather strip will it tend to right itself to some small degree?  Does the fault lie in the bodywork that I did?  The point is I can’t answer definitively what caused the clearance issue.  The car is 48 years old and we have owned for it for 5 years.  like most of us it has a past. 

Was it necessary to add the 2^nd strut or was there another way to solve the problem?  I can tell you that I believe the 2^nd strut is a positive improvement to a great car.  Nissan thought it was an expense worth adding to an already great car, beginning with the 260z.  My simplistic experimenting leaves no doubt in my mind that having 2 struts to balance the weight of the hatch is a good thing.  And finally, it appears to solve my clearance issue.  Do you need it to align your hatch?  I don’t know, but I needed it to align my hatch given my abilities and level of patience.  If you have a 240z I would check the spot welds on the hatch lift strut body mount.  I would also check the hatch tabs carefully as someone suggested earlier; this may be a manifestation of the uneven force placed on the hatch when it is being closed.

I hope this thread helps someone tackle a job that they might not otherwise attempt.