Hey Folks,

Okay, whoever can get me this info quickly wins one (1) internet!

I need to know the length, size and thread pitch of the bolts that hold the gas tank straps in place.

I know there are two long ones and two short ones, but aside from that I don't know. I don't have bolts and I am hoping to source them by the weekend since my car leaves its heated garage on Sunday to come home and I'd really like to mount the tank while it's in the heated garage instead of in my cold driveway. I have some folks across the country with bolts they could send me but they wouldn't be here in time so I want to try and source some locally.

As a bonus, if anyone knows the size and thread pitch of the nuts for the engine mounts that would rock too.

Jon

 

Just a guess, but I'm pretty sure they are M12X1.5

I would guess about 35-40mm for the short, and 50mm for the long. I don't think that the length isn't that critical, but longer does help it be easier to get started.

They may be M10X1.25. I'll try to check tonight.

 

M10X1.25, 2 to 2-1/2" in length.

 

Jon, any update with that front cover situation you were having?

 

T is correct. I had to drop the tank tonight anyway on a friend's car (been sitting for 6 years and had some seriously nasty gas in it ).

Threads are M10X1.25

The short bolts have a 20mm threaded length, and about a 5mm tapered tip. Just go for a 25mm-30mm threaded length for these.

The long bolts are 50mm threaded length w/ no tapered tip.

 

Sweet! Thanks Kent.


As for the oil pan bolt situation, I took the longer of the two sets of bolts and used some washers and they torqued down just fine. Unfortunately I had left it until the very end (I did it literally minutes before we dropped the engine in! I had forgotten, the engine was on the hoist, we were lowering it down and I was like -wait! I forgot about the oil pan bolts!-) So I didn't get thread/size measurements for them. I figured as long as they torqued down and didn't sit above the surface, no prob.

Jon

 

Did anyone manage to get the stats for the engine mount nuts?

Jon

 

Here's another question:

Which ones (short or long) go towards the front of the car and which go towards the back?

 

Short go in the back (near bumper).

I'll check on the nuts tonight if no one gets to you before then.

 

Awesome. I found a fastener supply place nearby that's open on Saturdays. I emailed them to see if they carry bolts of the appropriate size for the gas tank

If this works, I'm going to start documenting the size/thread pitch/length of every bolt I encounter on my car. Maybe eventually I can get a be-all, end-all list of the bolts needed for the car, for future reference.

Heck, at that point I would love to see what it would cost to replace every bolt and nut on the car with stainless steel equivalents! (though I'd only do it as part as a full overhaul obviously, it's not a weekend task, lol).

Jon

 

I know that Sam (dj55b) replaced all his chassis bolts with stainless, so he might be able to help you out there.

And if I don't get to you fast enough on the mount nuts, you should just ask Jeff20B. He is our resident nut/bolt size encyclopedia.

 

We really need to make a list like this:

https://www.rx7club.com/2nd-gen-archive-72/master-list-thread-sizes-2nd-gen-nuts-bolts-367392/

 

10mm x 1.25 motor mount nuts. That would be considered medium thread pitch. For reference, the tension bolts are fine pitch 1.00 and exhaust nuts are coarse 1.5 as Jon pointed out.

 

Ahhh... so the nuts for the engine mount are the same size and thread as the gas tank bolts!

That should make it easy to find - if they have one, they have the other.

I found a local fastener place that's open on Saturdays and emailed them. They have M10x1.25 bolts in 50mm and 40mm, nothing shorter. No problem though, I can always cut the 40mm ones down if needed and use an appropriately sized die to re-thread the end (or screw a nut onto it before cutting it, and as the nut comes off it will re-make the last thread).

And if they have the bolts, then I'm assuming (hoping) they have the nuts to go with them, and that will solve my engine mount nut issue.

Which means.... I can mount the tank this weekend! That's awesome, I can mount the tank, mount the muffler, install the fuel pump, fuel filter and hoses, then all I have to do is source out some vacuum caps and cotter pins, install the beehive and I may actually be able to start this beast this weekend

Wish me luck!

Jon

 

See..I told ya Jeff would know!

 

Wow, how do you know this stuff Jeff? Are you looking it up somewhere, or have you just had to source these bolts/nuts so many times that it's embedded permanently in your memory?

I tried looking in the fiche, but that just gives you a part number, no specs on what type of bolt/nut it is.

Jon

 

I must have a fascination with fasteners.

 

Bang-on perfect with the sizes of the gas tank bolts and the engine mount nuts.

And for anyone who's curious, the drain plug in the gas tank is the same size and thread pitch.

And the threaded holes in the master cylinder used for brake lines are M10x1.0. I've temporarily capped the one that would normally go to the rear of the car because the metal line from master cyl to the rear axel is missing on this car and I wanted to have enough braking power to stop it until I can replace that. Don't worry I won't be driving it anywhere (though I know a few people who have gone entire seasons without back brakes) other than the driveway and possibly the little circle on my dead-end street at 20kph.

I got measurements for the beehive nuts too, I'll post them later when I find the paper I wrote them down on.

Jon

 

- Beehive Nuts
M8x1.25 x3 mount the beehive to the stand
M6x1.0 x2 mount the stand to the engine

and since I got brand new beehive o-rings with my Atkins kit, I figured I'd measure them in case someone wants to source them independently. Here's what my caliper said about the measurements

Beehive o-rings:
ID 16.25mm
OD 20.25mm

Jon

 

M8x1.25 x3 mount the beehive to the stand
M6x1.0 x2 mount the stand to the engine

 

Oops, my mistake - edited and corrected. Thanks Jeff. I must have been pretty tired when I posted that last night.

Jon