Hello everybody. My mechanic friend offered to help me do an engine out at his shop this summer. I am doing this primarily to do the 120k timingbelt service but am curious of what are some of the other must do's. I am debating modding vs not. if I replaced the turbo's etc this would be the time.

Also thinking of doing a gasket refresh as well on it.

its a 1991 TT thoughts?

In addition to your list, Knock sensor and sub harness is a must. Reseal oil pan. Engine mounts. PS related items.
I would do as much as you can afford.

1. ALL gaskets and seals: upper/lower/ intake plenum, oil pan, front/rear main seals, cam seals, etc.
2. EFI Harness
3. Turbos if funds allow
4. PS hoses/soft lines

ok great thank you!!!

One thing you can do while doing the 120 kit is replace the idler studs with heavier duty studs, just for the piece of mind. I believe i got mine from concept Z

Bobbymudd wrote: ↑

Wed Mar 18, 2020 9:10 am

One thing you can do while doing the 120 kit is replace the idler studs with heavier duty studs, just for the piece of mind. I believe i got mine from concept Z

I don't think the "upgraded" studs are available anymore. Anyways BDE did a comparison between the OEM and RameyZ studs and the OEM are stronger. If you do want an upgraded studs go with the ARP2000 studs.

I have the RameyZ studs now and will be going back to OEM on my next TB change.

http://www.twinturbo.net/net/viewmsg.as ... id=2622062

Hey, got some questions regarding this. I'm going to perform the 120K mile timing belt job too very soon.

I'm looking at Ebay stuff (I know I know, I'm avoiding "made in China" stuff). But I want to buy this kit that's right under $300 that offers:
an OEM timing belt
GMB idler roller (not complete tensioner assembly)
GMB idler pulleys (lower left & right)
NPW water pump with gasket
Nippon camshaft seals
OEM camshaft o-rings
Nippon crankshaft seal
Gates or Motorad 77 Celcius thermostat and gasket
Bando (AC, PS, and Alt belts).

Is a brand new complete tensioner necessary, or can I get away with just replacing the roller to it (from the kit above)?

Supposedly all the stuff above is made in Japan and meets or exceeds the OEM specs, per the listing. Do you think that's a good kit, or are there other things that are crucial (that the kit's missing)? Please advise. I'm trying to do this on a budget. Thanks.

eekay wrote: ↑

Mon Mar 23, 2020 2:20 pm

Hey, got some questions regarding this. I'm going to perform the 120K mile timing belt job too very soon.

I'm looking at Ebay stuff (I know I know, I'm avoiding "made in China" stuff). But I want to buy this kit that's right under $300 that offers:
an OEM timing belt
GMB idler roller (not complete tensioner assembly)
GMB idler pulleys (lower left & right)
NPW water pump with gasket
Nippon camshaft seals
OEM camshaft o-rings
Nippon crankshaft seal
Gates or Motorad 77 Celcius thermostat and gasket
Bando (AC, PS, and Alt belts).

Is a brand new complete tensioner necessary, or can I get away with just replacing the roller to it (from the kit above)?

Supposedly all the stuff above is made in Japan and meets or exceeds the OEM specs, per the listing. Do you think that's a good kit, or are there other things that are crucial (that the kit's missing)? Please advise. I'm trying to do this on a budget. Thanks.

This is what I did : come to $357. All quality parts not second guessing on "made in china copies"
If you talk to Bernie (first link) he should be able to get you OEM WP and tensioner too.
http://www.twinturbo.net/nissan/300zx/f ... Seals.html

plus OEM WP:
https://conceptzperformance.com/nissan- ... _p_965.php

OEM tensioner:
https://conceptzperformance.com/nissan- ... _p_965.php

itsa300zx wrote: ↑

Fri Mar 20, 2020 10:56 am

Bobbymudd wrote: ↑

Wed Mar 18, 2020 9:10 am

One thing you can do while doing the 120 kit is replace the idler studs with heavier duty studs, just for the piece of mind. I believe i got mine from concept Z

I don't think the "upgraded" studs are available anymore. Anyways BDE did a comparison between the OEM and RameyZ studs and the OEM are stronger. If you do want an upgraded studs go with the ARP2000 studs.

I have the RameyZ studs now and will be going back to OEM on my next TB change.

http://www.twinturbo.net/net/viewmsg.as ... id=2622062

Thank you very much for the info, I was unaware of the comparison.

I got a couple questions if anyone can help out. I'm currently in the process of doing my 120K service. I bought the 120K kit from Concept Z. Concept Z suggests replacing both idler studs. Okay, so I did. I used the double nut technique they put up on their "tutorial" to remove the studs. The technique works. However, when I loosened both studs, my impact gun struggled to remove them. When I pulled out the old studs, the threads were "flattened." I'm thinking it's "no big deal." So I get an M10 x 1.25 tap to clean up the threads in the head and block. I was real careful and went slow. It worked fine. So I finally screw in the new idler stud (to the top) and to my dismay, it's turning (stripped). I remove the stud and see that the tapped thread not only weakened the existing threads, but destroyed them. I'm not too happy at this point, because I was hoping to get my Z up today. I'm gonna have to wait another weekend because I ordered Helicoils on Ebay. So my question is, are new idler studs really necessary? because I have doubts about it after experiencing what I did.

My 2nd question is, my new GMB idler pulleys spin but feel "heavy." The old ones spin fine and freely. Are the new pulleys supposed to spin "heavy?"

The threads that go into the engine are m10x1.5mm pitch. The 1.25mm pitch is the end that the nut threads onto.

Yes the new bearing will be slightly heavier to turn due to oil/grease in them to prevent rusting.

I recommend replacing the studs every 120k miles but can be skipped at 60k.

I screwed on a brand new nut onto both ends of the brand new stud and they thread perfectly. The threads are M10 x 1.25; I checked with the feeler gauge too.

Concept Z advises it, but Z1 doesn't (their 120K kit doesn't offer new studs, which implies you know what).....I'm really upset because of all this trouble I have to go through. If the idler pulleys broke off because of me not replacing them, I would place the blame on myself. Now, I just think they're unnecessary.

You better check those. I’m 100% sure oem idler studs are m10x1.25 on one end and the other is m10x1.5.
Maybe you were sent the wrong ones. Look at the TT.net link on the comparisons.
Go to CZP site and search idler studs for the z32, take a close look at them, especially evident in the arp 2000 studs. One is finer than the other.

13075 F6500
13075 F6501

Nissan OEM

Those are the correct part numbers, if you search them it shows what I’m saying. Two different threads on the ends

I just went to the Nissan dealer and picked up the upper stud (new one); I effed up the first, brand new one that came in the Concept Z 120K kit. You are correct. Thread to the head is M10 x 1.5 and thread to the nut is M10 x 1.25.

Now here's my question, since the damage is already done. I used an M10 x 1.25 tap into the head and block. It's stripped, both of them. Should I try to tap it with a M10 x 1.5, or should I just Helicoil it?

Personally, I would helicoil, will be stronger if done properly. Just be sure it is straight (normal to the surface) as possible.

itsa300zx wrote: ↑

Sat Apr 04, 2020 9:56 am

Personally, I would helicoil, will be stronger if done properly. Just be sure it is straight (normal to the surface) as possible.

Alright. I got my Helicoil kit, M10 x 1.5.....Screwed up again (no pun intended). So being anxious to finish this thing, I followed instructions of the Helicoil kit. I used a 13/32 drill; worked fine. Now was the stupid part. I naively thought the tap would go in straight. Boy was I wrong. So I thread in the Helicoil flush with the surface, and I realize it's crooked....So I Google "crooked Helicoil." People say that if a "turn is out" you can use needle nose pliers and go counter clockwise. I was lucky and did that to pull out the Helicoil.

Now, I have no choice but to drill the 13/32 all the way to the end of the hole, and I do so. So the second time around, I got my old upper idler and tap it through the hole. Wasn't much effort, just a couple minutes and I did it. So now, I get the old idler and make sure I push it up against engine so that there's no tapping in crooked....It worked. However, now the new Helicoil sits in the last half of the newly tapped hole. When I screwed in the stud and new idler, I used my Milwaukee impact wrench (3/8th one) to no. 2 torque setting.....It's spinning, and now my heart dropped. I thought I stripped it. But I remove the new idler and the stud, look inside but the Helicoil threads are fine; no stripping. My question is, since it spins whenever I tighten it should I just use Loctite on both ends of the thread. I used a torque wrench and set it to 32 lbs. but it kept spinning. I'm really afraid of doing more damage.

Update, I fixed that damn thing! I used "Big Sert" which is essentially a threaded sleeve that works if you eff up the Helicoil; that thing was a relief!! There are two lessons I learned from this 120K mile service thus far: #1 I highly disagree that the idler studs need to be replaced with new ones when doing it. Z1 doesn't offer studs in its 120K package, which implies the obvious. I bought this kit from Concept Z. Not talking trash about them, but I don't know why they emphasize replacing idler studs at 120K??? And when you use the double-nut technique to take out the idler stud, the threads are all flattened which means it's years of force pulling on it; so you got to clean up the threads afterwards. I think it would've been better to just leave be....There are so many bolts, nuts, studs, fasteners, etc. that cover the face of that engine, and a lot of them don't require replacement with new. I'm not trying to build my Z to 600+ hp where I need ARP studs for the heads or something LOL!!
#2, I shouldn't have got "comfortable" when tapping the lower intake manifold. I wasn't fully focused and tapped it in crooked, hence me using a "Big Sert" to correct it. There's this cylindrical sleeve in the kit that ensures that you tap it in as square as possible. Thing works like a charm!....I didn't go ahead and Helicoil the bottom idler stud hole. I used a "Time Sert" instead. I just don't trust Helicoil to such a crucial task as holding an idler pulley.