Replacement Clutch and Oil Seal Recommendations Please

[Aurigator]

I have a 1970 240Z with a 260Z engine and gearbox. The engine has been rebuilt in 2022 and a new clutch fitted the year before in 2021. I placed a recent post regarding distributor recommendations and we have fitted a 123Ignition system. This morning I took the car for a rolling road setup. It was found quite quickly that I had a slipping clutch and returning home, there as a pool of oil on the floor. Measuring it, it's around the bell housing.

Obviously I need a new clutch and the one I bought on eBay cannot be found. A little research and this one springs to mind:

https://partsfinder.bilsteingroup.com/en/article/blueprint/ADN13012

I remember back in 2021 finding this one too:

Competition Clutch Nissan 240Z / 260Z / 280Z (74-75) Stage 2 Clutch

Competition Clutch Nissan 240Z / 260Z / 280Z Stage 2 Clutch Stage 2 - Street Series 2100 Clutch kit.This assembly provides up to 80% increase in torque capacity and is properly suited for aggressive street use and moderate track use. The Brass Plus material with its alloy backing matched to a...

www.autoextreme.co.uk

However it was not recommended for typical road use.

My first question is ask confirmation that either these two clutched will suffice and whether they are recommended?

The next thing is the oil. Speaking to my mechanic this afternoon, this is obviously a leaking seal. He is busy and we would like to try and change the clutch, replace the seal and some other ancillary work in one day in August. Rather than remove the gearbox to research and leave the car there over multiple days, we would like all spares at hand.

My second question is, what seal has likely perished and where can I get one/them? The only thing that I can find is this:

Rear Main Seal Engine OEM 240Z 260Z 280Z 510

Rear Main Seal kit Engine OEM 240Z 260Z 280Z - 200-716-717 (). New OEM Genuine Nissan engine rear main oil seals for L24/L26/L28.

zcardepot.com

All feedback most welcomed.

 

[stuart barrie]

Gearbox oil or engine oil?

 

[jonbills]

Why is the clutch slipping? assuming you haven't done 100,000 miles since 2021, I suspect the problem is a mismatch between clutch and clutch release collar/flywheel. There are (at least) 2 different height clutches with a matching release collar over the 240z - 280z range that are in turn matched to the friction surface diameter of the flywheel which is either 225mm or 240mm. Both clutches will bolt up to either flywheel.

Do you still have the old clutch that you changed out in 2021? if you know that it had previously worked correctly in the car, you could measure the friction surface on it to know which clutch to buy.
Failing that, get one of each and then research the many threads here and on other z car forums that detail the differences so that when you open yours up, you'll be able to measure the release collar and know which clutch to fit.
Lastly, you don't need a funky expensive competition clutch. Just a bog standard luk/blueprint one etc. Should be about £125..

 

[Aurigator]

Gearbox oil or engine oil?

I guess we will not know until we remove the gearbox. Maybe we should replace the both? The key thing is, both the mechanic and I would like to get the fixes done in one day as [a] he is busy and he does not have the room at the moment to store the car. I'm thinking it would be more cost effective to have all parts needed including those which maybe potentially needed, rather than keep the car there when sourcing parts.

 

[Aurigator]

Why is the clutch slipping? assuming you haven't done 100,000 miles since 2021, I suspect the problem is a mismatch between clutch and clutch release collar/flywheel. There are (at least) 2 different height clutches with a matching release collar over the 240z - 280z range that are in turn matched to the friction surface diameter of the flywheel which is either 225mm or 240mm. Both clutches will bolt up to either flywheel.

Do you still have the old clutch that you changed out in 2021? if you know that it had previously worked correctly in the car, you could measure the friction surface on it to know which clutch to buy.
Failing that, get one of each and then research the many threads here and on other z car forums that detail the differences so that when you open yours up, you'll be able to measure the release collar and know which clutch to fit.
Lastly, you don't need a funky expensive competition clutch. Just a bog standard luk/blueprint one etc. Should be about £125..

We think oil has leaked from the engine into onto the clutch. The replacement will have done less than 500 miles before the engine rebuild and 500 miles subsequent. No, I do not have the old clutch. I suspect that was not original either. That clutch went all together and hence the replacement in 2021.

 

[jonbills]

We think oil has leaked from the engine into onto the clutch. The replacement will have done less than 500 miles before the engine rebuild and 500 miles subsequent. No, I do not have the old clutch. I suspect that was not original either. That clutch went all together and hence the replacement in 2021.

Could be I suppose. The rear engine main seal would generally leak between engine and flywheel, so would have to be a big leak to contaminate the clutch.
The gearbox seal might be more likely.
Gear and engine oil feel and smell very different - I'd think your mechanic would be able to tell which it is if you give him a sample.

 

[Aurigator]

Could be I suppose. The rear engine main seal would generally leak between engine and flywheel, so would have to be a big leak to contaminate the clutch.
The gearbox seal might be more likely.
Gear and engine oil feel and smell very different - I'd think your mechanic would be able to tell which it is if you give him a sample.

I'll give the oil on the floor a sniff. This is the oil on the floor in one week. I'll also take a peak under the car to see if I can see any dripping. I could not this afternoon as the Z and I were enjoying the blat! Either way, probably worth investing in a gearbox seal too.

 

[Farmer42]

You can get all your bits from RockAuto. Crankshaft seals and input shaft seals for the gearbox are not expensive so I would recommend getting both and replacing both whilst the gearbox is out.

 

[Aurigator]

You can get all your bits from RockAuto. Crankshaft seals and input shaft seals for the gearbox are not expensive so I would recommend getting both and replacing both whilst the gearbox is out.

Thanks a million. I will take a look.

 

[Kieronpollock]

Conceptua tuning based in Devon should have your seals