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  #31  
Old 22-03-2015, 05:48 PM
SKiddell SKiddell is offline
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Apologies for the banter Mr ZedHead, I will bow out with the following


Quote:
By 'get it right' I speculate that you mean optimise
No, in my books with a high performance engine there is no "optimise compromise"

Get it right, dont convince yourself otherwise

Now im going to leave the OP to tell us of his new toy as and when there is new info

If anyone wants to know any details of airboxes, dampers, pulse reflection or whatnot, lets start a new thread

(bowing out)
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  #32  
Old 22-03-2015, 08:38 PM
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SeanDezart SeanDezart is offline
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Quote:
Originally Posted by SKiddell View Post
No, in my books with a high performance engine there is no "optimise compromise"Get it right, dont convince yourself otherwise
Not sure I follow you ''no optimise compromise" as we all have different needs/applications from our high performance engines, there are different humidity and temperature levels unless for these last varied levels the fitting of an airbox reduces the delta...but then it's still (?) a 'best-solution once set-up' for general use hence my term 'compromise'.

Surely ideally if desired fro a cold and wet-day run, one would have a certain set-up compared to a circuit day on a hot-dry air day.....one setup is therefore a best-fit compromise.

We're perhaps turning around the definitio of one word here and I agree, better not to blather on Nicks' thread but elsewhere (sorry Nick).

I'd be very interested to hear what the engine-maker says on the subject of cold/hot air intake via airbox/under-bonnet filters.
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  #33  
Old 22-03-2015, 09:14 PM
SKiddell SKiddell is offline
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Ill respond on a new thread Sean

http://zclub.net/forum/showthread.ph...041#post224041

Last edited by SKiddell; 22-03-2015 at 09:36 PM..
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  #34  
Old 22-03-2015, 09:15 PM
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SeanDezart SeanDezart is offline
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Thanks - we can all learn.
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  #35  
Old 07-05-2015, 11:08 AM
strugrat strugrat is offline
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Any update on this? Interested to know how the engine is performing?

Thanks
Ryan
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  #36  
Old 10-07-2015, 10:37 PM
zedhed zedhed is offline
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Just an update as promised - my 204Z is finally back with the Datsun Spirit 3.1 stroker installed.

The engine starts with difficulty, and the car was bogging down under acceleration or even just cutting out entirely even under power. I nearly got rear-ended at a roundabout on my first breaking-in drive when the engine cut out completely.

This has been a good learning curve for me! I've posted some pics to help others who are (like me) completely new at this stuff and may end up doing this.

So please bear in mind this thread is for newbie inexperienced guys like me tackling stuff they don't understand, not for you mechanics LOL but it may help someone.

The engine arrived with this crank timing setup from the tuner who felt the engine was too advanced. He felt the sprocket markings were incorrect. What prompted him to check this and make the changes was that the emissions seemed wrong when he did a basic tune.

So here's where it was set to:




When I explained this to the engine-builder, he got pretty worried that the engine could now be severely retarded as a result of moving the chain up a link (18 deg), plus 3 degrees at the sprocket (total 21 at crank). He asked me to send a photo with sprocket removed so he could compare with a mockup of the build he made, as well as the photos he took of my engine during the build process.(Simply amazing service by the way). He said "I suspect you will find the dowel and the market positions to be almost exactly like this (undeniable evidence that the valve timing is now severely retarded and that how I had it was correct)." Here's the picture he referred to from my engine build album:



Here's my sprocket dowel markings for comparison:



So the builder told me the car would be dangerously lean, and advised me to change it to this immediately and not to run it until reset, which I did:



This involved making a chain wedge to stop the timing chain-tensioner from popping out (a bad thing apparently) and to immobilise the crank, so that I wouldn't be working to the wrong crank timing.

Here's the tensioner made from some blue 1" plastic scrap:



Here's the chain tensioner in place about to be pushed down (it goes pretty far down). The cords are so you can pull it out again. You really need to push it down hard all the way until it can go no further or you will be in serious trouble - probably have to remove the front engine cover to reset everything unless you have surgeon-hands...



Here's a view down the chain so you can see the curved path it takes when under tension. Hopefully you'll see what I mean by pushing it all the way down.



The car is now driveable and still bogging down a bit running lean on the idle circuit. ordered some 55F8 jets then 60F8 which are starting to solve that problem. Engine is running lean higher up in the rev range but I'm going to leave that for a bit to see how things settle in.

I thought I should check the valve clearances (because the tuner said number 2 exhaust was too wide and he adjusted that), and the engine manual says they should be same for exhaust and intake, namely 0.08" - 0.2mm which they are now - what a PITA that was to untighten the locking nuts. I need to find some as I rounded off a few and messed up a spanner getting there.

I bought a timing light with dial and I'm still playing around with the timing. Also got a Gunson colortune which helped me set the idle mixtures. Used ear for synch then got a synchrometer. Turns out ear is just as accurate, and free.

Jobs to do: The carbs need work. I levelled the floats (all over the place) but I need to install vibration dampening mounts with Thackeray washers.

Oh yes - some of you wanted to see the cam, well seeing a took the sprocket off to move the chain one link I took a pic of the cam:


PS: Any fellow Z owners in Norwich? Keen to compare notes!
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  #37  
Old 10-07-2015, 10:56 PM
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SeanDezart SeanDezart is offline
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All that and still on carbs Nick ?
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  #38  
Old 10-07-2015, 11:03 PM
zedhed zedhed is offline
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well we'll see how far we have to go really - I think it would be nice to have total control over the timing but still have the raw feel of carbs...
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  #39  
Old 10-07-2015, 11:22 PM
zedhed zedhed is offline
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OK so my next job was to raise the engine up, because the exhaust was hitting the frame rail, or rather resting on it. Here's some pics. I only noticed that recently.





Part of the problem was that my left engine mount was completely shot (the rubber had come away from the metal) which probably contributed to the lack of clerance by dropping the exhaust side of the engine.

Thanks to Peter Mac and Lawrence from Star Motorsports for spacers, and a competition engine mount for the left side. The spacers give 8mm clearance between exhaust and bay, and the harder mount stops the engine from twisting over too much when revving. Here's a pic of what Peter sent me:



Installing them was simple but awkward until I realised how to do it. Basically you loosen all the engine mount bolts and raise the engine on a jack, then slip the spacers and mount in. In practise, it takes a while jiggling the engine around until you get things lined up. I used a screwdriver to level the engine into position, by sticking it through the engine mount holes and wiggling it around a bit. I put a wood block between the sump and the jack-head to aviod denting the sump.I used a couple of wood blocks to hold the engine up in case the jack failed. I replaced the split ring washers on the engine mount nuts with nyloc nuts to stop them coming loose with vibration. The main engine mount bolts were M10 fine thread (one each side). The two bolts going through each spacer are M8 standard thread (4 total).

let me know if the images don't display
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  #40  
Old 10-07-2015, 11:35 PM
Albrecht Albrecht is offline
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Quote:
Originally Posted by zedhed View Post
The engine arrived with this crank timing setup from the tuner who felt the engine was too advanced. He felt the sprocket markings were incorrect. What prompted him to check this and make the changes was that the emissions seemed wrong when he did a basic tune.

So here's where it was set to:


Maybe I'm being thick here, but I'm confused about the "tuner" you are talking about?

As it's a Datsun Spirit build, I would have thought that Eiji is the "builder" - yes? So who is the "tuner" and why was he messing around with something as fundamental as the cam timing (which - I would have thought - would have been set by Eiji as part of the build, and specific to the cam...)? Eiji knows what he's doing.

Messing around with the carbs and spark timing is going to be a complete waste of time if the cam timing isn't right. It needs to be set with a DTI (Dial Test Indicator) measuring valve lift points at degrees of crank rotation, and that also requires an accurate crank timing wheel and pointer. It's fairly straightforward if you have the equipment and the cam timing card, but I would have thought that Eiji would have done all that as part of the build.

So has somebody other than Eiji messed about with it since then, or have I misunderstood?
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  #41  
Old 10-07-2015, 11:47 PM
Albrecht Albrecht is offline
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Quote:
Originally Posted by zedhed View Post
The carbs need work. I levelled the floats (all over the place) but I need to install vibration dampening mounts with Thackeray washers.
I strongly advise you NOT to bother with the vibration dampening mounts and Thackeray washers. Complete waste of time on a Nissan L6 engine. It just doesn't need them.

As you clearly have a Harada intake manifold, the supplied and fitted phenolic spacers and gaskets are all you need. They carry the gaskets, and act as insulation against heat transfer. 'Solid' mounting the carbs is absolutely fine on these engines, and any talk of carbs 'frothing' is from the four cylinder world with completely different engine harmonics.

You'll hear lots of people telling you you need them, but please trust me - you don't.
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  #42  
Old 11-07-2015, 07:48 AM
SKiddell SKiddell is offline
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Quote:
I strongly advise you NOT to bother with the vibration dampening mounts and Thackeray washers. Complete waste of time on a Nissan L6 engine. It just doesn't need them.
They do have one advantage, they carry an O ring which can be of great help when trying to get a good seal between components which may have an uneven surface.
Other than that, I agree, why is the secondary tuner altering the mechanical timing by anything more than a few degrees (often required to get optimal tune on the rolling road or dyno).

Last edited by SKiddell; 11-07-2015 at 08:01 AM..
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  #43  
Old 11-07-2015, 08:05 AM
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Nick, the cam timing may have been even worse than you say; I'd assume Eiji set it originally in the middle of the adjustment range, so your tuner moved it one tooth and 3 marks. Each mark is 4 degrees of crank so total change would have been 18 + 12 = 30. Which is a lot.
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  #44  
Old 11-07-2015, 08:15 AM
SKiddell SKiddell is offline
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Quote:
Originally Posted by jonbills View Post
Nick, the cam timing may have been even worse than you say; I'd assume Eiji set it originally in the middle of the adjustment range, so your tuner moved it one tooth and 3 marks. Each mark is 4 degrees of crank so total change would have been 18 + 12 = 30. Which is a lot.
Forget messing with jets and spark timing and focus on getting the mechanical timing correct
If it was set up correctly (and as Alan said Eiji knows what he's doing) then it will have been setup with a degree wheel (once again as Alan said) to incorporate the cam grind.
I would be very careful with this, contact Eiji, (or the cam supplier....looks like Schnieder) find out what it should be set to then get a dti a degree wheel read up how to do it correctly then set it to what the cam card specifies, otherwise you are in danger of pistons hitting valves, even a light kiss will bend one, and until you get the mechanical cam timing right, carb setting is worthless

Last edited by SKiddell; 11-07-2015 at 08:23 AM..
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  #45  
Old 11-07-2015, 08:23 AM
zedhed zedhed is offline
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Gents thanks for the advice on carbs I'm getting conflicting info here from several sources so will research this more. Seeing I've bought the o ring kit already I guess what I'm wondering is can it do any harm?

As for the other question about altering the timing chain position, the answer is "I don't know". I assume their tuner thought the engine was setup wrong. Eiji Sent me photos of the build with the dial guage and a protractor installed on the crank with everything up. Anyway I've reset everything and the car is now driveable. The tuner in question may have gone by markings but he did spot one misadjusted valve clearance and he also re-torqued the sprocket bolts which were too loose so I'm glad he checked it out. He did not get a chance to drive the car, or as he said he would have reset things until they worked. It's quite possible some other issue stopped the car from starting and it just kicked in after he reset things so he assumed (like anyone would) that his changes were correct, and what allowed the car to start. It is only when I drove the car (and logically I believe I was the first to do so) that I realised something was wrong.

Anyway no harm done and the engine is now correctly mounted with enough clearance to put some miles on it without damage to the zircotec coatings which is the main thing.
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