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  #46  
Old 11-07-2015, 09:51 AM
zedhed zedhed is offline
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I can see the piston top through the sparkplug hole at TDC, so I can hopefully use a long lever DTI from work or maybe one of our lasers or a micro bore scope to guage TDC. I just used the pencil method...

But if I put the sprocket back in exactly the same position Eiji did, resetting the valve timing to where it was, then why should I bother with a protractor ? Eiji already did that...
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  #47  
Old 11-07-2015, 10:14 AM
franky franky is offline
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I'm guessing the other 'tuner' was the place who installed the lump?
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  #48  
Old 11-07-2015, 10:24 AM
zedhed zedhed is offline
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No Z farm installed the engine and it was tuned by a local outfit
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  #49  
Old 11-07-2015, 10:38 AM
franky franky is offline
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Its good to make that distinction(for the z farm).
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  #50  
Old 11-07-2015, 10:59 AM
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Quote:
Originally Posted by zedhed View Post
I can see the piston top through the sparkplug hole at TDC, so I can hopefully use a long lever DTI from work or maybe one of our lasers or a micro bore scope to guage TDC. I just used the pencil method...

But if I put the sprocket back in exactly the same position Eiji did, resetting the valve timing to where it was, then why should I bother with a protractor ? Eiji already did that...

Yes, if you're sure you've set it all back where Eiji set it, then you're probably safe. But it is easy enough to check it for yourself with a protractor and a dti.
My protractor and dti only about 20 so not a huge investment.
If you trust the damper marks tdc correctly, then you can skip to putting the dti on the valves to check when they open/close or peak lift etc.
To do all this you only need the radiator out. There's loads of info and books around on how to do it.
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  #51  
Old 11-07-2015, 11:46 AM
Albrecht Albrecht is offline
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Originally Posted by zedhed View Post
No Z farm installed the engine and it was tuned by a local outfit
Sorry to be harsh, but it needs to be said: The "tuner" apparently has no idea what he is doing. Messing about with the cam timing to that extent when it was already set as part of the build by Eiji proves it. It's such a fundamental part of engine dynamics that I honestly can't understand how they came to the conclusion that it set wrong...?

You'll be lucky if you haven't kissed a few valves. Hopefully all will be OK if you're confident you've re-set the cam timing to where Eiji had set it, but if it was me I'd want to be double and triple checking just to make sure anyway.

Putting 'O' rings / anti vibration mounts and Thackeray washers on the carbs and manifold is going to lead to synchronisation and carburettor linkage problems further down the line. These engines just don't need them. Nissan never used them on any of the triple carb kits they made and marketed and never used them on their Works race and rally L6s. They are simply not necessary. They are necessary on other engines where engine harmonics can cause fuel 'frothing' and loosening of jets and fasteners (that's where the default knowledge comes from) but the L6 typically doesn't suffer from such things.


Stick with it. By addressing a lot of this yourself you'll build up your knowledge and experience, and you won't need to use a 'tuner' except perhaps for final rolling-road tuning.
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  #52  
Old 11-07-2015, 02:02 PM
zedhed zedhed is offline
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Quote:
Originally Posted by Albrecht View Post
Sorry to be harsh, but it needs to be said: The "tuner" apparently has no idea what he is doing. Messing about with the cam timing to that extent when it was already set as part of the build by Eiji proves it. It's such a fundamental part of engine dynamics that I honestly can't understand how they came to the conclusion that it set wrong...?

You'll be lucky if you haven't kissed a few valves. Hopefully all will be OK if you're confident you've re-set the cam timing to where Eiji had set it, but if it was me I'd want to be double and triple checking just to make sure anyway.

Putting 'O' rings / anti vibration mounts and Thackeray washers on the carbs and manifold is going to lead to synchronisation and carburettor linkage problems further down the line. These engines just don't need them. Nissan never used them on any of the triple carb kits they made and marketed and never used them on their Works race and rally L6s. They are simply not necessary. They are necessary on other engines where engine harmonics can cause fuel 'frothing' and loosening of jets and fasteners (that's where the default knowledge comes from) but the L6 typically doesn't suffer from such things.


Stick with it. By addressing a lot of this yourself you'll build up your knowledge and experience, and you won't need to use a 'tuner' except perhaps for final rolling-road tuning.
I have thought about this and I will stick with the solid mounts for now. As I say the tuner did what he thought was right at the time although I didn't understand the rationale myself, however the exhaust clearance thing was a mistake which should have been spotted. Assuming I ever get my strut brace back from Z Farm I will probably have to bend it to suit the new engine height. It was pretty close already. Perhaps that's why Z Farm never put it back on? I wonder if I'll ever know.

Albrecht, how do I check the valves aren't kissing the pistons? Got a step by step guide?
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  #53  
Old 11-07-2015, 02:04 PM
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Rob Gaskin Rob Gaskin is offline
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Originally Posted by zedhed View Post
No Z farm installed the engine and it was tuned by a local outfit
And so your contract was with Z Farm I assume who sub-contracted the tuner.

So worst case scenario you have a bent valve or two - you may have a problem with the warranty. Let's hope all is well.
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  #54  
Old 11-07-2015, 03:18 PM
Albrecht Albrecht is offline
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Originally Posted by zedhed View Post
Albrecht, how do I check the valves aren't kissing the pistons? Got a step by step guide?
Now that you've put cam timing back to what Eiji built it with, it should not be happening.

But if any of the valves touched any of the pistons whilst the cam timing was out of specs, they would at least leave witness marks on the piston crowns. Very hard to see with the cylinder head in situ, and I can only think of a borescope/endoscope as your best option.

Very hard to diagnose any slightly bent valves in my experience (very bent valves are easy...) but a leak-down test might help. The easiest way - and I'd probably do this if it was my engine - would be to take the head off if it displayed even the slightest symptoms of valves not seating correctly.

Mention of a valve lash issue by the 'tuner' makes me wonder whether he found this after he'd altered cam timing, or before. Valve clearance changes can be a symptom of valve seat issues (including bent valves...).
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  #55  
Old 11-07-2015, 04:14 PM
zedhed zedhed is offline
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Hi Albrecht how do I check if valves aren't seating properly, leakdown test or other method?
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  #56  
Old 11-07-2015, 05:30 PM
Albrecht Albrecht is offline
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A compression test should give you an idea of where you stand. I'd start there.
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  #57  
Old 11-07-2015, 07:53 PM
zedhed zedhed is offline
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I've done that already and all cylinders are about the same within a few psi of each other. Are there further checks I can perform?
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  #58  
Old 12-07-2015, 11:10 AM
Albrecht Albrecht is offline
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Can't think what else you can do realistically without taking the head off for a look inside. If you're convinced that the compression test results showed a healthy engine, then by all means proceed with final tuning.

If you've got away without valve damage then I'd say you've been very lucky.
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  #59  
Old 12-07-2015, 08:23 PM
SKiddell SKiddell is offline
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Zedhed.

If you have access to a compressor, You could try a leakdown test (you can make one or buy one), its a little more involved but compliments a compression test, it will highlight any leakage paths when the engine is static and valves are closed, if you have a bent valve it will be heard as a slight hiss from either the inlet or exhaust tract and show up as a percentage loss.
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  #60  
Old 13-07-2015, 04:06 PM
zedhed zedhed is offline
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thanks Gents, I will find a compressor, as this sounds like an easy enough check... I would imagine that the cylinders with bent valves would have different compression, and that some valves would bend more than others, and this would cause uneven readings. So because compression is pretty even across all cylinders, I'm hoping there is no problem...
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