Jump to content


Photo

Cam Timing - Is That My Issue?


  • Please log in to reply
43 replies to this topic

#21 oldmates260z

oldmates260z

    Senior Member

  • Members
  • PipPipPipPipPip
  • 752 posts
  • Location:Brisbane

Posted 18 January 2016 - 09:11 PM

Thanks Dave, appreciated



#22 d3c0y

d3c0y

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 2,848 posts
  • Website:http://garagesanmaru.com
  • Location:Brisbane
  • Tagline:Forum Jerk

Posted 18 January 2016 - 09:15 PM

My money is now on the wrong brake pads, you aren't running bendix are you???



#23 Lurch ™

Lurch ™

    Curator of the 'Gavin Collection'

  • Members
  • PipPipPipPipPipPipPip
  • 5,607 posts
  • Location:Victoria
  • Tagline:In my Den of Rust & Sin

Posted 18 January 2016 - 09:56 PM

I'm blaming Chemtrails.


  • d3c0y likes this

#24 600Z

600Z

    Advanced Member

  • Members
  • PipPipPip
  • 253 posts
  • Location:Tasmania

Posted 19 January 2016 - 10:12 AM

Where is your power at the moment as in what revs?

Have you checked that your timing mark on your harmonic balancer is actually TDC #1 ? Most likely it's right but something to rule out.

Do you have a dial indicator or access to one to check your cam timing?

It seams you have and are now starting to go around in a circle and you have checked the compression (which you can't really work out your compression ratio from as there are far too many variables), ignition timing which seams not too bad, and any real changes would now really only give you small gains, air/fuel mixture, the grade of oil in the su's (what air filters and do they allow good flow, try it without them) do the Pistons fully open on the su's? I can't remember if they are over filled if they with hydraulic lock and not fully open or not.

I think cam timing is due to be checked now unless you already have by now. There isn't too much more apart from going over the same things that will only give small degrees of increases.

If you want to quickly check your cam timing:

1. Place a dial indicator on your inlet valve retainer on the cylinder that's going to be on the roll roughly 20 degrees before TDC but make sure the valve is closed. Zero the dial.

2. Turn the engine over until you get to TDC and record the amount the valve opens.

3. Place the dial indicator on the exhaust valve retainer and make sure you allow for the dial to read in the negative as it will be closing.

4. Turn the engine over until the valve is fully closed and record the amount it was open.

5. Compare the two figures, both the same is neutral, intake open more its advanced (better high rev performance), exhaust open more (better low down torque).

Slightly advanced I have found is better but each to their own.

That's just my two cents mate but check one and get it close to being correct as you can then move on and check the next until everything is checked then tweak.

Edited by 600Z, 20 January 2016 - 06:54 PM.

  • oldmates260z likes this

#25 oldmates260z

oldmates260z

    Senior Member

  • Members
  • PipPipPipPipPip
  • 752 posts
  • Location:Brisbane

Posted 20 January 2016 - 07:28 AM

Thanks very much 600Z, great info.

 

I am likely just working on the fringes due to my lack of abilities and equipment. The car runs very well but lacks mid range power (2000-3500 rpm). Over 3500 it pulls really well.

 

The tweaking is making marginal changes. Fitting 3" ram tubes (sadly only fitted with socks) and dropping timing back to 8 degrees have made good improvements. 

 

The cam timing I believe is most likely my cause of the issue but I do not have access to the gear (or ability to use it) to do the check. I will get this done next as I think I have someone now that can do it for me.

 

I will however check that TDC is correct.

 

Thanks again


Edited by oldmates260z, 20 January 2016 - 01:52 PM.


#26 d3c0y

d3c0y

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 2,848 posts
  • Website:http://garagesanmaru.com
  • Location:Brisbane
  • Tagline:Forum Jerk

Posted 20 January 2016 - 03:59 PM

It's pretty easy to check if you are using the stock cam sprocket. I've moved to Brisbane recently, so if you don't live in the sticks I could come and have a look on the weekend if you like?

 

To be honest if it's only running 8 degrees of timing I don't think it's going to pull very hard at those revs.


  • oldmates260z likes this

#27 road rider

road rider

    Advanced Member

  • Members
  • PipPipPip
  • 212 posts
  • Location:Melbourne
  • Tagline:Life is like a bowl of hot soup.You need to be hot to get blown

Posted 20 January 2016 - 04:12 PM

Don't know if this has been suggested already, but you could just get the su's re-jetted to suit.

Would be cheaper than maybe going down the 'triples' path!
But if your budget allows you to go 'triples', please don't let me sway your decision ;) 
 


  • oldmates260z likes this

#28 600Z

600Z

    Advanced Member

  • Members
  • PipPipPip
  • 253 posts
  • Location:Tasmania

Posted 20 January 2016 - 06:42 PM

I'm glad that some of my last post made some sense as I just re-read it and bits of it was all over the place as I was in a hurry and quickly typed it out....... Should have read it before sending lol

Anyway another possibility as you did mention that it pings at times and that's why you retarded your timing. It might take a couple of you but could be worth checking that the advance in your distributor isn't coming on fully too early as this could create pinging and lack of power until things speed up.

Edited by 600Z, 20 January 2016 - 06:59 PM.

  • oldmates260z likes this

#29 oldmates260z

oldmates260z

    Senior Member

  • Members
  • PipPipPipPipPip
  • 752 posts
  • Location:Brisbane

Posted 21 January 2016 - 05:13 PM

d3c0y thanks for the offer and welcome to Brisbane :). I live in the sticks but happy to come to yours if you would be happy to have a look. Next few weeks I am tied up but if we could catch up after that it would be great. Will PM when I have a weekend free to see if it suits.  (It has a 72 degree CAM so I assume that is not stock.)

 

road rider I think you are 100% right and I need to get the jetting correct so the SU's meet my current engine spec. ATM I prefer to extract what I can from the SU's before going to triples

 

600Z interesting that the advance could come on early, have not heard of that before. I will need to reach how to check and verify that.

 

Thanks again all for advise.



#30 oldmates260z

oldmates260z

    Senior Member

  • Members
  • PipPipPipPipPip
  • 752 posts
  • Location:Brisbane

Posted 01 February 2016 - 09:24 PM

After doing a little research it appears that my flat top pistons and N42/F54 combo is not a great set up.....as noted by Toecutter in below thread.

 

Well at least that explains my knocking under load

 

http://www.viczcar.c...at-top-pistons/


  • Cozza likes this

#31 oldmates260z

oldmates260z

    Senior Member

  • Members
  • PipPipPipPipPip
  • 752 posts
  • Location:Brisbane

Posted 02 February 2016 - 10:32 AM

Bearing in mind I have flat top pistons and N42/F54 combo what would the best way forward?  (After I check cam timing....running very well now with ignition timing 8 BTDC)

 

Thicker head gasket?

 

Swap or rework head?



#32 d3c0y

d3c0y

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 2,848 posts
  • Website:http://garagesanmaru.com
  • Location:Brisbane
  • Tagline:Forum Jerk

Posted 02 February 2016 - 10:52 AM

What sort of fuel are you running in it?

 

Depends what you want to do with it, keep it stock?

 

Maybe just doing some chamber work like unshrouding the valves will have enough effect.

It's a massive guessing game at this point as you don't know what's been done to the head or how far you want to take it. How much has been milled off the head? Has it had any other work done?


Edited by d3c0y, 02 February 2016 - 10:53 AM.

  • oldmates260z likes this

#33 oldmates260z

oldmates260z

    Senior Member

  • Members
  • PipPipPipPipPip
  • 752 posts
  • Location:Brisbane

Posted 02 February 2016 - 03:03 PM

d3c0y I run 98

 

yes it is hard to know as all work done before I owned the car. Really just want a good street car that pulls well, the ignition timing has helped.

 

Just seems a waste to have it not going as well as it could. If I could get some simple head work done to fix it that would be the best option. Has had a heap done on it already.

 

We should catch up for a run one weekend, I do a few with a couple of the Sports guys.....



#34 oldmates260z

oldmates260z

    Senior Member

  • Members
  • PipPipPipPipPip
  • 752 posts
  • Location:Brisbane

Posted 21 February 2016 - 05:05 PM

Movement in the right direction....

 

Found a big leak in vacuum advance hose, fixed that but little change in timing. Will not go above 25 deg with hose on or off. So vacuum advance not working.

 

Took top distributor and found the magnetic ring broken.....

 

Is there anyone in Brisbane that rebuilds them?

 

Attached Thumbnails

  • IMG_8262.JPG
  • IMG_8263.JPG

  • MichaelT likes this

#35 d3c0y

d3c0y

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 2,848 posts
  • Website:http://garagesanmaru.com
  • Location:Brisbane
  • Tagline:Forum Jerk

Posted 21 February 2016 - 06:23 PM

d3c0y I run 98

 

yes it is hard to know as all work done before I owned the car. Really just want a good street car that pulls well, the ignition timing has helped.

 

Just seems a waste to have it not going as well as it could. If I could get some simple head work done to fix it that would be the best option. Has had a heap done on it already.

 

We should catch up for a run one weekend, I do a few with a couple of the Sports guys.....

That would involve my car going, 3 years and counting...


  • oldmates260z likes this

#36 dat2kman

dat2kman

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 4,033 posts
  • Location:Newport Waters Qld
  • Tagline:going sailing, see ya later!

Posted 22 February 2016 - 09:59 AM

Tim, the broken bits are nt readily available in Aust, unless you can canibalse them from another L28E dzzy
Possibly they were fitted to the mid 1980's L24 E engined Skylines.

Other option is to swing ver to some sort of aftermarket optical or induction type ie Pertronx, Lumenition, or the myriad f others!

I do have a outer magnetic ring, but I am away until the 12th Mar, if you can wait?
  • oldmates260z likes this

#37 gav240z

gav240z

    Administrator

  • Administrators
  • 12,400 posts
  • Website:http://www.viczcar.com
  • Location:Sydney NSW
  • Tagline:Jack of all trades, master of none.

Posted 22 February 2016 - 10:08 AM

That looks familiar, this is why I'm not a huge fan of the standard 280zx distributors. They have had a hard life by now and between the vacuum advance, the ball bearings in the plastic cage and the magnetic pickup they are all FUBAR.

 

I have a spare 280zx distributor I was going to rebuild for shits and giggles to see if I could make any good use of it. However I'll need to spend some time looking up the part no's of those broken bits.

 

You might want to ask Lurch what aftermarket distributor he uses on engine builds he is doing lately. I believe it's probably a cheaper / better way to go unless originality is important?


  • oldmates260z likes this

#38 oldmates260z

oldmates260z

    Senior Member

  • Members
  • PipPipPipPipPip
  • 752 posts
  • Location:Brisbane

Posted 22 February 2016 - 01:30 PM

I am thinking a older dizzy with points and put in a electronic upgrade would be best.

 

Looking at the complexity of this dizzy it does not look like a good option.

 

Thanks guys



#39 gav240z

gav240z

    Administrator

  • Administrators
  • 12,400 posts
  • Website:http://www.viczcar.com
  • Location:Sydney NSW
  • Tagline:Jack of all trades, master of none.

Posted 22 February 2016 - 01:32 PM

I am thinking a older dizzy with points and put in a electronic upgrade would be best.

 

Looking at the complexity of this dizzy it does not look like a good option.

 

Thanks guys

 

The problem with those might be shaft wear and axial play, hence my suggestion to go for a newer unit. Let me check how good this spare unit is for you. It looks rough though...


  • oldmates260z likes this

#40 oldmates260z

oldmates260z

    Senior Member

  • Members
  • PipPipPipPipPip
  • 752 posts
  • Location:Brisbane

Posted 05 March 2016 - 01:31 PM

Significant progress... picked up a SWR SW mapped 280 dizzy....set it a 15 DBTC and goes like a rocket compared to how it went before....still more room for improvement though.....

 

20160228 020.JPG


Edited by oldmates260z, 05 March 2016 - 09:17 PM.





0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users