Timing?

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Postby Lloyd » Mon Jun 29, 2009 11:36 pm

When the little cutout V is lined up with 0 then you are on TDC. If that lines up then you top timing marks on the cams should be also
Last edited by Lloyd on Tue Jun 30, 2009 6:27 pm, edited 1 time in total.
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Postby bluemaumau » Mon Jun 29, 2009 11:53 pm

maybe they become interference when you put 16v pistons in 20vs, im sure i read something
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Postby matt dunn » Tue Jun 30, 2009 12:05 am

bluemaumau wrote:maybe they become interference when you put 16v pistons in 20vs, im sure i read something


Yep, that for sure.

I bent 12 out of the 20 valves.

Image

I'd also be surprised if the Blacktop and possibly even Silvertop 20V's weren't interferance from factory?
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Postby thegreatestben » Tue Jun 30, 2009 12:11 am

Image
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Postby TRD_ZERO » Tue Jun 30, 2009 8:03 am

thegreatestben wrote:Image


Yeah i got that but im measuring off the crank pulley on the cover. So line the crank up to 0 and the cams to their dots. sweet
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Postby sergei » Tue Jun 30, 2009 9:48 am

matt dunn wrote:I'd also be surprised if the Blacktop and possibly even Silvertop 20V's weren't interferance from factory?


Blacktops are interference.
Silvertops are not.
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Postby sergei » Tue Jun 30, 2009 9:49 am

TRD_ZERO wrote:
thegreatestben wrote:Image


Yeah i got that but im measuring off the crank pulley on the cover. So line the crank up to 0 and the cams to their dots. sweet


Crank pulley is inaccurate, if it is factory item with harmonic balancer it can shift due to rubber layer between outer and inner.
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Postby TRD_ZERO » Tue Jun 30, 2009 5:01 pm

Damit so i gota take all that crap off to get to the crank gear. How do i get the crank bolt off now without it turning over?
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Postby Lloyd » Tue Jun 30, 2009 6:27 pm

sergei wrote:Crank pulley is inaccurate, if it is factory item with harmonic balancer it can shift due to rubber layer between outer and inner.


I doubt you'll ever see the rubber flex enough to show its going to be a tooth out
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Postby pc » Tue Jun 30, 2009 7:24 pm

Lloyd wrote:
sergei wrote:Crank pulley is inaccurate, if it is factory item with harmonic balancer it can shift due to rubber layer between outer and inner.

I doubt you'll ever see the rubber flex enough to show its going to be a tooth out
+1
I've never seen a balancer shift any noticable amount.

jondee86: I assume you're thinking of ignition timing possibly being 180degrees out.
lining up the cam/crank pulleys on the marks will assure that the cam timing is correct though.
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Re: Timing?

Postby jondee86 » Tue Jun 30, 2009 7:46 pm

Nah... conceptual problem on my part :oops: I was thinking of the
2:1 ratio of the pulleys, and the fact that the crank pully goes past TDC
twice to each full rotation of the cam pulleys. However, as pointed out
above, every rotation of the crank puts the piston back in the same
position. The 4-stroke cycle is controlled entirely by the camshafts.

So I should have been thinking of the camshafts being 180 degrees
out of position, rather than the crankshaft being 360 degrees out of
position. Made perfectly good sense when I wrote it :D

So yeah... use the timing marks... I do :)

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Postby neo » Tue Jun 30, 2009 11:10 pm

Timing marks + drawing on the belt and transfering the marks across. Saved me heaps of time last weekend when the tensioner pivot fell out and the belt went slack and stuffed up the timing :oops:
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Postby Crucible » Tue Jun 30, 2009 11:13 pm

TRD_ZERO wrote:Damit so i gota take all that crap off to get to the crank gear. How do i get the crank bolt off now without it turning over?


nah should be able to see crank gear tdc with top cover off. just use a torch.

sergei wrote:
Blacktops are interference.
Silvertops are not.


i thought all 4a base were non interferance?
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Postby sergei » Wed Jul 01, 2009 12:16 am

Lloyd wrote:
sergei wrote:Crank pulley is inaccurate, if it is factory item with harmonic balancer it can shift due to rubber layer between outer and inner.


I doubt you'll ever see the rubber flex enough to show its going to be a tooth out

I've seen it doing the runner ;).
I've also seen it slipping before doing the runner.
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Postby frost » Wed Jul 01, 2009 12:28 am

im sure i remember reading a thread about a guy who could not get his timing correct. he said it changed different degrees every time.
then it turns out the rubber on the pulley was split and was altering the timing when running.
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Postby Lloyd » Wed Jul 01, 2009 8:42 am

Yeah I know they break and have had to replace a few, usually not Toyota. Just saying its not usual for them to just slip a little bit and sit there. They tend to either fail or not
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Postby TRD_ZERO » Wed Jul 01, 2009 5:19 pm

True-No-Turbo wrote:
nah should be able to see crank gear tdc with top cover off. just use a torch.




Top cover? I cant take the cover off without taking the crank pulley off. Or do u mean try get it off as much as i can and peer through there?
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Postby Bling » Wed Jul 01, 2009 5:55 pm

True-No-Turbo wrote:
i thought all 4a base were non interferance?


I was also under this impression. I'm surprised silvertop and blacktop would differ given they are much of the same design.
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Postby sergei » Wed Jul 01, 2009 6:18 pm

BZG|Bling wrote:
True-No-Turbo wrote:
i thought all 4a base were non interferance?


I was also under this impression. I'm surprised silvertop and blacktop would differ given they are much of the same design.

blacktops definitely are interference, the cut-outs for exhaust valves are almost non-existent.
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Postby Crucible » Wed Jul 01, 2009 6:26 pm

TRD_ZERO wrote:
True-No-Turbo wrote:
nah should be able to see crank gear tdc with top cover off. just use a torch.




Top cover? I cant take the cover off without taking the crank pulley off. Or do u mean try get it off as much as i can and peer through there?


yeah, the plastic top cambelt cover, you should be able to shine a torch down towards the crank and see the tdc mark.
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