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> At TDC #1 but...
Literati914
post Jul 26 2024, 06:57 PM
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On a freshly built but never installed, never ran.. oil never added and sitting for years 1.7L engine: I've verified TDC @ #1 but the rotor tip is showing 180 deg. out.
Is that just a matter of loosening a bolt and rotating it to face towards the driver's seat (apprx).. or is it gonna be more of a 'pull the distributor and re-clock the gear down in the bore' ?

.
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Artfrombama
post Jul 26 2024, 07:03 PM
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QUOTE(Literati914 @ Jul 26 2024, 07:57 PM) *

On a freshly built but never installed, never ran.. oil never added and sitting for years 1.7L engine: I've verified TDC @ #1 but the rotor tip is showing 180 deg. out.
Is that just a matter of loosening a bolt and rotating it to face towards the driver's seat (apprx).. or is it gonna be more of a 'pull the distributor and re-clock the gear down in the bore' ?

The #1 piston is at TDC twice during a cycle. Once at compression, then on exhaust. Make sure you're on compression (both valves closed) when you time the motor.
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Literati914
post Jul 26 2024, 07:24 PM
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QUOTE(Artfrombama @ Jul 26 2024, 08:03 PM) *


The #1 piston is at TDC twice during a cycle. Once at compression, then on exhaust. Make sure you're on compression (both valves closed) when you time the motor.


Got it, thanks .. it's all coming back now. The builder had the distributor correct after all. Though, the valve adjusters feel awfully tight w/ the valves closed - I'll go ahead and check them all while I have the covers off. Tight side of .016" intake/exhaust, IIRC ?
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Artfrombama
post Jul 26 2024, 07:27 PM
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QUOTE(Literati914 @ Jul 26 2024, 08:24 PM) *

QUOTE(Artfrombama @ Jul 26 2024, 08:03 PM) *


The #1 piston is at TDC twice during a cycle. Once at compression, then on exhaust. Make sure you're on compression (both valves closed) when you time the motor.


Got it, thanks .. it's all coming back now. The builder had the distributor correct after all. Though, the valve adjusters feel awfully tight - I'll go ahead and check them all while I have the covers off. Tight side of .016" , IIRC ?

I think the manual calls for .006" for most 914's
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Literati914
post Jul 26 2024, 07:29 PM
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QUOTE(Artfrombama @ Jul 26 2024, 08:27 PM) *


I think the manual calls for .006" for most 914's


(IMG:style_emoticons/default/biggrin.gif) I might need to do some reading, thanks again!
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technicalninja
post Jul 26 2024, 07:36 PM
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If you've changed over to steel push rods, it's zero clearance!

When you're TDC exhaust both valves should be slightly opened and any movement either direction causes one of the rockers to descend.

At TDC compression, movement of the crank 30 degrees either direction doesn't do shit to the rockers.

On an engine with aluminum pushrods both rockers will have a "click" of free play in them.

Leak down tests are done at TDC compression, both valves are closed.

If you do leak down at TDC exhaust both valves will have airflow as they are slightly open.

You can twist the crank or add air pressure to determine which TDC you are at.
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technicalninja
post Jul 26 2024, 07:38 PM
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It's .006 and or .008 depending on year.

For an initial run in, first start up I'd just run .008 especially if I didn't hand lap the valves.

You should EXPECT at least .001 initial tighten up on un-lapped valves.

Do a good lap job and you WILL NOT see initial wear...
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Literati914
post Jul 26 2024, 08:13 PM
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QUOTE(Literati914 @ Jul 26 2024, 08:24 PM) *

.. Tight side of .016" intake/exhaust, IIRC ?

and
QUOTE(Artfrombama @ Jul 26 2024, 08:27 PM) *

..I think the manual calls for .006" for most 914's

and
QUOTE(technicalninja @ Jul 26 2024, 08:38 PM) *

It's .006 and or .008 depending on year.


OK, in my own defense - I was thinking tight side of .016" from memory - I meant .16MM which is basically what .006" is. I've had that filed away in my brain for some time now, knew I got it somewhere. (IMG:style_emoticons/default/beerchug.gif)
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technicalninja
post Jul 26 2024, 08:19 PM
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.016mm is .00062" or 6 tenths!

I'd have a HARD time hitting that number!

.16mm IS .0062" which is what you're thinking...

Edit, HA! you caught it before I could reply!
(IMG:style_emoticons/default/beerchug.gif)
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Literati914
post Jul 26 2024, 08:21 PM
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QUOTE(technicalninja @ Jul 26 2024, 09:19 PM) *


.16mm IS .0062" which is what you're thinking...

Edit, HA! you caught it before I could reply!
(IMG:style_emoticons/default/beerchug.gif)


Yup!! it still seemed goofy to me, couldn't leave it alone (IMG:style_emoticons/default/biggrin.gif)
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930cabman
post Jul 27 2024, 05:05 AM
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QUOTE(technicalninja @ Jul 26 2024, 08:19 PM) *

.016mm is .00062" or 6 tenths!

I'd have a HARD time hitting that number!

.16mm IS .0062" which is what you're thinking...

Edit, HA! you caught it before I could reply!
(IMG:style_emoticons/default/beerchug.gif)



6 tenths is indeed a small number (IMG:style_emoticons/default/idea.gif)
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