Uh oh, need valve clearance specs for BORED OUT 1600/2000

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soundquest

Uh oh, need valve clearance specs for BORED OUT 1600/2000

Post by soundquest »

Am setting/checking valve lash numbers in an attempt to figure out why I am not getting combustion on 3 and 4 and also in preparation for a leak down test. The problem is... this is a 1600 engine bored out to a 2000 (1.6L to 2.0L) and the numbers posted for both do not apply to a modified engine if I have read the posts on the matter in this forum correctly For a 1600, it's .017 on both intake and exhaust, for a 2000, it's .008 and .012 on intake and exhaust respectively. HENCE MY QUESTION, WHAT ARE THE VALVE LASH SPECS ON A BORED OUT 1.6 TO 2.0??? Would really appreciate any guidance I can get on this. Thank you.

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Datrock
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/200

Post by Datrock »

I would look on the passenger side of the engine block and locate the block #, if your engine is an "R" with pushrods set the rockers to the .017" hot or around .020 cold, if it is a U20 with an over head cam set them to the .008" & .012".

Not sure about your engine but I've never heard of a 1600 being bored out to a 2000, that would require allot of material to be removed, you can stroke them by changing the crankshaft which lengthens the piston travel to create the larger displacement. Hope this helps. Bill
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/200

Post by spl310 »

As Bill Cole said, the pushrod motors are one spec while the overhead cam is another. The fact that the engine is modified by boring/stroking would not impact the spec for the valve settings. Now, if it has a non-stock cam, all bets are off - you need to find out what spec the grinder intended for the cam. If your engine is the pushrod motor, go for the .017...
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/200

Post by xbornkilla2k4 »

As long as the rocker is not holding the valve open at tdc for each cylinder should have compression. The exact lash is not as important. It is when the motor is ready to be driven down the road, but when trying to get it running any lash between .016 and .020 will give you compression. Pop out the plug and do a static compression test.
soundquest

Re: Uh oh, need valve clearance specs for BORED OUT 1600/200

Post by soundquest »

Datrock wrote:I would look on the passenger side of the engine block and locate the block #, if your engine is an "R" with pushrods set the rockers to the .017" hot or around .020 cold, if it is a U20 with an over head cam set them to the .008" & .012".

Not sure about your engine but I've never heard of a 1600 being bored out to a 2000, that would require allot of material to be removed, you can stroke them by changing the crankshaft which lengthens the piston travel to create the larger displacement. Hope this helps. Bill
Thanks for the guidance -- and you are right, it has not been "bored out" as I suggested, but modified at the crankshaft to bring it up to 2.0 liters. Having said that, this engine is in fact an R1600. I will go back and set the valve lash to .017 hot on intake and exhaust.

Now as for timing... due to the fact this engine has been modified, do I need to do anything different here or just lock it in at the factory mark and leave it alone?

One last question with respect to getting things at TDC on each cylinder when doing the adjustment (I am using Bill Cole's method (dizzy points to corresponding spark cylinder # position on the cap; 1-3-4-2 going CCW))... how can I visually verify I am (other than the dizzy position) I am exactly right on the mark?

Thanks again for all the help, you guys are great.
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/200

Post by Datrock »

I have two ways of lining up the crankshaft for setting the rockers, I believe the easiest is to mark the crankshaft pulley 180 degrees from the "0" mark then turn the crank pulley until the mark shows up at the pointer and it will get you where you want to be on the two other cylinders. I have also marked the distributor housing at each sparkplug wire with a felt pen and with the cap off you can rotate the engine until the rotor lines up with the mark needed for each cylinder.
Before setting your timing I would check to see if the cam inside the distributor and under the backing plate is a 7.5 degree or a 17.5 degree advance cam, you want the 7.5 degree cam for the correct advance to run as a non-smog setup that the earlier roadsters used. once you find out the distributor is a 7.5 degree one then I would set the timing between 16-20 BTDC and adjust from there. The 16 BTDC is the stock setting and some reground cams like a little more advance so 20BTDC may work for your engine. If your distributor has a 17.5 degree advance inside of it then the timing is set to '0" TDC . You want about 30-35 degrees total advance on the timing marks when the engine is revved, if it goes up into the 50's with the timing set at 16BTDC then the distributor needs recurved to 7.5 degrees.... Glad to help.. Bill
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/2000

Post by Tonymig »

Hi everyone. I am about to adjust my valves for the first time . CAn someone please tell how to distinguish the exhaust valve from intake valve? Also not sure if this engine was ever rebuilt does that make a diff in valve adjustment ? If so what is the easiest way to determine that it was and do you figure out valve adjustment not knowing what went into rebuilding of engine ? 8mm intake 12 exhaust is not rebuilt? Thank you in advance tony
Last edited by Tonymig on Thu Sep 17, 2020 9:21 am, edited 1 time in total.
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/2000

Post by theunz »

The valves line up with the intake and exhaust manifolds. From the front of the engine...ex in in ex ex in in ex.
Per my shop manual...ex .3mm or .012”. In .2mm or .008”
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/2000

Post by Tonymig »

Where is the best place to buy a new valve cover gasket Thanks
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/2000

Post by mraitch »

check the vendors on this site
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/2000

Post by baxtersit »

I bought one of these a few years ago and have reused it 3-4 times. Never leaks.
https://datsungaskets.com/?p=19
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Re: Uh oh, need valve clearance specs for BORED OUT 1600/2000

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