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L20b 86mm pistons


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#21 flatcat19

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Posted 07 December 2017 - 07:44 PM

All this speak and no mention of an ignition miss.


Plugs good? Wires good? Dizzy installed properly?


Think gas, fix spark. Vice-versa.

You can't hang if your nuts haven't dropped...it's physics


#22 Kingcab

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Posted 07 December 2017 - 08:22 PM

Yes I staggered the rings I already took off the head though haha. And the valve are properly seated when I did the rebuild I resealed all the valve and replaced the valve stem seals

#23 Kingcab

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Posted 07 December 2017 - 08:25 PM

My thoughts are.... I put bigger pistons in it does anything else need to be done for it to run perfectly because all other internals are stock it's a w58 head

#24 datzenmike

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Posted 07 December 2017 - 08:42 PM

All L series pistons are the same pin height so if the bore is right they will fit and work. An 87mm bore only increase the L20B to 1997cc from 1951cc. This isn't going to affect anything.


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#25 Kingcab

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Posted 08 December 2017 - 01:14 AM

Not sure on the pin hight with these pistons but the stock ones didn't come up flush to the top of the block and the ones I installed are just about flush with the top of the block

#26 Kingcab

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Posted 08 December 2017 - 01:35 AM

And all plugs and wires are new dizzy should be instal properly it's pretty straight forward to do but I will take it off and chek it all

#27 Doctor510

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Posted 11 December 2017 - 02:04 PM

Don't make mountains out of mole hills, check the basics,



#28 Kingcab

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Posted 11 December 2017 - 06:22 PM

I've checked just about all the basics. I've been trying everything I can for like 3 weeks now. That's why I'm asking for help I'm totally lost on why it would run like this

#29 Kingcab

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Posted 11 December 2017 - 06:23 PM

Anyone know the torq specs on the crank bolts and piston rod bolts???

#30 datzenmike

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Posted 11 December 2017 - 06:56 PM

Probably the carb. Sediment stirred up removing or mounting it.

 

Firing order is 1342.

 

Set timing to 12 degrees BTDC

 

Check valve lash just in case.

 

Set engine to TDC turning the crank up to the zero timing mark in a clockwise direction only. If you over shoot back well up and re-do as  many times as necessary. Must be clockwise and stop to remove all traces of chain slack and get a good reading. Now take the valve cover off and look through the top hole in the cam sprocket. You should see the V notch in the back of the sprocket just below and slightly to the left of the small horizontal line etched into the cam thrust plate above it. Like this...

 

otMggUE.jpg

 

If you have this..... the cam is properly timed

 

1/ Are you sure you have exactly TDC as described????? Has to have timing mark set to zero on the pulley notch. Cars with big overlap cams have terribly low intake vacuum so this would suggest your cam is off.

 

2/ Make sure secondary is fully closed at idle.

 

3/ Check carb gasket and/or adapter are not leaking or cracked from over tightening.

 

4/ make sure intake gasket is sealing or manifold properly tightened.


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#31 Crashtd420

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Posted 12 December 2017 - 02:30 AM

Try looking here for some info....
http://www.davidcmur...dat/620tech.htm

And to answer the question.....
Screenshot_20171212-052914.png