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L20b power loss/valve problems?


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#21 datzenmike

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Posted 08 June 2016 - 07:51 PM

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I see the bottom exhaust valves get hot enough to clean themselves. Or there is less oil getting into those cylinders.

 

Valves look fine they are just dirty from too much oil. So either the rings are worn or the valve seals. I would replace the valve seals and call the head good. Seals are only a couple of bucks each. 


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#22 datzenmike

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Posted 08 June 2016 - 08:00 PM

 

Next I did a ghetto leak down test. (because harbor freight was out of leakdown testers) 

Set cyl 4 at TDC and ran air straight from my compressor into the cylinder and it air shot out the intake.( its not a slight leak either)

 

Was that TDC on the compression stroke??? If on the exhaust stroke, yeah, the valves are open.


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#23 MapleNuts

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Posted 09 June 2016 - 12:58 PM

I thought i did it on compression stroke but i guess i didn't. I forgot to check it the rockers had some play in them when at TDC. Im gonna replace my valve stem seals and put a new head gasket on it for good measure and then hopefully no more fouled plugs!

thanks



#24 banzai510(hainz)

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Posted 09 June 2016 - 02:11 PM

clean the head off good and reinstall.gasket ect...

 

I sometimes pour water in to my carb to clean the intake and piston on a real hot dayIt will steam clean the intake and valves just only do a fine amount.

 

 

I don't see a nice chain wedge hopefully you don't drop that chain


Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#25 MapleNuts

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Posted 09 June 2016 - 03:43 PM

definitely dropped the chain because the wedge spilled out, guna have a blast with that one



#26 banzai510(hainz)

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Posted 22 June 2016 - 05:08 AM

update?????????????


Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#27 MapleNuts

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Posted 22 June 2016 - 09:21 PM

Haven't had a chance to work on it yet due to school and work but i'll definitely post once i'm done. Should go fine after watching your videos hainz, thanks for making those by the way.



#28 610 Wagon Goon

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Posted 22 June 2016 - 09:35 PM

You can check if the valves are leaking by laying the head flat with the valves up. Put the spark plugs in and filling the space around the valves with water and let them sit. If the level drops you got a leak

#29 datzenmike

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Posted 23 June 2016 - 08:22 AM

Water is too thick, use diesel fuel.


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#30 banzai510(hainz)

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Posted 25 June 2016 - 12:20 PM

drop the oil pan if your doing a front cover.

 

all this time you can buy a timming chain wedge. 5-8 $ on amazan but 5 and give them away

 

 

I work on motor 1/2 hour a day all is needed till done


Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#31 MapleNuts

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Posted 30 July 2016 - 03:48 PM

Alright so i finally finished replacing the head gasket and the valve stem seals.

Seems the car is still getting some oil or gas (seems to have a gas smell but i'm no expert) onto the 4cyl spark plug and a little on 3cyl. I smell the same smell when i open the oil filler cap that is on the spark plug. 

Could it be

1. the fuel pump diaphram is bad, gas mixing with the oil, thinning out the oil and somehow making its way into the cylinders?

2. somehow its not burning up fuel all the way and its just gas on the spark plug, because it is still backfiring like crazy and i'm positive it is trimmed correctly.

and if any of those things were the case why is it really only affecting cyl4?



#32 Cheetahking

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Posted 30 July 2016 - 04:07 PM

Unburnt gas and your backfire are related I would think.  I would start with your plug wires - order correct I'm assuming?  A bad wire could show up intermittently and give you headaches.  missing - and you have unburnt gas in those cylinders.  



#33 MapleNuts

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Posted 30 July 2016 - 05:39 PM

I just ordered spark plug wires, plugs, coil, cap and rotor, and a fuel pump so hopefully that will do something. Order is correct and it's not missing



#34 datzenmike

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Posted 30 July 2016 - 05:39 PM

If faulty fuel pump the oil level would get higher.

 

Backfire???? out the exhaust or the carb???


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#35 MapleNuts

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Posted 30 July 2016 - 07:15 PM

afterfire out the exhaust (everyone wrongly calls it backfire though).

it wouldn't get much higher if it was just a small leak though?



#36 datzenmike

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Posted 30 July 2016 - 07:54 PM

Out the exhaust is raw fuel and air that was not burned in the cylinder. The simplest cause is an interruption of the spark to a cylinder or several cylinders. Fuel and air is pumped into the exhaust where it explodes. 

 

This can be from bad points. It can also be bad wires, cap or rotor that allows a spark from one cylinder to escape to ground and there is a misfire. 

 

As mentioned a cylinder that does not fire will pump gas into the oil.

 

 

I just ordered spark plug wires, plugs, coil, cap and rotor, and a fuel pump so hopefully that will do something. Order is correct and it's not missing

 

Don't forget the points!


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#37 MapleNuts

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Posted 31 July 2016 - 06:43 PM

Put on the new cap, rotor, coil, plugs, plug wires, cleaned and set the points to 0.020. and its still afterfiring. 

Could my distributor be bad? i'm still really only smelling gas on cyl4 plug.

I've messed with the carb mixture screw to see if it was just running to rich but that's not the case.

Could this be a problem with my intake manifold somehow? i've got no damn clue



#38 datzenmike

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Posted 31 July 2016 - 07:08 PM

Idle mixture screw only adjusts the idle mixture... and it adjusts ALL cylinders.

 

 

Put on the new cap, rotor, coil, plugs, plug wires, cleaned and set the points to 0.020. and its still afterfiring. 

Could my distributor be bad? i'm still really only smelling gas on cyl4 plug.

I've messed with the carb mixture screw to see if it was just running to rich but that's not the case.

Could this be a problem with my intake manifold somehow? i've got no damn clue

 

Take the cap off and watch the points open and close while turning the engine over with the starter. If the points open on all lobes of the distributor cam you must assume that everything is working.

 

If everything should be working maybe it is. This leaves a poor sealing combustion chamber. Do a compression check. Maybe you have a burned exhaust valve.

 

But first did you ever check the valve lash? Specially on number 4???


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#39 MapleNuts

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Posted 31 July 2016 - 08:07 PM

Here's a video of the points in slow motion. seems the spark isn't consistent. Does this call for new points, condenser, or distributor?

 

Its pretty much 120 across all cylinders for compression test

 

I'll have to double check the lash but i believe its good



#40 datzenmike

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Posted 31 July 2016 - 08:24 PM

Pull the coil wire off and hold near ground. All four sparks the same?

 

If not then one of the cam lobes is worn down or perhaps the distributor shaft or bearing is worn. Does the shaft wiggle?


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