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Charlie69's 86 720 King Cab DD


Charlie69

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I replaced the exhaust manifold gaskets and re routed my EGR vacuum lines. and replaced the gas cap.  Went through emissions at about half of the maximum limit.  So I am pleased.  I got online and paid for my registration.  Went up from $19.75 to $51.75 thanks to our governor adding a $32 fee to fund the State troopers.  An organization is trying to get the $32.00 removed as it was not voted on.  Doug Ducey is not a a legit governor he is the typical politician lining his pockets from special interests and also lobbyists.

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The repeal of the $32.00 fee goes into effect in 2020 is what they said. We will see.

Charlie69 you are right about Ducey. Met him here a few years ago. During the campaign.

Kingman is a hot spot for the Republican party. They had a town hall meeting at the diner next door to us.

 

Chopper Jim

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i hope the $32 fee added gets repealed since i get tags for my vw for 5 yrs instead of 1yr. it costs me $150 for a 5 yr tag but i think this year i will just get the 1 yr cuz im not down paying an additional $160 in gov. ducey's extra fees on top of what i paid for just getting a tag that expires in 5 yrs even though i don't drive my bug

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Well I scored a remanufactured Z20 engine from an 84 720 king cab today at a local u pull it for $250.  This engine has never been run.  It also came with a new clutch and throw out bearing.

 

I had it pulled, unloaded at my house, and in the shower by 11 am.  Did it by myself.  Sometimes it is faster by yourself. 

 

I will put it on my engine stand and pull the oil pan to make sure there has not been any moisture in the lower end.  I will also pull the intake manifold for cleaning.  The exhaust manifold was gone when I found it in the yard this morning.  I saw the exhaust ports were clean so I pulled the valve cover and it was as clean as the exhaust ports.  I then crawled under the truck and looked at the driver's side of the block and damn if there was a red metal riveted on  re-manufactured serial number placard.  This engine had been installed and never run.  There is dirt and spider webs on this engine.  I will check it out thoroughly before I install it in my 1986 720 king cab daily driver.  Pictures when I pull it out of my garage to check it out and prep it for installation.

 

It has been another great morning at the wrecking yards!  LOL

 

Edited by Charlie69
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  • 4 weeks later...

I finished checking out the Z20 engine and it is all good,  Has new 0.50 pistons on a fresh bore and hone.  All new bearings 0.10 under on rods and mains, and fresh fresh head with a new cam.  All I nead to so now is get the 3/4" hole in the oil pan welded up install pan with new gasket bolt up the trans and the starter.  Have a new Weber DGEV 32/36 coming for it.  As soon as I get the few parts I need along with the Weber these will be installed and the engine and the transmission will be swapped in my 86 720 king cab.

 

I am curious as to what the power difference will be between with this Z20 and the old Z24?

Edited by Charlie69
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On 6/26/2019 at 6:34 AM, ]2eDeYe said:

I am surprised you still have to do emissions on a vehicle that old.

We have an emissions cut off year of 1966.  66 and older do not have to have emissions testing. 67 and newer have to have emissions tested.

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I also put the 85 king cab red ST non electric doors on my 86 today.  I will have a couple of door lock cylinders keyed up to match my igniton key for this truck.

 

I will be transfering the 85 ST hood, right fender, and the bed to my 86 soon.

Edited by Charlie69
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  • 2 weeks later...

Here is what I found when I opened up my 84 720 Z20 junk yard engine.

 

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I noticed a mistake some one made.  The pistons are flat tops which is correct for this mileage plus engine.  When the pistons were fly cut  for valve clearance they cut the intake side of the piston the size of the exhaust valves and cut the exhuast side of the piston for the intake valve size.  This mistake is causing the intake valves to vit the pistons and bind up the engine.  Simple fix will be to pull the pistons and have a shop fly cut the intake side of the pistons to clearance for the intake valves.

 

This might be why the truck ended up at the junk yard.

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I do not believe I can turn them as there is a notch on the top of the piston marking the front of the piston that orients it to the front of the engine.  I have never run a piston backwards in an engine not sure what would happen, if anything.

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But if you turn the pistons 180 degrees will the valves clear?

Fact is I am not sure you can turn the rods around, but the pistons I don't see a difference but maybe there is a difference, I also am unsure if the wrist pins can be removed without damaging the pistons, my machinist seems to think they will not come off easily as we talked about this once.

Edited by wayno
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I know I cannot turn the rods around 180 on the crank as this would need to have the rods re-fitted to the crank.  I might have to buy new pistons and have them properly clearanced for the valves. 

 

Wayne I am not sure if turning the pistons 180 will clear the valves.  I am not sure if the valves a centered in the combustion chamber.  I will consult my engine builder and see what they suggest.

 

Might be easiest to buy new pistons and have them properly clearanced for the valves.

 

I talked to one engine builder about the remanufactured tag and he said it was a company that went out of business about 10 years ago because of so many problems with their remanufactured engines.

Edited by Charlie69
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I will re do the cam timing next weekend and check to see if the valves still hit pistons.  I am pretty sure they will.  You can see the smaller clearance cuts on the intake side of the piston and the larger clearance cuts on the exhaust side.

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Good observation Crashtd420.  Looks like I will be buying pistons!  So much for a $200 rebuilt engine.

 

Wayne looking at this picture I do not believe if the pistons were cut wrong for this block and head  (meaning cut for the 2 valves for each cylinder 180 out) that I would be able to turn the pistons 180 and make them work.

 

DSC02958.jpg

 

 

 

 

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Wayne, as soon as I removed the head I could turn the engine over with a 1/2" ratchet.  Withe the head and timing gears and chain on it it would tur about 1/4 turn and bind up.  I did not try to force it as I did not want to damage any thing.

 

My brother is comming over tomorrow evening and we will look at the rods crank and pistons and bore.  We will also get the numbers off of the cam and check to see i it is the correct cam.  I will also count the links in the timing chain to find out if it is the correct chain.

 

With the head off while turning the engine over with the ratchet there is a tight spot and then about 180 degrees after ther tight spot the engine turns real free.

Edited by Charlie69
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Those are correct flattop pistons for the Z20 and are on 6" rods.

 

The piston pin is off set, usually under 1mm, to the right side on a clockwise turning engine like the Z22. On a clockwise rotating engine the major thrust side is to the right side of the vehicle during the firing stroke and to the left on the compression stroke. The piston top actually rocks from side to side during compression and firing making noise. There would be more wear on the right (thrust) side of the cylinder so off setting the pin to the right side is an attempt to even this thrust out and reduce the loud rattling noise.  DO NOT 180 them as this would compound the noise problem. All engines have this. The second set of notches? maybe to prevent the piston being slightly heavier on the other side?

 

Charlie, turn the cam so an intake is at full lift and measure how much it extends below the head surface. Remove about 1.2mm for the gasket thickness. Measure the larger eyebrow that the valve may fit into. I think you'll find that the valve extends well down into the piston. This is called an interference engine in that at full lift the valves will hit the pistons at TDC. HOWEVER if the cam is timed properly this would never occur. The intake would normally be just starting to open and the exhaust almost closed at TDC. This is why the cam and valves must be returned to TDC before putting the head back on or an open valve will get mashed into one of the two TDC pistons.   

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