The 521... OK, after eliminating all the other culprits... valves???

[hessianben]

Well,

as I feared...

when I added a little oil (less than a thimble-full) to cylinders 2 and 3,

and then ran a compression test again,

the numbers jumped-

2: from 100 to 125

3: from 90 to 140

 

Soooooo...

 

with my mind full of helpful tips and tricks from Hainz video,

it's time to make 1 motor into many pieces!

 

On with the swearings!

And now...

beer.

 

I'm gonna go ahead and pull everything so that when we get the hoist over here,

it will be a smooth yank.

 

Here we go...

:cursing::cursing:

[ggzilla]

I'll put a dab of oil in each and see if that changes anything.

if it the compression improves...

that means shot rings, right?

Yes.

[banzai510(hainz)]

the brite links are on initial set up. More to make it idiot proff. Its to take the guess work out of making the chain one link off.

Once lined up then you just use your timming marks on the crank pulley,cam ect....

 

 

Personally I think the car would still run smooth enough with some worn rings just be stinky.Unless those rings are so badd that its not making enough comprssion to give it a good pop.(like pulling a sprk plug wire)

 

Run the car at night and get a flash lite and shine acrss the motor you should see a alot of smoke comming out the vent.

 

 

 

 

To pull a L motor out of L16 I remove the water pump and jack up the trans also to clear the steering barr across the oil pan. also remove the lower plate on the bottom of the trans!!!!!!!!!!!!!!!

Edited January 9, 2009 by banzai510(hainz)

[hessianben]

I don't get any smoke from the vent cover, so I didn't think it was rings in the beginning. The popping is coming back through the intake and carb making me think it was a valve that was shot or not closed all the way.

 

Could adding a little oil to each cylinder before checking compression have helped the valves seal a little better? and that's why I saw better numbers on the last test?

 

When I pull the head off- will I be able to tell if the rings are bad?

I assume there would be scratches in the cylinder walls?

 

Thanks

[banzai510(hainz)]

When I pull the head off- will I be able to tell if the rings are bad?

 

No if its worn correctly you wont be able to tell. But I have seen were people dont gap the rings and they expand enough to make a wear pattern in the bore.

 

what you can do is run the car and see when you pull the 2 and 3 spark plug wire and see if it changes abit. It should be more noticeable if you pull 1 &3 since you got real good commpression ratios on them. If you have weak charge in 2& 3 then its almost just blowing into the head .But I think you would see some kind of blowby or over prssure comming from the crank case vent or valve cover

 

Datzen MIKE??????????????????help.

 

 

Maybe somebody lined up the rings where the opening(ring gap) is all on one side. But you said this kinda happaned all of a sudden???????

Thats where I am looking at.

[datzenmike]

FIRST TIME:

 

I ran compression on all four cyl's:

 

1. 170

2. 85

3. 77

4. 150

 

 

 

SECOND TIME AFTER VALVE ADJUSTMENT:

 

Well I ran a compression test after adjusting the valve lash.

 

1. 120

2. 100

3. 90

4. 120

 

 

This is not what I would expect. Why has #1 dropped 50 lbs and #4 dropped 30 lbs on the second test???????????? Nothing should have changed or at the very least NOTHING should have gotten WORSE!!!!!!!!!!

 

 

Was the motor warmed up on both tests??

[hessianben]

motor was not warmed up on the second test-

turned the motor over with no spark.

[datzenmike]

Warming it up may raise all numbers into an acceptable area. 20-30 would be not too bad.

 

The continued backfiring could still be a burned intake valve, maybe and early failing h/g. Hopefully with a warm engine the compressions will come up and confirm that the rings are ...reasonably ok. This would mean putting a rebuild off for a while. If a valve is bad the head gasket will be changed anyway. Good luck

[hessianben]

Well, I pulled everything, hoping to get some more clues...

 

 

 

 

Looks as if the timing is off per: Hainz video...

 

 

 

Don't see an obvious break in the head gasket...

 

 

If you guys can see anything that looks amiss... please tell me.

 

 

I suppose I might as well rebuild everything while I have it apart... Is it worth taking the block to be machined as well as a chembath?

 

The deck seems to be fairly flat- the straightedge sits flat diagonally.

 

Lots of corrosion in the coolant passages though...

 

 

Does anyone know of a reputable machine shop in Socal?

Otherwise I'll just be gambling on the YellowPages...

Thanks!

BTW: Hainz' video made doing this much less scary than I had initially thought!!

Great resource!

[lynchfourtwenty]

soooo whats all that crap in the cylinders? on top of the pistons???

 

is it just pieces of head gasket from where u were scrapin the old one off??? or is it build up??? mine never looked like that when i tore my head off.. mine were all nice an clean an shit.. an none of my exhaust valves were all black like yours...

 

 

what type of gas do you run?

[datzenmike]

The valve train is really dirty from not enough oil changes. Gasket looks fine... I was sure you would find it blown between 2-3. Backfiring could still be a bad sealing intake. Josh I think you mean the intakes are dirty, they run much cooler than the exhaust and will carbon up. All that black might be from 2-3 blow-by sucked up by the PCV valve and distributed to all cylinders by the intake... or carb too rich.

 

Did this motor burn much oil??

 

Otherwise cylinder ridge looks minimal and ready for hone and rings. Definitely replace mains and rods.

[ggzilla]

Your engine looks good to me. I still see some hone marks on the cylinder. And the compression of the two good cylinders suggests it is good. You also didn't see any smoke at idle.

 

The gasket looks blown. Look at the top of the block face and head face between 2&3 -- it is not completely shiny, kind of reddish looking like it leaked there. Sometimes you can discern it from the gasket, sometimes it is very hard to tell.

 

Check the head -- valves for cylinder 2&3. Turn the cam until the valves are closed (confirm by checking for play on the followers), turn head upside down and fill the chamber with water. It should hold the water overnight -- not even leak a little bit. I expect you to find that 1&4 are holding but 2&3 are not.

 

If it is only burnt a little bit, you just get two used or new valves to replace the burnt exhaust valves, and lap them in. No machining is usually necessary. Do you know an old mechanic guru? They can assist in doing it right at low cost. Young mechanic gurus almost always go the high dollar route, as the customer is paying so it doesn't matter to the auto shop or auto schools.

Edited January 11, 2009 by ggzilla

[lynchfourtwenty]

sorry yea i meant intake valves..

 

so whats that crap on top of the pistons? is that from him cleanin the deck? i was real careful when i did mine.. i had all pistons at a equal level.. so they were all in the same position in the cylinder.. then i packed them with paper towels.. then when i was done pulled the paper towles out an hey look.. no crap on my pistons.. but i have seen pistons with similar stuff to what he has on his an i believe it was crabon?? or something.. but i think it was a bit blacker an crustyer..

[hessianben]

Yeah, It looks like someone has been cooking bacon in the motor for years!!

 

I don't know what kind of oil changes this motor had-

The recent owner bought it with this engine (not original)

and he barely drove it... cruiser.

The oil didn't look bad when I picked it up,

and I didn't really drive it long enough to tell if it drank much.

 

I'm debating whether or not to go ahead and replace the bearings and rods along with the pistons and rings...

Anyone else have insight on what is prudent and whether replacing everything is overkill?

 

What's a good way to clean all the carbon buildup?

Is it worth taking it somewhere and having them give it a bath?

 

 

Thanks

[Lozer]

Damn i wish i had caught you before your broke down the head i could have told you how to find where your compression is going.

 

Use a leak down tester in the cylinder thats failing put it to TDC for that piston and if you hear air blowing out the carb, its the intake valve. if you hear air blowing through the muffler its the exhaust valve. You will need a hose to check the rings but you stick a hose into the dipstick tube and listen for the tell tale blowing noise.

 

if you want to check and see if its the rings now its easy tho. fill all the cylinders with oil and see if the "bad" cylinders lose more then the "good" cylinders after 24 hrs.

Edited January 11, 2009 by Lozer

[ggzilla]

You can fill it with water instead of oil. Less mess, and you'll see instantly if it is really bad. If it's a little bad you see it leak out overnight.

 

 

whether replacing everything is overkill?

 

Yes, overkill. Fix what is broken, not what is still good.

 

The 'crud' is not very unusual -- it's somewhat common. Don't even worry about it.

 

That picture, it looks like the exhaust valve is burnt. Could just be the shadow, but you can easily test it with water or oil test.

 

Stop asking questions and test it :-)

[bonvo]

i dont see replaceing everythign as over kill you already have it preity much entirly torn down just do it and when your done you will have a brand new motor besides if everything is new the odds of somthing being rong is slim

[ggzilla]

If it doesn't need to be done, then isn't it overkill?

[lynchfourtwenty]

i agree, do the oil / water test an see whats leakin an stuff... i dont think replacing rods an pistons is needed... if piston rings are bad just replace those an maybe rod/crank bearings just so u dont have to doit later.. but pistons an rods are pretty tuff... however at the very least i would still clean the tops of the pistons + cumbustion chamber on the head + valves an get all that cooked on crud off of them.. altho maybe running some chevron gas may clean that for you... when i first got my truck an took the blown head off it didnt have any of that cooked on crap.. the head i got to replace the old one was clean too... an also my piston tops were clean too..

 

 

heres a pic of my valve train for example.. u will notice it doesnt have cooked on oil on the cam towers ect..

 

 

the head is a little dirty by the spark plugs in that first pic i have since cleaned it... its amazing what a little degreaser can do lol

[datzenmike]

The dirty cam towers are just an indication that the oil changes weren't kept up. The motor may also have only been driven short distances and not properly warmed up. It doesn't mean it's no good just dirty. As for the carbon deposits on head and piston, all engines collect it and if driven enough when warmed up it will flake off. If you clean the head just don't gouge the soft aluminum. A small wire wheel on a drill will work, but watch that aluminum. Alternatively, you don't have to clean at all, it will still work fine. In fact when running properly it will clean itself.

 

Once the heavy deposits on the combustion chambers are cleaned, you could immerse in a tank or old bath tub with hot water and a commercial degreaser. Make sure it's compatible with aluminum and not corrosive to it. Spray can degreasers will also work too. Be sure to rinse off thoroughly. Best would be to remove the valves as the cleaning solvent won't be good for the seals. If apart... replace the seals.

 

So far, to fix this you are only investing the cost of a h/g. Possible a pair of replacements for damaged valves, some cleaners and maybe some valve seals. If the compression loss is in the head, this should pretty much fix everything and no need to mess with rings and bearings. The pictures of the cylinders show no outward sign of scoring from broken rings nor any indication of excessive blow-by. Even the ridge at the cylinder tops looks minimal. I would be willing to take the chance that the head will fix the compression problem. IF this does not work, you are out only your time and a gasket. Any head work, like seals, new valve and cleaning, needed doing anyway. You are doing the work so you aren't paying a mechanic.... right? :D

[banzai510(hainz)]

hessianben

you have to dial the mark up to the most left notch on the crank that is Zero. Otherwise I think your motor cam timming is fine.

I swear in my vid I show myself dialing it up to zero going 20 15 10 5 then zero.

 

Datsun Mike or anybody elese could bens proplem been with the 2nd set of points or does that only work in 3rd gear only or 3rd gear and above.

 

That head looks OK. I wonder if just a wore out distributor????????

 

head gasket dident look that bad either in my opinion!!!!!!!

[hessianben]

I stopped the crank when the intake and exhaust valves were 10 and 2-

When I had the timing mark on the pulley at 0, the valves were a little off-

just off TDC, so I went with the valves at 10 and 2, just to see where the piston was

when I opened it up, and it was top dead center. If I move the timing mark to 0, the piston sits down a few mm.

[banzai510(hainz)]

10 and 2 o clock is a basic indication but not exact when your measuring true cam timming to ck for chain stretch

 

always use the crank Zero, your cam timming is base on the lower crank sprocket. Not from the Cam down

 

 

10(Lobe 2 exh )and 2(lobe 1 intake) o clock is a basic indication that your on the Compression stroke

[Fineline]

I dont remember off the top of my head but how many links are there supposed to be between the marks? I want to say 44 on an L-20b?

[banzai510(hainz)]

44 for the L20b

42 for all the other L motors

 

pretty much get head near TDC

Crank on TDC or very close to zero

 

Then if you have a Jap chain put the brite links on the dimples and it takes the guess work right out of it if everything is new and head isnt shaved alot.

 

just turn the crank or cam a cunt hair if the dimple isnt quet lininng up. thats it.

 

its up to u if you want to set it up on 1 2 3 on the sprocket.

L20 came from factory w/#2