Compression dissapeared

[Scrapson]

2nd Head Gasket done correctly the head is decked 12 thousandths over i had 210 compression previously but now its just got 0 in all cylinders i cant check for a vacuum leak since it will not run.

It is all set the timing is at 10 degrees it has new plugs wires and rotor, The valves checked out as good when I had it pressure tested and magnafluxed I genuinely am at a loss for where the hell the compression went I put the head gasket on right it was torqued in the right pattern to 65 ft-lbs. Last time it was torqued to 60ft-lbs and then it puked coolant through a warped part of the head. What the hell happened I have a neighbor who had this happen while he was driving his 76 datsun 620.

[Rice n Beans Garage]

0 compression ? was it running after you replaced everything you listed ?

 

If it wasn't running start with the head gasket:

 

1. did you match it up to the head ?

2. what material is it ?

3. if you crank it over with your finger on one of the plug holes do you feel anything ?

4. Check you timing, chain position

[DanielC]

No compression is a mechanical problem.  No amount of messing  around with the carb or ignition will fix it.

Check valve clearance.

Get a leak down tester.

If you cannot get one, go to a hardware store,  and get fittings to attach a source of compressed to the spark plug adapter on your compression tester.

Put each cylinder exactly at TDC for that cylinder, firing stroke, and supply compressed air into each cylinder at TDC, and listen for where the air is escaping.

Hiss in the carb, intake valve. Hiss in the exhaust pipe, exhaust valve.

Remove the oil fill cap, if a hiss there, rings, or other problem with the piston.

 

Caution!  If a cylinder is not exactly at TDC, applying air to that cylinder will cause the engine to turn forward or back. 

[wayno]

You sure do have a lot of trouble with your engine.

Does it spin freely(fast) when you turn it over or does it sound normal except you cannot get any compression readings?

Do you have the carb floored/butterflies wide open when doing the compression test?

Have you checked the valves to make sure they are not too tight and being held open?

 

When you put the head on and then put it back together was the engine at TDC and the cam at 10am/2pm???

When you got the head back how did you put the cam back to the way it was when you pulled the head off?

[datzenmike]

If your engine was set to TDC and you did not adjust the cam to match before fitting the head back on there is a real risk of bending the valves..... Again.

 

 

[G-Duax]

Nothing personal Scrapson, but you might consider that engine building isn't one of your strong points.

We each have strong points, and weak points.

Mine are paperwork, and relationships with the opposite sex.

(women think I value my projects more than them, for some odd reason)

 

Maybe just take it to someone else to build.

[demo243]

What did you use as a reference to put the engine back together? Ie did you download a factory service manual or a Haynes manual? 

 

Did you follow all the steps? Did you double check yourself after each step?Did you take notes?

 

When you took the head off did you wedge the timing chain? Or did you retime the whole engine? Got the right TDC?

 

When I built my ka I taped a few sheets of paper to my work bench. Allowed me to take notes of torque specs, and order of tightening... etc... and I printed the factory service so I could actually check off steps.

[Scrapson]

Alright so it’s just a regular old fel pro gasket the cardboard aluminum crap. I’m about ready to just swap in an L18. I am learning how to do this but yes this is a definet weakness. I had a timing wedge yes I didn’t reset the whole timing I just changed it all to TDC before I went to start it and put the head back on as a safety before I bend a valve. I do have a lot of play in the valve rocker/lash pad. Everything was torqued to spec just last night otherwise it was all hand tight or snugged up. I went by my “How to rebuild your Nissan/Datsun OHC motor” Haynes aswell as petersens. Everything was done correctly all was torqued including the valve cover. 

[demo243]

Fel pro should be ok.

 

Did you take the head off with the lower assembly set to TDC?

 

Was the head set to TDC to match?

 

Set the valve lash? - its supposed to be done warm... but this would at least ensure your within the realm of where you need to be - just gotta make sure both the lower and head are at matching TDC set up to ensure there is no valve interference 

 

 

[datzenmike]

Face it... if you can't get this one fixed and running an engine swap just puts it off till that one has a problem or has it's own problems now. Sounds right. Check the compression on another engine to test the tester.

[bilzbobaggins]

Wish you would have put together the halftime show, it would be over already.

 

But seriously, is the gauge bunk?

[wayno]

I would guess the cam is timed wrong, the valves are open when they are not supposed to be open and that is why you have no compression, there is also a chance that valves were bent the first time you turned it over or maybe you got real lucky and no valves hit any pistons, but if one hit then all 4 hit.

I have never heard of anyone moving the engine to TDC with the wedge in position, I suppose it is possible but I suspect it would not be a one man job and it would have to be turned over by hand to do that, one turning the engine while the other holds the chain up and keeps it tight while holding the wedge down in position and there is always the chance you will hit a valve.

OK, lets say you got lucky and didn't bend any valves, you need to turn the engine over by hand(should be easy since you have no compression) till you have it on TDC, pull the distributor cap to make sure it is the TDC that the rotor points to #1 spark plug wire on the cap, once you have that done pull the valve cover and look at #1 cylinders cam lobes, are they at 10am and 2pm, if not then you may be able to fix it, put your wedge in to keep from loosing the timing chain tensioner when you take the cam gear off, after removing the cam gear look at the cam and figure out which way is the shortest way to turn it to get the cam lobes at 10am and 2pm, then using something to turn the cam, turn it slowly until it gets where it needs to be(10am and 2pm) or until a valve hits a piston, if it hits a piston then try turning it the other way until you get it to 10am and 2pm, if it hits a piston again before getting it to 10am and 2pm then I give up as it is too complicated to try and explain to you how to get the cam/valve by the piston as that would require installing the cam gear, turning the engine by hand, then removing the cam gear and turning the cam then re-installing the cam gear to turn the engine back to TDC by hand just to see if you can turn the cam to where it needs to be by hand without a valve hitting a piston again.

 

It's a real pain when one gets impatient, you may have warped the head by driving it around without coolant in the engine.

[Scrapson]

I got the warp fixed but I was told cam timing could be off because of the decking

i had it all set to TDC when I pulled it apart and never did anything to adjust it. I can do the valve lash cold though right?

[demo243]

You can do it cold, but readjust it later...

 

As Wayno said though... I doubt it's the valve lash... total lack of compression across all cylinders leads me to believe the cam isn't timed right... so your valves are all open at the wrong time

[wayno]

Did you adjust the cam back to 10am and 2pm before installing the head??????

[Scrapson]

Yes I had it adjusted 10 and 2 the first and 4th cylinder valves were closed like they should be for TDC that’s all perfect the block was at TDC the cam is at TDC timing doesn’t seem to be the issue I think because we took the plugs off and put fingers to it and there was no compression  however it did backfire if that means anything to y’all. 

[datzenmike]

When transporting the head home did you set the head down on any surface or table with the valves facing down????

 

Does it hold water????

[banzai510(hainz)]

are all the valve lash correct????????????

If it was timed correct at TDC then it should be OK.

 

if you timed it so far off it would have smashed a valve.

 

simple rotate the motor back to TDC going clovk wise and rechechk the timming and cam position. If good then its OK and redo the valve lash.  if that good its something else.

 

even if the carb wasn't installed its still going to suck air in the head and compressed the air if everything closes

 

getting another motor might fix thjis but your pattern of mechanics is not helping. but this is really is simple motor. which a bushman in African can handle.

 

Is there a Kia dealership near you?

Edited February 3, 2020 by banzai510(hainz)

[datzenmike]

34 minutes ago, banzai510(hainz) said:

 

 

getting another motor might fix thjis but your pattern of mechanics is not helping. but this is really is simple motor. which a bushman in African can handle.

 

 

 

Even simpler... a Neanderthal. 

[Scrapson]

When I was taking it home it was in a box. The valve lash is off you can tell from the amount of play. The nearest dealership that is Kia is like 45 miles out. Yes it does hold water the loop is full. Everything is set correctly the only thing I didn’t change was the distributor advance and retard it I kept it at 10° of advance. 

Edited February 3, 2020 by Scrapson
It’s actually 45 not 60

[datzenmike]

Take the plugs out and use the starter to turn the engine. Does air blow out the holes??? If yes get another compression tester.

[banzai510(hainz)]

Just hook the wires back up and fire it up. I never have used a compression tester in 30yrs.

When I mean check the valve lash it means it supposed to be loose. If tight then the valve don't close all the way letting out the compression ,so it don't go BANG.Fire off the gasoline. ect…..

 

or as mike said see if air comes out!!!!!

[Stoffregen Motorsports]

If it backfired out the exhaust (or even intake for that matter) it obviously had enough compression in at least one cylinder to fire. This tells me that the cam timing was not so far off that you bent the valves.

 

We've all been there. I messed up my fair share of engines before I figured it out. My first engine in my first 510... had that cylinder head off at least three times before I figured out the valves were bent because I had the cam timing way off.

 

The secret to engine work is not rushing. Check and double check everything before parts go together. Take time to properly clean things. Take good measurements. Write things down. Make a check list.

- piston at TDC √

- head at TDC √

- both surfaces cleaned √

- head dowels in place √

- head gasket went on smoothly √

- head went on without hitting or bumping anything √

- timing guides installed √

- nothing moved when installing cam sprocket √

- head torqued √ (by the way - 65 lbs is a bit much)

- distributor drive spindle installed correctly √

 

You get the idea.

 

Now this is a total shot in the dark, but I have seen engines turn backwards when the starter is engaged. Totally rare and probably not the problem. Like 99% probably, but may be worth checking. It seems you've run into every possible problem along your journey, so something as crazy as this? Why not?

 

[Scrapson]

I’m going to pull the valve cover off and see if the cam is moving I torqued the cam sprocket bolt to 45ft-lb I had the strangest feeling last night if it did backfire the cam might not be spinning at all it might be at TDC still. The backwards starter thing sounds crazy but I can check that when I get home from school. 

[banzai510(hainz)]

the cam not spining is you forgot to put the chain on!!!!!!!!!!