What are the reccomendations on a whole engine rebiuld verses a head.  I know the head needs rebiuld, (money its tight)  but on compression the cylinders are at 125 to 130 (all 4)  and on a wet test they only jump up 3 to 5 psi.  oil pressure is 60.  with this info what are the reccomendations whole engine or head.  I know it is prudent to do the whole engine but money is tight. 

 

thanks inadvance

Lance

    I too am trying to get an engine running and spending the least amount of money doing it.  After compression, another check is a leakdown test.  You can get a leakdown tester, and it will give you a quantitative idea on how bad the rings, and
valves are, but you do not need to spend the money for it.
       I used the hose from the compression tester to blow air into each cylinder, after putting the cylinder on TDC firing stroke.  Then take another hose and listen for air escaping out of the carburettor, exhaust pipe, and oil fill hole, and other spark plug holes.  Pull the radiator cap and look in there.  If you hear air leaking out the carb, or exhaust, bad valves that cylinder. You should not hear any air at all here.  A little air escaping around the rings is normal.  No air in other spark plug holes, bad head gasket if there is.  Air bubbles or noise in the radiator, bad head gasket.
    I had to remove the schrader valve from my compression tester hose for it to blow air into the cylinders, put it back when you are done using the hose for leakdown testing.
    I pulled the oil pan off the engine I am working on, and cleaned it.  removed some sludge there, but I could not get the engine started and warm to do an oil change with hot oil. 
    With the pan off, use plastigauge to check the rod and main bearings.  You should check than all.  Visually check the bearings,  too.
    
   

I already know I have a bad head gasket and #2 piston is the bad cylinder.  by doing the wet test it proved the rings are in fairly good shape.  I also know the oil seals for the valves are bad (every time I start it get blue smoke)  then it goes away as it burns away.  So head job a certain.  also have leaking rear main. so I will have to pull the engine to change that.  with the oil psi at 61 that is darn good telling me the oil pump is good and the galley ways are not to openwhich probably means the main and rod bearings are in good shape.   so If I did a leak down test right now I would get leaks from several areas.  I like the idea with using the compression tester for the lak down test I will remember that.  So far I have purchaced the headgsket set rear main ,  oil pan gasket and new timming chain kit. 

So you see my dilima, it's the cost of a machine shop that gets expensive.  the whole engine verses a head.  In Jan I did my sons 93 paseo engine and the cost for to rebiuld was 1200 that was parts and machine shop I did the tear down and put backt together.   

I just don't want to do the work then have problems with the bottom half later or with a new redone head  may put more pressure on the rings and cause them to go, (what are the odds)

May be hten I will just pull the engine take the head int to be done then check main and rod bearings and possible the rings.

Lance

    I can sympthize with you, I hate having to give a machine shop a lot of money.  Try to get them to give you a steady customer discount.  I an also taking an automotive class at a local community college, and that can get me a discount.  I recently went to a meeting of a local Datsun club here in Portland, Or (Datsun NW) and membership in the club cost $24.00, and the first purchase I made at a local auto parts chain, I saved over $20.00 off retail on that one invoice.
    I have three useable Datsun L-16 cylinder heads, but all three need valve jobs.  One was already apart, and the other two are still on the engine, and were blowing air past the valves on the leakdown test I did on them.  I am actually considering buying some valve grinding equiptment.  The best price I have gotten around here is $175 for a valve job on a Datsun 4 cylinder head.  I would buy only the equiptment I need to grind (or cut) the valve seats, and not stuff I would need to replace guides, or seats.
    The plan I have with the head that is apart is to get .003 O/S stem valves, to tighten up the clearance in the valve guides, and see if I can clean up the valve seats in the head by just lapping them with valve grinding compound. 
    Once again, I would pull the oil pan, clean it, and plastigauge the rod and main bearings.  My service manual says Main bearing clearance is .0008 to .0028, Rod bearing clearance is .0006 to .0026.  If you decide to put rings in the block, that is a possibility, you could borrow or buy a ball hone to put some tooth back in the cylinder walls to seat new rings.  I have heard that Datsun blocks quite often do not wear enough to require boring to the next oversize every time you put rings in them.
    I too have heard that doing a valve job can cause an engine to wear out rings, or bearings, but I am sceptical.  I believe that the parts in question were already worn out, and would of failed anyway, but with bad valves, the engine would not run to make them fail.  Do you think this is exciting enough for Mythbusters to take it on?  
    I understand that if you are patient, you can get a serviceable L-16 or L-18 block for not much money, most people want a bigger displacement engine to swap in.
    A national chain of auto parts stores (Schuck's Auto Parts in this area) can sell you a rebuilt L-16 engine, I was quoted a price of around $1200, I think for a long block engine.
    I will let you know how the oversized valves worked out in the head I am working on.