questons about rebuilding an l20b

[king bee66]

ive got an l20 out of a '78 620, that was pulled by the owner to make way for an sr20 swap.  the block itself seems to be in perfect running order, but some of the accessories seem to have been left out and a little corroded.  my desire is to rebuild it without going into overkill,  besides the gaskets and clutch, which i intend on replacing, is there anything else on these motors that is commonly warn down?   what should look out for?  head bolts arent reusable on these motors right?

 

this is my first l motor, ive only worked on As before this,   is there a wiki link that i can go to similar to the one at datsun1200? i downloaded a 620 FSM but my comp takes to long loading it for it to be of much use.  lastly, is there a link for L parts numbers?   some of the bolts need to be replaced.

 

pics because...

 

 

[datzenmike]

Not much sense replacing gaskets on a worn or blown engine. Set the valves cold and do a proper compression test. If the numbers are even across the cylinders then it will probably run ok. 150s would be nice, higher even better. If this is the case, there's nothing to gain by replacing the head gasket or the manifold gaskets unless the owner has told you he blew the head gasket.This can only lead to a broken stud, so leave well enough alone. BTW the head bolts are totally re-usable. I would loosen each one ONE AT A TIME and torque to 60 ft lbs. Oil pan and the rear seal would be a good idea as it is very difficult to do later with the motor in. Pull the front pulley and replace the front crank seal. With the timing cover off replace the timing chain, guides and tensioner. A new fuel pump and valve cover gasket should do it.
 
Loose the Fram oil filter.
 

This is an EI distributor. Actually a 'Remote Igniter' type. For it to work you need the little box mounted under the pass side dash just above the kick panel. Igniter box below. If installing an SR he won't need this so cut it out with some wire leads so you can wire it back in.

 

Or you can use a General Motors HEI unit.

Simple to do like this...

[banzai510(hainz)]

King Bee

Says you got 2000 post so you should know already what you need

head bolt I still reuse them.

most times the crank and rod bearing most like you can get standard size if if doesnt look worn. I had 2 motor done and machinist just used stock size bearings. Pistons I had new ones put in and bore. Maybe you can get away with a re ring job. Thqats pretty much on the bottom end.

Hot tank it.

head you might ant a basic grind to it.

and reassemble.

http://vimeo.com/19077890

 

parts? Rock auto.com O rileys Napa autozome or a good import place.

[king bee66]

i have a good idea what i need but i like asking questions before i shoot myself in the foot.   the A series motors are so simple that i didnt want to assume i knew more then i did.  ill do a compression if anything is funky hopefully its not a bore,  because that will set my project back a bit further.  when is just honing it an option?

 

the head wasnt blown, i was just thinking freshening it all up while i had the chance,  but leaving it on makes sense too.  the exhaust mani will probably have to come off.  from what ive read an l20b exhaust wont fit a 510 right?  if so im guessing it wont fit a b210 either.   i think he might have given me the box for the HEI.  although i have the HEI type dizzy on my car already, would the l20 be too much for an a14 box?  

[datzenmike]

You can measure the cylinder bore about an inch down then at 90 to that then an inch lower and 90 to that and finally an inch lower and 90 to that... 6 in all measurements. This will give a good indication of taper or oval cylinder wear. If wear is slight a hone and new cast iron rings. If worn past then re bore (this will allow chrome rings) and matching new oversize pistons.

the exhaust mani will probably have to come off. from what ive read an l20b exhaust wont fit a 510 right? if so im guessing it wont fit a b210 either. i think he might have given me the box for the HEI. although i have the HEI type dizzy on my car already, would the l20 be too much for an a14 box?

The later W58 head exhaust manifold has a single large outlet. Around 2". Might as well just use the L20B exhaust and graft to your B-210 down pipe.

 

Don't forget the W58 head has round exhaust ports and the L16 manifold is square. Also the L16 manifold has two outlets to the down pipe. A single large pipe would be easier to mate up.

[king bee66]

nice, well that only leaves me on the hunt for a mid sump oil pan than. 

 

  for a hone,  what is the average lifespan of cast iron rings vs chrome ones?

[datzenmike]

Chrome rings need a perfectly round cylinder. They are very hard and will wear away the hone on an uneven wall before they seat and seal properly. Cast iron rings are softer and will 'wear into' a less than perfect cylinder.

 

Cast iron... 50K to 80K??? Chrome rings wear twice that up to unlimited.

[banzai510(hainz)]

If nothing wrong with this motor just install it.

 

I have got cast rings everything myself.

 

its up to you,ask your engine builder machinist what are the reports.

[Stoffregen Motorsports]

The cheapest way to "rebuild" a motor is to:

• Piecemeal your "rebuild kit" instead of buying one.
• Definitely use a Nissan head gasket. I won't skimp here.
• Cast rings are fine.
• Clean the gunk out of the ring lands.
• Use a ball hone to clean up the bores.
• At least check the timing set and replace the guides and tensioner (they are probably brittle and hard).
• Have a shop do a quicky valve job and install new valve stem seals.
• Pull the crank and inspect the bearings, but if they look good, re-use them. If you are going to re-use them, make sure they go back in the same hole they came out of.
• Find a used "Turbo" pump and stick a shim in it to bump up the oil PSI. After inspection and cleaning of course.

I have built plenty of motors where the only NEW part was the head gasket. It feels good to have something so cheap run so well.