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L20B Rebuild


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#1 deadmonkey

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Posted 17 October 2010 - 08:13 PM

OK, after reading and reading... and reading some more I think I'm gonna take the leap and do this.
I have the extra $ to get a full rebuild kit.
I have the extra engine I pulled and is sitting on the engine stand, just waiting.
I figure I can do the rebuild and still drive the truck with the smoking engine if I need to, then swap engines when it is rebuilt and painted.
I have a sand blaster and plan to blast it before pulling it apart and paint as I put it back together.
I hope to have this all done before the end of the month.

here is the kit I wanna get:
http://www.rpmmachin...t_detail&p=5251

I have not torn it apart yet to check the wear.
This is the engine that was ran with out oil for a few miles. Is there anything other than this kit I might look into buying as well? I don't have any of the piston type tools or honing tools but figure I can either rent or buy what I need.

I have a pretty standard set of tools and air ratchet with impact set.
I have a shop manual in PDF form from http://www.olddatsuns.com/620tech.htm
Tools I expect to rent/buy:
- Honing tool for drill
- Ring compressor
- Puller (for main pulley)

Am I missing anything Ratsun?
"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
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My '76 620 Project
L20B Rebuild
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#2 Zeusimo

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Posted 17 October 2010 - 09:39 PM

I'm Not The Smartest Feller Out There But Isn't The l20b A 2.0l Not 1.8l Like It Says On The Kit.
I'm Just Stupid 18yo Kid,
WITH A DATSUN!!!

#3 I'm BLUE

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Posted 17 October 2010 - 09:40 PM

When budgeting for an Engine Rebuild ,,, calculate all costs ( like you did ) and X2 = expected rebuild cost

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#4 Braden

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Posted 18 October 2010 - 06:19 AM

you shouldnt need a puller, maybe a brass hammer, alaso take your impact and hide it somewhere, the ring sompressors are like 8 bucks. get you some loctite, and also an l20b manual to refer to for specs, also get a torque wrench, not the clicker type as these can come out of adjustment and there is no way to calibrate them, get the old school bar type torque wrench. have fun!
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#5 deadmonkey

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Posted 18 October 2010 - 04:57 PM

So a question on how to measure the inside of the cylinder. I have calipers but how do you measure inside properly? I assume you just take the largest diameter and hone/buy over-sized pistons/rings according to that?
"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
~ Nikola Tesla

My '76 620 Project
L20B Rebuild
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#6 I'm BLUE

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Posted 18 October 2010 - 04:59 PM

also get a torque wrench, not the clicker type as these can come out of adjustment and there is no way to calibrate them, get the old school bar type torque wrench. have fun!


+1 ^^^ ,,, after having 2 clickers fly apart ,,, I am done with those kind ,,, I now own 2 beam/bar types ;)

(---------------For sale ------------------------)

(240z/260z/280z/280zx/200sx/KA24e/SR20det)---

DATSUN/NISSAN FOR SALE ITEMS ---> http://nwdatsuns.com...&p=39699#p39699

 

***Blue 1973 Datsun 240z ---> http://community.rat...lue-240z/page-8

***Copper 280zx-turbo ---> http://community.rat...zx-turbo/page-3

***240z V8 3-link solid axle project ---> http://community.rat...0z-project-•••/

------------------------------

http://nwdatsuns.com/

http://www.hybridz.org/

http://www.northwestfirearms.com/

 

------------------------------

 


#7 deadmonkey

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Posted 18 October 2010 - 05:14 PM

yeah... I have the old fashioned one too... More reliable AND cheaper... besides lasting a lifetime.
"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
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My '76 620 Project
L20B Rebuild
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#8 brodster

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Posted 19 October 2010 - 04:11 PM

deadmonkey, I am new to the forums (aside from lurking and buying parts) and I am in the middle of a L20b rebuild myself. I have never done a rebuild, and am halfway through the teardown phase. Maybe we could be of help to each other on this one.

BTW I just found this rebuild kit: http://www.rpmrons.com/Nissankits.html
I don't know anything about this supplier but Ron emailed back very quickly and so far has been good to deal with. Apparently his kit comes with a cam too (a regrind?) Anybody used Ron's kit before?

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#9 datzenmike

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Posted 19 October 2010 - 06:37 PM

So a question on how to measure the inside of the cylinder. I have calipers but how do you measure inside properly? I assume you just take the largest diameter and hone/buy over-sized pistons/rings according to that?


You need an inside micrometer. The cylinder must be measured several places to show if oval and near the top and compared to the bottom of piston travel to show if tapered. Usually there is between one and two thousandths of an inch clearance between the piston and the wall all the way around. To gauge this you also need to measure the piston and subtract. You think an L20B piston is exactly 85mm???? think again. The L20B piston is nominally 85mm but actually fall in a range of between 84.985mm to 85.035mm. Cylinder bores are also 85mm to 85.050mm. It's not cost effective to make perfectly bored cylinders and pistons so a range is used. A 'slightly oversize' bore is mated with a 'slightly oversize' piston that meets the proper clearance spec. You may have noticed a number stamped onto the top of a piston? This is a grade number so the assembler at the factory can quickly select the proper over or under size piston 'off the shelf'.

#10 deadmonkey

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Posted 19 October 2010 - 07:39 PM

nice info thanks!

I found a machine shop that my mechanic referred me to. They will hot tank the motor for $50. I think that is a pretty good deal? He was gonna measure it for me too so I know what oversize kit to buy. This guys shop was crazy. Engines in every state of rebuild scattered everywhere. The place has been doing engines for 53 years!

So I think I will tackle taking it apart tomorrow.
"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
~ Nikola Tesla

My '76 620 Project
L20B Rebuild
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#11 deadmonkey

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Posted 21 October 2010 - 01:46 PM

So I got the engine pulled apart today. I found what was making the knocking.

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BAD Bearing

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GOOD Bearing

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At this point I don't know if I need a new crank shaft or if I can just put in the new bearings down. I'm guessing that is a big no! Perhaps the machine shop can fix it? Chances are, it would be cheaper to buy a new crank. Sigh! :( Confirmed... Machine shop charges $150 to grind the crank.

OH! and Even though it says so in Hainz's video.... DON'T bind the cam to break loose the main crank nut unless it is already relatively loose. Put two of the flywheel bolts back in on the other side and jam a wedge/fork bar in there. If you put too much force on it... this happens.

Posted Image
"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
~ Nikola Tesla

My '76 620 Project
L20B Rebuild
Posted Image

#12 banzai510(hainz)

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Posted 21 October 2010 - 03:06 PM

The stub/dowel broke out of the cam?

If it was a L 20 I think I mentioned that you can put a Cresent type wrench on the cam boss(later L motors has this BOss on the cams) in the center and turn motor till the Wrench rest on the head bolt then you can loosen the crank bolt.
I dont like using the screwdriver method(mostly a in car head removal) but I dont have a impact wrench or want to use a breaker bar and rest it on the frame and hit the starter as some people might do to loosen the crank bolt.

I have a L20 crank you can have but IM not paying for shipping. If you lived close you can have it but Im Not pakaging it up.

you need to gring the crank and buy the bearings for that size.
or say fuck it and sand it with emerory cloth or very fine sandpaper and run stock bearing in there and see how it goes.


so now you need a new cam? you dont want that dowel to breack and eventually the cam dont spin but crank does!!!!!!Broke valves, pistons
Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#13 deadmonkey

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Posted 21 October 2010 - 03:27 PM

The stub/dowel broke out of the cam?

If it was a L 20 I think I mentioned that you can put a Cresent type wrench on the cam boss(later L motors has this BOss on the cams) in the center and turn motor till the Wrench rest on the head bolt then you can loosen the crank bolt.
I dont like using the screwdriver method(mostly a in car head removal) but I dont have a impact wrench or want to use a breaker bar and rest it on the frame and hit the starter as some people might do to loosen the crank bolt.

I have a L20 crank you can have but IM not paying for shipping. If you lived close you can have it but Im Not pakaging it up.

you need to gring the crank and buy the bearings for that size.
or say fuck it and sand it with emerory cloth or very fine sandpaper and run stock bearing in there and see how it goes.

so now you need a new cam? you dont want that dowel to breack and eventually the cam dont spin but crank does!!!!!!Broke valves, pistons


BTW, I love that video you posted... that VERY helpful.

I did put the wrench on the cam, but that's why it broke. Damn Crank bolt was on there tight! I thought I broke it loose... but then it kept spinning, followed by colorful cursing. I had to put in two flywheel bolts and jam my tie rod separator fork in there, put a crescent on the front bolt and smack with a mini sledge before it finally broke loose! If you were close to Idaho, I'd totally come get it. :( Since I'm swapping this out with the engine in my truck I won't need a new cam, I'll just bolt the other head on and carry on. But now I'm down a complete head. I'm betting some of the Boise folks can hook me up.
"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
~ Nikola Tesla

My '76 620 Project
L20B Rebuild
Posted Image

#14 banzai510(hainz)

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Posted 21 October 2010 - 04:29 PM

yeah the crank should have a nice torq snap when you break them loose.
Even the head bolts.

cant beieve that happened to you.

Yea I have done the crank engine bolts at the rear to loosen the front crank bolt. just put the flywheel bolts far enough unlike me and ruin soem threads.
Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#15 deadmonkey

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Posted 26 October 2010 - 04:42 PM

Thanks to Datsunny for the 'new' crank and cam. Now to get her hot tanked tomorrow!

Posted Image
"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
~ Nikola Tesla

My '76 620 Project
L20B Rebuild
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#16 deadmonkey

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Posted 28 October 2010 - 01:50 PM

oops, miscommunication on my part. Crank is for an L18. no biggie... anybody need an L18 Crank? Its actually in great condition!

So I took everything in to the machine shop today.
Here is what's getting done:
- Bore out the cylinders (my fingernail catches on the lip)
- Grind the existing crank
- Recondition the rods
- Press in the pistons
- Hot tank everything
- And put together a rebuild kit for me for $300 which is the same as some online prices, but at least this way I save on shipping and I keep $ here locally.

Total is about $700 but I will have a 'brand new' engine when I'm done. Not sure if he's going to put the rings on or not, but I'll find that out later.
"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
~ Nikola Tesla

My '76 620 Project
L20B Rebuild
Posted Image

#17 banzai510(hainz)

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Posted 29 October 2010 - 05:49 AM

before you get a big BONNER! make sure they ck the head gasket area between the water passage and head bolt go thru. L20s could have a crack there. Redeye and I had this proplem. I scraped 1 block and Redeye I believe scrapped 2.
Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#18 deadmonkey

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Posted 09 November 2010 - 07:36 PM

I will get the engine back tomorrow. It is supposed to snow but I have a carport. Sucks not having a heated garage.
"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
~ Nikola Tesla

My '76 620 Project
L20B Rebuild
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#19 hang_510

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Posted 10 November 2010 - 11:48 AM

before you get a big BONNER! make sure they ck the head gasket area between the water passage and head bolt go thru. L20s could have a crack there. Redeye and I had this proplem. I scraped 1 block and Redeye I believe scrapped 2.

i scrapped 3! :angry:
1 i could have re-used.

the Z22 i ended rebuilding was cracked there as well...

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#20 deadmonkey

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Posted 10 November 2010 - 05:05 PM

Well here she is. I got the rings in today and spent the rest of the day chopping up the cab of the parts truck so I can get it out the way and get my truck in for the swap. Tomorrow should be spent putting the motor back together, cleaning the parts etc.

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"Within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song or play of a musical instrument, conveyed from any other region of the globe."
~ Nikola Tesla

My '76 620 Project
L20B Rebuild
Posted Image