datzenmike Posted July 30, 2019 Report Share Posted July 30, 2019 You have to assume that the engine was put together with the proper piston to wall clearance. It's between one and two thousandths. About the thickness of a piece of paper. You also have to assume that there has to be some wear incurred and those clearances will be somewhat wider now. Most especially at the tops of the bore and less so at the bottom of travel. Also the bore will become out of round from side thrust forces. Maximum taper and out of round for an L20B between top and bottom readings is 0.0006". Six measurements need be taken. One in line with the piston pin about 1/2" down and one at 90 to this. Then another pair at 2" and another pair at 3". Bore out of round and taper will now be evident or not. Rings will have a hard time sealing an oval or tapered cylinder. If you can afford it go to the next oversize bore and pistons. Oversize rings will cost no more than standard. Done right you will have a brand new engine with hundreds of thousands of driving miles in it. 2 Quote Link to comment
d.p Posted July 30, 2019 Author Report Share Posted July 30, 2019 I can afford it but what would be the next size from 1mm over? 2 Quote Link to comment
mainer311 Posted July 30, 2019 Report Share Posted July 30, 2019 (edited) Original bore was 85mm. It seems like your bore now is 86mm (muscle car guys would call this "forty over" meaning thousandths). You could go another twenty over and just make the bore 86.5mm. Typical intervals are 0.010" or 0.25mm. A quick search shows that 2mm over on an L block is about the limit. Edited July 30, 2019 by mainer311 2 Quote Link to comment
Stoffregen Motorsports Posted July 30, 2019 Report Share Posted July 30, 2019 15 hours ago, datzenmike said: Cast iron rings would be better for a 'hone and ring' job would it not? Chrome or molly for a re-bored block with exceptionally round, non taper bore with a perfect finish. I've used chrome rings on a 'hone and ring' rebuild and 15K later it was back to where it was before. Hastings sprayed chrome rings are a cast ring, but the top ring is sprayed with a chrome-like substance (I don't know the exact coating). 14 hours ago, mainer311 said: ^-THIS. Except I would also get new pistons to be safe. Also, if you can feel a ridge at the top of the bore, get yourself a ridge reamer and knock the ridge off before installing new rings and/or pistons. I’ve always used cast iron rings. This isn't a small block Chevy. Nissan pistons don't wear out like their contemporaries. The block material was far better too, and most will never have a ridge at the top of the bore. 1 Quote Link to comment
mainer311 Posted July 30, 2019 Report Share Posted July 30, 2019 My R16 had large ridges, but, it had other issues too. 2 Quote Link to comment
Stoffregen Motorsports Posted July 30, 2019 Report Share Posted July 30, 2019 Some of my favorite L motors have been built using only new head gaskets, everything else used and in good shape. There's almost nothing to worry about with used parts. Bore a block and you have to worry about break-in. Old pistons with new rings and a "dingleberry" hone job...no worries. Your machine shop can inspect the rings lands for you and possibly clean them too. If the ring lands are in good shape, with not too much wear and nothing broken, just re-use the pistons. If you want to measure the piston to wall clearance, anything up to about .0025"-.0028" is do-able. 1 Quote Link to comment
d.p Posted July 30, 2019 Author Report Share Posted July 30, 2019 Yeah I am pretty sure its 40 over as well. I will talk to the shop and see what they recommend and/or can do for me. I am fine with "Old pistons with new rings and a "dingleberry" hone job" so hopefully I can go that route. While I wait to take it to the shop should I disassemble the head or just let them do it? 1 Quote Link to comment
Crashtd420 Posted July 30, 2019 Report Share Posted July 30, 2019 6 minutes ago, d.p said: Yeah I am pretty sure its 40 over as well. I will talk to the shop and see what they recommend and/or can do for me. I am fine with "Old pistons with new rings and a "dingleberry" hone job" so hopefully I can go that route. While I wait to take it to the shop should I disassemble the head or just let them do it? I would at the very least get the cam out and the rockers and lash pads so you know they go back in the same location... let them do the rest.... Really up to you.... 1 Quote Link to comment
Stoffregen Motorsports Posted July 30, 2019 Report Share Posted July 30, 2019 And don't let them cut the head, unless it absolutely needs it. Tell them to leave the cam towers on too. They can be a bitch to align properly. 1 Quote Link to comment
banzai510(hainz) Posted July 30, 2019 Report Share Posted July 30, 2019 they are there to make money They going to cut everything they can. Ride up in a bicycle otherwise if they see a Audi or Mercedes hes going to charge you $$$$$$$ and act like they doing you a favor/Well its a old head ectt….. also make sure the valve seats depth is all perfect otherwise you might need different size lash pads. I seen ones sunk and others not thinking it a Chevy V8 type seat up and think you just adjust it out. Im gonna tell you I told you so now. a head gasket, Bam your done oh get the Nissan side seals for the rear cap. 2 Quote Link to comment
d.p Posted July 30, 2019 Author Report Share Posted July 30, 2019 Ok, pull the cam, rockers and lash pads not necessarily in that order. Leave the valves/springs/cam towers and everything else alone? Will tell them not to cut the head unless they have to. Get nissan seals for the rear cap? those are the ones that go on the side right? With the little needles? Should I have them do anything with the crank? I am going to pull up in this my dude: 1 Quote Link to comment
d.p Posted July 30, 2019 Author Report Share Posted July 30, 2019 Or I could pull in my Datsun, which do you think will cost me more $$$$? lol 1 1 Quote Link to comment
mainer311 Posted July 30, 2019 Report Share Posted July 30, 2019 Are those real TE37's? 1 Quote Link to comment
d.p Posted July 30, 2019 Author Report Share Posted July 30, 2019 (edited) 10 minutes ago, mainer311 said: Are those real TE37's? Yes, no reps here. TE37SLs to be exact. Better pic on my last car: Edited July 30, 2019 by d.p 6 Quote Link to comment
Stoffregen Motorsports Posted July 30, 2019 Report Share Posted July 30, 2019 Mag and polish the crank. Do not grind. Your bearings looked good, so the crank is obviously ok. Are you going to buy mic's and bore gauges? Or are you going to plastigauge the bearing clearances? .0018" - .0022" rod clearance .002" - .003" main clearance (less than .003" is ideal for oil control) When you get to that point, I can walk you through how to check and set the clearances. 2 Quote Link to comment
d.p Posted July 30, 2019 Author Report Share Posted July 30, 2019 7 minutes ago, Stoffregen Motorsports said: Mag and polish the crank. Do not grind. Your bearings looked good, so the crank is obviously ok. Are you going to buy mic's and bore gauges? Or are you going to plastigauge the bearing clearances? .0018" - .0022" rod clearance .002" - .003" main clearance (less than .003" is ideal for oil control) When you get to that point, I can walk you through how to check and set the clearances. Was planning on plastiguages because I read about in the book I bought. Not sure what I would need mic and bore gauges for? But I haven't really thought that far ahead either. Figured I would cross that bridge when I come to it. 1 Quote Link to comment
Crashtd420 Posted July 30, 2019 Report Share Posted July 30, 2019 3 minutes ago, d.p said: Was planning on plastiguages because I read about in the book I bought. Not sure what I would need mic and bore gauges for? But I haven't really thought that far ahead either. Figured I would cross that bridge when I come to it. It's just another way to do it..... Measurements vs a squished piece of plastic..... Micrometers and bore gauges would just be more accurate if you're good at using them..... Hopefully the machine shop you plan on using will help you out.... they can do the measuring and sizing then all you have to do is verify clearances and assemble... 2 Quote Link to comment
mainer311 Posted July 31, 2019 Report Share Posted July 31, 2019 21 hours ago, d.p said: Yes, no reps here. TE37SLs to be exact. Dope. 1 Quote Link to comment
Stoffregen Motorsports Posted July 31, 2019 Report Share Posted July 31, 2019 The machine shop will likely recommend a line hone and rod re-sizing, which I don't like to do unless it's needed. Again, the distinction here is need-vs-want. As Hainz said, machine shops want to cut everything they can (to make money). If you ask them to set the bearing clearances, they will probably take that to mean you want the block line honed and the rods resized, so be specific. Check my clearances without any machining. Plastigauge is fine, but not as accurate as mic's. Again, I can walk you through how to make adjustments once you know the clearances. 3 Quote Link to comment
d.p Posted August 17, 2019 Author Report Share Posted August 17, 2019 Is there a trick to getting the rocker arms off? I backed off the nuts all the way down but I can’t seem to compress the valve spring enough to get the rocker off. I tired using a screwdriver to compress the spring to no avail. Quote Link to comment
datzenmike Posted August 17, 2019 Report Share Posted August 17, 2019 Be sure the piston is not at TDC or the head is up on some 2x4 pieces so the valve is clear to open. Quote Link to comment
d.p Posted August 17, 2019 Author Report Share Posted August 17, 2019 I got them out with the head on some blocks. But the #1 rocker has some gouge and wear. Should I be concerned? I pulled the cam shaft out. What else do I need to take off the head before taking it to the shop? Quote Link to comment
d.p Posted August 17, 2019 Author Report Share Posted August 17, 2019 Head as it sits now. Quote Link to comment
banzai510(hainz) Posted August 17, 2019 Report Share Posted August 17, 2019 (edited) I think rockauto had ITM branded ones for 15$ apc ck it out. That one you got is BAD. give them the head as pictured. Tell them if they cut the seats and valves every thing needs to be even across so you don't need to get new lash pads. Or hope not to as it still might change after being cut. This 100$ is going to be 2000 soon enough but the rocker is bad https://www.rockauto.com/en/moreinfo.php?pk=4800036&cc=1212321&jsn=904 cant tell but look like the good ones. can order on and see if says made in Japan. Then order 2 motor set one for this motor and another spare set for your L16 if needed laster PS look like there is cam tower shims already on there. Silver Seal has them if need more Edited August 17, 2019 by banzai510(hainz) Quote Link to comment
d.p Posted August 17, 2019 Author Report Share Posted August 17, 2019 What about the lash pads? Should I take them off? If so how? I got the rockers labeled in a box but want to make sure I put the lash pads with the right rockers. I’ll order some rocker arms. Quote Link to comment
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