I'm going to ask a lot of questions, so to keep my thoughts and maybe yours organized please address them numerically (I,II,III etc.)

Doing a stock rebuild, just need a motor to get running. History is this motor was built with less than 5k when person gave up on project. So i tore it down, and this is where I am at so far.

I. Head height - measured head height using a dial caliper at various points (i know its not as accurate as any would like) but came to the conclusion that its roughly off of spec by .02-.04". Service manual says heads should be 5.589-5.593". Obviously was resurfaced, is this a big deal? Was too much taken off? Will this be a problem?

II. Piston/Cylinder Clearance - Measured pistons .6" (Helms) from bottom of skirt (Evans Tuning suggests .5") numerous times, came with the roundabout piston diameter of 3.2080". Next, measured cylinder bore at various points (X + Y). Taper was within spec with a max difference in bore of .0014" (service limit for bore taper is .002"). Using my average max bore diameter (3.2113") subtracting piston diameter (3.2080"), you get a piston/cylinder clearance of .0033". Even at the smallest differences in bore piston/cylinder clearance is at .0028". Service manual says service limit for such clearance is .002". I suppose I need bigger pistons? Has anyone run with such clearances?

III. Reason why I used max bore diameters is because I hope to do a DIY hone from amazon (3 grits 100,220,400), just to get the crud off and give it a good hone (despite showing good crosshatches still), and possibly make a more "even" bore.

Should i just use some 2000 grit sandpaper to clean it up, just carb cleaner?

 

IV. Someone walk me through choosing appropriate main/rod bearings, if you dont mind. Measuring numerous times, came up with main cap diameter of 2.32312-2.32345" and crank main diameter of 2.1642-2.1644". Should I use the lesser, greater, intermediate values, and use lesser,greater, or intermediate values for bearing width. Just a quick walk through would be helpful (yes I am asking you to hold my hand here ). Yes Ive seen the simple equation to measure which bearings are needed, but still, help is appreciated.

Using telescoping gauge (my bore gauge wasnt small enough) got average rod diameter of 1.8897" (not as accurate as I would like). Rod journal taper was great (within .0002") and got average diameter of 1.7707-1.7709". Any help on either topic to get me through the other is much appreciated.

This is a stock, stock rebuild. Still waiting on a precision straight edge to see head/block warpage. All surfaces look really,really good, and smooth. im trying to avoid a machine shop as much as possible, unless necessary. I plan on "refinishing" head with new valve seals, and cleaning up valves/combustion chambers with carb cleaner, a small brass wire wheel, and re-lapping the valves. This head as stated, had a full valve job less than 5k ago.


Thanks for any input. Constructive/deconstructive criticism welcome

 

bump for some morning input please

 

1. I can't speak accurately on that.

2. That's going to be a pretty loose p2w clearence for a stock rebuild and that's more bell mouthing than I would ever want to see. The less taper you have in the bore the better. Ideally you want zero taper all the way down to get the least amount of blow-by possible and to end up with the best ring seal you can get. You said the engine was previously rebuilt? Sounds like the previous owner just used some spring loaded monkey honing tool or a ball hone. Neither of which will remove taper, they do more de-glazing than anything. If it had any amount of mileage previously and was just monkey honed, I can definitly believe you are coming up with .0035" p2w on the load axis. To remove taper you would need something like a sunnen hand hone. With that, you can adjust the outward pressure the honing stones have on the cylinder walls. That is what you need to remove taper. They are also about $300ish used in my experience. My opinion would be, if you can swing it, over-bore to 81.25mm and use new oem pistons, rings, and wrist pins. A cast piston at .0035" p2w in a stock all motor car with a bell mouthed bore will not lead to the results you want. Also make sure you know what ring pack you are using before you hone it. Different ring packs call for different grit final hones. I would strongly recommend taking it to a good machine shop and telling them exactly what you want done...ie, final p2w clearence and final hone grit for the rings you're using.

3. See #2 I kind of tied it in towards the end. Aside from what I said, if your still going DIY, you should ridge ream the top ring of carbon off. All you need if your just going to clean the bore up/deglaze it and re-ring is a 400 grit stone, and I'm saying that based off of how the hatching looks as it is. You can't remove taper through honing unless you buy the sunnen tool or something similar, or you take it to a machine shop. But as I said .0035" is too loose p2w for what you are doing anyway so you should strongly consider over-boring.

4. If it were me, I would not be using telescoping gauges to determine bearing clearences. They are great for getting a general idea on things, but for precision, toss them out the window. Pick up an inside micrometer for those measurements(big ends of rods, main caps, ect.) since your dial bore gauge doesnt read that low. I'm suprised your dial bore gauge doesnt go down that small really. Mine reads down to 1.4" and its just a run of the mill fowler digital.

So you want to be taking your measurements on an axis perpendicular to the mating surface of the cap for the rods and mains. For crankshaft journals, measure on an axis perpendicular to the oil holes going through the journals. Bearings are actually slightly ellpitical. Basically the elliptical shape provides a wedge of oil for the crank to spin around on. The closer you get to parallel with the mating surface the wider the tolerance gets. You need to be concerned with the tightest measurement, ie, perfectly perpendicular to the mating surface. You need to spec out every journal and cap individually if your going with oem honda bearings (which I would as long as your not using ls bottom end parts which would end you up with bi-metal rod bearings). Bascially spec out #1 main cap, spec out #1 crankshaft main journal, subtract journal from cap diameter, get free space between cap and journal with no bearing, then start playing around with the different bearing thicknesses on hondas chart and see what you need to get your target clearence for that journal. Then do the same for #2, #3, ect. Also note that the honda chart is just for one bearing half so you need to multiply what ever thickness on the chart by two because you are using two halfs.

5. Highly doubt the block will be warped out of spec. Head shouldn't be either if it was just machined and the car didn't over heat in that 5000 mile period. Get your self a bench top grinder and a fine wire wheel for it so you can remove the carbon build up off of all the valves since your giving it another valve job. That much build up doesn't occur in 5000 miles. Parts cleaner wont do much against the carbon. Get a couple cans of berkebile 2+2 gum cutter. You'll have to order it, but it works astonishingly well on carbon. If your getting your wire wheel any where near the valve seats in the head, make sure you grind concentrically to them other wise you'll create problems for yourself in regard to leakage, even after re-lapping the valves. Valves you don't have to worry so much about because they are hardened. A wire wheel will just remove the carbon build up from them.

One other thing, see how sharp the top of the bore is? That should have been chamfered slightly to prevent damage when installing the new piston rings. A ring is much more likely to get snagged on a sharp edge like that and get damaged during the install process than if that edge had been chamfered after honing. That right there tells me who ever built the motor didn't really know what they were doing.

Good luck.

 

First, thank you so much for taking the time to address each issue for me as im sure it took some time. I was getting nervous with all these views and no replies, no one would want to take on the headache this can impose.

I plan on taking this motor with me in whatever I end up doing. I have receipts from previous owner showing work from head shop and others; now was it done to this car is still debatable, but the timeline and receipts all seems to be here, even parts. This was someone's intended project to hold onto, built with stock internals, but with corners cut in the wrong places: some bootleg parts depot type by the looks of the receipt for pistons, o rings, and all bearings (which were lumped together, so I doubt they were per journal. The block was bored and hone by a shop, and the crank was polished. The car was boosted, would that explain the taper or large p2w? But thankfully the crank looks good, with what appears to me to be no scoring, and taper within in new specs as per helms.

In conclusion, it looks like to the machine shop I go, and new pistons are in order. 400 grit hone is the spec in helms, and Ill start looking into rings accordingly; I suppose something oem would be just fine.

Yea, I am still iffey about using the telescoping gauges as far as accuracy. I will look and see if anyone sells an attachment piece so i can use the bore gauge to that small of a measure, otherwise ditto on the inside mic. (really should have chucked out the extra $100 for the fowler bore gauge, but then again mine goes down to .00005" not like i need it)

I actually measured x's and y's for the rod journals, (underneath+above the oil holes, then perpendicular), and a few random axis points for the mains. Ill post pics of my notes if anyone would want to take a look since it can only help and someone can point out any other red flags. I plan on doing all measurements again, since I am getting better and more consistent the more i practice.

Did the motor overheat, no, oil starved at a point, yes. I found a cheap straightedge on amazon, so we shall see.

FYI - 2+2 gum cutter can actually be bought at advance auto (at least where Im at). I had asked the guy about it, he dissappeared in the back, and came out with a can of it, said its for commercial sale/use but could sell it to me.

Is chamfering something that a machine shop should do, or something you can do at home? i suppose since im asking i should let the machine shop do it. I understand that it "rounds" the top of the bore. I dont have access to air tools, but have an old dremel which I bought the brass wire wheels for and plan on doing the valves with. If so should i look for a 400 grit arrow shaped sanding bit? Not sure if id trust myself to do the chamfering. I suppose we'll see how my "valve job" goes first. I plan on mcguyvering my cordless drill into a position i can press the trigger to spin the valve and use the dremel for concentricity's sake or vise versa, whatever will work better and also being extra mindful in the actual seats. Theres actually a guy on youtube (look up cylinder head 101) that does this diy valve job on a 4g63 mitsu head if anyone is interested (though it is not the and all be all) but in my case, i think its applicable.

A big project by my standards and a rough introduction to the world of honda's, but im getting there.

 

and on another note, when/if i ever get to assembling this. when i plastigauge, what would be the accepted tolerance/clearance with bearings? .002"???

 

and on another note, what p2w clearance would you seek since were basically going to start from scratch in terms of this issue? I know i can find what helms says, but what would you deem appropriate for this type of build, or personal preference?

 

I'm happy to help out by sharing info because unlike most people now a days, you've got your **** together, and you have specific questions that the answers to which probably can't be accurately found with a quick google search.

Well shoot, I just realized that block has already been overbored to 81.5mm. I apoligize because I didn't think about that to begin with. You'll have to disregard where I mentioned using 81.25mm pistons in my earlier post. Well that leaves you in an interesting position. Really your only option now is to overbore to 82mm which is pushing it on stock cylinders, but I wouldn't sweat it too much because it's going to be stock, and your not going to spray it with a 100 shot or boost it. You'll have to source a set of 82mm pistons from a company like rs machines, nippon, ycp, ect. What ever rings they end up coming with will probably be fine on a 400 grit hone. Just don't get some off the wall chromed rings or something which would need more like a 280 grit hone.

1. The engine being built previously for boost explains the loose p2w clearence. Parts need more room to expand in a boosted engine so tolerances are going to be significantly looser than those on an all motor engine. NPR makes a pretty good set of rings in my opinion. Unfortunately you can not get oem honda rings for an 82mm bore.

2. I love my fowler dial bore gauge. You have to be careful on their new stuff though as most of it is now made in china as far as I know. I was lucky and found an "old stock" model that was made in the USA back in 1999 and had been sitting in a warehouse ever since.

3. As I said for determining bearing clearence, all you need is the measurement perpendicular to the mating surface of the cap.

4. Oil starved = no muy bueno. Engines don't really like that. Haha

5. You're really lucky if you can get the 2+2 at your local auto parts store. I can't find it anywhere in my area so I just order it online. It is awesome stuff.

6. Well, asking about something doesn't necessarily mean you are not capable of doing it, but in this case you should let the machine shop handle it. Bascially there is a spot on the head of the honing machine most machine shops use that has a carbide cutter on it. It is pre-setup at like a 60 degree angle if I remember correctly and after the cylinders are honed the machinist just sets it at the top of the cylinder wall and lets the honing head make a few revolutions. This takes away that sharp edge so you don't inadvertently damage a piston ring during installation. It doesnt effect the piston rings because they do not travel that far up in the bore.

7. One little tip I can offer if you plan to use your drill to lap the valves is to get a piece of hose to connect the drill to the top of the valve. That way you aren't putting any axial pressure on the valve stem while its running through the guide. In reference to the youtube video, does the fellow that made the video go by something like jafromobile? If so, I've seen a few of his videos, I don't recall seeing the one you mentioned, but of the few I've seen, he seems to be pretty knowledgeable. Of course not the end all be all kind of thing though.

8. If you measure everything out you should know every single one of your bearing clearences before you start re-assembling the engine. The plasti gauge is just to make sure you are not grossly off somewhere. So, that said, you should look for the plastigauge to read fairly close to your calculated clearence. Don't worry if it's off by a couple 0.0001"s. Its kind of like those telescoping gauges, great for getting a general idea, but useless if you want real accuracy. If I were specing everything out and building this motor as a "semi factory rebuild" sort of thing I would set it up for 0.0016" to 0.0018" on the rod bearings, 0.0018" on main caps 1,2,4,5, and 0.0020" on main cap 3. Basically nearing the looser end of factory spec. Honda sets the motors up pretty tight from the factory. Loosening them up a bit frees up some power and gives you a better oil film around the bearings.

9. My personal preference for your p2w would be about 0.0015".

Big projects with no set deadline are fun because you can do a little here and a little there to keep yourself occupied. You should be fine, these honda motors are pretty simple when your using all factory stuff so you shouldn't have any problems. Just check and re-check stuff. Also, please, please, please, don't take the numbers I suggested for clearences as the end all be all. They are nothing more than my opinion. I highly recommend you do some research and decide if they are what you want to go with. You may decide you want to run it tighter. It's totally up to you.

By the way, what block and head combo are we dealing with here?

 

its a b18c1. tonight im double triple quadriple checking my measurements and then tomorrow ill see what a machine shop has to say, but probably wait til saturday to sort out pistons/rings and grit of hone. practice makes perfect, and so im getting even more and more accurate with each time, using the bore gauge for stuff my measurements are now within .00005-.0001. i spent a pretty penny buying the right tools and things of that nature, literally starting from the ground up in terms of tools and knowledge. your specs for clearances are very similar to evans tuning vids, though there car was setup for high boost, and i think ill stick with that, gives me room for noob error for clearances. Ill use the smaller measurements i have, that way if anything, shooting for the specs u suggested for clearances, theyll be a tad tighter. At least in theory, because well we/i wouldnt want them any looser than you suggested. i still have some time to think/research. i was hoping to have the car up and running before my spring semester started (3 weeks), as mother is getting tired of me using her car to commute. Still plausible, but unlikely.

your definitely on the looser end of factory specs (which you already know) but i agree, oil over miniscule power gains is worth it to me.

and jafro's THAT DUDE!!!

I plan on using the drill to revolve the valves while i use the wire brush to refinish them. Thinking about it, probably clamp the dremel, and move the drill around to clean em up. I have a bench grinder, but not here, so i dont want to buy another one. then lap the valves using a hand lapping tool, hopefully hearing that sweet sound of a perfectly lapped valve. Then having the shop check my work and probably hot tank, hopefully theyll do it for cheaper since im already bringing them the block.

Ive never been to a machine shop, but hopefully ill be going in looking/sounding like at least i know something.

 

Looser end equals better oiling and more freed up power, but be mindful that there is such a thing as too loose just as there is such a thing as too tight. That has been the answer I've gotten from every machinist I've ever talked to and every book I've ever read. In my opinion evans had that motor a little on the tight side for 700hp, but who the hell am I to tell them how to build a motor. Lol. As I said, you'll eventually come to your own conclusions on the issue. If you have questions about a part, call the manufacturer. They know whats best and they are more than willing to help. Forum talk is all well and good, but if you have a question about bearings, call ACL, or Clevite, ect. If you have a question about a set of pistons call the manufacturer. If you want to know what to torque your arp headstuds and rod bolts to, call arp. Get the picture? Haha

Trust me, I know how expensive precision tools are. Don't count on any machine shop giving you a break on prices unless you are spending about $10,000 with them. They have to make a living too and getting you for small **** is how they do it. Honestly though, most people don't understand how much work is involved in what they would consider a simple process.

 

Agreed. So using a precision straightedge the head is off in between chamber 2 and 3 by .004 (service limit is .002) and off by .002 in places, obviously needs to be resurfaced/decked.

Also, block is off by .003 and .004 in places. (New limit .002, service limit .003)

Should i be weary of taking off a total of .006"? How can i determine valve to piston clearance in this instance?

Previous receipts state head was resurfaced but not decked, and nothing was done to block in this regard.

 

1. Nothing to really worry about taking 0.006" off total. That isn't too bad. Cam gears might not line up perfectly at tdc anymore.

2. Clay the motor to check for clearence. I'm 99.9% sure you would be completely fine with out doing so, but it would be a good thing for you to do once, just so you know how to do it, then you can rest assured that your good to go.

3. Resurfaced = material was taken off. I'm suprised about the block, I've yet to see one warped out of spec, it's almost always the head, because the head is bolted down to the block from the factory.

 

Tried to source some info on claying a block (curiousity). Ive heard people speak of it here but how exactly its done/why/and proper way of doing it i cannot find, on any motor for that matter.

 

claying the motor checks your v2p clearance. with a vtec head you lock the rockers in vtec in just one cylinder and apply the clay in the valve reliefs in the piston. bolt the head down on the block with the head gasket you intend to use and time the motor up and rotate once. disassemble and measure the clay to see how much room you have between the valve and the piston. different people have different ideas about what a good clearance is. just reasearch and ask around....if your gona use stock cams you should be fine unless its had a insane amount taken off but its a good idea if you wana up grade cams later as you will already know your clearances....as far as taken to much off the block or head to affect anything...the only thing it will really affect besides p2v which would have to be alot with stock cams is the cam timing as after a certain amount it starts retarding it. but a set of adjustable cam gears advanced a degree or 2 will even everything back out. also with milling and decking check a compression calculator to see where you will be at. you may wana run high octane gas or even street or dyno tune it if its up there.

 

A semi-useful how-to for claying a motor: http://www.c-speedr.com/howto/claymotor/clay.php 0.030" is the absolute minimum clearence you can have in my opinion of course.

Most machinists don't go by those marks you're talking about. There is a spec for head height and block height that they use.

 

bookmarked and will do for sure since everything is out.

I just realized something. Reading over the thread, you kept saying about "measuring perpendicular to mating surface". By that, is that the same thing you are referring to as the "tang". If so, my measures are off for the main caps and rods, because I measured simply in a way perpendicular to the floor if the block was upright, and parallel to rod bolts. Ooops

 

No, sounds like your fine. By mating surface I mean where the bottom of the main caps mate to the block, and same goes for the rods, where the bottom of the rod caps mate to the rod itself. The tangs that align the bearings are not what I was referring to.

 

Started cleaning up the valves (finally). Theres a material on my valves i feel should definitely be there. I uncovered it is in rough shape on some, and with my wire wheel I could take more of the material off if i wanted, and may have in a few places. Should I? Should I leave as much of it on as possible. Some of this material came off due to me polishing the **** out of it.




The material that I took off is very very minimal and I have shot off to the forums right away to find the answer. As you can see that second valve in the picture looks like my dog chewed it. This was the shape i found it in after uncovering the carbon buildup.

 

Also, I was infuriated when I found a big PR4 stamp on my oil pump cover. I took it apart to clean it up and see whats up. This seems to be a controversial debate here. In your opinion, can I use this oil pump for my P72? Some argue that a pr4 oil pump can be used, but only on non vtec models. If I were to use a oil pump, its debated that I should use any a 94-96 vtec oil pump or any 96+ oil pump and definitely not a pr4 (90-91 gs ls). Heres a pic, I dont know if that would help.

 

That stuff on the valves is carbon build up. See why I said you need a bench top grinder. Lol. That stuff is hard to get off with one so I knew you weren't going to be able to get it off with out one. I found that video from jafro you were talking about. The process he uses in it with the drill and bench grinder to remove the carbon from the valves is how you do it. So, you've got quite a bit more work to do.

If you use a pre 1996 oil pump it would have to be a p72. If you use a 1996 and up, it doesn't matter what b series the pump comes off of, they are all the same.

Here is a great reference video for how NOT to do ****:

 

The brass wire wheel/dremel combo worked pretty well i think. It would take me some time and i would go through a few wheels to get it done to remove all the stuff completely. All carbon build up was removed pretty well. But if you note the botom 3 in the pic, those are the ones i did. Theres a material i feel like it should be there, but i could be wrong. It looks like a coating. Should i remove all of it till the surfaces are completely clean?

A brass wire wheel would cut the time im putting in in half. Maybe a neighbor has one and i can buy a brass wheel to use.

 

Also, I will never use sandpaper on the valves/head. Lol. I cant imagine that being any good.

Sourcing pistons, trying to keep it stockish. There are all sorts of different compression pistons to look at. I understand that lower compression is more for boosted engines, and higher for all motor. What would you recommend for a good compression ratio. 12:1 , 10.25:1?

I think id like to stick with someone oem -ish. pr3, p73, ctr? From what ive read i think ctr could not be an option because of the aggressive dome height, but what would be a good option?

 

What you are calling a coating is carbon build up. You should remove all of it. The surface should be completely clean metal that is black/dark grey in color.

What happened to stock rebuild just to get it running? If we're now "building" an engine, things need to be re-evaluated.

A good option is the p72 piston that came out of the engine to begin with unless the above is the new situation.

I ******* hate ctr pistons. They are heavy as ****, and the domes distort the crap out of the flame travel. Some people have used them with success, and therefore believe they are fantastic, you can draw your own conclusions. Having a huge dome on a piston is probably the worst way possible to raise the compression ratio of an engine, but that's a whole nother subject that I'm not going to get into.

You need to decide if you are doing a stock rebuild or if you are "building" the engine.

Everything I've told you so far was based on a stock rebuild, so if the plan has changed we need to re-evaluate a few bits and pieces.

 

Well before we talked about bore taper, and from a number of people except one (your opinion, my cousin-who works/builds evo's etc for a reputable tuning shop, and a mechanic shop in the area ive befriended), the bore taper is unacceptable for rings to seat properly. max taper of .0009. helms states service limit is .0020. This measurement was for sure taken from .24" into the cylinder and down. not sure exactly of exact taper, when i get home i can look at my notes. Also p2w is also unacceptable in those areas of bellmouthing, so either way ill be ordering pistons, hopefully selling the old ones. Goals are still stock-ish. After a little digging id like to go with p73's if possible. Prices are very similar in terms of pr3 and p73, ctr is actually cheaper but id rather not. What about p30's?

My goals now, as they were all along. Stock rebuild, saving money where i can, but doing it right the first time.

 

Did some more cleaning up. Cleaned up the head too. Im somewhat happy with my results. Unfortunately out of wire wheels, definitely need to source a bench grinder from someone.

I now see what you mean by it being carbon. However, I disagree with you in that the exhaust valves do have some sort of coating. There is an F that is still imprinted on a few of the valves and i think that it served some purpose in a prior life. Removing the material removes the F. Nonetheless, I dont see any harm in removing it, and hopefully will be able to, but its really stubborn with what I have at the moment.

Still needs some sprucing up, but i think its a good start. I was sure to move in concentric motions. Theres still gunk in the chamber, but for the most part the seats are pretty darn clean.


Onto my valve seals, these from a little digging i think are viton valve seals. They were replaced about 5k ago. Should i rip em out and put new oem ones in? A cheap investment, but another task. Just wondering anyones take.