b18c rebulid ?


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oli_125

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Jul 3, 2016
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hi all
going to be rebuilding my b18c from my 1996 dc2 soon due to it using about a litre every 500miles and heavy smoke occasionally on vtec and more on overun .car is just coming up to 200k in kilometres,so think its due a refresh . a couple months ago i replaced the valvestem seals to see if that cured it oil consumption but it only reduced it consumption a little .engine has good compression at 225psi across all four cold or hot and it preforms perfect powerwise ,loads faster than my friends stock ukspec dc2.
ive had a good look around on here and alot of people say dont rebulid a b18c etc why is this ?
is there anything i should look out for whilst doing it or change whilst i have it apart for improved bits ?
any information welcome
thanks
 
@Yazza54 has just done a fresh rebuild, so I'm sure he can give you some pointers,

As for not rebuilding a b18? Not sure why anyone would say that ,
If done right how can it go wrong?
 
Did you check the condition of your valve guides when doing the stem seals?

If your guides are badly worn (not uncommon) then new stem seals won't really do a lot
 
Leej8 said:
@Yazza54 has just done a fresh rebuild, so I'm sure he can give you some pointers,

As for not rebuilding a b18? Not sure why anyone would say that ,
If done right how can it go wrong?
Click to expand...

For a period we had alot of rebuilt b18s burning oil, spinning bearings, dropping valves and all sorts going on.
Like you say clearly wasn't done right.
 
My engine is sweet as a nut and I'd never built one before, hasn't burnt any oil either. I'm already tempted to start tuning it but as it stands it's a good motor. I can't understand why anyone would suggest you can't rebuild one, total bullshit.
 
Some times engine are built a bit "loose" depending on the needs of the design. This "looseness" (more clearance of piston to cylinder wall) is good for racing applications. With forged pistons you also go way looser than factory spec. Forged pistons tend to burn more oil than cast pistons, due to the larger clearance needs, if daily driven - but when racing the piston swells a bit more, taking up that clearance. Quality parts also help....alot... Forged pistons also seem to give off false knock signal, because of this looseness until fully expanded. If your gona boost it, or work the engine hard, than forged pistons are stronger and are more resistant to detonation. But if your concerned of burning a bit of oil, and running a stock ECU, than I would recommend quality cast pistons.
Just my 2 cents.
 
Compared to B16, B18 and B20 cylinders tend to wear a lot more in oval shape due to a more important rod angle with cylinders (hence applying more force to the cylinder wall).

While rebuilding a long block, first you have to control correctly and measure with accuracy the cylinder roundness at several heights.

Pretty sure it will be oval shape out of tolerance or just at the service limit. Most of them need at least a 0.25mm oversize but a lot of people just throw in new rings, ACL bearings and go back to the road.

Stick with cast OEM JDM pistons oversized and find a shop who knows his job to measure your pistons and oversize your cylinders according to what they measured. And most important, give them the workshop tolerance as Honda engine clearances and tolerances are much tighter than most other brands. When I rebuilt my engine the guy at the workshop told me he was mainly making Renault, Peugeot/Citroën and BMW engines and he was surprised when I gave him the Honda piston to wall clearance.
 
Thanks for the responses guys ,after waiting for space in the garage for a month I got the engine out and striped down this weekend .from comparing measurements to factory specifications I found that my piston ring gaps are way out , almost double the maximum gap Bore size seems to be spot on to factory spec . Also the oil control rings Barely stick out past the piston , at least half of what the top two rings stick out by . Gunna take my block down to a engine builder in the week for his opinion on the bores I'll try and post a photo on here for you guys to see so you can share your thoughts
 
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The bores seemed really good condition for the miles , one thing I noticed was no obvious cross hatching visible , should I be seeing some ?
 
Probably not given how many miles it's done but if you're happy with the size/shape of the bores (I.e not oval) I would just run a light gone through it to hatch, new rings, bearings and seals and run it again... Better if the engine is fairly loose anyway long as it still seals up well and has good compression
 
My own 2 cents- I have rebuilt a b18c in the past by running a light hone through it ( to "rough up" the cylinder walls to the new rings can seat- done at a professional machine shop), installed new rings, bearings, and rebuilt the top end. Customer used her car to daily drive with a mix of spirited weekend driving. The car ran great after wards, but did burn a bit more oil than we all wanted. Great for track, and a quick rebuild- but if you don't want it to smoke, over sizing the bore with matching pistons would be my recommended way to go. Honda/Acura sells .25 over factory pistons- should give you enough room to clean up the cylinder walls. And yes cross hatches are good-helps seal the compression and oil rings. After doing many head gaskets and rebuilds, it is very rare to see the cylinder walls so smooth, that there are no cross hatch marks at all- shows signs of heavy use.
If your ring gap is twice what it should be at the top of your cylinder wall, you'll be amazed at the gap when measured at the center of the bore where all the "side loading" takes place.
Again, just my 2 cents.
 
MotorMo said:
if you don't want it to smoke, over sizing the bore with matching pistons would be my recommended way to go. Honda/Acura sells .25 over factory pistons- should give you enough room to clean up the cylinder walls.
Click to expand...

Agree with this. It will cost more but the result will clearly be better quality.

Order some oversized JDM piston (better CR) + rikken rings at autodynamics, Bernard has good prices compared to Honda (at least that's applicable here in France).
 
MotorMo said:
My own 2 cents- I have rebuilt a b18c in the past by running a light hone through it ( to "rough up" the cylinder walls to the new rings can seat- done at a professional machine shop), installed new rings, bearings, and rebuilt the top end. Customer used her car to daily drive with a mix of spirited weekend driving. The car ran great after wards, but did burn a bit more oil than we all wanted. Great for track, and a quick rebuild- but if you don't want it to smoke, over sizing the bore with matching pistons would be my recommended way to go. Honda/Acura sells .25 over factory pistons- should give you enough room to clean up the cylinder walls. And yes cross hatches are good-helps seal the compression and oil rings. After doing many head gaskets and rebuilds, it is very rare to see the cylinder walls so smooth, that there are no cross hatch marks at all- shows signs of heavy use.
If your ring gap is twice what it should be at the top of your cylinder wall, you'll be amazed at the gap when measured at the center of the bore where all the "side loading" takes place.
Again, just my 2 cents.
Click to expand...
thanks for your advice man ,as i want it to be as smoke free as possible i think ill go for a rebore and o/s factory pistons i would hate to put it back together and find out it still burns oil . i plan on going on trackdays with it when its done so needs to be spot on !
 
Back on the engine build again , got the block back from the engine shop after much discussion with the engine shop guy he just gave the cylinder walls a light honeing as that's all they needed , he acuratley measured each one and found no ovaling and a true 81mm top to bottom on all 4 . I tried my new piston rings in to check and the gap is within factory tolerances .awating a new set of shells and oil pump from Honda until I can go further .
I need to know what people do for Conrod bolts
Autodata says a stretch value and to replace the bolts , so should I get new genuine bolts or arp bolts . Arp seem more readily available and maybe cheaper than parts from Honda .
 
Unless you're planning any major tuning ARP bolts aren't worth the hassle, they are press fit and then the rod has to be checked to make sure it's round. Re use your standard bolts. There's nothing wrong with them.

So you're basically back to what I recommended in the first place. Hone, rings, bearings seals etc.
 
Iirc the OEM rods are studs and nuts not bolts...
 
i think your right, p72 rods have studs, I think...

Just re torque them as per the Honda manual,

A word of advice on your new oil pump, strip it clean it and lube it before fitting it,
 
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