By on February 9, 2018

TTAC commentator PandaBear writes:

Hi Sanjay, (First Sanjeev, now we’re using my brother’s name? – SM)

I have a ’97 Acura Integra RS on which my mechanic recently did a top end rebuild. The radiator got stuck closed and somehow created a vacuum in the cooling system, overheated and warped the head. Soon after the rebuild a new grinding noise started and the mechanic isolated it to a failing water pump bearing. Before the rebuild my car had a noise that I thought might be exhaust or valvetrain related, but ended up being the failing water pump. After the water pump was replaced the car is a lot quieter, and because it is a lot quieter, I’m now hearing cold start piston slap that I never heard before.

The cold start piston slap seems to remain till the engine is completely warmed up. It seems to come when the outside temperature is about 50F or lower. The car has about 260k original miles and is in OK condition, and I’ve replaced the ignition coil, radiator, axles, struts / shocks, hoses, oil pan gasket, so far so it actually drives OK for its age (kind of hard as the bushings are old). How much should I worry about the piston slap if all I care is durability of the engine? My goal is to daily drive another 5-10 years and 100k miles out of it if possible without a rebuild or an engine swap.

Sajeev answers:

From my googling, the Honda B18B1 is not known for piston slap but anything’s possible at this age and mileage.  But that’s really not the point.

If nothing more external (so to speak) could be the source of that noise, I still wouldn’t bat an eye at the sound of pistons slapping against cylinder walls. The rate of increased engine wear is likely irrelevant, even at your mileage: there are too many variables at 21 years and 260,000 miles, provided you keep those oil changes coming!

Drive the wheels off that Integra and love every minute of it.  Then restore it into a street cruiser/weekend toy, as I’d regret selling such a loyal soldier for next to nothing.

What say you, Best and Brightest?

Send your queries to [email protected]com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice. 

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25 Comments on “Piston Slap: Batting an eye at B18B1 Piston Slap?...”

  • avatar

    I’d just keep an eye on oil level and condition and run the engine until it expires. If you’re really curious to do some more diagnosis, low end boroscopes are cheap and available at harbor freight or online. Pull the plugs and turn the engine over to study the cylinder walls and see if you can find the culprit.
    If you really love the car, once the old motor is dunzo then as Sajeev implied any level of mild to wild B-series swap has been done a billion times on these, and is really straightforward and affordable (relatively speaking). I also highly recommend refreshing the suspension bushings, it really makes a big difference. I’d recommend staying away from polyurethane for control arm bushings, something as short travel and stiff riding as a double wishbone Honda does not need even less compliance on the street IMO.

  • avatar

    A former co-worker had a mid/late-90s Integra sedan with a ballpark 250k miles on it when it sent a rod and a few other pieces through the engine block.

  • avatar

    Drive it; repairing the piston slap issue would cost more than swapping in a junkyard engine. Have plans lined up to buy said engine and swap it, or plan what you would buy for your next car.

  • avatar
    Jean-Pierre Sarti

    Having grown up driving these Integras I will say piston slap was not common at all.

    Not knowing the financial situation you are in I would have gone in a different direction than just a head rebuild.

    You have got 260k and you want another 100k out of it? As good as these engines are they are not that good.

    A lowmilage JDM engine swap would have been more economical if you want to keep it for another 100k miles IMHO.

  • avatar

    Trigger Warning. ;-)

    LS engine swap FTW!

    • 0 avatar

      Is it so wrong to hope for a 540-degree spin into a tree or wall, writing off a Monte Carlo SS but leaving the driver and LS4 unharmed?

      Or are you thinking longitudinal LS with a custom, Unitized Power Package-style installation?

  • avatar

    The most important thing to do is find a new mechanic since this one was looking out for his best interest not yours. A “low mile” imported from Japan engine would have cost less and you would have a vehicle that would go another 100k or more w/o an problems.

    At this point the only thing that makes any sense is to drive it until it dies.

    • 0 avatar

      I’m going to second that because what kind of mechanic rebuilds the head but doesn’t put in a new timing set and water pump?

      • 0 avatar

        When Dad had the Iron Duke rebuilt (at 120,000 miles) before handing the car over to me at 16 – the mechanic reused as many parts as possible. But Dad was a cheap ba$tard and gave explicit instructions to do so.

      • 0 avatar

        He originally suggested all new belt and pump. I was trying to reuse because at that time, they were only 30k old (the rebuild was a few years and many miles ago). Didn’t realize the noise was from the pump so I though it is good and has enough life left as a beater (moved close to work, driving only 5k miles a year by then).

        I took a chance and I lost, won’t blame the mechanic for that.

  • avatar
    cimarron typeR

    Drive it till it dies, consider different oil weight. I know Subaru’s EJ 2.5 whatever motor is pretty common to have piston slap, I know sister’s old Outback had it after a top end rebuild for notorious head gasket leak and the mechanic wasn’t worried about it and it was trouble free for several years. It wasn’t a quiet car anyway so the noise bothered no one.

    • 0 avatar
      Jack Denver

      My EJ25 is very noisy when cold. Was noisy before and after changing the head gasket and we didn’t even try to do anything about it. Once it warms up it goes away. Piston slap in a Subaru is a design flaw due to the piston skirts being too short (they were trying to reduce drag, increase fuel economy). If you can bear the noise, it does not appear to affect the longevity of the engine. This may or may not apply to other engines from other manufacturers, but the consensus is that in a Subaru the noise is annoying but harmless. Wish I could say that about their head gasket leaks. Or the CV boot that is situated right above the red hot manifold. Or the shock towers that rust out. Or the rims that leak air. Etc. Subarus seem to have a lot of design flaws and they don’t seem to affect how much people like them, which is pretty strange to me. I like them a lot less now that I have owned one.

  • avatar

    This is my favorite Acura model outside of the early nineties NSX. I would keep driving it and make sure all rust is attended to. Rust has killed almost every car I’ve owned.

  • avatar
    Firestorm 500

    I would not have put just a head on such an old engine. Either do the whole thing top to bottom or get another engine or car. I have always been of the opinion that if you tighten up one end, the other end is going to let go. I have seen that happen many times.

  • avatar

    Thanks SanJeev (I was just working with my coworker Sanjay before writing the email to you, so typed Sanjay in a reflex) and everyone here.

    I was the cheap bastard that went with a top rebuild (and try to reuse the water pump) because friends who go to tracks told me it is better to pick the devil you know (head rebuild) than the one you don’t (junkyard pull).

    Financial situation is good (software engineer in SV, almost done with my mortgage). I have other cars (IS250, Prius V) that I can use for other duty, but I’m keeping my Teg because it was my first car, and to be honest I like driving it better than the bigger IS. Plus, it comes in handy when I need to do something quick and dirty (wife won’t want me to use her Prius for municipal free compost run).

    I am always wondering if I was silly trying to hold on to the car every time something “minor” broke on it, like axles, head warp, AC, struts, etc. Every time I though, just another grand and I’ll use it for another 10 years. If I knew 5 years, 30k miles ago, I probably would decide to sell it at that time and get a minivan instead (kids duty).

    • 0 avatar

      I guess you should look for better friends as well as a different mechanic. The devil you don’t know is if head is salvageable before you’ve spent a lot of money on labor to pull it apart and just how bad you hurt the bottom end from the overheating until it is all back together and you’ve spent a lot of money.

      The people who sell the engines imported from Japan usually have oil pressure and compression test results for each engine and offer a decent warranty that will cover labor when installed at a shop and certain other criteria like replacement of thermostat and water pump are met.

  • avatar

    Now there’s a collectible.

    Get your Integra/RSX while you still can.

  • avatar

    I like the cut of your jib. I have a 2000 Lexus with 1UZ with 280,000KM, I’d be happy to put another 200,000KM on that car.

  • avatar
    MRF 95 T-Bird

    As the Car Talk guys used to say. “There are many fine additives available at your local auto parts store that could help”
    I’ve used the 4,6,8 additive with Teflon that is in a silver can as well as Lucas which is very good. At that mileage it’s can’t hurt.

  • avatar

    I had a 96 RS, but I flipped it long before getting anywhere near those miles. Sweet car, keep it. Having just replaced control arms in my ‘ru, I second the above recommendation to replace bushings when you get a chance / reason. The teg always put the wheels exactly where I willed them, but I can’t imagine it’s as good as it ought to be with tired compliance parts.

  • avatar

    My roommate had a Volvo 740T that had piston slap so bad it sounded like a diesel even when warmed up. He put over 100K on it that way with no issues at all.

    Just drive it and don’t worry about it.

  • avatar

    I find the recommendation perfectly sound. The key is Sajeev’s admonition to keep the oil changes coming.

    My sister did the same thing with her Rambler, except without the oil changes, or even checking the oil, until the light came on. Then she had my dad add three quarts.

    It didn’t hurt her – the car ran fine when she got married and gave it to me. I was the one who had to deal with the crankshaft main bearing that exploded at 60 MPH.

  • avatar
    Eddy Currents

    When the noise is present, pull one injector wire/ignition coil at a time and see if the noise is affected only for one cylinder.

    If all are the same, I’d just drive it. Don’t thrash it till it warms up.

    Please note, sometimes an overheat will damage pistons. Not sure how sensitive Honda is to this.

  • avatar

    You’re planning to get 360,000 miles out of this engine without a rebuild? You are very optimistic. It might happen, but don’t be surprised if it doesn’t.

    Are you sure the noise isn’t related to valve lash?

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