SaturnV

Hi all,
I've had a misfire issue present for the last year or so and would really appreciate some input in diagnosing. I need to detail the history of service, so please bear with me.

I got the car in 2020 with 116k miles (2000 AP1), and it had a habit of burning a quart of oil a week. Lowish compression on all cylinders so I thought I'd give the engine a freshening up. Removed the engine, no problem, had a local Honda guy rebuild it. Dropped the engine back in, ran like a damn clock until I randomly got a misfire a couple thousand miles later. Adjusted the valves, problem went away for a bit, but then it came back in full force and no amount of valve adjusting would help. This went on for some time, and I eventually gave it to a shop near me to look at the head. These guys said that the valves were worn too thin due to age (did not replace valves during last engine build). So they surfaced the deck, installed nice valves, etc. etc. Ran like a clock again until the issue came back. Misfire on all cylinders, sounds mechanical in nature. Weird thing is that it'll stutter and wheeze at idle, but once I give it some revs it runs like a clock again. Weird. So between two engine rebuilds I have what sounds like the same problem.

And here I am removing the transmission once again. I don't really know what could be causing this. I've replaced the coils, plugs, gotten the injectors cleaned, that hasn't helped. I'm thinking this issue is more deeply rooted, maybe with a bad sensor causing the engine to destroy itself. Thinking of sending the block to InlinePro for better diagnosis. But I was hoping someone here could shed some insight.

Thanks.

noodels

So whats the compression like now & how much oil are you using ?

windhund116

Unfortunately, this sounds like mechanics not familiar in rebuilding the S2000 engine were involved. Surfacing the head and possible boring of the cylinders maybe irreversible.

Sorry.

SaturnV

Before I did anything to the engine, it was 150 all around. Thought that was low. After the first rebuild when it was running well, I did another check and it ended up being 150 all around again. No drop in power or oil/coolant consumption. Weird.

I did get cast iron sleeves installed in the engine, so I'm assuming the cylinders were bored. I thought this was a common installation for these engines--was originally, and still am, planning on a supercharger down the line.

Do you think it would be a good idea to send the long block to Inline anyway? Maybe they would be able to give a definitive answer.

noodels

what octane fuel are you using,what compression ratio of pistons did they use with new liners ?

B serious

Are you using Denso coilpacks? And NGK platinum plugs?

Slowcrash_101

NGK coil packs are decent enough, they've held up fine so far (3 years). I've got a set of OEM packs on stand-by, but if it ain't broke....

Car Analogy

Another rebuild failure story pending. All too common after just a few k miles.

Worn valves on a rebuild indicates someone incompetent or at best super lazy or not detail oriented. Head resurfaced indicates someone not familiar with these engines.

Not a very high chance of a happy ending.

SaturnV

Car's never seen below 91, usually at 93 though. I didn't ever check with the new liners but I called out 11:1. That would've been good to keep tabs on.

Yep all Denso/NGK hardware. Replaced them anyway, no help.

So you really can't reliably rebuild these engines? I get the bearings are touchy, they have to be individually clearance-fit, but the bottom-end is fine AFAIK. As for the head resurfacing, can it still seal well with the head gasket? Thought engines twisted a bit over time, and truing them up fixes that. Related--what's the deal with not being able to resurface the heads?

So for boost applications, obviously you want to freshen up the engine... if they can't reliably be rebuilt do people just send it with stock internals?

Anyways, dropped an AP2 engine I have in and it's running great again. Probably sticking with this until I most likely K swap lol

B serious

These engines are extremely finicky when it comes to any kind of rebuild....especially a non-stock one. Not just "anyone" can do the rebuild either.

People push pretty impressive power on stock internals. 500-700hp, internally stock F series are documented. I think people toss in thicker head gaskets or stronger head studs sometimes, to prevent heads from lifting. Though, everyone's definition of "reliable" is different...in my eyes, it is almost impossible to have a totally reliable boosted setup.


No, you don't need to refresh for boost if the engine is already good. Lots of people are boosting F series engines with 6 digit mileage on them.

In either case, boring out and sleeving the engine is way beyond "refresh".

I haven't heard of blocks twisting over time as part of normal wear. The most common bottom end related source of burning oil is stuck rings, or ring to wall spacing.

Sometimes, the engines burn oil due to something stupid like a clogged PCV valve. And sometimes, changing oil brands can stop the burning too.

Best to try the simple stuff first.

I think whomever rebuilt yours likely ruined it in some way, to be honest. It would take some investigating to prove that out...but...its likely the case.

Its so far from a traditional engine that the risk of messing it up with major work is huge.

You will 100% have better luck with the K series if you're into building engines with aftermarket parts.