Jub

I am authorizing the shop to put in a full head gasket kit. I am still shocked that a head gasket would go bad without overheating or anything though. I would really like to know the cause if that ends up being my only problem but it may just be age/bad luck. It had a 2 year span where it sat for a majority of the time with its previous owner who as in her 60s (<3k miles). It is probable that it was not run for a significant amount of time and maybe got brittle? Other than that, the only things I can think of are age, old coolant (was on my to do list, may be original), and heat cycling. I've definitely gotten the engine hot (Not overheated but 15+ back to back autocross runs) and shut the car off soon after during test and tune events. The plan is to use an OEM top end gasket kit, resurface the head, and use ARP head studs. The shop has done everything right and has diagnosed it methodically. I will still be holding my breath that the head gasket addresses the real issue.

windhund116

Just outta curiosity, why did you decide to go with ARP head studs?

Thanks!

Jub

The shop recommended it and I went along with it having some background on ARP's reputation and knowing the shop builds road race engines. I know ARP head studs and con rod bolts are fairly standard across other honda engine build threads I've seen. Before I had my S2k, I was into Integras (B-series engines). Most any engine build thread I had seen involved ARP head studs for multiple reasons. I know most of them involved boost and preventing heads lifting which does not seem to be a problem with our engines. If I remember correctly, most OEM head studs are only good for one torque cycle. I have actually not researched this on the F series but it typically holds true across engines/manufacturers. I do not believe torque cycle is the correct term I am looking for but what I mean by it is that they stretch out slightly once they have been torqued to spec once and should NOT be re-used. I believe ARP studs are able to be re-used a few times if I remember correctly. ARP has a good reputation in the tuning community and while they are in there, I figure it is a decent idea being that I should replace the studs anyways. I have not had anything aside from alignments done at this performance shop but they have treated me well so far, have a good reputation, and seem to make reasonable recommendations. I appreciate that they seem to want to do it correctly and do a whole gasket kit, resurface the head, replace the head studs, etc. I could maybe knock 400 off the price by replacing the head gasket only with a non OEM gasket, not resurfacing the head, and not replacing the head studs. I am glad they are not recommending this as it seems like a stupid thing to take shortcuts on given the labor that I am already paying for. I bet they would not be willing to do it if I cut too many corners or at least void any liability and rightfully so.

In addition, I plan to leave the car completely stock for the next few years. I bought it to learn to autocross with the intention of tracking at some point. I love the car, figured it should be reliable (find me a big piece of wood please), and should not lose a ton of value if I decided to part ways. Eventually, if I keep it for as long as I expect, I'd like to do a supercharger of sorts. ARP studs should help mitigate any risk of head lift that could come with boosting engines. I have not researched building F series engines too much, as I do not have any desire to make more power than our stock blocks are capable of, but I do not think lift is a high risk even with OEM studs. In summation, why not?

jun11

Don't forget valves/retainers were a big cause of symptoms like this in the AP1.

Slowcrash_101

Oem head bolts can be re used 95% of the time. They're good for up to 600hp worth of boost. These are not B series engines, the F2Xc engines are what people with B series spend thousands of dollars to get to.

4 angle valve job from the factory, huge ports, huge valves, FRM liners, forged pistons, forged crank, forged rods, ventilated oil pan with a baffle plate, high compression pistons, oil jets for pistons, etc.

Also unless your head is warped, you should insist that the head is not shaved, because you can only shave .008" off the head. If it's not warped more than .002" then just let it be, just have them clean up the mating surface.

HarryD

Re: ARP studs, one of the best s2000 mechanics in the world says:

Jub

I appreciate the post about ARP studs. I will be calling immediately to change to OEM bolts with that tidbit of information and a quick search. The more I read on this engine, the more I seem to learn how dissimilar it is to other honda engines and most production engines in general. I also agree on the sentiment of not wanting to have the head shaved. I wanted to post it without any particular opinion to see what the general consensus would be. I challenged that when I called in about the estimate and was given the answer that they always recommend having it done. This particular shop specializes primarily in subarus but works on and tunes other cars as well. I am still having real heartburn about this whole thing for many reasons to be honest.I believe in their process during diagnosis and they have been seemingly honest so far. I still am struggling to grasp that it is a head gasket for many reasons though. This is the only local shop I am aware of that is a true performance building/tuning shop and they seem to have a good reputation. I certainly didn't want to have this done at a dealer or a ma and pa shop. I am really hoping they are correct and this story has a happy ending and I give them great reviews. The tech seems genuinely surprised that a headgasket would go in an F2XC but confident that it is the root cause of my issues. I just don't want to be taking an expensive gamble because if I lose this round, I don't have too many left in me.

As for the valve/retainer theory, I am fairly certain it is not the culprit of this issue. Given that my valves were not overly tight, the leakdown test didn't turn up anything odd, and the borescope checked out, I am very doubtful that I dropped a valve or anything of the sort. From what I've read, most burnt valve scenarios would have shown from an overly tight valve and/or some leak down already.

Slowcrash_101

Since they're going to pull the head, I'd have them inspect the valve guides, I know you said they didn't detect any valve leakage, but still, if you're going to go through the trouble, might as well check. Your valves could be fine now, but if the guides are worn they'll ovalize the valve seat over time.

rpg51

From the info you have provided it seems pretty clear that the head gasket failed and needs to be replaced. The thing that would give me a slight feeling of unease is that we don't have any information that explains why the head gasket failed. But, that is something you can't change - the unease. It failed - and it has to be fixed.

Just out of curiosity, have you had any other engine problems in the past with the car?

Jub

Thanks and I am wondering the same thing. After some advice from the tech, I called the Honda dealer that the car was serviced at throughout its life before me to check if it had ever had any issues or the head had been off. They did not have records of anything outside of normal maintenance. I have had the car for 1.5 years and about 15k miles. It has given me absolutely no issues or signs of any issues outside of what has been discussed in this thread. As for the slight hesitations/bogging I described in the first post: I was under the impression that this was often one of the few quirks with this car and have not been worried about it. The head will be inspected when it is removed and I am looking into the additional cost of having AP2 retainers put in. I know that this would be the right time to do them. I have been extremely careful not to over-rev and do not expect to during normal driving or autocross. I'd eventually like to track it and that would be where I would really appreciate the extra insurance.

Old coolant, age, heat cycling, and a high compression motor are the only contributing factors that I can think of for a blown headgasket. It has also been over a month since my last autocross event and I have not been driving it hard very much. For the most part, I drive like a grandma on the streets. I really conjectured that autocross stresses just about everything except this engine. Clutch, diff, axles, suspension components, brakes, and tires were parts that I considered as taking significantly more wear due to autocrossing it but I have not been launching it much (< 5 times). I'm still learning to drive and am not attempting to win a test and tune. I also had budgeted for a clutch since it is the original clutch at 102k miles. I expected that the stresses placed on the engine would be significantly less than those who track these engines without issue. It is not like we are seeing 6-9k rpm's for 20+ mins on end. We also don't have the same type of sustained g's on sweepers and are not typically running those high RPM's while pulling the g's.

You've made me feel slightly better about the head gasket diagnosis. I guess it is just not what I expected in terms of how the car was driving and a seemingly sudden failure. I also have to trust the shop as they have wayyy more experience than I do. I've done top ends on 4-stroke motocross bikes but haven't really delved into car engines. If I had a garage, this would actually be a great excuse for me to dive into the s2k for the first time. As long as I could take my time and triple check everything, I'd be comfortable doing it myself with the exception of having a machine shop inspect the head. The shop was able to knock my original estimate down a few hundred dollars which I appreciate. I'm feeling more confident that all will go well and I should have the car running shortly.