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300,000 miles AP2 - fix or engine swap?

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Old 06-08-2021, 04:23 PM
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Default 300,000 miles AP2 - fix or engine swap?

Hey guys,


I have a 2004 AP2 with 318,000 miles now. After compression test, all looks good except for cylinder 3 with around 170 psi, the rest are around 210.
The car still runs pretty well, but it's probably something I need to think about.

I talked to a few mechanics is California and I have a few choices:


1) rebuild the top end, around $2600 with labor
- bottom end would still have around 300,000 miles, and I'm reading that rebuilding the bottom end on these is not a great idea

2) get a used motor + tranny (if a good deal), around $5500 - $8000, at least on ebay (around 60k miles with good compression)

3) k swap (but most likely difficult to pass smog in CA)

4) spoon engine $14,000 or brand new oem engine (sometimes in stock) for around $12,500


Thanks for your recommendations





Old 06-08-2021, 06:27 PM
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That depends on how much are you willing to spend and also the condition of your car. If you have the money, and you car is in pristine condition, and will keep the car for more years, then I would do number 4. Otherwise, number 2 would be good.

Why is it not a good idea to rebuilt engine block?
Old 06-08-2021, 08:12 PM
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Is it possible to get a K-swap to pass smog in CA? It would suck to have to pay for a hot smog every two years, if you could even find someone to do that.
Old 06-08-2021, 08:59 PM
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Where's the loss of compression coming from? A leak down test would show it much better and give you an idea. A friend of mine as losing compression from some exhaust valves and a valve adjustment did the trick on his 280k mile AP1.
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Old 06-08-2021, 09:57 PM
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Leak down test as suggested.

K-series are newer, why wouldn't they pass smog? From my understanding, swapping in newer engines and engine controls should be fine. Just can't go backwards. But I'm not in CA so what do I know.
Old 06-08-2021, 10:33 PM
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Originally Posted by OlyRRR
That depends on how much are you willing to spend and also the condition of your car. If you have the money, and you car is in pristine condition, and will keep the car for more years, then I would do number 4. Otherwise, number 2 would be good.

Why is it not a good idea to rebuilt engine block?
They say the short block (bottom end) has a special coating, and makes it very difficult + very costly to rebuild.


Originally Posted by JamesD89
Is it possible to get a K-swap to pass smog in CA? It would suck to have to pay for a hot smog every two years, if you could even find someone to do that.
I'm not sure if k swap is legal in CA since it's coming from a FWD car. I think going to the state ref could be something i would be interested in.



Originally Posted by Live Fast
Where's the loss of compression coming from? A leak down test would show it much better and give you an idea. A friend of mine as losing compression from some exhaust valves and a valve adjustment did the trick on his 280k mile AP1.
That's good to know, I'll try another valve adjustment in the near future



Originally Posted by zze86
Leak down test as suggested.

K-series are newer, why wouldn't they pass smog? From my understanding, swapping in newer engines and engine controls should be fine. Just can't go backwards. But I'm not in CA so what do I know.
Yea, I was told by a mechanic that it has to be coming from a same platform car. Since K20 is FWD, it makes it hard to pass the state ref. Unless someone here has passed a k20 in CA.
Old 06-09-2021, 06:55 AM
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You have to find cause first. Leakdown test.

Once confirmed its the head, a head rebuild will fix it. But there are some important gotchas that can ruin this job.

The head has to be removed and installed properly. Loosen head bolts a little at a time, in sequence, as described in shop manual. Otherwise head warp which will ruin it.

Use only oem Honda parts. No aftermarket springs, seals, etc. These aren't an upgrade no matter what the machine shop says.

Don't mill the head unless absolutely necessary, and then there are limits as to how much can be removed without causing timing chain geometry issues. Again,most machine shops won't be familiar with this, since its unique to this engine. Their experience will get them in trouble here. What always works on other engines won't work here. We've done this a million times, we know what we're doing attitude will ruin head. Research in this forum how much Billman says can safely be removed from head, and make sure machine shop knows that is the limit (I don't recall limits).

Any replacement valve stems have to be carefully pressed in. Its easy to go too far. Shop needs to be informed up front about this.

This is all a bit like going to the Dr, where you have to be your own health advocate and do some research on your own to get the best care for your situation.


But a properly rebuilt head can last another engine lifetime. Worth doing, just need to find a machine shop that knows these engines.
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Old 06-09-2021, 07:19 AM
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Those "sometimes in stock" brand new OEM engines I would not even consider. Even if some are left, sounds like the few that some purchased failed within a few hundred miles. There is a thread about one of them here and I believe the replacement failed as well? I think those were sitting in some warehouse for years, found and then sold. And likely since they sat for so long, all lubricant fell into the pan and they corroded internally. I am not big on any new engine that has sat in a crate for 10 + years to be honest. I would want it totally torn down and checked out.

K swap unfortunately may be out for you.

If searching for a good used motor, while a ways away from you, may be worth contacting Andy at ASM in Wisconsin. That guy has done a ton of S2k work and has helped more than a few find solid used engines for decent prices. So even with shipping may be worth it. He also sells all the Kswap stuff if you did go that route, but again in CA may not be a good option for you.
Old 06-09-2021, 07:23 AM
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Oh, also there is a guy on the FB groups claiming Honda started making new engines and is selling them for about $4800. I tried questioning him on thie "honda started making them again" and he said you can only order from the EU and only via phone so he could not prove that they listed them. I am calling 100% bullshit on this, especially since he is selling them for less than they retailed for from Honda even back when they still actually offered them. So beware of this as he is either going to ship you a crap motor or nothing at all in my opinion. I asked if these were some of the few that were found and had issues and he claimed he can order them all day long from Honda. Would love if this is true but have not seen any evidence of this at all.
Old 06-09-2021, 10:12 AM
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Originally Posted by Car Analogy
You have to find cause first. Leakdown test.

Once confirmed its the head, a head rebuild will fix it. But there are some important gotchas that can ruin this job.

The head has to be removed and installed properly. Loosen head bolts a little at a time, in sequence, as described in shop manual. Otherwise head warp which will ruin it.

Use only oem Honda parts. No aftermarket springs, seals, etc. These aren't an upgrade no matter what the machine shop says.

Don't mill the head unless absolutely necessary, and then there are limits as to how much can be removed without causing timing chain geometry issues. Again,most machine shops won't be familiar with this, since its unique to this engine. Their experience will get them in trouble here. What always works on other engines won't work here. We've done this a million times, we know what we're doing attitude will ruin head. Research in this forum how much Billman says can safely be removed from head, and make sure machine shop knows that is the limit (I don't recall limits).

Any replacement valve stems have to be carefully pressed in. Its easy to go too far. Shop needs to be informed up front about this.

This is all a bit like going to the Dr, where you have to be your own health advocate and do some research on your own to get the best care for your situation.


But a properly rebuilt head can last another engine lifetime. Worth doing, just need to find a machine shop that knows these engines.

This is great information, thank you.
My only concern for a rebuilt head is, once the short block (bottom end) goes bad since it has 300k miles, the options become a bit iffy. Seems like a few have done the sleeving method and have reliability issues.

Do you guys think my short block (bottom) can last another 100 or 200,000 miles as is? If so, rebuilding the top end may be a nice option.




Originally Posted by engifineer
Those "sometimes in stock" brand new OEM engines I would not even consider. Even if some are left, sounds like the few that some purchased failed within a few hundred miles. There is a thread about one of them here and I believe the replacement failed as well? I think those were sitting in some warehouse for years, found and then sold. And likely since they sat for so long, all lubricant fell into the pan and they corroded internally. I am not big on any new engine that has sat in a crate for 10 + years to be honest. I would want it totally torn down and checked out.

K swap unfortunately may be out for you.

If searching for a good used motor, while a ways away from you, may be worth contacting Andy at ASM in Wisconsin. That guy has done a ton of S2k work and has helped more than a few find solid used engines for decent prices. So even with shipping may be worth it. He also sells all the Kswap stuff if you did go that route, but again in CA may not be a good option for you.
I have heard of the OEM engine being corroded as well, which would be alot of labor from a mechanic to tear it down. The Spoon s2000 motors look to be freshly built, but crazy expensive ($14,000 +) but seem to be oem spec or better. The spoon engine is prob not an option for me, but pretty cool that they keep building solid parts for our car.

Thanks for the contact at ASM, will looks into them.



Originally Posted by engifineer
Oh, also there is a guy on the FB groups claiming Honda started making new engines and is selling them for about $4800. I tried questioning him on thie "honda started making them again" and he said you can only order from the EU and only via phone so he could not prove that they listed them. I am calling 100% bullshit on this, especially since he is selling them for less than they retailed for from Honda even back when they still actually offered them. So beware of this as he is either going to ship you a crap motor or nothing at all in my opinion. I asked if these were some of the few that were found and had issues and he claimed he can order them all day long from Honda. Would love if this is true but have not seen any evidence of this at all.
For $4800, man that would be awesome if that were true! I guess keep me posted on this, i'll try to dig a bit on this as well





I appreciate all the comment so far. I would like to keep this car for a long time, so a little bit of investment on my part is ok, just don't want to redo something in the short term by going the wrong route.







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