Coolant leak and the story that followed

[jwmelvin]

There's not much of a story yet but I'm starting this to track things as they progress.

2000 with CTSC as originally sold by the dealer, now at 39k miles. All new coolant hoses, TB, and WP 7 months and 5k miles ago. New plugs and injectors cleaned 3k miles ago.

I drove my car a few times today. Early in the morning to pick up a friend at the airport 25 min away and home. Then out to lunch. Then home. I didn't notice anything unusual. When I went to drive about three hours later, there was a puddle of coolant under the car and some telltale drop marks as I had pulled in to the garage. The overflow tank was nearly empty.

I put the back up on stands and added some coolant. Unfortunately it appears to be leaking out the rear-bank head gasket.

I just checked the oil a couple days ago and didn't notice anything unusual with its color or smell. Over the past few months I have had an occasional stumble on start (with random misfire P1399) and just a couple weeks ago replaced the fuel pump. The misfire would only happen on cold start, has happened about a half-dozen times, and always went away after ~20 sec.

Obviously things look a bit grim. The car is on its way to Ben at Daisy Import Auto to find out where we stand.

 

[blue_myriddn]

Very sorry to hear about this - I hope it ends well. On the plus side, its getting to be lousy weather so it is a good time for the car to be off the road for a bit.

 

[docjohn]

that is a rare failure on an unopened motor with just a ct blower.....had you ever had any lean condition cels?

 

[jwmelvin]

Only CEL I know was for Cats p0420 And the recent p1399

 

[shawn110975]

another reason why I prefer stock engines they rarely fail esp headgaskets

sorry it happened to you good buddy keep us posted with updates

Ben will find out what has happened and have her back on the road in no time

if its the head gaskets get ur wallet ready :wink:

 

[Honcho]

That happened to me. Good luck!

http://www.nsxprime.com/forum/showthread.php/178055-Head-Gasket-Repair-Part-1

 

[RYU]

Dude! What kind of bad luck are you having man! Fwiw... I think it's too early to tell yet. Hoping the best for you Jason. This is tough to read knowing your history.

Let us know if we can help. I just went thru a HG replacement this summer but I was boosted on the weak 91 HG (known issue).

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BTW... Jury still out on time certs and certain camps like the OEM head studs while some like the APR. I'd recommend looking into head bolts.

 

[jwmelvin]

I've looked around and haven't seen anything negative about ARP head studs. Only that they may not be necessary. I will wait until I find out what is actually wrong with my engine but it seems prudent to increase the strength of whatever I am replacing. I will report back when I know more.

 

[bngl3rt]

My HG went at 78k miles and I went to ARP studs on both heads. Fresh hoses and a Koyo radiator and it goes all day at the track when it's triple digits outside. No regrets!

 

[jwmelvin]

A small update. The engine is out and the rear head off. Apparently four or five of the head bolts pulled the threads out of the block. That will all be addressed with Time-Serts and ARP studs. I'll know more when we get deeper, to see if the cylinders, rods, and pistons are okay.

 

[Mac Attack]

BTW... Jury still out on time certs and certain camps like the OEM head studs while some like the APR. I'd recommend looking into head bolts.

Hi Regan, care to share more please on the Timesert concern?

 

[jwmelvin]

I visited my engine last week. Here are a couple pictures of the cylinders in question (those where the surrounding head-bolt threads were pulled out of the block). I think I still have the spiral of aluminum threads in my jacket pocket, showing how the aluminum threads sheared of as the bolt pulled out.

Anyway, any thoughts on the the condition of the cylinders? The scratches are pretty minor but I could feel them with a thumbnail. I haven't heard what the engine shop thinks yet. I will be replacing at least the valve guides, main and rod bearings, and rings. I'd like to avoid sleeving the cylinders and replacing pistons, but that may change if the pistons show any issues. I will likely be moving to a high-boost pulley, as I am adding an F/IC and 550 cc injectors.

Thoughts?

 

[Honcho]

If you can feel the scratches with your nail, it's not good. Can't remember if this is a 3.0 or not but if so, I would have them honed assuming they can go back to round within the stated spec. If it's a 3.2 you're looking at a re-sleeve I think because IIRC the FRM material cannot be honed.

I know it's more $$, but if you are going high boost now would be the time for a low-comp build.

 

[jwmelvin]

It's a 3.2L so resleeving would be required. It will increase the cost considerably but if it's necessary I will do it. The scratches seem very short and limited to the very top of the stroke so I am hoping they are okay. But that's why I'm asking.

 

[Mac Attack]

I would reconsider the valve guides. If there is no wear, then there should not be a reason to replace them. I reused mine with 125k miles on them... and this is coming from a person that bought all-new OEM springs, spring retainers, and locks - but those are cyclically-stressed components.

Do all of the cylinder bores have those wear patterns, or is it just the ones nearby the pulled studs? I'll bet it is from the pulled studs. You can see it was just from the top rings not receiving any oil, and where the stress is placed on the bores (since it is not a uniform wear pattern). I'm curious if all of your bores are "egg-shaped" since your car was FI'd almost from the factory. The higher stress and cylinder pressures will deform these weaker bores over time.

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But to answer your question - No, I would not put the engine together like that. It's looking like you'll need to sleeve. I highly recommend Dan Benson.

Now you'll need to decide if you want to reuse the pistons, or go aftermarket. If you reuse pistons, you probably don't want to use Honda rings. I don't know if Honda used special rings for the FRM liners or not, and whether they will be compatible with aftermarket sleeves. Then you run into the issue of aftermarket rings in Honda pistons.... Personally, I would go with aftermarket pistons if you are forced to sleeve.

 

[jwmelvin]

I spoke with the engine builder. He says the cylinders are perfectly round and the pistons are in great shape. He sounded rather impressed with how it all measured. He says he cleaned up the cylinders with a scotchbrite pad and that the marks at the top are insignificant. I pushed back a bit but he says there is no concern.

If I were to sleeve the block, I would definitely change to forged pistons.

Thanks for the comment on the valve guide. I think I misunderstood the plan (because I know squat about rebuilding engines), which is only to inspect the head in all regards and replace the valve stem seals, but not the guides unless required. I haven't yet heard about how that aspect of the project is going.

Thanks for the feedback; I hear what you are saying but I do have to trust the people who have the engine in front of them. He's got 30 years experience building engines. I guess that's a lot of what I'm paying for. I don't want to seem like I'm ignoring your input, but I seem to be getting many different views, and our budget couldn't exactly accommodate this type of project without pause. Sleeving the engine would add at least $4k to the cost, and that is significant. Of course, if the compression or blowby is rotten after the rebuild, I will beg your forgiveness.

And thank you for the Time-Sert kit rental; those threads are amazingly deep in the block!

 

[Mac Attack]

I'm certainly no expert on engines and pictures are no replacement for being able to see it in person. If the engine builder came highly recommended I would go with what they say!

If he didn't get too aggressive with the scotchbrite pads and tried to evenly work on the cylinder bores, then that should be OK.

Were all of the cylinder bores worn like that, or was it primarily where the studs pulled?

Sounds like a good plan on the heads. Replace the valve stem seals, clean the EGR passageway, and remove the head oil passageway plugs to clean (replace plugs with new ones of course). A few people here have observed oil leaks from the head plugs over the years, and they are just a couple of bucks to replace.

Ask him for documentation on the bores (diameter, taper, ovalness), final main and rod bearing clearances, piston ring gaps, etc when reassembling. You can reuse the main bolts and rod bolts no problem since they are not torque-to-yield. I would not even bother to weigh/balance the rotating assembly. Crankshaft journals are probably fine too and don't even need to be micropolished.

Two things I do recommend though and they are relatively cheap to do now. Later they are a PITA: Buy two new knock sensors (~$200) and the crankshaft/camshaft position sensor on the front head. That's the thing that dribbles black potting material after it ages. Very knowledgeable people here say it is fine to keep using, but it is relatively cheap and I want to make sure my sensors won't be able to move around for the next 10 years.

I also recommend a new TB tensioner/pulley, spring, and bolt. If your mechanic follows the service manual for TB replacement and tension, keep in mind that the tensioner spring may need a little "help." Tension should be like this: http://www.nsxprime.com/forum/showthread.php/45564-DIY-Timing-Belt-Question/page3

Lastly, you know about the harmonic crankshaft dampeners failing, right? If yours is original, I would replace with a new OEM (~$250) for peace of mind.

Dave

 

[jwmelvin]

Thanks Dave. If I remember correctly, it was just the cylinders where the head bolts pulled. At least that's where I thought it worth taking pictures.

The engine builder had the same comment on balancing; that if we weren't changing a component other than rings then there was no benefit to balancing on a good Japanese engine.

I will think about the sensors. The potting is still intact on the crank sensor. For the damper, I do have a TiDave shield for protection. And definitely going to use a new TB and tensioner. Actually, Ben determined that the car had a cheap, non-OEM (GMB) tensioner, notwithstanding that the service right before I bought the car, which was done by a shop with accolades on Prime, listed and charged for the OEM part.

 

[jwmelvin]

I thought some of you may appreciate seeing the failure mode of my engine. This (if my linking attempt works) is the piece of block threads that one of the head bolts pulled out. There were a couple of these.

 

[Valhalla]

Yep, my old '97 did the same exact thing. I Timeserted every bolt on both heads and never had to worry about it again. Good luck.

 

[jwmelvin]

Yes mine too has been running strong since the timeserts. I just thought the sheared block threads were interesting.

 

[Jinks]

Guys, what caused the bolts to lift out of the block?

 

[Mac Attack]

Guys, what caused the bolts to lift out of the block?

The picture above shows that it was not a problem with the bolts themselves, but the block threads that sheared right off.

I'm sure Honda overly designed the thread pitches and length with sufficient factors of safety, so I'm guessing it was a quality issue with ingots used to make some of the blocks. When we specify minimum material properties at work, the product we get back from our suppliers has widely varying ultimate yield and ultimate tensile strengths.

Thanks for posting the pics Jason. Interesting.

 

[Jinks]

That's shitty. I had Shad save all my old parts so I can inspect them and have momento's like the one above.