Head Gasket Replacement - 97 Prelude SH - Honda Prelude Forum

TJ97SH · 04-19-2010, 09:39 PM

Okay so I am fairly convinced I need to replace the head gasket on my motor. My car is a 1997 Prelude SH. This engine was especially bad about burning oil, and I had it rebuilt December 2008. The motor got too low on oil too many times and one of the rods was bent. Fortunately no other serious damage occurred. I pulled the motor myself and had a local shop perform all the machine work and re-assemble it before re-installing it myself. I also had them swap out the stock pistons and camshafts for Type-S components which I had lying around for such an occasion.

After I got it up and running (Around Feb. 2009) I ran a compression test. I got 240 PSI on all four cylinders. This seemed like a good sign. The car had 84,623 it at the time of the rebuild. It never really ran 100% since I had it rebuild, but it was running okay. It doesn't pull very hard in VTEC as it used to. I am still unsure about this.

As of the last 4 months or so, I have been having to add coolant every week or two. I don't drive it very much at all, so it is losing coolant at a very fast rate. I maybe drive 100 miles/week at most. Sometimes I only drive 200 miles in a month. The car only has 87,954 miles on it now. So that is less than 3500 miles in over a year since I have had it running. I would say that it never really ran great since the rebuild, but the initial compression test did not show anything like what I saw today.

So I did some serious searching for coolant leaks over the weekend. I jacked the car up so I could get underneath it and look around. I found nothing once again. After letting the car idle and studying the white smoke coming from the exhaust I was convinced it was coolant and not oil. (On a side note, the oil retention is great since the new pistons/rings install). I decided to do another compression test today to see what that would give me.

When I went to check the compression of Cyl 4 freaking coolant shot out of Cyl 3, and vice versa. Coolant shot out of both Cyl 3 & 4 when we checked the other two cylinders. It was clear that the problem is worse in Cyl 3, but it is likely that Cyl 4 is having some coolant leaking into it as well.

The good news is that the compression is great. When I checked it in Feb 2009, it was 240 psi across the board. The results from this compression test are as follows:

1) ?
2) 260
3) Off the scale
4) 265

We didn't finish Cyl 1 (I did the test in reverse order i.e. from left to right) because when I fired it, we had the spark plug wires positioned just right that the excess fuel shot up one of the Cylinders and ignited. Had a little flame thrower out the top of my engine. I will re-check the compression later.....after I put a new head gasket on it.

So I am now trying to decide what parts to order. I was thinking I might go with a thinner head gasket, but couldn't find any from any remotely reputable manufacturers for the H22. I only found some crappy eBay one, and I am definitely not doing that. At this point I will probably either get a Cometic or a Honda OEM head gasket.

I just bought a Tri-Y header, so I have a new exhaust manifold gasket that came with that. I will need to get a new intake manifold gasket. I was thinking about getting one of those insulated thicker ones like the Hondata or Blox ones. Does anyone really recommend these. I didn't really know of the Blox one until I started looking around, but I had heard of the Hondata one. I guess if the Blox is just as good, I might try it out because if is a little cheaper. Do these really give any benefits, other than not being a pain in the ass to remove like the OEM paper ones?

If anyone has any suggestions that would be appreciated. Also, if you have any quick tips or can think of something I have possibly overlooked I would appreciate it. Thanks everyone and sorry its so long. I look forward to any input.

TJ97SH · 05-22-2010, 04:14 PM

So I have been doing some work on my car towards getting the head gasket replaced. It turns out that the head gasket was not damaged and did not appear to be faulty. I think the combination of two factors lead to my engine leaking coolant into the combustion chambers:

The head bolts were not torqued down evenly. On one end they broke loose at approximately half of the torque specification.
The shop I had rebuild the engine used liquid gasket in conjunction with the OEM replacement metal head gasket.

I used a torque wrench to break the head bolts loose, and on the end where the coolant leak was occurring 2 or 3 of the bolts were tightened significantly less than the others. They broke loose at no more than 50 lb/ft - probably more like 40-45 lb/ft. The other head bolts seemed to break loose at or above the recommended torque specification of ~7X lb/ft (I don't have the manual in front of me).

Also, it appears that they used a liquid gasket (like hondabond) in between the head and block. I spent quite a bit of time cleaning this off both surfaces with some cleaner and a rag. I have attached some before and after pictures. The before pictures were taken part of the way through cleaning the head surface.

I have ordered nearly all the parts I need to do this head gasket replacement and some other things as well. I went with a Cometic 0.027" head gasket (that is 0.003" thinner than stock and is the thinnest gasket they make for the H22). Today I changed my auto tensioner over to the manual tensioner kit. I will also be installing a Blox insulated intake manifold gasket, Blacktrax racing dual intake manifold spacer kit and IAB valve delete, and some ARP head studs.

bouckarooo · 05-23-2010, 11:06 AM

The real benefit of using the Hondata intake manifold gasket and the like; is the fact that they are reusable and eliminate the need for scraping stuck paper off.

TJ97SH · 08-01-2010, 09:21 AM

Okay so I finally got the car all put back together and running again. It has been running great so far. I have eliminated the coolant leak (no more white smoke) and rid my car of the long standing ATTS code. I had a bad left oil pressure sensor that was nearly impossible to get to - even with the head and intake manifold out it was still very difficult. It took a while to get all of the parts together and doing the labor myself on just the weekends was a slow process.

The following parts were installed:

Cometic 0.027" std bore head gasket
Blox insulated intake manifold gasket
Blacktrax racing dual intake manifold spacer kit (removes the IAB valve assembly). Also, since these parts are so nicely machined on a CNC, they match the intermediate IM gaskets perfectly. Because of this, I decided to port-match and polish the inside ports of the upper and lower plenums.
New knock sensor (old one was damaged when removing the head and intake manifold).
New left ATTS oil pressure sensor (was throwing a code and believed to have been damaged when re-installing the motor after the rebuild in 2007/2008).
ARP head studs
New power steering and A/C/Alternator belts
New power steering lower arm dust boot (old one was torn up).
Hayame adjustable cam gears (they came with my Type S cams, but I never installed them. I decided to put them on now because I had to take the OEM ones off the cams).
OEM Honda manual tensioner conversion
Blox black anodized aluminum extended open lug nuts

I also did the moon cutout on the upper timing cover so the gears can be easily accessed. I probably will never need to adjust them, but I figured I'd do it anyways. The timing belt was reused as it only had 3,331 miles on it and looked fine.

After getting the valves adjusted and double checking all the vacuum, fuel and electrical connections and topping off the fluids I tried to start it up. I apparently blew the 100A fuse for the battery circuit at some point, so I had to go pick one of those up. Once I got back from Napa with it, the car started right up. It has been running great since then.

I am going to do a compression test after maybe 500-1000 miles of driving it to double check against the values I got before. I am hoping to get 240+ psi on all 4 cylinders since I got that when I first had it rebuild and I have since increased the compression (in theory).

Mike95lude · 08-05-2010, 05:35 PM

Quote:

Originally Posted by TJ97SH

Okay so I finally got the car all put back together and running again. It has been running great so far. I have eliminated the coolant leak (no more white smoke) and rid my car of the long standing ATTS code. I had a bad left oil pressure sensor that was nearly impossible to get to - even with the head and intake manifold out it was still very difficult. It took a while to get all of the parts together and doing the labor myself on just the weekends was a slow process.

The following parts were installed:

Cometic 0.027" std bore head gasket
Blox insulated intake manifold gasket
Blacktrax racing dual intake manifold spacer kit (removes the IAB valve assembly). Also, since these parts are so nicely machined on a CNC, they match the intermediate IM gaskets perfectly. Because of this, I decided to port-match and polish the inside ports of the upper and lower plenums.
New knock sensor (old one was damaged when removing the head and intake manifold).
New left ATTS oil pressure sensor (was throwing a code and believed to have been damaged when re-installing the motor after the rebuild in 2007/2008).
ARP head studs
New power steering and A/C/Alternator belts
New power steering lower arm dust boot (old one was torn up).
Hayame adjustable cam gears (they came with my Type S cams, but I never installed them. I decided to put them on now because I had to take the OEM ones off the cams).
OEM Honda manual tensioner conversion
Blox black anodized aluminum extended open lug nuts

I also did the moon cutout on the upper timing cover so the gears can be easily accessed. I probably will never need to adjust them, but I figured I'd do it anyways. The timing belt was reused as it only had 3,331 miles on it and looked fine.

After getting the valves adjusted and double checking all the vacuum, fuel and electrical connections and topping off the fluids I tried to start it up. I apparently blew the 100A fuse for the battery circuit at some point, so I had to go pick one of those up. Once I got back from Napa with it, the car started right up. It has been running great since then.

I am going to do a compression test after maybe 500-1000 miles of driving it to double check against the values I got before. I am hoping to get 240+ psi on all 4 cylinders since I got that when I first had it rebuild and I have since increased the compression (in theory).

Thanks for the update. Looking forward to hearing how she runs