EJ25D w/ EJ22E Heads, Headgasket Question

[skid542]

Wow, I feel like it's been a long time since I've been on the BBS in a personal manner other than to thin the garage. It's great to see that some of the 'old' names are still around and active, or active again.

That said, I'm going to jump right into my question - after my disclaimer.

Disclaimer - I'm asking a technical question for my 99' OBW. I know the subject has been covered but there is a fair amount of conflicting information and I trust the crowd here more than anywhere else and therefore I'm asking it here. Todd, I've read your recent threads and suspect you found the same mis-information issue.


Yesterday the plastic passenger intake cam gear on my 2.5L 99 OBW decided it was done with life and imploded on my wife while driving down the road. Needless to say, this is less than ideal. I have not been able to pull the heads yet to see how the pistons actually faired but the drivers side intake cam is seized so I know I've got essentially one dead head and this doesn't give me warm fuzzies about the passenger head.

In my garage I still have my EJ257/EJ22E motor (approx. 1k mi on it) from my old 96' OBW that got crunched. I've been saving the shortblock to marry to some EJ252 I have (I think 252) to drop into the Leggy. This would leave my EJ22E heads available and I had them completely rebuilt during that motor rebuild.

So, the question is 'simple' - which headgaskets are ideal for this setup? I know this is a high-comp setup and I know there are conflicting reports/thoughts about using thicknesses for comp ratio adjusting and all that. I have heard reference to a Cometic gasket set specific to this setup, does anyone here have direct experience with it? Does anyone else have a direct experience with a OEM gasket for this setup?


Thanks for the input guys. I know I'm lacking a little on my use of the search button but I'm still kicking 60-70hr work weeks and won't have a ton of time for bringing myself back up to my old technical knowledgebase standards I used to maintain .

Thank you in advance for the help!

- Lee

[86BRATMAN]

The gasket you're looking for is the H1631SPK051S. There is no oem gasket that suits the 99.5mm bore and the 22e head coolant ports, early on people were drilling the 25d MLS gaskets but I don't think that worked out too well. Although I've never ran these personally, I've ran other cometic gaskets without any issues.

[cj91legss]

subbed.

[skid542]

Thank you for the quick and concise answer! Very much appreciated.

I got it pulled apart last weekend and both exhaust valves on #4 tagged the piston slightly and are bent. The piston looks to be in pretty good shape with on visible material movement - it contacted right on the edge of 'flat' and the square machined recess.

So it looks like I'll be swapping heads. I'll keep everyone posted on the progress as it goes.

Thank you again for the help.

- Lee

[skid542]

I figured I'd just follow up with everyone on the path I ended up choosing.

I decided that I didn't have much extra time to be swapping heads, water pumps, oil pumps, etc over to the old short block. Therefore, I decided it was more responsible of me to just drop in the whole EJ257/EJ22E engine setup into the 99'. The upshot, now I have a brand new motor in the 99' and it's up on the road again.

The downside, I just used up the EJ257 short block I had been planning on mating up to a set of EJ253 SOHC heads and intake I picked up. So at some point you'll find me asking some questions about options for using my 2.5 SOHC heads in the legacy... *I hate changing plugs in the EJ20H heads...

Thank you again for the help guys and if anyone needs a decent 2.5D shortblock I've got one to get rid of.

[wtdash]

Lee,
How's the low-end on the ej257/ej22? Should be about stock CR w/those turbo pistons?

And If i'm following the above, you want to use Phase 2 heads? That'll cause grief if intending to use stock EM as you'll need the Phase II intake manifold, harness, IAC, TPS, etc, which don't play well w/the Phase 1 stuff.

If you're on a stand-alone, etc. never mind.

TD

[skid542]

Todd,

The low end on the new motor is fairly snappy. When I build the motor I want to say the comp ration was 11:1-ish. Not quite as high as the typical high comp NA motors but high enough that I run premium. I get about 22mpg around town and haven't had it on the highway recently to give highway numbers. It pulls nice and should be great for basic daily driving and my camping/boating rig. You can feel the heads choke out at the higher RPM's but the overall power curve is still pretty nice.


And yes, I'm planning on running the phase 2 heads. I'm running MAFT-Pro piggy back, a fairly intensive piggy back which lets me tune most everything except timing and it lets me run a speed density setup to get away from the MAF sensor issues. I currently have the IAC blocked off and it works fine - I have my idle set high to account for my radiator current draw and lightweight flywheel. I'm planning on swapping the whole throttle body to handle the TPS issue and I'll tap the manifold for my IAT and MAP sensors. I'm after about 300hp at the crank *basic stock STi power levels* so I'm not after terribly high power - I just want the car to be more spunky without having to deal with the DOHC plug issue.

In the mean time I might finally turn up my boost past wastegate as I know my current setup can high my power goals. Too many options and not enough time or money...

[wtdash]

Todd,

When I build the motor I want to say the comp ration was 11:1-ish. Not quite as high as the typical high comp NA motors but high enough that I run premium.

I'm not the expert but if a normal (?) Franken-build is around 10.5-11:1 - based on what I've read, then I'd think your EJ257 w/its stock CR of 8:1 in the STi and the EJ22 heads would be 9.5:1 or so....depends on the HG, too.

I'm tempted to still try this hybrid setup just for the low-end.
Thanks,
TD

[skid542]

Regarding the comp ratio - you may very well be right Todd. I'll be honest that it's been too long since I had my head in the CR game and was crisp but what you are saying rings a fair bell. I do remember calculating it higher than stock but I did chose the turbo block explicitly to reduce the ratio a touch so it wasn't as at risk to pinging.

It is a little more torquey down low than the stock 2.5L but it is not quite spunky higher up - you can feel the head flow difference above 5k.

[WRXish]

I like the approach you have taken with your build, however I have a question about it that the rest of the board here might be able to address...if you do a little cam work and a little head work on the 2.2 heads, can you gain enough to make them flow decently above 5k rpm? Has anyone tried this or do they know a reason one should not do it? Inquiring minds want to know

[Legacy777]

I know this may not be directly applicable, but adding cams to my EJ22t did improve the low to mid-range torque. They do have a higher grind cam that may improve things in the higher rpm more, but you will likely sacrifice day-to-day drivability and idle. You can see my before and after dyno curves in this graph. I increased the CR from stock 8:1 to 8.5:1 and added the Delta 220 grind cams.

(Click for larger image)

[WRXish]

interesting looking at the dyno results, seems like the compression bump helped midrange with very little loss up top, I like the results a lot...area under the curve is quite a bit larger and I bet very noticeable behind the wheel

[Legacy777]

Yeah, the increased lower end torque is definitely noticeable.