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Old 01-07-2009, 11:52 AM   #1
fastenova
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OMGHi2U Third motor: SOHC/DOHC hybrid, Delta Cams...

So last summer, I installed a used motor (83K) to replace the original (200K mile) motor after resealing it (HG, cam/crank seals, etc.) I installed Delta's mild reground cams and saw an increase in power. However, the motor never idled right, and kept throwing a CEL for misfires. I replaced and checked numerous components and never found an answer.

Well, with about 83K + 5K on the clock, the motor started knocking bad. I had taken the car to the store, driven home, and parked, with no issues. I went back out to the car 10 minutes later, started it up, and got some bad noise. I checked fluids, oil was a little low but nothing to be concerned about. Noise persisted after letting the motor cool down. I wonder if the motor dying was related to me never finding a good idle or the recurring CELs. =\

So, I decided that I was tired of screwing with this motor that had never really worked right, and called around to see what my options were.

I'm going to be pulling that motor later this week and taking it to my local machine shop, whose owner is a Subaru enthusiast. He has a built 2.5L in his sandrail. He just happened to have a freshly rebuilt 2.5L SOHC block sitting around. I talked to him for a bit about my options, and he's going to bolt my DOHC heads with the Delta cams onto the rebuilt SOHC block, which he said would raise compression by about a half of a point.

He will also be using by DOHC block as a core credit, and giving me some credit for my first motor that had rod knock. Should have a freshly rebuilt motor with the valves adjusted for my cams for under 1K.

I'll be using new seals, DOHC 4-layer head gaskets, and having the heads totally reworked with new valve stem seals, valve grind, and checking/adjusting the lash for the Delta cams. I will be reusing the head bolts that were new 5K ago.

I'm really hoping not to run into any problems, and that this motor will give me a long life with a bit more pep over my old setup. I'm not sure what to expect as far as power, but I am guessing for just a little bit more all over.

Are there any problems with my planned setup, or anything I need to watch out for? My original goal when I installed the cams was to keep this as my daily driver. I feel like since I've been able to drive it maybe 5 months in the past year, that idea has gone out the window a little bit, so I'm venturing away from the 'mostly OE' mindset.

Wish me luck!
Aaron
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Last edited by fastenova; 01-07-2009 at 06:12 PM.
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Old 01-07-2009, 05:51 PM   #2
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Good Luck!

Sounds like a fun project!!!!


Jay
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Old 01-14-2009, 03:15 PM   #3
fastenova
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Anyone got some good information on what my CR will end up at? I've been told a half point above the normal DOHC CR, a full point above, and a few in between.

I'm using the thick MLS Phase 1 HGs...

I also tried using the TWE spreadsheet Patrick Olsen is hosting, but couldn't seem to get intelligible values out of it.

Thanks!
Aaron
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Old 01-14-2009, 07:52 PM   #4
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What year is the replacement block? There's several different options.
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Old 01-14-2009, 11:43 PM   #5
fastenova
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I think I remember him saying 2000 or 2002. I'll check tomorrow.

Thanks for the reply, Matt!
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Old 01-15-2009, 12:38 PM   #6
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My memory isn't as bad as I think: the block is from a MY2000 vehicle. What are your thoughts, Matt (or anyone else)?
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Old 01-15-2009, 04:48 PM   #7
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My memory can be terrible, so you may still want to do some math or get a second opinion. However, with that block and those heads I want to say the number is 10.8:1. Maybe Pat or Jay will pop in and confirm or deny.
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Old 01-16-2009, 05:09 PM   #8
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Finally talked to my builder, who tells me the motor is done and ready for pickup.

Sounds like I'll end up at 10.26:1, based on the mill specs he gave me and the TWE spreadsheet. He ended up decking the block .010" which brought the piston at TDC to deck height, and the heads .017" (seemed like a lot to me...?). So that's .85:1 higher than stock. I was hoping for low 10's (CR NOT 1/4 mile, haha) so should be a noticeable power increase.

Motor is going in tomorrow! May Kenji Kita be with me...

Cheers,
Aaron
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Old 01-16-2009, 05:28 PM   #9
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i really hope your issue wasn't with the mild grinds...i'm having them installed as we speak...
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Old 01-16-2009, 05:33 PM   #10
fastenova
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I doubt it. Everything I've read here and elsewhere has indicated that the cams, even with supporting mods (intake, full exhaust, LW flywheel, etc) are not enough to throw a code. John up at Delta said that the mild grind really is mild and shouldn't cause any issues.

Let's hope I am right, because I sure don't want to have to deal with that again!

I will say that you will REALLY enjoy them. I know they were a lot of fun, even though my old motor had 'issues'.

Aaron
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Old 01-18-2009, 10:13 PM   #11
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Let us know how it works out and give us FULL specs as to what you have done (exhaust, intake, flywheel) and make a video please.
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Old 01-20-2009, 01:42 PM   #12
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Well, I got the motor buttoned up and installed on Saturday, in <8 hours start to cranking, so that went well.

We forgot to plug in the coil after we had primed the oil system and installed the plugs, then one of my friends forgot to reattach the brake booster line... so we ended up flooding it a bit. Had to pull plugs and let her air out a bit. After reinstalling them, it fired right up... sounds great!

I took it for its maiden voyage (~20 miles) then came home and changed the oil filter, topped off the oil, and checked the cooling system for air. Everything looked good, so I spent some more time driving it. The pickup around 3k at 60mph is amazing! I am keeping it under 4k RPMS until I get about 500 miles on the motor, so I've yet to see what it can do, but it feels much torquier (sp?).

The bad news is that the funny idle problems I was having with the last motor are still present. It hunts for a good RPM at times, but not all the time. I'm not too happy about that, but I'm going to visit with the owner of the machine shop that built the motor to see if he has any input. So far, I've got the same check engine light once (cylinder 1 misfire) and it is having a pretty hard time idling on a cold start.

Mods:
DOHC heads with MY2000 SOHC block with ~10.2:1 CR put together by Steve's Precision Automotive in Tigard, OR
Delta mild grind cams
Grimmspeed 8mm intake spacers
custom cold air intake
LW flywheel & crank pulley
MSD high voltage coil
Borla headers
Stromung HF cat
custom 2.25" catback
Apexi S-AFC Neo currently in passthrough mode

I think that's everything engine-related, besides stiff mounts everywhere. I will post up some audio/video clips once it's broken in and running synthetic, and I can rev past 4k!

I am starting to think I need to start checking wiring to critical sensors/parts to see if I have an intermittent short/disconnection. But, I'd like to think the ECM would tell me if that was the case... On my list of connections to check: TPS, IACV, Cam sensor, Crank sensor, Knock sensor, ECT sensor, MAF sensor, MAP sensor, and o2 sensors.

Aaron

Last edited by fastenova; 01-20-2009 at 03:53 PM. Reason: plugs
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Old 01-20-2009, 03:27 PM   #13
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Sounds very similar to our NA RS build! the only problem we really ran into was adjusting the valve lash.. maybe check that out?

Mike
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Old 01-20-2009, 03:52 PM   #14
fastenova
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Quote:
Originally Posted by GrimmSpeed View Post
Sounds very similar to our NA RS build! the only problem we really ran into was adjusting the valve lash.. maybe check that out?

Mike
Mike,

Thanks for the reply. I just had a valve job done (valve seat grind, new stem seals, new retainers) and they adjusted the valve lash to factory spec. which is what John at Delta recommended. I was told by one member here to open them up a little bit, but I'm a little leery to do so since it's such a pain to adjust them all... especially since I've already got the motor installed!

What did you adust the lash to on your RS setup?

Aaron
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Old 01-20-2009, 05:14 PM   #15
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Does anyone know whether the ECU uses its metal case as a ground or has some reference voltage associated with it? I know it has several ground lines that feed it but I'm wondering if the case itself acts as a ground...

Reason being that when I did my 5 speed swap, I had to ground one pin on the ECU so it knew it's a manual trans. I believe I grounded to the case. Could that be causing me any issues?

*beats head against wall*

Thanks!
Aaron
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Old 01-20-2009, 05:47 PM   #16
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I don't think the ECU case is a direct ground. If you needed a ground for the AT/MT designation, the case would ground to the chassis. Tough to say if it's causing issues though.....

If you have an OEM coil, I would try that instead of the MSD.

Jay
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Old 01-20-2009, 05:51 PM   #17
fastenova
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Jay- I actually installed the new MSD coil last summer to replace the working OE coil on the last motor to see if that would eliminate the issue - it had absolutely no effect.

So, I'm sticking with this coil since it's the same save for the higher voltage. I hope my logic makes sense...
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Old 01-20-2009, 06:35 PM   #18
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Based on the history, I am sticking to my diagnosis from a year ago. I think it's the cams.
And before all the Delta fan bois jump all over me, listen for a minute. First off I was one of the first people here pushing Delta cams before the performance community found them. I am pro Delta.

Historically, you have seen different cars and ECUs behave differently with cams. When I got my Cobb Spicy cams there were half a dozen guys here with them in their cars throwing misfire codes. I never once have thrown a code. I've had these cams in both a MY00 RS with MAP and a MY99 RS with MAF. They have just never been an issue. People before me and since have have problems with these cams. The same story holds true for Delta cams.

Each car is different. You may never get this problem sorted out, unfortunately. But if the car drives fine other than the code, drive it like you stole it and only worry about the code when it's emissions time.
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Old 01-20-2009, 10:25 PM   #19
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I had to use ecuexplorer to raise my idle to 900. That helped alot.

Josh
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Old 01-21-2009, 09:43 AM   #20
fastenova
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Quote:
Originally Posted by Whiteghost 2.5 View Post
I had to use ecuexplorer to raise my idle to 900. That helped alot.

Josh
That WOULD help a lot, I'm sure, but since I'm pre-2000, I don't know of any ECU editing tools out there. From everything I've read, our ECUs are still a black box of sorts.

I did try buying a cable and connecting with some of the common tools, but had no luck even establishing a solid connection. Then add to that the challenge of decoding the ECU...
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Old 01-21-2009, 11:04 AM   #21
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you should NOT adjust the valve to factory specs...10/15 is factory. Jon & Ken at Delta have both recommended 8/10 intake/exhaust for the mild grinds.


Quote:
Originally Posted by fastenova View Post
Mike,

Thanks for the reply. I just had a valve job done (valve seat grind, new stem seals, new retainers) and they adjusted the valve lash to factory spec. which is what John at Delta recommended. I was told by one member here to open them up a little bit, but I'm a little leery to do so since it's such a pain to adjust them all... especially since I've already got the motor installed!

What did you adust the lash to on your RS setup?

Aaron
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Old 01-21-2009, 11:12 AM   #22
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I'll actually be doing a similar build within the next month or so. except it's with an ej22 lower end. Did you happen to get a spec sheet when you got the cams back from delta? just curious how mild the mild cams are. I was going to go with their more extreme grind but if you're having issues with just the mild grind...maybe I won't be going with that lol
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Old 01-21-2009, 11:13 AM   #23
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Quote:
Originally Posted by doubledribble View Post
you should NOT adjust the valve to factory specs...10/15 is factory. Jon & Ken at Delta have both recommended 8/10 intake/exhaust for the mild grinds.
I'm truly lost. I'm looking at the FHI factory service manual and it clearly says that valve lash for the 2.5L DOHC motor should be:

Intake: 0.20 0.02 mm (0.0079 0.0008 in)
Exhaust 0.25 0.02 mm (0.0098 0.0008 in)

I don't know what you mean by 10/15 or 8/10. When I called Jon and specifically asked what I should set valve lash at, he told me factory spec. I verified that he meant .20 and .25 mm for intake & exhaust respectively and he said that was correct.

EDIT: I checked the MY2000 FSM (SOHC 2.5L) as well, and the lash specs are the same as they are for DOHC - .20 and .25 mm.

Aaron
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Old 01-21-2009, 11:14 AM   #24
fastenova
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Quote:
Originally Posted by tonzo View Post
I'll actually be doing a similar build within the next month or so. except it's with an ej22 lower end. Did you happen to get a spec sheet when you got the cams back from delta? just curious how mild the mild cams are. I was going to go with their more extreme grind but if you're having issues with just the mild grind...maybe I won't be going with that lol
Yes, I can post up the specs I got from them when they ground my cams. I got a printed spec sheet that showed the measured values for my cams. I will find it at home.

Aaron
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Old 01-21-2009, 03:17 PM   #25
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I dont remember exactly but it was whatever delta told us to do so im sure that isnt that problem.

Mike


Quote:
Originally Posted by fastenova View Post
Mike,

Thanks for the reply. I just had a valve job done (valve seat grind, new stem seals, new retainers) and they adjusted the valve lash to factory spec. which is what John at Delta recommended. I was told by one member here to open them up a little bit, but I'm a little leery to do so since it's such a pain to adjust them all... especially since I've already got the motor installed!

What did you adust the lash to on your RS setup?

Aaron
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