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Which would you run now and which would you build for NA later?

  • JDM OBD2 d15b with y8 head

    Votes: 1 20.0%
  • d16y8

    Votes: 4 80.0%
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Discussion Starter · #1 · (Edited)
NOTE: I realize that the way I structured the poll makes NO sense. It's not a this-or-that question. Let's make it simpler: pick the one you think I should BUILD. The one with the least votes is the one that I will use now.

Hey everyone.

I thought I'd ask for some opinions on which motor others would consider dropping into their vehicle now and which they would build for a future swap.

I have a '93 del Sol Si that had an NA built z6 making 158whp. An exhaust valve dropped and destroyed the motor at the track. I've had a JDM OBD2 d15b with a y8 head sitting in the garage for the last two years that I was thinking of dropping in to have a working motor and get back into the track. As most you know, finding parts for this motor can be a little difficult in the North American market. I recently attempted to replace the water pump and accidentally broke a bolt in the block… it's been a nightmare trying to get that bolt out. Easy Out doesn't work...

Out of frustration I decided to look for another motor. I found a D16Y8. Now that I have these two motors, I'm considering my options. I can still swap over many of the salvageable parts from my blown motor like the camshaft, springs, and retainers. I have spare z6 head that I can get ported and polished and build with new aftermarket valves. It can go on either motor.

The d15 can spin a little faster and freer to high RPM. The y8 can have parts found easily. Whichever motor I go with to build I will have it rebuilt and may go 0.5mm over bore again but use PM6 pistons instead of P29 for the y8 and a comparable piston for the d15. The one I drop in now will get some refreshing to have it running well.

Which would you use now and which would you build for later?
 

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Discussion Starter · #3 · (Edited)
Using a PM6 piston in a d15b block won't be good... 8.83:1 not good. Compression height of pistons on d15's are different than d16's.
You know I knew that!

I've been playing with the zeal calculator for that exact reason. I should have specified that it would be for the y8 and not the d15.

Correction made! Thank you!

Edit: the PMS-A00 (01-03 GX) pistons yield 11.22:1 compression with ~0.020" PTD in. D15B. That would be with ~0.010 milled from the head but the zeal calculator doesn't consider the head. It only considers the block. The combustion chamber size of the head would be a little smaller to yield slightly high compression but the PTD height would be a little off. I did a calculation of what the combustion chamber size would be of a head that is milled a few years back. Regardless, the GX piston is an option and Honda makes over-sized versions - if you can find them!

Head milling calculation:
http://www.d-series.org/forums/naturally-aspirated/154772-head-milling-timing.html
 

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I'm not sure about obd2 d15b's but I know that on obd1 d15b vtec engines a few d15z1 parts will work. I also have read that d15z1 and d15b vtec cranks/rods will swap into usdm d15 non vtec blocks if all else fails.

As for your broken bolt. I've found easy outs aren't the best option.
The two best ways I've found to remove a broken bolt are drilling it out and picking out the threads or my favorite which is drilling a hole in the center of the bolt then using a left hand or reverse drill bit that is slightly larger so it bites into the metal and backs the bolt out.

The last method works best with a high torque drill and I also apply some liquid wrench and heat
 

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Discussion Starter · #5 · (Edited)
I'm not sure about obd2 d15b's but I know that on obd1 d15b vtec engines a few d15z1 parts will work. I also have read that d15z1 and d15b vtec cranks/rods will swap into usdm d15 non vtec blocks if all else fails.al to the y8.

As for your broken bolt. I've found easy outs aren't the best option.
The two best ways I've found to remove a broken bolt are drilling it out and picking out the threads or my favorite which is drilling a hole in the center of the bolt then using a left hand or reverse drill bit that is slightly larger so it bites into the metal and backs the bolt out.

The last method works best with a high torque drill and I also apply some liquid wrench and heat
Unfortunately the OBD1 and OBD2 d15's are not the same. At least not for the oil pump. I had ordered both the z1 and the y8 oil pump and it is identical.

I have looked EVERYWHERE for reverse drill bits. No store carries them. What you suggested is what I wanted to do but went with the Easy Outs. I think I'll have to order them off of amazon...

Edit: just ordered them
 

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Honestly I would build the D16. I say this because I had a turbo B7/Z6 mini me, and while it was fun (10.4 CR + boost). Once I upgraded to the stroked Z6 ... well ... even N/A I preferred that engine to the boosted D15. The extra displacement is great for just about everything ... I guess what the domestic guys say is true.

To be perfectly fair, I did daily drive the car, which may be part of the reason I preferred the extra displacement. I also AuotCrossed it, and it made a big difference there. I've never done a road course so I'm not sure how beneficial the extra grunt down low would be for you.
 

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Discussion Starter · #7 ·
Honestly I would build the D16. I say this because I had a turbo B7/Z6 mini me, and while it was fun (10.4 CR + boost). Once I upgraded to the stroked Z6 ... well ... even N/A I preferred that engine to the boosted D15. The extra displacement is great for just about everything ... I guess what the domestic guys say is true.

To be perfectly fair, I did daily drive the car, which may be part of the reason I preferred the extra displacement. I also AuotCrossed it, and it made a big difference there. I've never done a road course so I'm not sure how beneficial the extra grunt down low would be for you.
Hey AutoXCivic.

Thanks for the reply. I've been toying with the idea of building a stoked d16/17. I actually have all the parts I need sitting in a bin in my garage. I took them from a donor d17a2 a couple of years ago before I decided to build the z6. A stroked d16/17 may not hit the high RPM's like the d15 does, but it makes good power throughout the useable RPM range.
 

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Hey AutoXCivic.

Thanks for the reply. I've been toying with the idea of building a stoked d16/17. I actually have all the parts I need sitting in a bin in my garage. I took them from a donor d17a2 a couple of years ago before I decided to build the z6. A stroked d16/17 may not hit the high RPM's like the d15 does, but it makes good power throughout the useable RPM range.
If you do it with proper pistons (and not vitaras like I did) you should be able to get some good N/A oomph. I think mine was making 120hp/130wtq (ish) when it was N/A and that was with just a cam and I/H/E, no significant head work. I thought I had a dyno of the 1.7 ... I'll have to go digging.

Ninja EDIT:

Found it this is a comparative dyno of the 10.4 CR 1.5 mini me vs the 9.4 CR D17z6

Same Turbo, same head/cam

 

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Discussion Starter · #9 ·
If you do it with proper pistons (and not vitaras like I did) you should be able to get some good N/A oomph. I think mine was making 120hp/130wtq (ish) when it was N/A and that was with just a cam and I/H/E, no significant head work. I thought I had a dyno of the 1.7 ... I'll have to go digging.

Ninja EDIT:

Found it this is a comparative dyno of the 10.4 CR 1.5 mini me vs the 9.4 CR D17z6

Same Turbo, same head/cam

Great info!

I wonder how well a stroker d16/17 build would handle the stresses of maintained high RPM and lateral g-force during lapping/road racing... My previous build had ARP rod bolts and ACL race bearings and managed the punishment just fine (it was that damn valve that failed me!!). I would consistently be pegging the motor between 5000-7500RPM.

I've sent a brand new Honda OEM y8 oil pump to be be ported. I have to look at my info but I believe that I would have to use a d17 oil pump if I went with a stroker. Still not entirely settled on a decision... I may just rebuild the bottom with track events in mind, keeping stock bore and stroke but build the head again. I was having a blast chasing down "faster" cars at the track when the motor was making 130whp. I'd be happy with anything between 130-160whp.
 

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I believe that I had a z6 oil pump on mine. It all depends on which end of the oil pan you don't want to fit quite right. Part of the problem is that you can use either the D17 or D16 oil pan but one end is off either way (either the pulley or the pump end). And you can't just chop the ends off and make a hybrid one because they're different materials (this is all very vague recollection from years ago when discussing the build with my tuner/builder so take it with several grains of salt). Anyone with a little more knowledge/experience actually putting one of these together ... feel free to correct me.

I had SCAT rods, ARP rod bolt, and Vitara pistons, and a lightened OEM flywheel (12 lbs ... maybe) never leaked ... but I think there was a lot of RTV on the end of the oil pan that didn't seal quite right. It was happy to rev and stood up to 80k miles of abuse (Autocross) and daily driving (both boosted and N/A) ... and probably would have taken more (and more boost) if it hadn't walked off.
 

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For the oil pan issue:

This was for a different engine but same thing applies.

First is obvious. You need a y8 or y7 oil pump. Second you need the timing belt cover and dipstick setup from the y8 or 7. Then you need to plug off the hole where the dipstick used to go through the block. (I used honda bond and a small bolt)

Now for the part that tripped me up the first time. The z6 rear oil seal had leaked like crazy around the pan seal and here is why.
20140705_140241 by rabidflickr, on Flickr

Here was the fix. I used jb weld metal putty to form a curve. Left it for one hour to cure and then shaped it with a die grinder and sandpaper.
20140705_162143 by rabidflickr, on Flickr
 

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Discussion Starter · #13 ·
I believe that I had a z6 oil pump on mine. It all depends on which end of the oil pan you don't want to fit quite right. Part of the problem is that you can use either the D17 or D16 oil pan but one end is off either way (either the pulley or the pump end). And you can't just chop the ends off and make a hybrid one because they're different materials (this is all very vague recollection from years ago when discussing the build with my tuner/builder so take it with several grains of salt). Anyone with a little more knowledge/experience actually putting one of these together ... feel free to correct me.

I had SCAT rods, ARP rod bolt, and Vitara pistons, and a lightened OEM flywheel (12 lbs ... maybe) never leaked ... but I think there was a lot of RTV on the end of the oil pan that didn't seal quite right. It was happy to rev and stood up to 80k miles of abuse (Autocross) and daily driving (both boosted and N/A) ... and probably would have taken more (and more boost) if it hadn't walked off.
Thanks again!

For the oil pan issue:

This was for a different engine but same thing applies.
That's an amazing hack!
 

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My desired D15Beast7 2.0 would be a low mileage D15 bottom, Y7 head, Y8 or ported Z6 intake.

Not only for the power curve, but also for the MPG tuning.

Local JDM engine importer has listed what I want, but seems to never be able to get one in, hence the CRX has been idle since it blew up.
 

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Also, if I remember correctly you run into dipstick issues if you use the D17 oil pump on a D16 block ... could be misremembering. I took my D17 to 7200 often, it was only limited there because the turbo ran out of breath, and then because I only got a safe tune for it while it was N/A since I was going to go with a bigger turbo and then get a full retune.
 

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run a 1.6. z6 head is better then y8 but if you have y8 you could run that as well.

do what you did, you know what to do. you have more then half the parts.

run a aftermarket piston.

run 12:1 comp.

stratton.
 

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Discussion Starter · #17 ·
My desired D15Beast7 2.0 would be a low mileage D15 bottom, Y7 head, Y8 or ported Z6 intake.

Not only for the power curve, but also for the MPG tuning.

Local JDM engine importer has listed what I want, but seems to never be able to get one in, hence the CRX has been idle since it blew up.
I feel your pain....

Also, if I remember correctly you run into dipstick issues if you use the D17 oil pump on a D16 block ... could be misremembering. I took my D17 to 7200 often, it was only limited there because the turbo ran out of breath, and then because I only got a safe tune for it while it was N/A since I was going to go with a bigger turbo and then get a full retune.
Good to know!

run a 1.6. z6 head is better then y8 but if you have y8 you could run that as well.

do what you did, you know what to do. you have more then half the parts.

run a aftermarket piston.

run 12:1 comp.

stratton.
True. I've been thinking exactly this. Won't take much to build another 1.6L. This time with aftermarket valves
 
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