Take 2: Second Head Under the Knife
- Thread starter flat_black
- Start date
Excellent work Flatblack. I bought a spare head from Focus and I will be doing some porting on it before replacing the stock head. I plan on only cleaning and deburring the intake side and do a port match with my headers on the exhaust side (and also polishing the hell out of it). I also want to have the head decked so I can raise the compression ratio a little. Since I have the cams also, I also wanted to have the intake cam repinned for use on the exhaust side.
I have a question about the clover design you plan on doing in the combustion chamber. Everyone I talked to seem to think it will create hot spot in the combustion chamber and create more problems than anything else by allowing pinging and augmenting detonation. So how does that clover leaf design helps???
Nice work by the way
I have a question about the clover design you plan on doing in the combustion chamber. Everyone I talked to seem to think it will create hot spot in the combustion chamber and create more problems than anything else by allowing pinging and augmenting detonation. So how does that clover leaf design helps???
Nice work by the way
flat_black
Member
Vice-versa, actually. I will remove hot spots, in particular by containing the expansion of gasses and burning material, and keeping it in the proper part of the chamber, rather than having it spread everywhere. If you do that, then smooth it into the rest of the chamber, then polish the chamber up, you'll have no hot spots, which are caused by sharp edges in the combustion area. Since the location is actually a quench zone, it will force the explosion OUT of the area where you'd be adding an edge.
This increases compression, and decreases the chance for detonation, which is caused by gasses expanding in an erratic fashion (Such as in old Hemi heads, where there's no quench whatsoever). Controlling the explosion AND increasing compression is definitely a win-win to me.
Send those cams out to Crower to get reground, by the way. =) It's definitely worthwhile! And only about $200 at most.
This increases compression, and decreases the chance for detonation, which is caused by gasses expanding in an erratic fashion (Such as in old Hemi heads, where there's no quench whatsoever). Controlling the explosion AND increasing compression is definitely a win-win to me.
Send those cams out to Crower to get reground, by the way. =) It's definitely worthwhile! And only about $200 at most.
flat_black said:
Ok thanks for the explanation. For the cam, I'm only getting these next winter, and I will get blanks from Mazdamotorsport and have them ground to spec I will get for them. I need a clutch, flywheel, shock first so I'll get the rest later. Anyway, when I get new cam, I'm also going to rebuild the base, get the old head a professionnal post&polish, valve job, full ecu, etc...
I'm at 110 whp now with complete exhaust and intake (VTCS removed, spacer and light porting) and nothing else. So I figured I'll be pretty close to 120 whp with what I have in mind and an MP3 ECU.
Keep going the build, I haven't posted much here but I am a regular readers, and all the work you guys have done have help get where I am at. (first)
flat_black
Member
I've visited the dyno, but have no scans of the results, so I generally don't mention what I make. =) I'm pretty happy with it so far, since it's just light head work with modified intake manifold, full exhaust, MP3 ECU, and a buncha-cruncha other stuff, too, that I keep forgetting about. Cams, et-cetera. 120whp shouldn't be unreasonable for you, so you know. =) I think you'll be happy with what you get, actually.
flat_black said:
Thank for your word, I sure hope to be there. My objective now is to have the fastest Protege in Quebec (thumb) Maybe not on this forum because there is some nice one here, you, Twillghtprotege and Installshield in particular.
I will start a new thread soon on building a block for N/A. I have quite a few questions about the work I plan on doing.
How much oil were you burning and what were the symptoms? I've had an oil consumption since day one with the new motor... we replaced all seals including the valve seals, but no idea. I'm going to start tear down and inspection soonish so just wanted to keep my eyes opn.
TurfBurn said:
Turf...my 2nd motor was burning oil immediately after I rebuilt it. I had it bored 1st over w/ new pistons and rings. I did the same thing you did w/ replacing all the seals including the valve seals and it never stopped burning oil. Have you checked the compression yet? The rings in mine never sealed good at all. I think the bore job I got was sloppy. I rebuilt another low mileage motor using stock bore by just re-honing and new rings and dropped that in the car and it's been perfect ever since.
Mine did it from day one.. it has gotten a little bit "better" with time... but it was re-bored and honed and all seals were replaced when it was built. I checked compression and am at 150 psi dead even on all 4 cylinders. Also, I have done leak down and am at or below 15% on all cylinders... so I'm good there. My consumption was initially as high as about a quart per 300 miles, and since stabilized out to about a quart per 850 miles.
flat_black
Member
Wow... I was burning about a quart every 2500 miles or so, and I was complaining about that. =) My rings are sealing quite well. 152psi, variance of .5psi across them all, and I havn't yet tested leakdown. My head is off to the races, now, and should be back sometime in the next month or so, after it's all welded up, and whatnot.
- :
- 2001 Pro 2.0 LX
any theories as to what is causing the oil burning?
flat_black
Member
Sounds like for these guys it's the piston ring issue... For me, it was definitely my valve seals.
well, but my piston dishes typically look wet through the hole, so I wonder if it is the valve seals... but it doesn't smoke on startup... but it does supposedly smoke at take off from some lights and during decel down a hill... but nothing I can ever see... I'm hoping it's just my turbo but I doubt it.
yeah, and that's kind of what I"m expecting is that is the rings.. but I'm still hoping it is something else... won't be cheap having everything rehoned and re-fitted again... my tolerances and the like are a little rough (aka tight) and it takes some extra work to put the motor together. But again because my compression and leakdown are good is part of the confusion.
we should probably get back to the head at hand though 
. Flat.. you are actually doing a change that is similar to the original mini cooper heads that was famous for it's good combustion qualities. There is a whole section on that style of heads in the Four Stroke Performance Tuning book by A. Graham Bell.
. Flat.. you are actually doing a change that is similar to the original mini cooper heads that was famous for it's good combustion qualities. There is a whole section on that style of heads in the Four Stroke Performance Tuning book by A. Graham Bell.To add to the oil consumption...
I'm also burning a decent amount of oil if I'm hard on the engine. I'm not sure where it's coming from, but it seems that it's getting through the PVC valve. I've pulled the intake mani the other day and discovered oil in every runner of the manifold, but only about an inch into the runners. I also noticed oil on the coned part of the intake valves, but not much on the actual surface of the intake ports. The engine always has positive crank pressure coming from the valve cover and I notice white smoke from the breather filter.
I'm also burning a decent amount of oil if I'm hard on the engine. I'm not sure where it's coming from, but it seems that it's getting through the PVC valve. I've pulled the intake mani the other day and discovered oil in every runner of the manifold, but only about an inch into the runners. I also noticed oil on the coned part of the intake valves, but not much on the actual surface of the intake ports. The engine always has positive crank pressure coming from the valve cover and I notice white smoke from the breather filter.
I replaced my PCV and that was what pulled me down from 300-500 miles per quart up to the 800-1000 miles per quart.. I have a catch can on it right now and that never gets anything in it at all... so I know it's not going through there... I'll start tearing the motor down in about 2 weeks... so hopefully I'll find it then!
flat_black
Member
I change my PCV every oil change, anyway, so I've had no problems there.
