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For a long time, my car had low compression in one cylinder. To make a long story short, it turned out to be bad exhaust valve or seat (thank you Mr. leak-down tester). So with that in mind I decided to rebuild a spare head that I had and swap it in. Keep in mind that because I've made so many modifications at once, results from one mod may be skewed by the effects of another.

The head
I took the head to a local machine shop which did excellent work. The head was milled .006"-.008", the valve guides were found to be worn and were replaced with new stock ones (cast iron), the stock valve seats were cut 3 angles and lapped with the new standard size valves which I provided. The head was also steam cleaned, glass beaded, then steam cleaned again, which restored it to beautiful bare aluminum! I did not do any porting at all. The stock ports on the 1G head are big enough, and well engineered from the factory. Only if I were previously making upwards of 500hp (just a guess) would I see any appreciable gain from porting. The stock head works on the street, and the street/strip is where it will be used, so it's staying the way it is.

The valvetrain
I elected to go with Crower's single spring and titanium retainer kit. I chose standard size, stainless steel valves from Road Race, and got a set of the redesigned lifters as per the cheap lifter thread in Parts Talk. The only hardware I did not replace were the rocker arms. I did, however, soak them in brake cleaner for a long time and scrubbed each one with a toothbrush to remove any gunk from them. All of the aftermarket items (springs, retainers, valves) were noticeably lighter as you weighed each in your hand. I do not have a scale so I can't offer exact figures. The difference it made was phenomenal in terms of how snappy the engine revved up. I'm sure it would have been even better had I removed the balance shafts during this whole operation.

The cams
I went with the HKS 264/272 combo. Everything that I have read over time suggests that this combination is good for 16G'd cars. Larger turbos warrant the use of straight 272s, so when I get around to upgrading the turbo, I will most likely swap in a 272 intake cam as well. For now, I didn't want to sacrifice too much low end torque. It's also my understanding that the 264/272 combo is more emissions test-friendly, which may or may not become an issue in my area within the next year.

The cams obviously made the biggest difference in terms of seat-of-the-pants power. Don't be fooled, they do rob you of some low end torque. I'm finding that I have to downshift a little more often during around-town or uphill driving than I did with the stock cams. But the gain up top over the stockers is well worth it. Past 4k, the cams' true colors emerge, and whereas the stockers would die past 6k, these pull just as hard past 6k as they do at 5k -- all the way to redline. Second gear is that much more enjoyable going around corners now! The cams really wake the car up. If you're hanging out at the right RPM and punch it, watch out. The idle is lumpy and wouldn't really noticeable were it not for the stiff motor mounts (see below).

The rest
Lots of other items were incorporated into the head swap. I used a Mitsubishi metal headgasket, which is slightly thicker than the amount of material which was taken off the head. This brings the cam timing to about where it should be (not perfect though). Because it's close enough, I decided not to get aftermarket cam gears and degree in the cams. I used some copper gasket spray on the new headgasket to ensure a good seal, as metal headgaskets are not as malleable as stock or graphite gaskets, and therefore don't mold with imperfections in the sealing surfaces as well.

For fasteners I used ARP head studs and torqued them using 30w motor oil. These are 12mm studs to which I could apply 120 ft-lbs of torque. I re-torqued them after a couple of heat cycles (none were loose though) and will probably do it a couple more times in the next month.

At 96k miles, I did the timing/balance belts and water pump at the same time. The piston tops were absolutely CAKED with carbon buildup (as were the valves). There was so much that you could hardly discern the embossed lettering and symbols on the pistons! So with trusty MCCC and a brass wire brush, I scrubbed and scrubbed for hours and got it all off. There must have been almost a millimeter of buildup on them, which would explain why the compression in the good cylinders had been abnormally high (170ish psi).

I also got the Dejon Tool BOV leak-stop kit for the 1G BOV. Modding the BOV was easy as I had an assortment of taps and dies on hand. I followed the VFAQ to the letter and everything went smoothly. I have not tested it past 20 psi yet, but I will say that before I took the car apart I was running 15 psi, and now I run 17 psi, having not touched the boost controller at all. Coincidence? Maybe the stock BOV leaks a little bit at even under 20 psi. To add fuel to the fire, though, I also removed the emissions equipment from the car, eliminating all the numerous vacuum hoses from the system. Perhaps doing that alone got rid of some leaks and that's why more boost is building. Or maybe it's just the cams. :) I know, I know, why did I remove the emissions crap when I let it affect my cam choice as mentioned above? Well I don't have a good explanation, other than I had wanted to remove it for a long time, and realized during the head swap that the emissions system really isn't that complicated, and that I could hook it all back up pretty easily if need be. So I yanked it.

I added Prothane motor mounts to the mix, which has made in a big difference in terms of the character of the car. As mentioned in a previous review of the Prothanes, the car just sounds meaner. Vibrations from the engine are transmitted into the cabin so you can "feel" the engine a lot more, like when starting up or revving up. It also has made the car louder inside during around-town and especially highway travel. Because the engine is more firmly held in place (a couple of the old mounts were torn), shifting is more precise under any set of circumstances, be it hard acceleration, hard braking, or hard cornering -- something that had been a problem with my car in the past (especially during my spirited backroad driving). At idle, the car vibrates a lot, especially below 1k RPM. With the cams it's even more noticeable. I think it's cool, and my wife doesn't mind ;). As jap drifter's old sig stated "Prothane motor mounts: warming up the girls so I don't have to." :)

I got most of my OEM parts from Conicelli. I shopped around a lot and believe I got decent prices on pretty much everything. I had made a rebuild rubric from which I worked, here.

At the moment, I have no pictures available or new timeslips to offer, YET. I documented most of the work and will be posting the pictures soon. I've also located a 4-bolt rear end which I will be installing in the coming week, and then hopefully I will be heading to the track on Friday -- after a 5-month hiatus! More to follow later.
 

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Sweet Victor! Now I can finally go for that ride huh? ;)

How did you do at the track?
 

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Discussion Starter #3
This coming Friday, not last. Still trying to tune the thing. Shoot me a PM if you still want to do that pressure test.
 

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Did a compression test today which put a big smile on my face. Previously the compression was 175-130-170-175. The good cylinders were too high because those pistons were absolutely CAKED with carbon buildup (normal compression should be 160ish psi). After thoroughly cleaning off the pistons and putting on the new head, the compression is now 160-160-160-160. :D

I spent a decent amount of time tuning the car yesterday on a few gallons of VP C-16 race fuel. It's now dialed in at 22 psi, 1 count of knock, lots of timing, and 840*C EGT. It is also very consistent. With the new cams, boost begins to build at 3000 RPM and full boost occurs around 3600-3700 RPM. An extra surge of power comes on between 5000-6000 RPM, and it keeps pulling until my rev limit of 7800 RPM. The only downside is that I think the Big 16G is running out of steam with these cams. Boost falls off from 22 psi to about 18 psi at 7800 RPM. The fall-off wasn't was bad before the cams. I guess it's time for a new turbo. :)

I was having some problems tuning on pump gas which is when I went straight to the race gas. An interesting thing to note is that even when getting crappy timing advance (10 degrees) as a result of knock on pump gas, the car was still pulling as hard as it did on race gas before I swapped the head. Of course a number of things could have contributed to that, like the cams, the good compression, the lack of buildup which created hotspots, etc.

Still trying to make it to the track this Friday. :cool:
 

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Now that is the kind of results you hope for when you are finished a project. :)

I am looking forward to see the improvement at the track.
 

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nukefission said:
... and it keeps pulling until my rev limit of 7800 RPM. The only downside is that I think the Big 16G is running out of steam with these cams. Boost falls off from 22 psi to about 18 psi at 7800 RPM. The fall-off wasn't was bad before the cams. I guess it's time for a new turbo. :)
yeah i was about to ask that how the turbo was doing up there in that range...apparently not so good :(

do you plan to further jack up the rev limit with this new head once you switch turbos (or keep it somewhat mild for the tranny's sake). my car is being sold to my buddy and im just thinking about what type of head setup to go with on it.

good new on the compression

;)
 

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Discussion Starter #7
Yeah, I would like to raise the rev limit even further, when I get a new turbo. In order to do that, though, I will probably have to buy the TMO mods all over again as I think the TMO chip I have is counterfeit, which they don't support. :(

The tranny will probably get rebuilt/beefed-up before I do the turbo anyway. Even so, my current stock tranny is holding up really well. I baby it on the street and as a result it has been able to take the abuse at the track in stride, i.e. high RPM shifts.

I may be wrong about the turbo. It could be that at high boost levels, the internal wastegate is being pushed open a bit, causing boost to drop off. I plan to milk this turbo of everything it's got before I replace it, meaning I'm going to redo everything exhaust-oriented post-turbine. I have Buschur's 2.5" press-bent turbo-back exhaust which needs to be replaced with the 3" mandrel-bent version. I also plan to get a tubular O2 housing with a 40mm external gate, routed back into the exhaust, to take the place of my current ported 95 O2 housing. The external may provide better boost control as it's simply stronger than the stock internal gate and will stay shut (hopefully). Of course, whether or not all that will help the boost fall-off with the 16G, I will be upgrading the turbo shortly thereafter. :) I probably won't see any of this for about a year.
 

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I did make it to the track on Friday. Got the 4-bolt rear end in there and armed with some C-16, attempted to best my previous records. Of course when I arrived at the track, I realized that I had forgotten my gas can for pump gas. The needle was almost on E, but I couldn't drain the rest out. I let the car run for a while, but losing patience I threw some race gas in and went to the staging lanes.

It actually had been 7 months since I last raced, so I was a little out of practice. After a few shakedown runs, I started to get a little better. The problem was that since the race gas was mixed with pump, I couldn't lean the car out as much as I had it tuned previously. This deterred me somewhat, but nevertheless I managed a 12.4 @ 111 by the end of the evening. Same ET as before, but 2 mph better.

I'm pretty sure I'm chasing down a boost leak, plus I wasn't taking advantage of the power past 7000 RPM (I was shifting sooner, out of habit), but in spite of that the cams so far have netted a 2 mph improvement. I also forgot about a lot of other things that night, like removing the spare tire, and spraying down the FMIC with some water. Once I get the other issues sorted out and learn how to drive better I think the results will improve. I have every intention of returning to the track this coming Friday (remembering my pump gas can, among other things) to try again.
 

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leaks

When I dynoed my car my boost was hitting 17lbs and slowly dropping to 15.8 lbs in the upper RPMs. Since then I have replaced my 1G Bov with a HKS SS and fixed a couple of boost leaks. While I have not been able to dyno my car since, the boost numbers on the street appear to hold much better. I would fix all of your boost leaks before you blame the turbo.

Chris
 

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Discussion Starter #10
Didn't I just say that? :confused:

Either way, thanks for the input. I have the Dejon seal kit on the 1G BOV and it seals really well, so I don't think I'll need to swap it for an aftermarket one anytime soon.
 

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I went to the track again last night and put down a 12.252 @ 112.11 with my best launch to date of 1.728. It turns out that there was indeed a big boost leak which I fixed earlier that day. The car felt a lot stronger than it did before, no doubt because of the boost leak. Boost was holding better in the high RPM range and for that run I had it set at 22 psi.

The car had yet more in it but the track was packed and they closed it early, so I didn't get more than two runs in. Things I'm going to do next time are lean it out a bit and get the boost up to a stable 23 psi or so, and do more fiddling with the suspension settings and tire pressures in order to get the launch down better, as I was getting some wheelhop through the end of first gear.

This time I was taking advantage of the good valvetrain and winding it out to my rev limit of 7800, something I failed to do last time. The cams definitely provide more power over stock from 6500 RPM to 7800, but this B16G isn't providing the oomph at those RPMs. Need something bigger. :)
 

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Very nice Victor. Congrats!

I fight the wheel hop thing too. It sucks.

You know that you're gonna be needing a cage real soon right ?!:D Just curious if you want one. I'm debating that one right now.
 

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I used to race at an IHRA track which was pretty lax, to put it lightly. Now I'm stuck with an NHRA track which is pretty strict. They actually have a tech inspection before you race. Two weeks ago when I went to race, I told the inspector that I would be running 12s. He checked my helmet to see if it was SNELL approved, and looked under my car and told me that I needed a "driveshaft loop" or some crap. I'm not used to this stuff! Next time, I'm telling them I'm running 13s.

Either way, when 11s come, they'll make a fuss over there not being a cage in the car. At that point, I don't know what I'm going to do. I really don't want a cage because if I ever did get one, I'd want a really nice one and it wouldn't be cheap. I'm not sure I'll have an option with this track, though. I only use the rear seats for storage, so that's not an issue. When I do get a cage, it'll be chromoly or painted, with swingouts, etc. We'll see.
 

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Nuke, can you go into more detail on how you cleaned the top of the pistons. Did you just bring each one to TDC and then dip the brush in the MCCC and scrub away? What about all that crap (carbon&MCCC) running down into the bottom of the engine area?

I'm actually going to do everything you did except with a twist. Instead of the upgraded cams, I'm going to have Martin port and polish the head for more flow instead of using bigger cams. With a 16G, it might work better, but only time will tell. I know it sounds backward, but I only want to send out the head once :rolleyes:
 

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The pistons really had a lot of buildup on them. I had plenty of MCCC handy and I soaked the tops of the pistons for a day or so. Because the motor is tilted forward a little bit, some fluid did drain down past the pistons if I pooled it up on top too much. Whether at TDC or BDC doesn't make a difference. After soaking, I went at it with a brass wire brush, being careful not to score the deck surface around the cylinders. It took several iterations to get them clean. I spent hours on it but I wanted them spotless. If you have air tools and a whiz wheel/scuff-pad, the buildup can be removed much more quickly. And yes, the carbon and spent MCCC do get into the oil in the block, but that can be easily fixed by changing it before you start the car. :) I ran the motor with dino oil and a cheap filter for a day to flush it, just to be on the safe side.

As far as porting, not what I would do (or what I did :)), but the results on a 16G should be interesting. People have gone far and wide on the stock 1G head. It would seem though that the stock intake manifold is the biggest flow restriction, after taking care of things like exhaust, turbo, cams, pre-TB intake tract. The results of the FRH sheet intake manifold support this theory.
 
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