2008 Speed 3 Rebuild Questions

N

Nactan

Greenie N00B Member
I've had my Speed 3 for about 4 years now and it has 155k on it. In the last 8 months it has started having engine problems. To my knowledge, it's mostly stock. It has a Cobb cold air intake, and a cat back exhaust. July of 2021 I replaced the K04 cartridge with a re-manned one and did the VVT actuator at the same time. Last December I replaced the PCV since the engine has started burning over 1qt every 1000 miles and blasted the intake valves. I also upgraded the PVC plate with a Damond plate. Still, it's down on power and burning oil. So that leads me to think the piston/oil rings are bad especially since my compression test results were 150 150 120 150. I haven't done a leak down test though. Initially, I thought replacing the rings wouldn't be terrible but after some reading I'm not so sure now. I'm not looking to make more power or tune. I just want it to run like it used to.

So, my questions.
1. Can I just replace the piston/oil rings with stock equivalents from EdgeAuto and hone the cylinders or do I need to upgrade to 88mm pistons and new rods?
2. Is it possible to pull the pistons without pulling the block or removing the crankshaft?
3. I saw someone mentioned deleting the balance shaft, is that recommended because it has to be removed to pull the crankshaft?
4. Aside from friction washers and gaskets, are there any other parts that must be replaced?
 
Once you get deep enough into the engine to access the piston/rings and hone the cylinders you wont be spending much more money to do a proper rebuild (assuming your cylinder head is ok). In order to take measurements and hone the cylinders the crank will need to be removed. You need to measure and inspect the cylinders to find out if you need to bore them to 88mm also requiring new pistons. Boring to 88mm is usually done to repair minor damage to the cylinder that cant be removed from honing or true up the cylinder because of taper. Mileage on the engine isnt a very good metric to figure out what it will need for repair unless you know how the car has been driven and maintained for its full life.

Balance shaft needs to be removed to remove the crankshaft. I havent disassembled an MZR, but Id assume the unit will also need to be removed to easily access the con rod caps. Putting the BS unit back in is the hard part and it needs to be shimmed and timed properly to the engine. If you remove the unit as (I think) most people do, you need a BSD kit.

Check out some of the build threads here. Extremely knowledgeable people share tons of info here.
 
Sounds like a rebuild is more work than I have time for. I guess it's time to join the slow car gang.
 
Your compression isn't really that bad. If you just want a little boost in power to get it back to where it was consider getting a mild tune
 
A leakdown test would help you diagnose where you might have sealing issues(valves vs rings etc). From there you could decide if a short block rebuild would get you back on the road. However at 155k, your head could be due for a refresh too.
Also, oil in your intercooler? Even a reman K04 will still oil your intercooler free of charge, if the crank case pressures arent in check. Do you have an OCC. Damond has a great can setup (even just the Stage1 enclosed can) with a check valve...a very important part to the system.
 
There hasn't been oil in the intercooler since rebuilding the turbo. There has been oil in the intake though. I don't have a catch can. Finances are kinda tight right now. Thus the reason I was hoping to just be able to do the rings without removing the block. It is my daily so that makes things a bit more difficult. I kinda think I'm getting an excess of blow by because the more often I get on boost the more oil it burns.
 
Im inclined to agree with you based on mileage and the info you have shared. I do think a leakdown assessment should be your next move. It would be a shame to concentrate on the bottom end to find out the valves were tired too.
Perhaps a complete lower mileage engine swap would be an idea. Keep your existing engine till funds are available.
 
That can vary based on a few variables. But Im currently in the early stages of costing estimates for a full rebuild with rods and pistons, head and main studs, but largely OEM rebuild. So far Im at $5500 with me doing the measuring and assembly and no hiccups. North of the border tho, pricing may differ for you. Wish I could be clearer than mud.
 
Nactan said:
So worst case, what would a rebuild cost?
Click to expand...

I think the cost will vary based on your approach. You can take the ‘do everything in the best way’ approach and spend more, or you could do a ‘good enough’ job (which I personally I think can be fine).

If I wanted to do it for minimal cost I wouldn’t bother even taking the block out—I’d just refresh the bearings and rings and service the head (to make sure lower compression isn’t related to the valves). It could be argued that if you have it that much apart then just ‘do it right’, but it depends on your goals and how much you’re wanting to put into it. Maybe doing that would have little or no effect, but I may not be willing to do a full rebuild so it’s worth the effort to try something.

I learned so much rebuilding my engine and am glad I did it, but if I knew what I know now back when I bought my MS6 I honestly have done what I just said above. I just wanted the car running :)

Also, there are degrees of a full rebuild with varying costs and labour. Depending on how detailed and anal you’re wanting to be.

Just some thoughts…
 
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If I leave the block in, can I pull the pistons without removing the balance shaft and removing the crank?
 
Nactan said:
If I leave the block in, can I pull the pistons without removing the balance shaft and removing the crank?
Click to expand...

No to balance shaft and yes to crank as long as you aren't touching the crank and keep all of the balance shaft shims and make sure that you get it reinstalled on the same tooth of the crank you can reinstall the balance shaft. The main reason people don't put them back in is due to the challenge of setting the lash correctly with all new parts
 
Nactan said:
If I leave the block in, can I pull the pistons without removing the balance shaft and removing the crank?
Click to expand...

You definitely don’t need to remove the crank to get the pistons out. I’m having a bit of trouble remembering how much the balance shaft obscures the rod bolts, but you may need to remove it. I suppose it’s possible you could finagle a wrench to get to the rod bolts which are obscured by the BS, but I’m not certain. For what it’s worth, I didn’t reinstall the BS on mine and I don’t find my MS6 especially vibrational (though I’ve never ridden in a properly functioning stock MS6 to compare).
 
So I did end up pulling the block. After getting everything cleaned I noticed that cylinder 3's injector port looks like it's been deformed. Is this normal?
First photo is what the other 3 ports look like. The second photo is what cylinder 3's injector port looks like.

20220424_145340.jpg

20220424_145332.jpg
 
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