Blue Smoke/Low Compression on New Engine
Turbo Mini Forums

what did you lube the rings with on assembly(in-case its relevant)

Its hard to tell from the photos but the mores do look glazed.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

No chance for further tear down this weekend but a couple comments:

Fuel wash could be a potential. I was having issue with flooding initially and it was definitely running really wet when I was trying to get it started.

I do not remembered whatever I used to lube the rings.

Thanks again all for the help. I'm super bummed that is almost 100% an engine out issue but I do really appreciate the knowledge being shared here.

100% bore wash then, I had the same problems you described and it was this!

well that's a good lead, potentially. What did you do to fix it?

I don't know if I totally understand bore wash. If the gas cleans the bores, wouldn't that make it even more likely to bed the pistons in?

it isnt that simple, one of the functions of the crosshatching on the bore is to retain a little oil so the rings have some lube, they are metal on metal but they still need some lube.. if crosshatching gets wiped of the bores before the rings get the chance to bed in, its game over. I should point out im no expert, I have likely built more engines than most but certainly dont know everything so this is just my understanding.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Okay, made it out to the car for a little bit of work.

Piston ring gap (consistent within bore, measured in the middle): 0.016"

Based on the Haynes manual, my bores are too big.

Bore diameter (averaged caliper readings so maybe not super accurate): 2.57"
Piston diameter (also caliper): 2.581"
That gives a clearance of: 0.011" or 0.0055" per side.

Is this too much, and likely the root problem? At this point, I don't think I can overbore this block so if it's a new bore that's even worse!

Edited by seahuston on 22nd Jun, 2017.

If the clearance really is 0.011" then way too much.

But be very careful of where you measure it.

Any half decent piston is a more complex shape than a simple round tube.

Where you need to measure the piston "diameter" is on the skirt about 1/3 of the way up and at 90 degrees to the gudgeon pin (ie, front to back on a transverse engine). It is the skirt across the loaded sides that sets the running clearance, if you measure higher up you will almost always see more.
It is unlikely you will have been able to measure in the right place with calipers.

Schrödinger's cat - so which one am I ???

like i said , just bung a piston in the bore and see what feelers you can get down the skirt to bore gap .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

If I'm reading that correctly, your pistons measure larger than the bore?

In the 13's at last!.. Just

you need to measure the psiton near the bottom of the skirt 90 degress to the pin, as the pison is tapered so it is the right shape when up to temperature. ( they expand A LOT)

http://www.timelessmuscle.com/videos/video...wall-clearance/

Well looks like I TOTALLY buggered up that measurement. So let's just ignore that and pretend it didn't happen lol :)

Drop the piston in the bore upside down to that I'd be measuring the skirt side to the bore with my feelers?

Okay. So I got out there and dude this:

Placed feeler gauge along side of upside down piston along the skirt. Pushed piston with gauge into the bore until the bottom of the skirt is fully in. Went up in sizes until I couldn't get them in anymore:
.004" was a tight fit (had to press a little bit)
.005" was a very tight (had a lot of trouble getting the gauge out)

So say .0045"
Still a bit loose but considerably better than .011"

Light blue Haynes (99H engine) says .0022"-.0033" top of skirt and .0004"-.0014" bottom of skirt.

But that is factory clearance for a brand new standard engine.

Now, everyone on here will have a different opinion as to what the best clearance is for a performance engine, esp. a turbo one.

Personally I opted for 0.06mm at skirt (my pistons have a parallel skirt and reduced top diameter and crown) which is .0024" in old units. That is on a 73mm piston (1360cc).

My machine shop's comment was "a little bit large, you must be going to turbo it..."

You would expect your clearance to have increased with a few hundred miles running but it looks like they started too large in the first place.

Just my opinion, and I'm sure others will differ.

Schrödinger's cat - so which one am I ???

yup i agree with rod ,

my guess is maybe they bored it with a big v8 type of clearance ,i think i run 4 to 6 thou on the tvr with high expansion forged omegas .......buick 215 v8 .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Well fook, machine shop was friendly but the owner is out until next week.

Thanks again all for the help