Freshly built boosted D16

after doggin' on the car my coolant overflow tank is constantly filled to the top and coolant even comes out wtf?

 

head lift.

 

i had the same problem last year on the motor stock...now i'm running ARP's torqued at 85lbs.

 

what is your timing at full boost?

 

umm..not sure, are we talking valve or ign timing?

 

Igntion timing. If it is too high you will actually lift the head off the block slightly, and therefore make it act like a blown headgasket only at full boost. The Dseries heads are so small and the bores are so thin you concentrate a lot of pressure on the head which is why they lift, often times before you even see detonation. Decrease the timing a few degrees up top and the problem will go away.

If you don't have a ARP head bolts, get them. They will help. May be worth swapping the headgasket too by the way when you make this change as lifting the head can damage the gasket.

 

I have ARP studs and they are torqued to 85 FT lbs, should I goto 90 on them?? Also, how will retard in ignition timing affect my tune??

allow me to reitterate that everything in this motor is brand new, about 1 month old.

 

I thought head lifting is automatic blown hg requiring change?
The more your timing is advanced, the higher your cylinder pressure

Is your motor sleeved? Cracked sleeve?

 

No, 85 is already way more than you really should be. May be worth checking the torque though. Mine is at 65, 27psi and I've never lifted the head.

Doesn't matter how built the bottom end is, too much ignition timing causes too much cylinder pressure, and it pushed the head up. Think about it this way.

Pressure = Force/Area

On a Bseries, the common bore is ~82mm. Common bore on the Dseries is 75mm. Doesn't seem like a whole lot, but that little difference increases the pressure exerted on the head by quite a bit. So much so that you can actually achieve cylinder pressures that will push the head up off the block before you detonate. The more timing you run, the earlier before TDC the ignition is started in the cylinder and therefore the closer to TDC the piston is when it goes boom. Thus, higher cylinder pressure, more force, more power. Retard it a little bit you'll get less cylinder pressure, a bit less power (there is actually a zone in which you can pull timing back and not really lose much power), and not lift the head.

How much boost and how much ignition timing are you running?

Also, yeah, good practice to change the headgasket. It may not be damaged, but likeliness of that is slim lol.

 

Any overheating ?

 

If you are moving half a bottle of coolant i mean the over flow bottle. The head is lifting i went thru 4 head gaskets and the best option was

torque the head in 5ft lbs incruments to 65 ft lbs i believe. I think 85 is too high and now your turning that stud into an elastic. I think arp said 70 was the max that stud should see.

 

I have experienced some overheating, but its funny because the temp drops within minutes..like its a really brief overheating session, i'm talking passed the halfway point on the gauge for about 3min then drops down to normal

 

again..how will retarding the ignition timing affect my tune?

 

if your lifting the head the headgasket is no longer good....its a crush once type gasket...
either you have a bad radiator cap or you need to remove the head and use a new headgasket and arp headstuds.

 

Won't throw off the tune too much retarding it a few degree but idk how your tuner tune so afr should be checked.
some might have different experience but I torqued my headstuds 4 times and no problems for me. But after the first lift, did u have the head resurfaced?

A bad cap can cause overflowing coolant, it's a cheap change to rule out compared to a hg.

 

I have a new mishitmoto radiator with 19psi cap installed..I beileve if my head is lifting it is ever so slightly, I'm going to try the retard in ignition timing and maybe check the TQ on my headstuds just to be sure they are still all good as I have yet to do this since my rebuild. I haven't seen any indication of white smoke from the car I've even had friends tail me while in full boost and they see nothing out of the normal..so I hope and think my HG should still be in good shape..

wish me luck gents i'll come back with a report after the weekend..

 

The only reasons why you have overflow of coolant from my experience is
bad cap
overheating
pressurized from pressure ie boost, hg or cracked sleeve

 

just got in from spirited driving with a built d16 turbo too. had the same thing, bottle filled right to the top and even a little spray came out from the overflow bottle into the bay...i let it idle and the level in the overflow bottle came down a bit, i'll check it in the morning and report any new info.

 

all these stories sound like the common d16 head lift to me. i had it happen too many years ago on my z6. if you are already running arp studs torqued properly with fresh head and block surfaces, the next step is to retard the ignition timing up top. try 2 degrees and see how it does. the d16s with the smaller bore etc dont really need a lot of timing. retarding the timing will reduce the total cylinder pressure. if in doubt just try it. it takes 2 seconds to do with the laptop