YASVT (Yet Another Sixteen Valve Turbo) - now 16V Whiteblock (LS)

Those racecaR CR4599XP bearings?

https://www.summitracing.com/parts/kgb-cr4599xp
http://www.king-catalog.com/Catalog/Set/CR4599XP

Dunno, if you've never had to think twice about your bearings they're doing a good job. I really don't have enough miles to say how long they'll last.

Only caveat is that as far as I know they're only sold in standard size. Not that much of a huge issue, my 240K PnP junkyard donor motor still fit standard bearings. At least this last one did, the previous one with similar miles needed to go to the first OS.

I think there was some thought/specs going around that they were slightly wider, which might help fill out the wider big end of a crank steered rod (vs. the slightly narrower big end of a stock configuration piston steered rod) but in person, they are the exact same width as normal.

Haven't swapped the HG yet because I'm going to be out of town for a few weekends.

But yesterday I thought I'd mess around with is a tiny bit more before taking the head off. Two changes:

1) Swapped my black 75 kpa radiator cap for a green 150 kpa cap. Vague theory being that perhaps I'm just getting some flash temps down in the bores that don't register on the gauge, but which force a steam bubble to blow out loads of coolant.

2) Moved my radiator expansion tank. I had moved it onto the inner fender in front of the shock tower, but it sits an inch or two lower there. I was thinking that filling the system in that position might be leaving the rest of it only partially filled. A partly empty top hose seemed to lend credence to this theory. I tucked it back onto the shock tower, squeezed over to the fender side away from the turbo, but still higher than it was. I poured almost a half gallon more into the system after I moved that.

Sounds good! Maybe I fixed it!?!?!

Nah, took it out for a quick drive, got on it the first time (15 psi boost) and the rear end was squirming around, pulled over, it had puked a whole bunch of coolant out the cap again.

Yeah.... it just needs a headgasket.

That is a very nice and gentle failure mode on the Cometic gasket, though. Drive it gently and it's fine. Drive it hard and it apparently vents combustion gasses into the cooling system. But the gasket just doesn't fail violently once and then be plain busted. Could also be some weird head bolt torque things going on? It's ARP studs and nuts, which I put on after some prior headgasket weirdness (pretty damn similar) before, after that it behaved for a good long while until the wrist pin broke.

JohnMc said:

But it was really hot Friday afternoon, and when I got into KC the car was running a bit funky. *Way* lean at idle, somewhere over 18:1 and off the scale and wanting to die, put the pedal down some and it would drop to normal. Really annoying to drive around like that, it would die pretty much immediately if you didn't have your foot on the pedal. I turned autotune on and set 'very easy' on it and it carved out some weird pimple looking bump ad the bottom left of the map. Why? Dunno, but at least it would run, sort of, without dying as much.

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What was your intake temp and where is the sensor located?

I didn't check that in MT, it was a real PITA to keep running at idle, but it would run fine once moving (with the throttle open a little), so I just kept going to the hotel.

I used to have the IAT sensor in the cold side intercooler piping, but I've had it just sitting out in the engine bay right next to the air filter for a long time. There's a hole in the inner fender where cool air (sort of) comes in to the air filter, the sensor is clipped right there.

I really can't think of the last time I drove it in close to 100 degree temps, with hours of driving to get everything heat soaked.

JohnMc said:

I didn't check that in MT, it was a real PITA to keep running at idle, but it would run fine once moving (with the throttle open a little), so I just kept going to the hotel.

I used to have the IAT sensor in the cold side intercooler piping, but I've had it just sitting out in the engine bay right next to the air filter for a long time. There's a hole in the inner fender where cool air (sort of) comes in to the air filter, the sensor is clipped right there.

I really can't think of the last time I drove it in close to 100 degree temps, with hours of driving to get everything heat soaked.

Click to expand...

There is the MAT/CLT correction curve that works pretty well.

Since my IAT sensor is right outside the passenger compartment and does not take a reading that is specifically commesurate with the actual intake temperature, I just have the IAC duty to increase 7.5% between 160 and 200 deg coolant temp.

The only downside to that is that the engine will race a bit if the engine is overheating in less hot ambient temperature.

Autotune was making a huge blister ad the very bottom/left of the fuel map when I had it trying to work its way around whatever was happening. It wasn't making any changes at all at MAP's over 50 - 60 or so. Just down at idle vac, and very near there. And even then, only at lower rpms. Actually, sort of sounds like a small air leak when I type that, if it was a MAF car. But generally speaking air leaks don't matter nearly as much on a MAP based car. It all just sort of averages together with the ambient pressure in the manifold.

odd. mine pushed coolant on the dyno back in '11, but I didn't have the head off til... 14 I think? (course, the car sat up for a long time too, so that may be why). Never did see anything wrong with the old gasket, think it's still hanging on the wall...because...I don't throw things away?

Cracked head?

I think a cracked head would leak much more consistently. The symptom here is that I can drive it 6 - 700 miles in hot weather and not need to add any coolant, yet you romp on it hard, warm or cold (well, not totally warmed up) and it will push a lot of coolant out almost instantly (and then want to overheat because there's not enough coolant).

This is pretty much how it was acting one other time, I pulled it apart, didn't see anything too unusual, other than the Cometic looked a bit oddly shiny around the fire rings, like something had been moving around some. And the crimped ring was split in a couple of small areas. All I did then was put it back together with another Cometic and some ARP head studs and it was good for a long while afterwards.

I've been back from vacation for a week, but it's just been ridiculously hot and humid here, I've barely touched the car. Spent an hour or so taking off the turbo piping and the intake manifold on Saturday, but then the heat drove me out of the garage. Thought about it a couple of times on Sunday, but changed my mind when I went outside. I rode my bike 30 miles in the heat, but working on the car is a different matter.

Good news: a cool front just rolled through. Once the rain settles down, we should be in the high 80's/low 90's, and I'll get that hot side off and take the head off and see whats up.

just go v8 already

Texas240 said:

just go v8 already

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Soon... sooon. The 16V kicks all sorts of ass (relatively speaking) when it's together and working. A HG is not a big deal.

Next time something lets go in a big way, though, it's going V8.

JohnMc said:

Soon... sooon. The 16V kicks all sorts of ass (relatively speaking) when it's together and working. A HG is not a big deal.

Next time something lets go in a big way, though, it's going V8.

Click to expand...

Not that im hoping it happens in the next time.. but i'll be there to gather some purrts

JohnMc said:

Soon... sooon. The 16V kicks all sorts of ass (relatively speaking) when it's together and working. A HG is not a big deal.

Next time something lets go in a big way, though, it's going V8.

Click to expand...

After the forth time taking the head off mine I was like "**** it, I'm going v8". Didn't even have the 16v in the car for 3 months and the head was off. Haven't even needed to come close in V8

Yeah, that's pretty much my motivation too. I want it to have faintly ridiculous HP, but I also don't want to be tearing into it every 5K miles.

Got the head off. It's another odd Cometic failure. I have no doubt it would have spit a regular gasket out of the side of the head and I'd have been towed home months ago, the Cometic just starts spitting coolant out under high boost but keeps working normally at low boost.

Main sign of trouble on the bottom end - a shiny part of the crown on #3, everything else looked normal down there.


The head has some marks on the intake side of #3 and #2:


The headgasket itself shows some odd signs. Just like the HG I replaced the time before last, when it had similar symptoms. It just sort of looks like the head has been very slightly wiggling around, and thus rubbing those raised crimped rings around the combustion chambers. The black coating of the cometic is worn off, and on all 4 cylinders there are sections where the crimped area has cracked, or worn, and there is a split along the crimp. #3 is the worse, split around a pretty good arc, on both sides. Surprisingly enough, even the center layer of steel is cracked in this area.






I double checked, with it on the block that section of gasket is not hanging out into the bore, fits properly on the head too. Not exactly sure what is going on here. I did notice that the center head nuts were slightly looser than the ends when taking them off, and the one between #2 and #3 on the intake side (where it looks like it was leaking the worst) was the loosest. Not 'loose', but just looser than the others. I did a proper pattern and tightening routine on it when it went together, even went as far as to do one last 'double check' round where I bumped the torque rating up 1 ft lb and made sure they all felt the same. Not sure why they'd have different tightnesses when taking it off.

Maybe I'll shoot these pics by Cometic customer service, they've probably seen it before and know what causes it. I'm guessing low head bolt torque?

Maybe you should go with the "I don't give a rats ass" attitude and just willy nilly the torque rating on the head studs. I sorta paid attention on the last amount of degree torquing and apparently its been fine or I haven't heard from the new owner of failure. "crosses fingers"

But I give a rat's ass!!!

Eh, sort of. I'll probably just clean it up and bolt it back together again and proceed to beat on it more. It's so fun when it's working right. *sigh*

Let's see, so far I've got the LS/240 motor mounts, the drop sway bar, the narrowed Ford 8.8 with 240 suspension mounts. Yeah.... (looks at CL to see if there's anything particularly cheap in the LS variety)

get a l33 pullout from ebay, or just a standard lm7, best bang for the buck

When was the last time the block deck and head were checked for flatness?

JohnMc said:

But I give a rat's ass!!!

Eh, sort of. I'll probably just clean it up and bolt it back together again and proceed to beat on it more. It's so fun when it's working right. *sigh*

Let's see, so far I've got the LS/240 motor mounts, the drop sway bar, the narrowed Ford 8.8 with 240 suspension mounts. Yeah.... (looks at CL to see if there's anything particularly cheap in the LS variety)

Click to expand...

Dibs on the 16V junk when you get sick and tired of it.

Block was a 240K mile junkyard motor, I stripped it down and had the machine shop bore it to first OS (96.5) and very lightly deck the block. This was a couple of years ago, after I split the #4 bore in the old block. It hasn't been touched since.

At the same time, the head had some pitting due to detonation (which also lead to destroyed pistons and the split block, lol, I never heard anything) and needed to be lightly skimmed to smooth it out again. I forget how much they took off, but it was minimal. So that was a couple of years ago, maybe 10K miles (sigh...).

After that build I had one prior incident of coolant burping, with similar damage to the Cometic, put it back together with a new gasket and some ARP studs and it was good for a long while until the wrist pin broke. Put it back together with a new Cometic, proper torque routine/pattern, and it's only been a couple of thousand miles since then before it started puking the coolant under high boost. No problems at all under normal boost (9 psi, wg level). I drove it 700 miles and didn't add coolant. Flipped the boost control on and one quick blast of 16 psi and it puked half the coolant out in seconds.

I might as well have the head checked while it's off, though.