No Crust Racing

Status I was thinking the same thing, low input pressures to set it implied it was for small engines, but I've replaced the leak down % gauge with another -150psi gauge so calibration is not an issue now. A mechanic on another forum is telling me that on a good engine there should not be really notable air flow into the crankcase so that's enough info regardless of what the gauges say. I'll have some more good data hopefully this evening when I can leak down test another mates rebuilt CA which makes good power so we know it's tight enough. From there I can make a call, and it may just be turn down the boost a touch, run thicker oil and modify the catch setup to keep driving it. As for the catch setup it's a standard exhaust cam into catch, catch into intake setup, no venting. (I have baffled it so it actually catches the oil...) If I modify it I'll delete the PCV, pipe the intake into the catch also, plumb a drain into the catch back to the sump and vent the catch to atmo so the engine can breath back through it as needed. I'm also considering one of these little guys to help sealing. http://moroso.com/catalog/categorydisplay.asp?catcode=13023

I did that already, came up as 155-160 all pots

OK more info on this. Replaced the leak down % gauge with a regular 0-150psi gauge. Dialled in 20-40-60-80 and 100 psi inputs and no matter what input I put in, when connecting up to the spark plug hose BOTH gauges would always drop 5psi, as per usual the air can be felt leaving the dipstick. This doesn't make sense to me, 5psi of 20 is a huge 25% drop but 5psi of 100 is obviously only 5%. Further to that, both gauges dropped down by the same amount, I'd have thought that the input pressure gauge should stay at the set pressure but how can that ever work if both gauges on the spark plug side of the regulator. Of course the gauge is going to drop in pressure when connected as you've just opened up a larger volume of space for it to pressurise. Should both gauges be dropping like that?

OK on the valve cover pipe side I can blow through it and when I suck it seals, the opposite is true for the plenum side, suck through OK blow seals it up.

How do I test it? It's just a one way valve isn't it? So apply vacuum to one side and see what happens?

Hmm I was sure I'd seen people plumb catch cans back into the sump, maybe it was after an oil air seperator. Oil is just shell helix HX7 10-40, might be too thin? That's not going to account for air in the sump, would a blocked pcv cause that though?

Yeah no worries, you fund it and I'll get going I need to know if it's a legit problem first, then I can decide if I just plumb back the catch into the sump, run thicker oil and turn the boost down to get a few more track days in.

I'm replacing the leak down % gauge with a standard 0-150psi gauge, will be much easier to use. So, thoughts on the air in the sump? Can a car comp test well and leak down test poorly?

Chances are you're right and I've been asking myself that same question about leak vs compression test results. I've got a buddy with a freshly built CA that I'm going to test for comparison. No doubt the leak down % gauge is suspect, I was thinking of replacing it with a standard 0-150psi gauge and I can just compare the two readings. I've mulled this over as well and spent considerable time testing in and around both instances of TDC in the cycle. I'm using fairly low pressures, see above, so I can work it myself, when I rock the piston back and forth the results get worse (implying a valve opening) but never better than about 30% and on rare occassions 20% . If you watch this clip, this is the method I'm using and almost identical gauge, mine doesn't have the sticker down the side but given everything else is identical my guess is that's just another branded version of what is a mass produced item. I've tried turning the reg pressure up also (ignoring the set gauge) to see if the extra pressure helps seal the rings, nope, just more hissing from the dipstick.

I spent some more time on it tonight and with the leak down % gauge on set it's only reading 10-20psi on the regulator side (ideally I would like to swap out the second gauge for just another 0-150psi gauge that way i can just compare the two readings and do my own % calculation as the leak % gauge is dodgy as hell). Never the less, I tested each cylinder cold/dry on both TDC positions (just before TDC actually) so I could be sure I was on the comp stroke TDC as the exhaust stroke TDC obviously allows plenty of air to escape the valve prior to true TDC. In each test the gauge gave me approx 30% leakage, and that was at only 10-20psi input pressure. In each example I could clearly feel/hear air escaping from the dipstick. What I can't work out is how the comp test could read so well if it's that shagged. (When i did my comp test it was a dead cold motor that had been sitting for a week or more so it was dry/cold and it came back around 155-160 each cylinder.) Keeping in mind the reason I started down this path is because the car spat out a heap of oil at the last track day, which it has never done before, and only after I swapped to a JDM S15 turbo and put in some more boost. So my guess is the rings just can't hold the extra pressure, but as I said if it was shagged why did the comp test come back good - and where is my coolant going! If it was a head gasket, surely I'd have seen bubbles in the radiator? Or maybe not when it's cold/dry and not enough pressure to show up a headgasket leak. My other thought is it's so little input pressure that it's just cruising around the rings and not supply enough pressure to seal them up properly. Perplexed!

There are two other things that have come to mind that bother me. 1 - To get the % leak gauge to the set position only requires 20-30psi of air, when I connect that to the cylinder of course it's going to show a huge difference straight up because it's now connected to a large volume of space it has to pressureise, so I'm guessing I should be waiting for the tool top pressurise that newly available space first? 2 - In the end of the hose that connects to the spark plug adaptor, there's a one way valve, like on a bike tyre. I can see now way for that valve to ever be acted upon by the compressed air and there's nothing in the spark plug adapter to act on the needle either. The only way I could get air into the cylinder was to remove that valve.

"You definitely have more then 100psi coming in from your compressor too when checking" <-- is this a question or a statement? "are you certain you are holding it on TDC on whichever pot you are checking?" Yep, if I rotate the engine backwards the intake port opens implying it's on the comp stroke, if it was TDC on the exhaust stroke I'd have to rotate forward to crack the intake valve. I also removed the upper time cover and checked the marks, I should be able to do some more testing tonight or tomorrow.

I've just had a bit more of a fiddle, disassembled the leak down % gauge, adjusted the needle so now it sits at the starting position properly when there's no air supplied. I'll do some more testing when I can get away with running the compressor for extended periods.

That was my next question, if it's shot, why would static compresssion read nicely? I'm certainly going to return the tester, but in the meantime, my question boils down to how much air flow i should hear/feel from the oil cap and dipstick on a healthy engine. I realise that's a very hard question to answer, but given it spat out 2L of oil at the last track day (I don't think it was over filled at the time) it made me think there's just too much boost and the rings can't hold it all in, or maybe the valve seats are shot and it's escaping into the rockers directly?

I guess my point was missed, I don't think 145ks is a small amount on a 23yr old turbo car, I also couldn't care less if it was 445ks, I put that detail in there more for the "unopened" part. The car at the very least has a full service history since coming into Australia which was 70ks ago, all signs show it to have been well looked atfer and a fairly original car, so my "guess" is it still has the original, and no doubt tired, rings in it. As mention in my first post, compression test came back as 155-160 across the board. cold/dry, new is 170-172ish. My leak down tester is playing funny buggers on the % leak gauge, as mentioned above, and I can clearly hear air coming from the valve covers, while I know there will always be "some" amount of blow by, should it be that obvious at 100psi on the regulator.

Car is an S13 with a CA18 in it, original 145ks on the odometer, unopened. At the last track day I filled my catch can twice and wasn't making the power I thought it should given the recent mods (I realise the power component of this equation could be tuning alone). A compression test (cold/dry) cam up with 155-160 across the board, new is 170 or so (warm and wet) according to the FSM. I've since bought a leak down tester and had some odd results. When dialing in some pressure from the regulator, 100psi,The leak down % gauge (it's a twin gauge model) reads off the chart whether it's hooked up to a cylinder or not, and by off the chart I mean 0 is a fully blown cylinder and the other end of the gauge is perfect seal, it's going well beyond the perfect seal portion. As it's a cheap gauge I'm not surprised. That part aside, if I ignore the % gauge and just use te tool to fill a cylinder and listen for leaks, at 100psi I have noticeable air flow from the valve cap hole (or the dip stick if I put that back in), or the pod filter if I seal that back up and let the air flow from the rockers to the catch can and back into the intake piping. I realise there will always be some air flow through these channels but how much air should really be flowing past the rings and into the sump, pressuring everything else. Should this be minimal? I'm confident I'm at TDC on the compression stroke also. To add to the mystery, the car has also been using coolant but there was no air flow in the radiator during my testing of cyl 1, I will test the rest, but I thought I'd stop and clarify what sort of air flow I should hear coming from the valve covers. It seems like a bit to me given it was only 100psi of pressure. Is it as simple as needing to do the test on a warn engine and am I using the thing wrong if the % leak down gauge climbs up to the set position with only 10-20psi of air in it and then climbs way beyond if you add more? Seems like there should be some way to add the amount of air you want then set that gauge so it knows this is your starting point. Assistance always appreciated.

Auctions finish tonight and all disks will be selling, quite cheaply too by the looks of it.

Drives are now on eBay at $1 No Reserve, I think forum rules prohibit me from linking to the ads but if you go to my eBay profile and click items for sale you will find them, hopefully that's OK. http://myworld.ebay.com.au/action*dan

My house is a brand spanker so I got a big square of commercial carpet and put it down over my existing carpet as an added layer of protection. All my plates are metal only.

Sounds good, what did it all set you back?

Hah, that's the plan. Thought I'd tinker for a week or so and see if I had any success. Elbow has come back nicely, but the back hasn't.

LOL No, but if it's a daily and you need to keep driving it you don't drive it at 100% WOT until you've fixed the miss... I get your point, all I was saying is that I'll avoid those movements right now until I've had a chance to get into physio, have it assessed and continue with recovery steps, in the mean time I can at least get a little leg work in with some lunges without straining that nerve/muscle/whatever it is. I've got a holiday starting this Friday so can give it some rest then, be lucky if I see the gym at the hotel twice while I'm away. You didn't have to edit out Laser GLI and change for Meteor either, I got it the first time

Well despite stretching, ball rolling, etc it's still flaring if I dead or squat even at half weight so might have to cancel those for now, light dumbbell lunges seem OK though.

I just watched a clip of that, I'm already doing it so happy days.

Dunno, I'm not super savvy with all that but Kate gave me a bunch of her stretches from physio that supposedly related to the hips so I've been doing those. If you know of something specific feel free to share.