Breaking in New Engine, Leaks...crankcase pressure? Options

[BeatNavy]

The last week or so I've been breaking in a new engine I built last winter and finally manage to install a couple of weeks ago. I'm pretty happy with how it pulls, and after a LOT of fiddling with the MPS and timing I think I've got it where it will start right up, idle cold (barely), idle nicely when warm, and run with nice cool head temps. I do seem to have a slight bit of ping/detonation under load around 2800 to 3000 RPM, so I guess I need to play with timing a bit more.

I am much less happy with the oil leaks. I know building a leak-free Type IV is a challenge, and given this is my first effort, I didn't expect perfection. But right now it's leaking pretty badly in a couple of places: out of the transmission weep hole (probably RMS, I guess), somewhere around oil filter console and/or pressure relief valve, and, surprisingly, what seems to be sort of spraying out and around oil filler neck.

Here I need help from the World; I see a combination of three possible causes for this many leaks (when I otherwise took my time and tried to follow guidelines, using Jake's recommended sealants):

1. My own inexperience
2. Too much crankcase pressure from rings not seating yet
3. Too much crankcase pressure from no head venting.

Here are some details on build:

2056 with 9950 Cam using D-Jet
Brand new AA Heads built by HAM, and Len sealed up the vents
96mm KB Pistons with Hastings Rings
8.6 CR

A couple of notes: I didn't gap the rings per Jake's philosophy that crankcase pressure is what causes oil leaks, and the rings come properly gapped. Also, Len (and Jake) don't like head venting for oil flow (so my heads had vent plugged). If I understand him correctly, Len told me the stock PCV vale should provide enough crankcase pressure relief on a street car. RMS is the Sabo brand (the "good" one).

Any thoughts on 1, 2 or 3 above? I'm willing to pull the engine and reseal, but I wanted to see if 2 or 3 are possibilities that I need to address. Is the stock PCV valve (which I am sure is not clogged) enough pressure relief?

Thanks for any help.

[Superhawk996]

Sounds an awful lot like too much crank case pressure. How many miles are on it? Even if only a few miles, I've never seen that much crank pressure even before break in to have oil coming out the fill neck / breather assembly.

When you say you didn't gap the rings, I'm assuming you mean ring end gaps. Do you at least know what the end gaps were when you built it?

Likewise, did you stagger the ring gaps between top, middle, and oil scraper rings? If all of those ring gaps are lined up, that could be a source of too much blow by.

Likewise you could potentially do a leakdown test and see if you have cylinders that aren't sealed and blowing into the case.

[BeatNavy]

Thanks for the ideas.

How many miles are on it? Even if only a few miles, I've never seen that much crank pressure even before break in to have oil coming out the fill neck / breather assembly.

Right now I've got only about 65 miles on it.

When you say you didn't gap the rings, I'm assuming you mean ring end gaps. Do you at least know what the end gaps were when you built it?

Correct, ring end gaps. I don't have it written down in my notes but I seem to recall gaps being roughly 15 thousandths or thereabouts. I really debated whether to gap them further, but deferred to Jake's philosophy.

Likewise, did you stagger the ring gaps between top, middle, and oil scraper rings? If all of those ring gaps are lined up, that could be a source of too much blow by.

Yes, definitely tried to stagger the gaps.

Likewise you could potentially do a leakdown test and see if you have cylinders that aren't sealed and blowing into the case.

Good point. I don't have a leakdown tester, but that may change.

[HAM Inc]

Rob try this. Remove the oil filler cap and fashion a plastic water bottle bottom to fit over the filler that you can tape in place. Before you tape it in place drill a 3/4" hole in it. This is more than enough breather for a 8000 rpm race engine.

Drive it and it and see if the leaks go away. If they do then the pcv system isn't enough ventilation, at least not while you're breaking in the engine.

Once everything is broken in crankcase pressure shouldn't be that high. A properly functioning PCV system should handle it. But maybe not. This trick will tell you.

I would zip tie a clean shop rag over the assembly, over the opening.

You can fool around with different size openings in the plastic bottle to see what size breather you need from the chimney, which is baffled by design and is the highest point on the engine.

Breath the engine from the highest point, locate sump pick up at the lowest point. Pretty basic engine theory.

[Superhawk996]

0.015 ring end gap is great. Factory manual is 0.014" - 0.022". I definitely wouldn't have gapped them further either.

Buy (or make) a leakdown tester. probably your best bet to ID where it is blowing by. By 65 miles you should have enough break in to not be seeing these types of crank pressure issues.

On the rear main seal leak. Did you use a new flywheel? I've had issues in the past with the flywheel being worn such that a new seal still can't seal properly due to groove/taper wear in the sealing surface. The other possibility is a cocked installation of RMS or folded seal lip.

When you say leaking at the filler neck. Is that at the base of the breather? You do have the case to breather gasket in there right?

I'm so sorry you're going through this.

Are the head vents welded or plugged? I just bought a set of Len's AA 2.0L heads and they are threaded. if just plugged with a tapped plug, you could pull the plugs, install barbed fittings, route hoses to an EMPI breather and see if the situation improves. However, I would fear that is just a band aid even if it did improve.

[Superhawk996]

Great suggestion Len! Simplicity. I love it!

[Olympic 914]

Regarding KB pistons ring gap. They recommend a larger top ring gap.

http://www.hughesengines.com/TechArticles/...cticpistons.php

Also I suspected a RMS leak and it was one of the oil galley plugs I had put in.

[BeatNavy]

Great suggestion Len! Simplicity. I love it!

So do I! Good stuff, Len, thanks. Just to be clear (and because I'm stupid), I should leave the top of the water bottle off but cover it all with a rag to keep oil from spraying around, correct?

The flywheel was resurfaced, and I used a fine sand paper, like emory paper, to polish the surface where the RMS runs.

On the oil filler, I definitely have the gasket. I ended up putting Dirko on it to try to seal it in place, thinking that may be the issue. I don't actually SEE oil spraying, but it collects all over the top of the engine and on the flanges of the oil filler. I changed oil filler caps thinking maybe I had one that wasn't sealing.

Heads are threaded.

[HAM Inc]

Great suggestion Len! Simplicity. I love it!

So do I! Good stuff, Len, thanks. Just to be clear (and because I'm stupid), I should leave the top of the water bottle off but cover it all with a rag to keep oil from spraying around, correct?

The flywheel was resurfaced, and I used a fine sand paper, like emory paper, to polish the surface where the RMS runs.

On the oil filler, I definitely have the gasket. I ended up putting Dirko on it to try to seal it in place, thinking that may be the issue. I don't actually SEE oil spraying, but it collects all over the top of the engine and on the flanges of the oil filler. I changed oil filler caps thinking maybe I had one that wasn't sealing.

Heads are threaded.

Yes. The rag is to filter oil vapor exiting the crankcase and filter air moving into the crankcase. Crankcase pressures pulse from negative to positive with every crank revolution.

It doesn't have to be the cut off bottom of a water bottle. I just used that example to illustrate the concept. You can make the thing out of anything that you can drill a hole in and get taped and sealed tight to the filler neck. If you had a junk oil filler cap you could drill a hole in it. That would be the easy button.

[rhodyguy]

Is the PCV valve functional?

[Superhawk996]

I just gotta ask on other question that I've assumed.

When you installed the rings, there is usually one side marked Top that goes toward the piston crown.

Hoping that you installed with ring oriented top/bottom correctly.

Even if rings were pre-installed on pistons as they usually are, you can usually shift them side to side and see the Top mark.



NOTE: that is interesting on KB pistons. I was not aware that they specify that large of an end gap.

[BeatNavy]

Yeah, interesting on the KB pistons. Hmmm....hope that's not an issue.

Good point on the RMS versus galley plug. I did install galley plugs, so that's certainly a potential point of failure.

I did mind which way the rings were installed (oriented up/down). They were not actually preinstalled, and I double/triple checked proper orientation.

Thanks, Len. I'll give that a shot and see what happens.

Edit: Yes, sorry Kevin. PCV is functional. I can still taste oil on my lips from testing it (IMG:style_emoticons/default/blink.gif)

[BeatNavy]

Just to follow up on this. I tapped a hole in the oil filler, threaded a fitting in it, and connected it with vacuum hose to air cleaner t reduce crankcase pressure. I also realized that I'm missing a sealing ring on my oil filler neck. Not the cork gasket, but there is a sealing gasket below the oil filler. Comparing with one from my other engine, I realized that must be part of the issue, so I swapped oil filler housings.

Right now the oil leaks on top have stopped. Some combo of relieving crankcase pressure, making sure the oil filler was sealed, and/or rings seating seem to have helped. I don't see anything really bad underneath, and I am now thinking at least part of the oil under the case was actually leaking from on top.

Now I still have three outstanding issues to deal with:

1. Oil temps seem fairly high (240-ish after 15 minutes of driving, with ambient temps around 80). I can see a freshly rebuilt engine having tighter tolerances contributing to higher temps. Anyone have thoughts on that?

2. Can won't idle cold. Idles too low to the point of stalling until head temps get over 240 or so. AAR is working. Need to figure this out best I can.

3. Exhaust leak, probably at heads. Need to redo these, and it may be part of my issue(s) above. Not sure I trust my AFR readings at idle if I have an exhaust leak.

Thanks to Len and everyone else for thoughts on this (IMG:style_emoticons/default/beer.gif)

[Superhawk996]

Try this trick for item #3. Anneal the copper exhaust gaskets for a better seal.

Heat to dull red with torch, drop in water. Now you have a dead soft copper exhaust seal that will deform nicely to the heat exhanger pipe. Still need to make sure pipe mating surface is reasonably squared and snugged in all the way but soft copper seal will help a bit.

Don't go crazy over tightening the exhaust studs trying to pull a poorly fitting or cocked heat exchanger flange home. That doesn't end well. Ask me how I know. (IMG:style_emoticons/default/headbang.gif)

[Superhawk996]

On item #1, oil temp gauge or temp sensor could be offset by 10F or more degrees.

IR temp check the case sump immediately upon shut down as a 2nd check or if you have access to a Fluke thermocouple reader, I'd drop thermoucouple down the dipstick tube into the oil to get a 2nd data point to check the gauge accuracy.

[BeatNavy]

Try this trick for item #3. Anneal the copper exhaust gaskets for a better seal.

Heat to dull red with torch, drop in water. Now you have a dead soft copper exhaust seal that will deform nicely to the heat exhanger pipe. Still need to make sure pipe mating surface is reasonably squared and snugged in all the way but soft copper seal will help a bit.

Don't go crazy over tightening the exhaust studs trying to pull a poorly fitting or cocked heat exchanger flange home. That doesn't end well. Ask me how I know. (IMG:style_emoticons/default/headbang.gif)

Good stuff, yes, thanks. In the past I have annealed the rings with good results, but I did not do that this time. Don't ask me why (ok, I was "in a hurry"...to do it half-assed). I did the shop vac blower test which has also worked for me in the past. Sure enough, HE on 1/2 side was leaking big time. Waiting for new exhaust nuts to arrive.

On item #1, oil temp gauge or temp sensor could be offset by 10F or more degrees.

IR temp check the case sump immediately upon shut down as a 2nd check or if you have access to a Fluke thermocouple reader, I'd drop thermoucouple down the dipstick tube into the oil to get a 2nd data point to check the gauge accuracy.

Good idea. Buying an IR thermometer now.

[Superhawk996]

Good luck! If heat exchanger 1/2 was leaking a lot, that is dumping 1600F exhaust gas right out onto your heads and could help explain the elevated oil temp a bit.

Keep us posted. Don't give up! (IMG:style_emoticons/default/beerchug.gif)

[BeatNavy]

Ok, small update. It took a frustratingly long time to get proper exhaust nuts shipped to me. Got the 1/2 side HE installed again after annealing the exhaust rings. Before tightening the nuts up, I tested again with the shop vac technique. I think I'm good with no leaks now.

Took it out for spirited driving. It runs great, although I'm still hearing what I think is detonation under hard load between 2800 and 3200 RPM. My variable timing light is giving me fits -- it won't fire, so I'm using the standard timing light which makes it harder to determine where timing really is (anyone else have issues with a timing light and 1-2-3 distributor?). I'm already running premium fuel with CR calculated at 8.6. Maybe it's something else rattling.

Oil temp hit 240+ on my gauge with ambient temps at 90. Although I did buy an IR thermometer. Pointing it at the tuna can sump and it read more like 200+ degrees. It's possible I didn't match the sending unit to the gauge correctly even though I tried to. Should I trust the IR reading more?

Lastly, oil leaks are better, although I've got a persistent one that seems to be coming either from the oil filter console or the pressure relief valve. I think I need to reinstall that sealing ring and tighten it up to see if that relieves it.

Cold idle is still non-existent. Need to work on that too. Maybe try a different AAR although I know the one I'm using is at least mostly functional.

Progress, but it takes a ton of time to fine tune this bugger!

[Frank S]

Progress, but it takes a ton of time to fine tune this bugger!
[/quote]

Went through this with two different engine combos, latest with same combo you are running.
Much easier and faster if you measure what you adjust.
If you hook up a vacuum gauge, using a T-Piece in front of the MPS and route the hose to the gauge, it's pretty easy to adjust the MPS, as you can clearly see in which region you are running (part load, transition, or full load).

Tune for drive ability first, then start to play with idle settings (ignition timing and maybe recalibration of AAR)

[BeatNavy]

Thanks, Frank. Good points. The knocking/detonation thing is perplexing me a bit. Tried adjusting the MPS a little richer at WOT to see if that would help, but there was still some under heavy load. Still need to fiddle more with timing, I guess, but I either need to fix my advance timing light or buy a new one. Also entertaining buying a cooler range of spark plug. Anyone have thoughts there?

Good news is oil leaks are significantly better, and the engine gives nice power - a lot of fun to drive (IMG:style_emoticons/default/driving.gif) and the weather is looking NICE for the next few days.