I'm not understanding the ring sealing argument, and have a nasty habit of wanting to understand. I am not an experienced engine builder, but do understand Physics and Engineering. My initial assumption would be that a higher pressure difference (combustion, now plus vacuum) between the cylinder and the sump would increase the leakage. Could you explain how the better sealing is achieved?

 

I would guess that one nut came off completely first. Perhaps the other nut started loosening, causing the bolts to bend and the big-end to break. Pure speculation though.

 

I've considered that.

From what I know about the internal combustion engine, a connecting rod with a nut loose or off would survive for mere seconds.

The bearing clearly failed....the crankshaft was worn about .100"....which didn't happen in just a few seconds. I'd guess that the pounding an distortion of the rod made the nuts come loose. Just a coincidence that they both ended up off at the same time.

 

The difference between you and me....you have to go onto the internet and search for answers. You have to call people and ask their opinion.

I simply refer to my own experience, my own logic, the engines that I've had apart, and the pieces that I have laying around my own shop.

 

I approve of trying to understand things! If this stuff can't be explained to someone with solid high school physics knowledge, the person doing the explaining probably doesn"t know what he's talking about. Below's how I've understood it to work out.

Here's what I believe is going on. Without a pressure differential between combustion chamber (cc) and crankcase (ckc) the only thing pushing the rings to the cylinder wall is the ring tension. That's not much. Luckily, when cc has higher pressure than ckc, the following thing happens (with exceptions below). The pressure first pushes the ring to the bottom of the groove. This exposes the top of the groove and, importantly, back of the groove and the ring, to the cc pressure. This pressure behind the ring is the reason why the ring seals, you have the whole cc pressure pushing the ring to the wall. The ring tension alone would be totally insufficient.

Why does ckc vacuum improve ring seal and reduce blowby? The piston ring makes it to the bottom of the groove quicker if the ckc has a lower pressure.

At high rpms, the tdc deceleration is an important force trying to pull the ring up. When the cc to ckc pressure differential is not large enough to offset the ring inertia, we get ring flutter (and blowby). Apart from the ring material, for conventional shape (not dykes) ring, one of the main determinants of the ring flutter critical rpm is ring width (a lot of other stuff cancels in the formula). Another is cc to ckc pressure differential. That's why lowering ckc pressure increases ring seal at high rpms - the faster ring sealing effect is much larger than the direct pressure differential effect on the blowby flow.

 

My thinking is that the failure mode of the R1 rod might be pulling up, rotating, deforming the bore, and bending the rod bolt.

Suppose that the rod bolt is held tightly to the cap with friction. Suppose further that there's some resonant or whatnot condition that starts rotating the bolt (not nut) at every cycle and at the end of each cycle bends the bolt a little more (or deforms the bolt bore in the rod a little more). This could lead to a situation in which the rod bolt slowly pulls out but the bind due to bolt bending (or bore deforming) keeps the rod cap on relatively tightly while the process goes on. Then, at some point the rod cap parts from the rod, bearing clearance grows dramatically, bearing spins, and the engine fails. A theory.

 

Greg,

Replacing the valve stem seals was done at the request of Joe to make your system work.

What you're saying is that every 300-400 miles he should take out the filter and clean it so that your system can work. I've tried to clean a few of the ProVents, the filter is a royal pain to actually get the oil out.
We spoke about this before changing the valve stem seals, why didn't you ask me to take a picture and show you then? They were off for roughly a week?
How about this then, I will recreate what I saw in pictures and will post them right here for all to see. That way, you can tell me if they were installed incorrectly. Or maybe, if there is the possibility for them to be installed incorrectly, it's because you need to supply those who buy your "kits" better instructions so that they cannot be incorrectly installed.

Now you state that you have 40 years experience, and that you only have to refer to your own experience and logic, while I go to the internet and call others to get their opinion.
But then again, previously you stated you called GZ motorsports and it was their statement that made you decide not to go down this path.
Which is it, as one is a lie?

The fact of the matter is that regardless of what books I read, what I find on the internet, if I am contemplating something different or new, of course I am going to contact other experts in the field who are doing this to other engines to see what pitfalls they might have seen. Other failures possibly encountered. Only a fool would believe that he would know all because he's been working on mostly a single engine for a number of years. It doesn't matter who you are, or how much experience you have. When you are looking at something new, you should always consult others (if there are any), who have been using the equipment, or doing this to other engines to prevent making costly mistakes.

I did my research before, and did not come across even one little bit of what you are referring to regarding increasing wrist pin to clip distance, or increasing bearing clearance with any reference to vacuum in the sump. Not one document/book I've read, nor one piece of information online, nor one pro engine builder I spoke with stated any of these would be needed at all.

It was however noted that at higher vacuum leaves (20"+ Hg) that most engines likely need modifications to the wrist pin oiling. Some notch the rods as shows before, others install a piston squirter like the early 87 S4 blocks had. But not one of them stated that at the lower vacuum levels I run they would even consider it. However I am still not going to be a fool, I am contacting a number of these people again to get direct answers regarding what you have stated from industry leaders and will report them back here.

As to your "kit" pieces helping my system, not really a chance on that. The oil goes in the valve cover, not out, so the baffles under there will make no difference. The baffle in the oil filler neck MIGHT help to extract a slight bit of oil from being lifted into the neck, but all this will do is to remove a small amount of oil that the separator has to separate. I have run my car without this baffle and have less oil being sucked out than Joe's car with it.

 

Colin:

Clearly you and I have a difference in opinion.

I'm not sure what you think you have to gain by continuously biting at my heals like a tiny dog and wish you would just stop!

You are not going to change my experience or my mind. I'm clearly not going to help you with your research. I'm clearly not going to tell you what I know and why.

Pretty simply, I think that you did not have my best interests in mind, and at best, did nothing to help my system function. Stating it was too hard to clean the Provent filter element is priceless! 30 seconds in a jar of solvent and an air hose is all it takes!

Whatever. What has happened is done. The past is difficult to change.

The future.....that can be altered!

I feel that you have inadequately researched, thought out, or tested your system. I believe it will do severe engine damage.

I feel the exact same about your internal transmission spring, BTW.

Like I keep telling people.....more of these cars need to be turned into junk, be blown up, or burned for the rest to be really, really valuable.

And I'm absolutely positive that your efforts will be appreciated, in the future!

 

Ok so July 18, 2012 Greg posted about this "kit" here https://rennlist.com/forums/928-foru...ation-kit.html

First attached picture is of Greg's kit. He however purposefully leaves out a few parts.
In there you see two valve cover elbows which have been drilled out so that they have no restrictions. The two factory ports which are already on the valve covers get drilled out to the same size as these two.

But before you drill them out, you will remove the tube which is on the one elbow shown in attached picture #2.

Then picture 3 shows the 4 factory posts which you are to drill and tap. The factory rib which sits between those two posts gets a little material removed so that you don't get a puddling between the posts (the fraction of a millilitre that would be).

Picture 4, shows how the supplied plate is to be installed. There were 4 plates and these get installed below each of the 4 valve cover outlets.

Now I did not install his kit. I simply had the covers off doing what Joe had requested in an attempt to make his system work. And gave Greg the details of what I saw when I had it off.
According to an email from Greg the 4 plates below the cover outlets should 100% remove all oil from the air leaving the covers. Yet he does add a ProVent for some reason after these......

I will be back down to the shop tomorrow and can quickly whip up a plate like his, which I will then bolt on to the back of the valve cover and take another picture if anyone still does not understand how his plates are supposed to mount.
But I really am not sure how he expects a shop to really mess up the install of those covers which would prevent his system from not working........

Or alternatively he states that you can pull out the filter and clean the filter every 200-400 miles, maybe even less if you really don't want to end up with a puddle of oil in the intake. And that it might take time for the system to work out as it has taken 20 years for the car to build up to this oil consumption (even though there are many records of engines having this oil consumption as they left the factory).
All this can be yours for the low low price of $1,695.00 plus shipping!!!

Feel free to point out how the under cover system has been sabotaged Greg, or how the other shop did not follow your instructions for the installation.

 

To my knowledge you have this correct, the one thing I have to add supports this, that is the types of drillings added to various race pistons. In drag racing you get vertically or top drilled pistons where say ten holes are drilled into the top ring land. These holes block up quickly and that is fine for drag racing.

The other style is lateral drillings, this is used in NASCAR, not quite as effective but because they are drilled on the side at the top of the top ring land they don't block up so quickly as such suitable for longer races.

Then the other piston mod that is commonly used to deal with combustion gas pressures is the so called "accumulator groove" this is between the top and second ring land and is there to reduce ring flutter.

 

Add up the price of all the pieces, *******. See if you can build it for that.

 

An observation by a bystander: Almost hundred kits sold by Greg Brown according to his post. Colin quotes $1695 for the price. That's almost $170k in revenue. That's if not good profit at least very good revenue, if my naively taking all these numbers from this thread is right.

Greg "the other Greg" Gray aka "slate blue": I think they have done away with the lateral gas ports in new pistons now, where they can hold the groove to the exact spec and can design the pistons to expand evenly. Those lateral gas ports are really useful in less well designed pistons where the groove may be close to binding or some other unexpect piston distorion happens. But since you know more about this, please tell me if I am correct. (Did you post the above from the pits during the race? Can't keep track of the time zones.)

 

I was certainly writing some private emails at the track, however I never got to the actual F1 race, I had one of the best seats too I got and I am writing this email one eyed, wiped out by a dust storm and ended up at the emergency dept with what felt like gravel in my eyes. So I won't be welding any inconel headers any time soon.

With regards to the lateral gas porting, I believe they are still using them.

I am away so I can't access my technical publications, however if we are talking in the last 5 years or less? We can simply look at EBay,

http://www.ebay.com/itm/NASCAR-TOYOT...282d6d&vxp=mtr

http://www.ebay.com/itm/NEW-NASCAR-C...231da1&vxp=mtr

These pistons both have them and both are recent engine types, the TRD and the R07, the thinnest rings I have ever heard of is 0.6 mm and the above pistons are using 0.8 mm and 0.7 mm and the 0.6 mm ring may only be for the restrictor plate races? Again I would have to check.

A interesting development in pistons comes from Capricorn, they have a very new skirt design which lowers the skirt in relation to the ring set but doesn't add extra material which would add weight and friction. Apparently it adds to stability and their alloy is very advanced too. They claim, the strength of 2618 with the low expansion, low wear characteristics of the 4032. I will look into this for my engine.

 

Back to the GTS wrist pin thing- I found my bucket of parts from that engine today in the storage garage, here are the wrist pins from the 4 pistons I didn't throw away. The two in the foreground were much harder to tap out of the piston, the two in the background were much easier. I'll leave it to the forensic metallurgists to read the tea leaves.

 

If you look at the kit there are many Porsche parts, the Mann+Hummel parts and some custom made parts. Substract all costs for those. Pay overhead, other expenses, substract depreciation, R&D costs, pay interest and taxes. I think you can make more money supplying parts then you can making kits.