95 replies to this topic

[Danny Steyn]

Here is my contribution to the off-season discussion that is sure to get the opinions coming from all directions…..

Before I jump into this topic I am sure some of you might have figured out that there was some tension leading up to the runoffs between Drago and myself, but I am glad to say that we have put that behind us and moved on.

However I am definitely not in Drago’s East Street camp and this is NOT to be interpreted in any way as anything to do with what happened at the runoffs. That championship has been won.

This post is about looking FORWARD to make things more transparent in the tech shed for ALL dumb racers just like me.

The reason that I bring this up is that Jim brought a cylinder head and some NEW test tooling to the ARRC to show a possible new approach to cylinder head testing to make sure that the head measurement issue that happened at the runoffs does not happen again to ANYONE.

The cylinder head that he showed to Mike Rossini, Jeff Labounty, Alex Bolanos, SCCA tech, and myself was prepared as follows

• 2 cylinders were bone stock (no machining whatsoever)
• 1 cylinder – machined to slightly under the spec ( .005 under)
• 1 cylinder – machined slightly over spec (.010 over)

The 4 NEW test tools (not the ones used at the Runoffs) that Jim brought were prepared by a machinist, and as a qualified mechanical engineer, IMO they were simple and well made, and they tested the plunge cuts and the relief cuts for both exhaust and the intake valves. The idea is to produce these tools and have them available to ALL engine builders, prep shops, concerned drivers etc. I did not take a micrometer to check, I just took Jim’s word that they were made to the correct size.

The test is simple - if the tool drops into the cavity the cylinder head is a FAIL. If they don’t drop into the cavity the cylinder head is a PASS.

Real simple, you would think ……… well not so much!!!!

What was fascinating to me was that depending on how you use the tool, EVEN the new tool that Jim showed us can produce completely different results.

If you let gravity take the weight of the tool down, and the tools do not enter the cavities, then the head passes, and Jim demonstrated the tools passing the test on all aspects of the two untouched stock cylinders. He then showed that with a gentle push, the relief-cut test tool would fail the 3^rd cylinder machined just under the spec (.005 under). On the 4^th cylinder the test failed all aspects – the tools fell into the plunge cut cavities and the relief cut cavities, an obvious FAIL.

So here comes the part that Jim did NOT expect. Based on what I saw on the 3^rd cylinder, I took the tool myself and confirmed it myself, and then just messing around I found that I was ALSO easily able to gently push the test tool into the cavities on the two UNMACHINED STOCK cylinders with little to no force. You could tell from the look on Drago’s face that he had no idea that the relief cut would fail on the stock cylinders on this head.

So ………… if I was the guy doing the tech and I pushed in the test tools that were provided to me, I would have failed the stock head, NO QUESTION! If someone else had used the same tool and let the tool fall under its own weight, the head would have passed.

In my opinion all test tools must allow ZERO room for interpretation, so even these new tools raise some questions, or the specs need some reworking.

So here is the dilemma. There are for sure going to be some BONE STOCK cylinder heads that fail this test based on the published specs we have for our engines. However, if we all have access to the same tools, we will, or our engine builders will measure the stock head like this one, and reject it even before we or they start working their magic.

But from what I saw, I personally think there has to be some re-investigation on the dimension spec for the relief cuts as it worries me that this dimension (not sure how it was decided on) is going to put many existing engines in the FAIL category.

Jim – if you can, I suggest taking some pics of the tools themselves and the tools in the cavities showing PASS / FAIL conditions and even doing a simple short video with your phone and uploading to YouTube so others can see what Mike and I saw this weekend.

I think Drago is going in the right direction with the tools, I just think the spec needs some consideration based on the variation in stock engine specs. Bye the way there are absolutely stock untouched engines that will NOT pass the plunge depth dimension too, there is that much variation in mass production.

If there are any others out there that have a better idea or some ideas for improvement, our class will be most appreciative. And I take my hat off to all the contributors like Drago, Wheeler, Collins and others who selflessly contribute so much of their time to make this class, without a doubt, clearly the best place to go racing!

[Mike Collins]

Danny, thanks for the post! You are correct a lot of the testing lies in the hands of the tech inspector. This is where some of the problems come in and some level of understanding are needed.

So... Theoretically when matching all 8 valve seats, ports, relief cuts, etc... you make the cut with same cutter head. You are correct that it is possible for a stock location to fail, but it so unbelievably unlikely that all 8 would fail. This where the tech inspector needs to understand how to test for this. When using the test, it should be pass/fail. Not each port, but each side of the head I / E... If one of 8 fail but the other 7 easily pass you are looking at a machining anomaly, likely from the factory or casting. If two or more fail it may be a signal to look closer at the head since the Pass/Fail tool has some margin of error built into it. If the rest are on the edge it may require a measurement because some builder elected to push the rule too far.

Thanks to Drago for building the first set of sample tools. We are actively exploring how best to implement them and make them available for purchase. Please feel free to share here as this process is on the fast track so we can all get on the same page for 2013, with all engine builders building to the same TESTABLE spec.

THANKS!

[FTodaro]

Danny I saw the same head and tools that you are talking about.

My first comment is that the relief cut, the cut around the outer edge of the valve seat, if it were 1/1000's of an inch to big for example it would have absolutely no affect on performance. If your saying that the spec of the stock head is manufactured in a way there there is slop meaning that in mass production they do not get it down to the last 1/1000's of an inch cut then I think the only fair way to deal with that variation is to have the tools made such that they allow for x. 1000's of an inch over, so that a fail is a clear fail of the spec and not just a machining or manufacturing variation.

In other words a failure is a clear failure with some intent behind it.

Otherwise folks with stock heads could be busted just because they did not spend money getting all that checking and tooling done.

In My mind these rules should do 3 things,

1) create a method of measurement to develop a spec limitation, that eliminates manufacturing variations.

2) the spec limitation should be to prevent a competitor from obtaining a competitive advantage

3) to punish a person who is intentionally trying to gain advantage. Must be clear and convincing that it was a manipulation.

If you cannot do all 3 above then its not a good rule or system to enforce the rule.

[Caveman-kwebb99]

I for one think the coment that many stock heads will fail this tech inspection is funny, while that statement is very true, what competitor at the runnoffs is running a stock head? The fact you even mention that will scare the hale out of every mid pack guy racing in their local region, IF YOU ARE RUNNING A STOCK HEAD... YOU WILL NEVER BE COMPETITIVE ENOUGH TO GET TORN DOWN, therefore by default you passed the tech shed with your bone stock head.

I am not sure how to best handle this tech issue and how in the world could you ever account for every variation that could possibly be in a valve guide? I think MIke said it best the tool is not a pass/fail it is an instrument to cause one to look further into a cylinder head after this tool gives him reason to do so, the old tool for that matter does the same thing, the problem is the Tech person needs to be trained on what he is really looking for, and I have no idea what the mechanism for doing just that is????

[Bench Racer]

So ………… if I was the guy doing the tech and I pushed in the test tools that were provided to me, I would have failed the stock head, NO QUESTION! If someone else had used the same tool and let the tool fall under its own weight, the head would have passed.

In my opinion all test tools must allow ZERO room for interpretation, so even these new tools raise some questions, or the specs need some reworking.

Having not viewed the tools is it safe to presume the new tools (thanks Jim/Sam/whoever)are similar but improved to the existing SCCA shaft & flag tools.

Did anyone take a bore gauge & measure the inside diameter of the valve guides of the Jim head?

Were the inside measurement of the valve guides measured at 90* one measurement to the other as is specified in the FSM? (Looking for a round or oblonged hole.)

If someone did this measurement what were the measurements?

What is the measured diameter of the flag shaft which slides into the valve guide?

IMHJ, we need to exclude a tech inspector from the measurement part of the process.

Can we presume that by the process of valve seat grinding that the valve guide/valve seat are concentric to each other within a Nats arse.

As Danny mentioned, if some pictures of the tool/Jim head were posted more people could throw out their thoughts.

[Jim Drago]

First off, I made these tools for my own benefit, at my cost, this has nothing to do with the SCCA at this point. I plan on using them whether SCCA adopts them or not. All of these tools are made to check our heads.. They are all made intentionally .001 under the spec. They did not work as clearly as I anticipated. The throat cut tools work perfectly. The relief cut tools leave too much to interpretation imo. What tech is checking the hardest is the corner of the chamber. In many of the cuts, the tool fits in he corner, but covers up the other side of the cut. The relief cut tools IMO are not something that I would feel comfortable using. IMO, the only way to make these tools is too make all 16 holes .003 over the current spec or any arbitrary number over, then make a tool similar to these that does not drop in any of the holes.By guesstimate, that tool would need to be about .008-.012 larger than the spec. This round tool takes the guide play out of the equation for the most part.
The SCCA tool is similar, but the stem is thinner and fits with a little more slop when in the guide. It is not round, but a flag.

Here are some pictures of what Danny is talking about
Jim
http://s307.photobuc... tool pictures/

[Dan Tiley]

Danny... thanks for starting this topic, as I think it's an important one.

Here's another one that I see not very often, but every once in a while....

Rule 9.1.8.f.4: Maximum Throat Depth (from bottom of ferrous valve seat) (millimeters) = 9mm

This photo is from a low mileage completely stock head that has not even been cleaned yet. Both intake valves in this cylinder shown (as well as one other pair not shown), have factory throat machining marks that extend to nearly 11mm below the bottom of the steel seat! No matter what I do with this head, it is non-compliant before I ever make the first cut, and there's nothing I can legally do to bring it back to compliant. With 99 core engines becoming more scarce, I don't have alot of options here. Do I scrap this head, knowing that this head will never make it though the tech shed of any major event?




My thoughts on the Go, No-Go gauges are simple... these gauges need to be significantly oversized (relatively speaking, say ~.010" diameter for unshrouding tool that Drago showed photos of) such that a trained monkey could use them, and there's no interpretation. Will builders exploit these allowances? Of course they will... but the advantage of doing so typically results in performance gains that won't even show up on a dyno, and always at the risk of being bounced at a major event.

NASCAR has a pit road speed that is monitored with electronic scoring loops, and they give a 5 MPH allowance over the posted speed, which can be significant. Do driver's push this limit? Absolutely, but when a driver is caught speeding, and they often are, there is absolutely no wavering, wheeling or dealing. There's no question that the driver was at least minimally over the limit, and the penalty is handed out.

--Dan
www.TiSpeedEngineering.com

[Danny Steyn]

It appears to me that while the guys who came up with the Specs were very well intentioned, there is quite a bit more variation in the stock castings that we might initially have suspected. However I am sure that they said to themselves that these specs should be good for 95% of all the engines out there, and we cannot write a spec that will handle 100% of irregularities found in production castings, and having produced both aluminum and bronze production castings in a previous life I fully understand how much variation there can be.

• Dan - as the rules are written - that head is absolutely a FAIL and IMHO you don't use it for your customers that are likely to be teched. There are no doubt many heads similar to that one running around in SM races around the country!
• Dan - I like your logic, but I think it should be VERY clear - yes lets make the testing tools for the PASS/FAIL test slightly larger than the spec - you guys on the SMAC decide what that is based on the stock castings you see. HOWEVER - DO NOT change the spec AT ALL. If the pass/FAIL test says it passes, but it appears that there is machining beyond what the spec allows, then there must STILL be the protocol to FAIL that engine,

So here is my UNTRAINED NON ENGINE-BUILDER opinion on that head that you show above ...... with a tool that is slightly oversize, it might PASS the tool test, but when someone notices the plunge cut machining below the 9mm mark, the rule must be sufficient to FAIL that engine.

I absolutely DO NOT WANT to see all the nationally competitive drivers (and other drivers with money) having to pull out their engines, shipping them off to their engine builders because we have moved the bar even further, and believe me if there is ANY gain to be had by increasing the spec in any way then drivers will be doing this and engine builders will be selling that service, none of which helps this class, no disrespect intended.

[High Chair]

A lot of info here and it will take some time to digest; however I think the discussion is on the right track.
Danny thanks for starting this thread.

[Bench Racer]

Thanks Dan for the wider view of what occurs with an OEM head. More info is good as is said or is more info dangerous.

Danny, I like this "UNTRAINED NON ENGINE-BUILDER" because I am only learning about Miata engines, I'm a retired _ _ _ _ _ _ _ _.

With the info we have from statements from folks who have viewed the head/tools/Jim photos or who have not touched the tools lets hear some root causes for the (no disrespect) unexpected gauge results.

From my perspective during test, the head or the tool didn't change other than the different relief cuts.

What may be the root cause for a good relief cut to fail when Danny applied a slight finger load to the tool?

Bent the tool stem?

Tool stem fit to valve guide inside diameter, tool wobble excentric, tool enter OEM or undersized relief cut?

A easy process to prove or disprove the two above items would be to use a gauge pin to check the valve guide inside diameter hole for a finger push fit. Make the checking tool flag to have a hole that hand tight fits the gauge pin and use a known dead weight on top of the tool.

Or make a new gauge with the gauge stem being the same size as the gauge pin and insert tool into valve stem hole with a known dead weight on top of the tool.

I understan tools cost money and it's not my money. I also understand the KISS principle when designing tools.

There are a couple other slightly more sophisticated relief cut tools that come to mind that could be discussed.

[Jim Drago]

It appears to me that while the guys who came up with the Specs were very well intentioned there is quite a bit more variation in the stock castings that we might initially have suspected. However I am sure that they said to themselves that these specs should be good for 95% of all the engines out there, and we cannot write a spec that will handle 100% of irregularities found in production castings, and having produced both aluminum and bronze production castings in a previous life I fully understand how much variation there can be.

• So here is my UNTRAINED NON ENGINE-BUILDER opinion on that head that you show above ...... with a tool that is slightly oversize, it might PASS the tool test, but when someone notices the plunge cut machining below the 9mm mark, the rule must be sufficient to FAIL that engine.

I absolutely DO NOT WANT to see all the nationally competitive drivers (and other drivers with money) having to pull out their engines, shipping them off to their engine builders because we have moved the bar even further, and believe me if there is ANY gain to be had by increasing the spec in any way then drivers will be doing this and engine builders will be selling that service, none of which helps this class, no disrespect intended.

Danny
After 2009 the class wanted specs. A lot of time was spent by Jim Stewart and myself coming up with these specs. The specs are IMO where they should be even though they almost bit me in the a$$. I don't see any need to change the specs, we just need a better method of enforcing them. As for Dans head, sad but true, that head better never see a tech shed or it is done. That is nothing new, ALL of us have had heads that were cut too deep here and there. When we presented the specs and said that this could and would happen, many snickered and said yeah sure...
As we said in Atlanta, I am fine with untouched heads failing <5% of the time. If you calculate the chances of one of those heads being installed in a engine capable of winning, in a car car capable of winning driven by a driver capable of winning it is under 1/4 % or so IMO.

We will come up with a fool proof method before next years Runoffs, but IMO, there is no need to change the specs. If all the engine builder have idiot proof tools ( like the throat cut tool) a non compliant head will either be intentional, built before the tools were available or so totally careless. I think all want the same thing, a simple way of knowing that their car is compliant. IMO I would rather 10 people get away with .005 over in any of these dimensions than have to go through what I did. The advantage of that in every cylinder, in every cut in not measurable on the dyno IMO.

The head shown is a 1.8 NA head, for the record, I have looked at a few 99 heads and the relief cuts in the few I looked at are smaller? 99? Luck? Not sure. We randomly picked this head as it was warped and not usable, so we cut up on it.

[Bench Racer]

As was said previously I am only learning about Miata engines.

BlueSkying:

What is the length of the press fit for the valve guide in the head? Is it possible that with the tool stem inserted that the valve guide fit to head along with some tool stem to valve guide I.D. clearance along with the unsupported length of the tool stem could let the tool wobble sideways so that the tool failed on a legal relief cut?

Back under my rock.

[Dan Tiley]

I think all want the same thing, a simple way of knowing that their car is compliant. IMO I would rather 10 people get away with .005 over in any of these dimensions than have to go through what I did. The advantage of that in every cylinder, in every cut is not measurable on the dyno IMO.

My thoughts exactly.

[Danny Steyn]

Regarding the questions related to "tool wobble" due to the tool stem being undersized relative to the valve guide, IMO this was NOT an issue for this head. The tool ft snugly in the valve guide and in many cases I suspect that it would NOT have dropped under its own weight unless some really thin lube was used. The tool needed to be pushed down in the valve guide, so the question of how much force is needed is what raises these questions.

As to the questions of any gains to be made in the 0.005 over on the relief cut, I have no idea if this is zero or not. We jsut want to avoid ANY of us being thrown out over an incorrect use of a tool, a poor tool design, or the misinterpretation of a rule or spec. It needs to be cut and dried, with zero room for interpretation.

I like Dan's logic (NASCAR) - build the tool to an arbitrary oversize spec. THEREAFTER, if even one valve fails the tool test - YOUR OUT - No wiggle room, no interpretation. ZERO - we all know there is some safety built into the tool. Feel free to exploit that additional dimension if you feel it is worth the risk, but if you fail even one valve then you are out - no excuses about the head not having enough time to cool down, no excuses of worn valve guides, no excuses of how much force the tester used to push the tool down..........

[George Munson]

The only comment I have is that the "Spec's" or "Tools" need to account for manufacturing flaws. There are a lot of racers who simply go to the Junk Yard or use the engine that came with the donor car. I wouldn't want to mandate those guy's pull the heads of a perfectly good running stock car to go racing. This adds unwanted costs to those who have limited budgets. Just my 2 cents.

And "Thank You" to all who are working on this issue.

[Mike Collins]

The only comment I have is that the "Spec's" or "Tools" need to account for manufacturing flaws. There are a lot of racers who simply go to the Junk Yard or use the engine that came with the donor car. I wouldn't want to mandate those guy's pull the heads of a perfectly good running stock car to go racing. This adds unwanted costs to those who have limited budgets. Just my 2 cents.

And "Thank You" to all who are working on this issue.

George, while I truly understand your concern. How may cylinder heads do you know that were removed this year in the entire country? To the best of my knowledge only 4 were torn apart to this level of a tear-down and inspection. That includes both NASA and SCCA. I very seriously doubt someone running a stock head would EVER be torn down to this level. That means 2,496 SM's should not worry.

So if you are running a "stock" part you are good to go. What we are talking about should not put the fear into any of of our home built cars running stock motors.

[FTodaro]

George, while I truly understand your concern. How may cylinder heads do you know that were removed this year in the entire country? To the best of my knowledge only 4 were torn apart to this level of a tear-down and inspection. That includes both NASA and SCCA. I very seriously doubt someone running a stock head would EVER be torn down to this level. That means 2,496 SM's should not worry.

So if you are running a "stock" part you are good to go. What we are talking about should not put the fear into any of of our home built cars running stock motors.

Mike I do not mean to hijack Danny's Thread but I have a sort of related question.

I was one of the guys at the NASA nationals that had a shock removed for testing. My shocks were 3 years old and I am sure not up to spec of new. I was worried that my "old" shocks would fail the test. I assume at some tracks a softer shock could be viewed as an advantage.

I do not claim to know the shock standard or what is being looked at but along the lines of George's concern, could a well used or warn Shock fail the shock dyno. We do know that many more shocks are tested than Heads????

[Bench Racer]

The cylinder head that he (Jim Drago) showed to Mike Rossini, Jeff Labounty, Alex Bolanos, SCCA tech, and myself was prepared as follows

• 2 cylinders were bone stock (no machining whatsoever)
• 1 cylinder – machined to slightly under the spec ( .005 under)
• 1 cylinder – machined slightly over spec (.010 over)

The 4 NEW test tools (not the ones used at the Runoffs) that Jim brought were prepared by a machinist, and as a qualified mechanical engineer, The test is simple - if the tool drops into the cavity the cylinder head is a FAIL. If they don’t drop into the cavity the cylinder head is a PASS.

Real simple, you would think ……… well not so much!!!! What was fascinating to me was that depending on how you use the tool,

EVEN the new tool that Jim showed us can produce completely different results.

If you let gravity take the weight of the tool down, and the tools do not enter the cavities, then the head passes, and Jim demonstrated the tools passing the test on all aspects of the two untouched stock cylinders.

He then showed that with a gentle push, the relief-cut test tool would fail the 3^rd cylinder machined just under the spec (.005 under).

On the 4^th cylinder the test failed all aspects – the tools fell into the plunge cut cavities and the relief cut cavities, an obvious FAIL.

So here comes the part that Jim did NOT expect. Based on what I saw on the 3^rd cylinder, I took the tool myself and confirmed it myself, and then just messing around I found that I was ALSO easily able to gently push the test tool into the cavities on the two UNMACHINED STOCK cylinders with little to no force. So …………

if I was the guy doing the tech and I pushed in the test tools that were provided to me, I would have failed the stock head, NO QUESTION!

If someone else had used the same tool and let the tool fall under its own weight, the head would have passed.

In my opinion all test tools must allow ZERO room for interpretation, so even these new tools raise some questions, or the specs need some reworking.

If there are any others out there that have a better idea or some ideas for improvement, our class will be most appreciative.

With the info we have from statements from folks who have viewed the head/tools/Jim photos or who have not touched the tools lets hear some root causes for the (no disrespect) unexpected gauge results.

Are we continuing to pursue the root causes for the unexpected tool results, without changing the specs?

If so, I will for a second time suggest a root cause for the tool to fail the OEM un-machined cylinder relief is that the tool flexed away from the proposed relief cut surface. To prove or disprove this tool flex, dial indicator measurements will be rquired when taken on the OEM non-machined cylinder from the side opposite the side that one would machine the relief cut. I do not have the head or the tools therefore I can not do the measurements.

Also it is my understanding the tool does not fall from gravity...........

We can re-concept a tool after we find the root cause for the unexpected tool results.

If my understanding is correct there were zero issues while using the tool to check the throat cut if the throat cut was OEM or machined to the maximum spec.

I understand there may be some sensitive issues involved with re-designing/proving an SCCA tool.

[Dan Tiley]

Mike I do not mean to hijack Danny's Thread but I have a sort of related question.

I was one of the guys at the NASA nationals that had a shock removed for testing. My shocks were 3 years old and I am sure not up to spec of new. I was worried that my "old" shocks would fail the test. I assume at some tracks a softer shock could be viewed as an advantage.

I do not claim to know the shock standard or what is being looked at but along the lines of George's concern, could a well used or warn Shock fail the shock dyno. We do know that many more shocks are tested than Heads????

Hey Frank,

The shock limits have a max value only, tested at shaft velocities from 0.5 to 4.5 in/sec at 0.5 intervals for both rebound and compression. Your worn out shocks are good to go!

--Dan Tiley
www.TiSpeedEngineering.com

[Mike Collins]

Mike I do not mean to hijack Danny's Thread but I have a sort of related question.

I was one of the guys at the NASA nationals that had a shock removed for testing. My shocks were 3 years old and I am sure not up to spec of new. I was worried that my "old" shocks would fail the test. I assume at some tracks a softer shock could be viewed as an advantage.

I do not claim to know the shock standard or what is being looked at but along the lines of George's concern, could a well used or warn Shock fail the shock dyno. We do know that many more shocks are tested than Heads????

Your shocks tested EXACTLY the same as the new ones. no degradation in performance from new.