What did Mike Jones recommend?
Go with that.

 

FYI.......when I pulled the heads, I found the intake gasket that was installed was an AFR 6900. That gasket is for the STREET 195 heads and is smaller than the AFR 6901 gasket, which is the correct gasket that should have been installed on the AFR RACE heads that I have. Since the gasket is smaller in height.....some of the sealing material would be exposed to the intake tract....and with less sealing surface where it should have been, so NOT sealing as it should have been. This mistake added to the overported intake manifold would clearly increase the likelihood that the intake was sucking oil, and a vacuum leak, especially on the intake manifold side of the gasket..

 

To give Mark the benefit of the doubt, is it possible that this was done intentionally to make up for the badly-milled intake (or heads) from the previous builder?

Doesn't matter now. Everything will be new, and better!

 

A couple of things I have learned after days of studying and talking to several people:

- Desktop Dyno computer programs are not accurate......Mike Jones says they are not accurate, same with Gkull..and others. And....I plugged the Mark Jones engine into DD,.....and the volumetric efficiency shown on the program was way less than 100%.....although...I could have done something wrong in the program.... Leigh....what are you showing on DD for VE on the Mark Jones engine? Is DD correct....or is the dyno results I got correct?

- Actual dyno results are not necessarily correct.....as they can be manipulated, intentionally or not. I remember this from years ago on Harley dyno discussions. I have been told that the numbers on the dyno runs on my engine are too optimistic. My engine was not dyno'ed with Marks dyno....as he had not yet had his own dyno set up after his move from Colorado to Texas....this was done by a dyno shop in his local area.

Since I really don't care about numbers......neither of the above matter, and they are nothing more than tools for relative comparisons.......but if it is true that there are not accurate, then my biggest question now is whether the actual torque gains that are being presented in DD with a lesser duration cam at lower RPM's are actually real. If Jebbysan is correct that the Mark Jones cam 234/238 combo as built will only LOSE torque with any smaller cam......then this makes the DD info wrong. I think his point is that the actual build combination, with the right heads and the right cam.....will actually raise the entire torque curve to a higher point than the smaller duration cam increases the torque. THAT would make sense to me if that is all true. The missing piece is WHAT are the torque values of the Mark Jones engine as built....below 4500 RPM. If I had those real numbers, I would have the answer. It also explains why so few people choose smaller cams........I can't find anyone on multiple forums who are choosing small cams like I am considering in a 406. The increases in torque with the lower duration cams are really very small....and it would not take much of an increase in the torque curve, with a bigger cam.....to make it a wash. This really matters.....because this is the crux of the whole entire discussion. If DD is not accurate.....is it even accurate with this torque gain.....theory versus reality?

On the other hand......Mike Jones spec'd a 220/224 cam after I exhaustively told him how I drive my car and what I want. And when I spoke with him yesterday about choosing his 224/228 cam instead, he told me that he feels the 220/224 will produce a better result for me, with great low end HP, ....but either will work. His knowledge and experience far exceed mine....so I should believe it.....right? Well....thing is,....I don't believe anything anymore unless I fully understand it. My biggest concern about this 220/224 is the pinging....especially given the large RPM drops this wide ratio 4 speed transmission puts me in.....I don't want to be lugging out of a lower RPM which will equate to pinging and detonation. I just don't think I need to push those limits. I was getting pinging with the first build....and had to limit the vacuum advance. Mark Jones recommend NO vacuum advance for this reason.....even on the bigger cam....!

Thing is......there is a contradiction here. Jebbys side of this does not match up with Mike Jones. I am trying to get to the bottom of the contradiction. If I can get to the bottom of this contradiction....then I can be comfortable with a decision.

Ultimately....I will choose the lower duration because of the improved throttle response, better idle vacuum, better carb signal, better MPG......so I am pretty convinced I want less than the 234/238 Isky cam for those reasons alone. But.......I am not yet convinced about the low RPM power question.

By the way.....I have read enough now to stop calling this a "torque" question......the proper terminology is low RPM power....measured in HP. If you have more torque at lower RPM...you will have more HP at the same RPM....since its math.

 

He didn't mention it to me...if he did. . And just FYI to all......there is zero evidence Mark Jones did any additional porting to the heads. The factory CNC machinining is completely untouched in the ports and in the combustion chambers...as far as I can see. Mark did replace the valves and completed a valve job....so if he did anything special on the seats....then so be it....but I couldn't tell you. I am sure they are very well done. But again....these heads are just the way AFR made them otherwise. They are probably the best in the industry...so no real need or reason to try to improve them.

The first builder decided to port the intake manifold to better match the AFR head ports. Then Mark had to clean up the block deck down to zero deck....which may have created a less than ideal port to port match. I think with the incorrect gasket installed on the overported intake manifold.....resulted in what I believe is obvious evidence of intake gasket leaks....this problem is solved with a new intake manifold and correct gasket. I think that problem is solved....as long as I get a good seal when I install it.

 

I can understand that many folks reading this very long post have become exhausted with all the questions.....but there is a lot to be learned in this forum, and is its purpose. I hope that all of you, especially those who have contributed regularly, REELAVIATOR, JEBBYSAN, LEIGH, GOrdonR, and Mark Jones all are willing to continue to answer questions, and add to the technical discussion. I wish Mike Jones was on this forum...as over on Speedtalk....he regularly contributes. Nobody should be afraid to add to the discussion, ........all opinions are welcome. Some of you have PM'd me, because you ARE afraid to oppose certain viewpoints....I encourage you to not be worried about that....and say what you think. All I ask is that it be respectful, and not personal....which is not useful.

I really want Jebbysan to respond to my above posts.

 

I’ve said this in several posts.
Pick the cam that says it will perform within the rpm range you are looking for.
Run the engine on a dyno and see where it actually makes power in “your” engine, which will probably differ slightly from what the cam manufacturer says.
If you are happy with the results, perfect.
If not, swap in a different cam and run it on the dyno again.
It might cost you some for the other cam and dyno time, but you can fine tune it on the dyno.
That way when you drop it in the car, you’re set, ready and can tear up those twisted roadways.
The cam we chose for my 496 was a custom grind by Crane Cams.
It wasn’t perfect for my engine builder during the dyno tune, so he suggested swapping cams to one which yielded much better mid range results.

 

Thanks OCB...

 

Running it on a dyno will also reveal if there are any other issues going on, like, well you know all too well.
Have a Happy Thanksgiving!

 

You answered your own question:
I believe Mike said it best: "Both of those cams will give you what you want" "he told me that he feels the 220/224 will produce a better result for me, with great low end HP, ....but either will work." Based on: "how I drive my car and what I want."

OCB has a great point. To help you understand it.
All of these thumb-rules, Dyno software and even actual Dyno runs, are just "tools" to assist you.
None of them will give you perfect answers.
There are just way too many variables that go into an engine build.
A real Dyno run is an undoubtably better tool than a software dyno run.
But even they are not perfect.
The only thing you can know for sure is between 2 runs, on the same dyno, on the same day, it differed by "X" HP at "X" RPM.
As OCBs dyno run proved, people get frequently surprised, and make a change because of it.
That happens all the time on dyno runs.
It is very easy to click one wrong button and get totally ridiculous results on Desktop Dyno software. So a lot of people don't trust it. I get that.
But it shows the difference between result "A" and result "B" very well, very quickly, and very cheaply.
Real engine Dyno runs do the same, but they are much more costly. So obviously people do not test as many variables.
Typically the engine dyno "calibration factors" are paid close attention to, but not always.
Even the tune that runs best on an engine dyno frequently needs a change to run best in the car.
That's where the "car dynos" excel, for AFR and timing at cruise, and throttle tip-in response. But they are horrible at peak HP/TQ #s.

DD showed the highest VE at higher rpms, with the 234 cam, of the 3, and the highest VE at lower rpms, with the smaller cams. As common sense would expect. That is where the extra TQ comes from. They do not match the real engine dyno runs exactly, nor would I expect them too. Even two different engine dynos would not match.

By the time my car is complete, I will have used all 3 versions. I changed the cam because of DD after my Dyno run. My engine is going back on the engine dyno for a 2nd time to do some more tuning. Once in the car, it will get tuned again.

 

That's a no brainer unless your building at home and then find a place that has a engine dyno .

 

I have never had any success in finding any place near Western Pennsylvania who even advertise having an engine run stand.......??? THere are chassis dynos, but mostly for modern cars.

 

Do some more research and ask around, I’m sure you could find one close to home.
Leigh makes an excellent point that running a comparison on a computer is much cheaper and will get you into the ball park.
But an engine dyno is real results and you can see exactly what your engine is doing and where it’s doing it.
As Leigh said, even two runs with the same engine can be slightly different.

I had my builder run my new engine on his dyno for a couple of reasons.
One was to do the first start of the new engine before it gets installed in the car.
If something doesn’t work right or if something goes wrong I don’t have to pull the engine out to repair it.
This is where the builder found he wasn’t happy with the lifters making noise, the oil pressure throughout the full rpm range and the cam creating higher cylinder pressure for a street driven car than he was comfortable with.
Without a dyno tune, I would have never known there were potential problems.

Second, was to see if it performed where I wanted it to.
It was great, the builder knew it could be better and suggested a cam that would change the torque curve and bring down the cylinder pressures.
These were simple swaps with the engine out of the car.

Third was to get a good tune.
Like Leigh said, it is perfect on the dyno, close for the street, but like you I want it as close to perfect as possible.
The builder ran it on the dyno without the vacuum advance set up, but I already know I’m adding the vacuum advance and that will change a couple of things once in the car.

Final reason, the builder guaranteed the engine and if any problems happened during the dyno tune, he repaired it for no cost to me.
The only thing I paid for was the new replacement cam since it was ultimately my decision to swap the cams.
Plus I get one year warranty parts and labor guarantee.
If I didn’t dyno it, it’s all on me.

The engine builder had the engine for approximately five weeks rather than the estimated one week.
It did take time to get the new parts, install them and get the engine back on the dyno.
It was so worth it to me, because now I have much more confidence in the engine build than before the dyno tune..

 

That's why all my engine builders have engine dynos in there shop so I don't have to have any problems like oil leaks and stuff and I find that a lot of engine builders prefer it as well to iron out problems if they arise before customer gets motor .

 

My engine builder knows several shops in my area with chassis Dynos, so I would think the opposite would be true as well.
Ask some of the chassis dyno shops who has an engine dyno and they can probably give you a couple of names.

 

I hope this thread lasts forever....much information to learn!

 

Well you could always ship it or carry it across PA to Bristol at Lorenzo's.
His engine dyno goes to 1000HP, and he has needed it.
Maybe we could make it a two-for day! LOL
Phila is just a little bit bigger market than Pgh.
Or I could ask him if he knows of someone closer to you.

 

I was thinking about asking you about that. Its a consideration.

 

Had a phone call with Mark Jones yesterday. He is going to buy my AFR 195 race heads. And he talked about the dyno runs on the engine. I guess he is following the thread and saw my comments. Bottom line...he is confident the dyno runs are within 15% of accurate. He explained the correction factors that are applied to the observed dyno indications to adjust it for barometric pressure, temperature and humidity, and adjusting it down to sea level, from the 900 feet elevation there. I think he said the observed HP peak was 484 HP....and then the adjustments are made. Its interesting information. I really don't know much about dynos, except what I have heard over the years. I still wish I could have had accurate dyno information down in the area that I drive my car in,...i.e. 2000-4000 RPM.....but it really doesn't matter at this point. I know I am giving up top end HP for more torque on the bottom......and whatever it is, its going to be good enough.

 

I would only accept the correction factor "SAE smoothing 5". Allows for comparisons from around the country to be on even playing field.