I did talk to Peyton yesterday about his head porting. He agreed with my assumption that the port volume was too large, resulting is little to no HP gain. He has new CNC porting that leaves the port around 15 cc's larger but has the same flow. When I get back to Livernois I will disassemble and clean the Gen3's we have up and ship them back to him. He will epoxy up the ports and remachine the heads and send them back. They would probably be tested in April, if we get them back in time.

Just keeping the group updated.

jerry

 

Wow. So what's the takeaway here? Bigger isn't always better? Flow bench numbers don't mean squat? The combination needs to be maximized?

I'm asking from a consumer point of view. I'd be pretty upset after dropping that kind of coins on some "max effort" porting, only to find it wasn't worth it.

 

I’m not surprised at all by this. Peyton does some excellent work, but I’m always leery when max flow numbers are emphasized, and not mid lift flow.
I’m already working on a package using the new small block head on a big block combination. It’ll be a bit, but I’ll forward the results once I have them.

 

It's an excellent question that the answer isn't straight forward. What's the takeaway? As I put in one of my write ups, we don't race flow benches. Flow numbers are relavant, but so is the port volume. I don't think that many head porters advertise port volumes, but they should. Cylinder head manufacturers advertise port volume, but porters rarely do. In an ideal world you want the most flow you can get with the smallest port. If the velocity gets too high (approaching sonic) then you have to make the port volume larger to slow the air down (most people with an Oldsmobile will NOT run into sonic air velocities). Think about a sheet metal tunnel ram. All those runners are very large at the plenum and in only 6ish inches that same runner has reduced a LOT in cross sectional area, this is for velocity. On any engine if the port is large and the air slows down when it comes out of the runner, you aren't going to have an optimal system. I feel that this is what happened with Peytons heads.

I know Peyton wants to be able to offer a great head for an Olds. And he will get there, but it will take some time. Dave, the cylinder head whisperer at Livernois, has told me many times that if you really want to make a great head you have to make a small change to the port, flow it on the flow bench and then put it on an engine in a dyno cell to see if it likes it. Doing this you are LUCKY to make changes to 8 ports and test it all in one day. It will a LOT of time to develop a great head, but it can be done. If you have a really great head porter (and I bet there are less than a few dozen in the country that would port for an individual) they have this thing called experience. So they can port a set of heads, and they will make power straight away. But again, there are very few of these out there, and your local guy that is talked up, probably isn't one of them. Dave did a set of Speedmasters for me a good 5 years ago. He never flowed them. They are on a friends race car and that engine makes just over 600 HP on an engine dyno. The cam isn't huge (0.600" and about 252@0.050"), compression ratio is upper 11's, but it makes good power. That is experience. Dave is doing another set of Speedmasters for me that are about 90% of the previous mentioned heads. I asked him to keep the 2.07" valves, minimal port volume changes (all of these to keep velocity high) but get them to flow 300 at 0.500" lift. He has done that on a few test ports. If a complete set is done and ready, I will run them next time I'm up there.

I applaud Peyton for realizing that what he has now isn't good enough and he's trying to make it better. No idea how he deals with customers that had heads ported and they weren't up to "snuff" for power, but flowed good numbers.

Not sure I answered your question. If I didn't, keep asking, I'll keep trying.

jerry

 

A good head porter will tell you at what RPM your peak power will be by knowing the Minimum Cross section Area of the port.

PDD heads are CNC’d so he knows exactly where where and what the MCSA is , or it should be easy for him to figure out.

when you know the MCSA and the CFM, peak power and at what RPM it’ll happen is a given.
I would think those big flowing PDD heads on a 455 would work better with a short duration aggressive lobe big lift cam…long duration with slow lobes and those heads are a real bad deal. Way too many guys think big flowing heads need big duration cams,, they absolutely don’t, especially if you want a broad power band. they need the opposite

that’s what was seen in those tests

 

Wow, thanks for heads up lol, PDD heads looked amazing on FB but in reality no HP gain is a real surprise, easily would have cost me a few grand Canadian. So if somebody had the max effort heads is there any way to fix them or are they the way there going to be?

 

That is a question better answered by Peyton. I don't see why one couldn't do what he is going to do to the set he ported for us, epoxy them up and then re-machine them. I personally don't see an issue with epoxy in cylinder heads, if it's prepped correctly and the right epoxy is used. A lot of race teams do this. But I am not an epoxy cylinder head expert by any means. I wouldn't mind hearing what Mark Remmel has to say about expoxy in cylinder heads on a "street" car, I would have faith in his opinion.

jerry

 

Different schools of thought on epoxy. Most will agree, as you mentioned, if done correctly it can last a very long time. Others don’t see it that way.
Champion Race heads for example, used to do a lot of epoxy’d heads, no issues.
And as I mentioned before, unfortunately, Peyton has taken a path that I don’t like, and that others have taken as well, in that they post Max flow at lifts that most will never see. In this case .800 lift.
But as I expected, Peyton will do whatever is necessary to revise his program. May be a street program on one and a Race program on another? That would make more sense, and for the Street program I wouldn’t hesitate to use the small block head in place of the big block one for virtually everything.
Just a thought..

 

Gluing anything inside an internal combustion engine is a gamble I'd rather not take. Once it fails, you're screwed and, more than likely, your engine is a pile of junk.
My point was more about Peyton and his fancy computer models. It seems that some airflow modeling would have been done prior to pressing the big green button.
To Jerry's point- yes, small increments during design with that big, nasty T word, "testing"..

 

I agree. AND you get to pay the full cost of building a new engine. There is often a big difference between "advertising" and "results".

 

there is nothing wrong with epoxying the intake port using the right epoxy. unfortunately, most Olds heads have a low floor relative to the deck, so it’s the only choice, especially with iron heads.

Aluminum head floors can only be Tig welded near the entrance unless a special extended Tip is used ..but now you’re talking many many hours and expense
Epoxy is actually better because it won’t screw up the valve seat fit like the heat from welding does and it can be removed and added to again over and over for testing or for when the head goes on a different size engine.

I’ve never had epoxy fail on aluminum or iron heads. With the new heads having extra meat above the intake port, they can have the roof blown out to the max and the floor filled to suit whatever cube engine they are going on.

 

It can happen, I remember reading a thread where Mark and another member were in a pretty heated exchange when the epoxy or melted metal of some type broke loose and destroyed his build..

 

that happens when hacks don’t know what they’re doing. then those same hacks spread bs and say because they can’t make it work, nobody can…so don’t do it

it’s very simple..I use JB weld, prep the surface with a 36 grit course cartridge roll and lay the epoxy down extra thick ..then grind to what I need.

over 1/2” thick sometimes…or paper thin, it works. been doing it that way for decades. it’s still there in the engines running around tracks year after year.

all three of my Engine Masters Engines were loaded with Epoxy. In 2019 my 373 sb stroker for the Race Engine Challenge used huge port Battens that flowed 340 cfm. obviously way too big for a 373 that needed TQ from 3500 rpm on up ..so they got a floor full of epoxy to get the desired min cross section.

it made just under 500 TQ down low and 590 peak hp.

 

It wasn’t epoxy, it was aluminum in the crossover of the Cyl head. He ran another carburetor on it that I told him not to run because it had issues, and ran it so lean that it loosened the filling, which then broke apart. And it didn’t destroy the build, it bent a valve but short block was fine.

 

Jerry do you know how many cc's the intake port is on the PDD cnc ported heads?

 

I do not know. But I’ll be back up there in a week and I plan to measure them as well as a stock Gen3.

jerry

 

Copy that. Just for reference Knowlton's Thunderheads cnc'd my speedmasters several years ago and his program does the intake ports to 236 cc's. They flow 286 cfm @ .500 lift intake and 202 cfm @ .500 lift exhaust.

 

You see that cam discussion a lot more in the LS world... small MCSA rectangle port heads use big duration cams to make power (and remain streetable), but if you use that same cam in a sewer port rectangle head (like an 821 LS3 head) you create a turd.

I talked to one of the Olds Super Stock guys a long time ago about epoxy in the head intake runners. He mentioned they had a few instances of partial pieces breaking off but they had just totally disappeared with zero engine damage, no seat damage or anything. Must just turn to powder.

 

all true.

as far as the epoxy going through the engine, that’s correct too. very similar to when piston top ring lands break off and disappear without hurting anything.

there are some bad epoxy mixes out there that I don’t trust because I’ve seen them separate from the casting. the Moroso two part putty epoxy is garbage.

at the 2019 Race engine challenge I did the legality tear down inspection of Eric Roycrofts winning LS engine He used Liberty heads with a healthy dose of epoxy on the floor. On one port the whole piece of epoxy had separated from the floor…he dodged a bullet there….if it had lifted up completely, it would have blocked all flow to that cylinder and killed his score.
I could tell what he used was similar to the putty style Moroso stuff because of the colour.


don’t trust that stuff

 

Well? Any updates on cylinder head testing?

 

Yes. We (really Ron) has measured all the port volumes for various heads, as well as combustion chamber size. I talk about this in write up 11 (not published yet) but the valve seats on the Edelbrock heads seem to move after some thermocycling. Not uncommon, even at the OEM level. After we fixed them and put them on the stroker engine we made 9 more HP with one intake (Torker I think) and 25 more with the modified Torker. We will run them with the 455 (really 461) after I get back to MI this week. I attempted to get ahold of Peyton and almost 2 months later there is still no communication (poor way to run a business).

More in the write up.

jerry

 

I'm always leery when air speed over the short turn isn't emphasized-where HP is made or lost...............................

 

Anymore news / updates???

 

Good to hear re Port Volume measurements.
Jerry, I just discovered your 10-Part writeup and have been crunching through it like I used to binge watch Sons of Anarchy.
It it superb and a good read regardless of engine type.

Have you also considered measuring intakes?
Jay Brown of the FE Ford community (I go by WerbyFord over there) did a similar study on the Ford FE almost 20 years ago.
He reported the stuff Edelbrock does, measurements A and B for height, then port sizes, but also the total intake volume in CC.
Very telling re whether an intake will be soggy or run out of plenum, just tape off the ports & use a measuring cup to fill the intake with water is a quick method, a few CC error doesnt really matter.
I've found I always look for those measurements in Jay's The Great FE Intake Comparo book which is now a classic as I'm sure your writeups will be.

Thanks again for doing all this work.

 

We have not thought of measuring the actual intake volume. It's probably not that hard to do. I'll have to see if Ron is up to it or not. We don't have all of them left up there, but we certainly have some of them....

jerry