Inliners International Forums General Discussion Hi Performance 1.94 valves

Just wondering. Exactly what is entailed in installing 1.94 valves in a 230/250 head? Shrouding issues? Water? I'm not worried about the bolt boss or lumps, just the valve work and maybe some light porting. I got Leo's book and phone number, I'm looking for your input. Thanks gents.

The shrouding is going to be the most sensitive issue that you face. If your machine shop hits water, it is only because they plunged too deep with their cutter. Thats the most common mistake that people do when putting larger valves in these heads. For some reason they think they have to sink the valves a mile by installing them, but they also kill the short side radius even more by doing this. Thats a lot of the reason they don't see much flow gain by going to the bigger valves in the first place, they ruin the head from the get go, and are disappointed when they dont see the results they thought they should get, not realizing the machinist is too blame. Don't forget to open up the bowls accordingly, this too is often overlooked and doesn't get the maximum bang for the buck for putting in larger valves either.

Adding to CNC's comment, I have also used 1.94 and then on another build used 1.90. It is amazing how much less shrouding there is. Having a old head cut up in my possesion, it would be hard to hit water unshrouding for the 1.94 valve. Can supply pics if needed. Tom

Thanks, this is exactly what I'm looking for. The most bang for the least buck (being a Scott and all). Pictures are good!! Did you cut down the valve to 1.90 or is there a readily available one out there? It's good to have this information logged into the site in case someone else would like to know. On another note. A lot has been made over the P.E.S. VS. the other lumps available but I don't think I've ever even seen one. Are they still made?

I think Tom cuts down a 1.94" valve to get that size. The PES plates are still available, a set is currently on ebay as a matter of fact. From what I have seen posted and mentioned by others, they seem to require more patience and work to install them. I personally can't confirm or deny any info regarding performance #'s between the standard lumps vs. the PES. I think Tom as well has used both styles before and could expand on this from his experiences.

Armond, the problem area is in the bowl...machinists using a serdi or a vgs20 use a bowl hog to cut out the area below the seat.....it is safer to use the grinding method with appropriate stones.....the flow around the valve is not concentric and hand blending of the bowl after grinding will bias the flow towards the exhaust side of the chamber.....I use a 1.875 for the street to keep the velocity up(turned down 1.94)....not competent on pictures but have a head in progress; perhaps I can send pics to someone who can post when done......fats

Fats, You could just send them to my home email rebelce@juno.com It looks like the port naturally biases the flow that way but more couldn't hurt. It's keeping the flow in a straighter line that way. I'm not shy with a hand grinder!
I found the PES plates on ebay. A lot of searching proved pointless till I read your post and changed the search name. This is all great information.

I should have them roughed in this week-end .....I'll do the seats after the final clean-up of the bowl......the bowl hog method is quicker but it really trys to encourage flow in relatively inactive areas; improving the narural bias is best....fats

Thanks. Does anyone have a direct number for PES? Web search was fruitless.

I think it is in the ebay ad, i'll double check or you can look again.

I use a ferrea 1.90 intake valve. They can be ordered in that size. For SBC.
PES (Precision Engine Service) Clyde Norwalk is owner. 704-843-5477
Waxhal N.C.

I have used PES lumps in my own engine. They fit like dog****. Either the HI-FLOW brand or Larry's are far superior in fit and finish. Having installed all 3 brands, I can say this.

I will get a few pics of the cast iron in the intake chamber wall. Tom

I think Clyde is focusing on his Lock-In-Tool. It appears he is selling Precision Engine Service. All his machinery and parts have been for sale for close to a year.
Lock-In-Tool

Z

Pic's of a head cut up. This the area between the intake valves. This head had intake seats installed, hence the funny machine work.



It had 1.72 valves and of course the seats were bigger in diameter.

Nice pictures Tom!

Thank you,

LG

You can see from the pics above, that if you hit water by either unshrouding the chamber or putting in larger valves, you are doing something terribly wrong. There is plenty of material there to even accomodate 2.150" valves and unshrouding, been there done that many times, so 1.94" is no problem....

Very nice, that's a very informative set of pictures! Could you give me an idea how much the chambers should be opened up to unshroud the valves? I take it port biasing would have an effect on how it should be done.

Armond, place the bare head on a bare block, turn it over and view it from the crank side....you will probably find that the intake side of the chamber is equal to or slightly extends beyond the bore.....if the chamber is opened up beyond the bore then the top of the block becomes restrictive....when I open up the chamber I blend a radius to match the head in this area of the block....please don't take this as gospel;it is something I have done over the years with different engine packages .....I don't have the capability of flowing a block and head together; perhaps someone with more research capability could verify the practice for us.....fats

Fats, depending on which cylinder head you choose to begin with, that is the only accurate method to unshroud the chamber effectively. As you can probably conclude, each head and final bore size will be tailored precisely to the way each chamber/bore indexes as it is bolted to the block. The best scenario is to have the chamber come just to the edge of the cylinder bore, if you have to hand blend it. If for some reason, the chamber extends beyond the edge of the cylinder, then as you have said, the cylinder bore is now the restriction, and muct be chamfered to unshroud the bore/chamber combo, much like the older BBC blocks that have the exhaust notch in the top of the bore. Most enthusiasts don't realize that the cylinder bore is an extension of the chamber, and equally important in how the cylinder head works and reacts. Its a whole package, and the head is only one component in that package. Just like the airflow in the intake tract begins in the intake, so if you just focus on the intake port of the head, you wont get the full potential out of the package either, the runners in the intake manifold are also equally important to this combo of parts. In our race heads with the 2.150" intake valves, that was common to have the cylinders chamfered to unshroud the valves.

Dude, thanks for the positive reinforcement; most of the conclusions I've reached over the years came from the school of hard knocks....years ago I worked on small displacement small blocks that were bore restricted (CID requirement)....the relationship of valve, combustion chamber and cylinder bore was critical to high rpm breathing....the stopwatch took priority over the flowbench at that point.....fats

Most of the time thats the best school to attend.... Headrick told me once, that most racers spend too much time in outer space trying to make rocket science out of going fast, when all they need to do is just use common sense to figure out most problems. Good input there fats.

OK my question is this......can the installed seats be milled/ground to accomodate the 1.94 valves without having to install a new set? If need be I can have my 1.94's cut down to a more managable size. (will I need to do this?)

Randy S. Hager
Venus, TX

So you are saying your head currently has hardened valve seats installed already. If so you typically can't enlarge the bowl area thru the seat and cut it for a larger valve by too much. First you need to know what size valves the seats are machined for now. Its usually not good to start out with a head that has seats in it already, because of this limitation that is placed on these areas. It can be quite expensive to have the old seats removed and then recut the head for larger seats for bigger valves. I would probably look elsewhere for a better casting to start with, just to avoid having to spend extra bucks needlessly, to end up back at the same place basically.

Well, My current build is from a late 60's truck which I doubt has hardened seats. So I will need to replace these instead of machining/grinding them to the 1.90 or 1.94 dia? What about having my SS 1.94 turned down to 1.90? Is this the best of valve size vs chamber size? Looks like it might be so. I'm kinda cautious about having a machine shop hose up my head while doing the valve seats. Anyone from the DFW area know of a good machine shop that has and will do this right? One more question......do I have someone turn on a lathe or grind my SS valves????????

They can be turned down in a lathe quite easily.

Randy, disassemble your head and check out the seat area.....the only time the intakes require seat inserts is when they have been sunk (abuse or incorrect grinding)....normally the exhaust are up-graded with inserts for unleaded fuel compatibility; not required on the cooler running intakes.....if the intakes don't have inserts they can be ground for the 1.94 even if they are down a bit with the 1.72......fats

Thanks Fats. I'll pop it off and see what's what......... I do think I'll have the 1.94's turned down to 1.90's to help with the shrouding effects. This is going to be an N/A TBI motor anyway so no need to go too big.

Thanks again
Randy S. Hager
Venus, TX

Randy,
there should be a ton of good shops down where your at. Hop on some of the DFW car clubs (northtxcamaros for example) and get a good machine shop recommendation, or go out to Kennadale dragstip some night.
Or, 2 hours north of you is Glenn Self in Durant OK if you want to build a race head.

Is there an affordable intake valve between the 1.72 and 1.94 for a street driven engine? Someone mentioned a ? 1.85?? Are these readily avialable?

thanks,
tad

Didn't some of the Fords come with a 1.88?

Heater63,
Yes, the 1.84 intake valves for smallblock chevy V8. They are cheap to buy in regular quality and slightly more in high quality. Tom

If memory serves me (at all) the HO 305's had 1.84 valves.

Are stainless steel valves worth the extra cost for a turbo street engine?

yes, especially for the exhaust. The valve tends to hold more heat in turbo applications. If the boost is really turned up or for super hard endurance, than inconal(sp) is a good choice. My engine has stainless valves, no problems for me. Tom

If you are going to buy valves,the higher quality ones should be for the exhaust.


MBHD

So for a mildly to moderately warmed up street engine, the 1.84 and 1.6 valves would be a smart/good value upgrade right?

thanks for all the input guys!

-Tad

The 1.84" intake valves will be a good upgrade over stock. We will be dyno testing several stages of heads for an upcoming magazine article, and I think you will see a steady increase in power with each upgrade in valve size up to and including the 1.94" valve head we will be testing.

CNC-Dude:
If I do not un-shroud around a full 1.94" intake are the dynamic bad enough that the incoming charge will not swirl toward the exhaust? How much more shrouded can you get but the new heart shaped chamber in these new heads, but they swirl the charge around and that helps with deterring detonation. Would we not have this going on inside the chambers of our heads too even though they are not heart shaped??????????????

Randy S. Hager
Venus, TX

It largely depends on which cylinder head you are using to put the valves into. Naturally, the larger chamber 70cc+ heads will have a lesser shrouding effect than the smaller 50-ish cc heads. Also, the difference between a 1.90" valve, and a 1.94" valve in the same head will only be .020 bigger around the area closest to the edge of the chamber where shrouding is the most noticeable anyway. As for the swirl effect, that is greatly influenced by the shape of the port and bowl area. Ok Larry, im fixing to do another product endorsement for the lumps, so get your checkbook out(LOL). A siamese head as cast, has a flat floor with no short side radius to speak of, a huge bolt boss obstruction that breaks up the airflow, and all the way around is very undesirable for promoting and establishing any good traits we think are good for creating swirl before it enters into the bowl and then the cylinder. When you remove the bolt boss, and add the lumps, you make the air direct itself into a more desirable direction and flow pattern, and it also speeds the air/fuel velocity up, which is very desirable especially at low valve lifts and RPM's. Its then up to the shape of the chamber to maintain and complete the swirl effect up to the point of combustion. The piston top shape also contributes to this as does the quench area. In a perfect world, you would like to see a nicely formed SSR, a bowl area enlarged to an appropriate size to match the valve being used, topped off with a shallow heart shaped chamber with a good tight deck height piston and tight quench clearance. Since none of the current siamese heads have a heart shaped chamber, this will require a person to physically reshape and fill it to achieve this. And rarely do many heads exhibit more than two or three of these other characteristics without having to alter the head. So, many of these things are good to have in a cylinder head, but are not an absolute requirement to have a decent performing street or race engine.

I currently am making a new toy for the many do-it-yourselfers out here on the forum, to have the ability to actually "see" the airflow into the intake ports so that trouble areas can be detected and corrected, and also see if the chambers are creating swirl as it enters the cylinder. Before, you had to rely on someone with a flowbench to be able to do this for you, and this is only if they have a velocity probe. But then you still couldn't actually "see" what the air is doing in the ports or chambers.

That's why I come here.....to learn all I can to build my engine. You guy are great!!!!!!! CNC-DUDE please read my new post on balancing. I really need advice there.

P.S. I have the lumps and will install them in the head also. Every little bit helps.

Thanks a lot guy's
Randy S. Hager
Venus, TX