building my 240 ci long con rods slant, I had ordered MP 1.7 1.44 OS valves. Now that I got them, Lou told me that his .100 over slant has 1.7something 1.5 valves. I can get those measures down here (inline 6 chevy valves) for peanuts, so I might go that way, especially building a high cubes slant. bore is 89,36 (almost .120 over). Question, the space between the seats if I install 1.720 intake 1.500 ex valves is 1/8" is that enough "meat" considering that I'll be porting? and another question. Overall valve lenght is 1/8 taller than stock. If I mill about that from head/block, would that solve the valvetrain geometry issue? dynamic CR would be 8,04 milling that much (.125)

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

The issues with using the Chebby valves are:
- Smaller valve stem size = all new guides required.
- Longer valve stem = geometry problems but machining the head and/or rocker arm shims solves that issue.
- Longer stem = new valve springs and / or setting spring pressure to where you need it. Valve springs are manufactured and rated at set installed heights. (ex: 1.700 or 1.800) Installation can get complex if your combo of parts puts the installed spring height in some "in-between" place.
DD

I can get them in slant six stem size (the larger stem oversize avalible for chevy). But since I was going for all new guides... would it be good to keep a smaller valve stem? I mean for flow purposes and keeping the valve weight down?
that's what I thought... take the extra lenght by milling and shimming the rocker arm assy if I don't need to mill that much
so far I have the MP 340 sb valve springs wich are rated at 1.7 installed height... installed height with "normal" slant six valves was 1.65, I have a margin there, don't I ? I mean, .125 longer stem... OR I can have machined (or machine myself) thicker plates?

other calculations on this engine includes: 52 cc combustion chamber, thin steel gasket and ARP studs all-around (mains, head and con rods) -2mm negative deck height, 89,36 flat pistons, floating wrist pins with teflon plugs AND retainers, that would result in 10.8 SCR and according to a DCR calculator I'd be at 8,04 DCR. I haven't checked for sure and real the valve/piston clearance with a .465 lift cam. If I have little or no clearance I might as well reduce the SCR, but I have to lay off my computer and get hands on the business for knowing that for true fact.
Dyno 2003 simulation is very encouraging, this is the preliminary table:



that was with 1.7 1.44 MP valves

this is with 1.72 1.5 chebby valves:



I don't plan on revving it past 6000 rpm (MSD cookie limiting to that)
I don't see much change in the lower end, but if I install the cam 4º advanced, there's some more low end grunt there. I'd go with taller rear end ratio for sure... say 3.31

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

I must be wrong, because no one else said the same thing.
That's what determines facts isn't it? The number of people who agree?
Never mind.

Brainfart! my bad! so I guess taller stems are not a good idea!

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Must be that "other Hemisphere" thing......

I have Chev valves , guides and springs.... they install NP and work well enough. The longer stems mean they are a little harder to keep adjusted. If I wasn t so cheap I would buy new pushrods. I run 9.25 CR and a Comp 264 cam....I wish I had your Erson cam...the Comp is too little.

I used "half nuts" as jam nuts to keep the adjusters from loosening ,,,and had to "adjust" the V/V cover a teeny bit to clear the rockers.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

I'm beggining to think that even the erson 270º is too little!
we have cast steel rockers that have that screw/locking half nut arrangement. I might go with those since they have more space under the regulation screw side I'm kinda cheap too!

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

[quote="argentina-slantsixer"]building my 240 ci long con rods slant, I had ordered MP 1.7 1.44 OS valves. Now that I got them, Lou told me that his .100 over slant has 1.7something 1.5 valves. I can get those measures down here (inline 6 chevy valves) for peanuts, so I might go that way, especially building a high cubes slant. bore is 89,36 (almost .120 over). Question, the space between the seats if I install 1.720 intake 1.500 ex valves is 1/8" is that enough "meat" considering that I'll be porting? and another question. Overall valve lenght is 1/8 taller than stock. If I mill about that from head/block, would that solve the valvetrain geometry issue? dynamic CR would be 8,04 milling that much (.125)[/quote]

>>>*A couple of things happen that are best to take into consideration. The /6 valve is 4.80" OAL, the stock Chev valve is 4.910" so you are dealing with .110" overlength right off the bat..

*Milling the head effectively makes the pushrod longer in relationship, but take into account the rocker arm ratio. If you get the geometry right, you won't be readjusting the valves every few weeks and you will make more power with less sideloading on the assembly.

We have run .100" milled heads with stock length pushrods and SBC valves, of course we need to set in 11/32nds guides but that is NBD for any machine shop.

In the old days we got hollow tube blank pushrods from TRW and cut them, then just pressed the ends into them. I am not sure many suppliers offer those any more.

Of course now you need to deal with valve spring length, we like to install the 340 Duster 4V spring as a nice option, they are cheap and a performance piece. There are similar aftermarket, lots more expensive and often just that spring in a pretty box.

Another option is the Ford #1177 and it's mate, 300" valve, it is 4.775" long, actually a shade shorter. A bit of spring pad cutting and those can be fitted, too.....*EB

hey man. If you're ted, I got them valves from YOU! I'm jicaino @ ebay. Top stuff boys, 12 OS valves plus retaining clips plus teflon (?) valve seals and 12 manganese bronze guides! I'll recommend engnbldr anytime! good pricing and superb treat to do business with him

Ted (assuming that you're you ) I'm talking chevy inline 6 valves. They're 1.720 in 1.50 ex .110 longer then stock and the stems are smaller (but they come in several oversize stems size up to a stock slant six valve. I have purchased MP springs from summit PN MP 4120249
.206 wire .430 - .500 range lift with damper, and the seat pressure is given @ 1.700 installed height (little more than slant six installed height)

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Don't take the Dyno program at face value, it's programmed for Ford and chevy V-8's in mind. I plugged in a guy's Volare that had much more head work and cam, and the Dyno said 350hp at peak...the real world dyno sheet said "287". So far to get close with the slant in the program you have to set the head to "low performance" (we ain't got the honker Cleveland ports like they think we should), and you have to take a "guess" at your intake type (single plane isn't close since the program assumes you'll be using something like a Mopar Performance M-1 intake), for the hyperpak intake tuned port is a close estimate, but it falls short also. With the curve it suggests, you'll want more rear gear, but I'd put it together and see what it does after break in, then make the changes.

-D.Idiot

Yeah, I knew that in advance, plus I always like to cut off 10% of what desktop dyno sez. Also I introduced many values by hand instead of letting dyno assume those. As far as intake is concerned, I'll be using one out of 3 induction set that I have: I have one M1 double barrel manifold, reworked and port matched, crossection slightly enlargened, one dual manifold fitted with 2 x 2barrel webbers, also port matched and reworked, and I'm building 6x 36 mm mikuni carbs combo.... so far I have "raised" the intake "manifolds" to enlarge the port section, still in the mist with that, but it's one chance. Anyway, it's gonna be hard for most 318 AND 340 guys down here to keep up with this they still run on hidro lifters!
As far as rear end ratios is concerned, I'm planning on swap for sure to a 3.31:1 (13/43) or maybe a 3.58 (12/43) because a) I have the close ratio 833 and B) as you say, with that curve, good gearing may be the key for unleash all that power to the pavement

_________________
Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

never heard of such thing before. In an otherwise stock everyhing mill, why should I have longer valves OR lower rockers for increased lift? not trying to pick up a fight but to understand that equation. Would you care to elaborate?

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Ted (assuming that you're you :lol:) I'm talking chevy inline 6 valves. They're 1.720 in 1.50 ex .110 longer then stock and the stems are smaller (but they come in several oversize stems size up to a stock slant six valve. I have purchased MP springs from summit PN MP 4120249
.206 wire .430 - .500 range lift with damper, and the seat pressure is given @ 1.700 installed height (little more than slant six installed height)
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>>>*Yep, it's me. I was wondering if that was you about the same time I hit the button. Glad you liked the stuff. I am on old six banger nut, have been since the 60's.

The nice part about using the chevy piece is weight of course. Some folks say the reduced stem diameter helps with flow and we could see it on a flow bench but we couldn't prove it on the dyno.
One of those things that after 40 years I still don't know for sure so we just do it just in case.
The nice part about using a ready made valve is it saves on hardearned when you get to the machine shop.

Lots of confusion about what happens when a head is surfaced. We need to remember that the pushrod side is a fixed point and does not change, the tip of the pushrod stays in the same place.
Milling the head moves all points downward, including the valve at it's seat and the tip, thus the pushrod just got longer in relationship.

.110" out of geometry is a lot, we have run them that way but it takes constant valve adjustments. Lots of wear and wear isn't good. So running the slightly longer GM valve comes out nice when we mill the head and pretty much on the button. Trouble is, the exhaust valve is now too big, at 1.500" we almost run out of room to install a seat ring. I have installed 1.562" OD seats, and cut the ID but it is spooky close to coolant on some castings. 1.500" OD seats are better, or just use a daisy and heat then cool them rapidly, the seat gets nice and hard.
I did use the V1371 Sealed Power valve out of a 267" Chev V-8 once, head size is 1.380" but that is only .20" oversize. It worked OK but for bigger we use a 21-4N stainless Chev valve and cut the head to 1.440" They machine easily using Tungsten carbide cutters and are consistant material all the way to the core.
The neat part about the /6 is the sizes are real close to lots of other makes, so performance stuff is easy. We even used the little 1.250" chevy springs with the 11/32nds stuff, I have put .600" lift SBC springs in the 225, easy with some spring pad cutting. That is fun if we want to run a big lift stick.......*EB