8BA Valve length
 

Hi all.
I’ve just spent a few hours this evening mocking up some stock Chevy Manley 1.6 valves with my Potvin 425 cam. I’ll be using stock non adjustable lifters so was measuring to see what valve length would be closest to get the desired lash.
One bank is spot on with a bit of grinding for the 4.911 length.
The other bank will require 0.040” longer valves.
I knew they were offset but not by that much?
What did they do from the factory? Grind the valves on one bank a lot more?
How far can you grind valve tips before going through the hardened tip?

Thanks everyone
Kev

Re: 8BA Valve length
 

When we used the 425 cam in our old dragster engine,we needed the .100 longer valves.
Lawrie

Re: 8BA Valve length
 

Hi Laurie, that’s what I thought I would need, 0.100” over valves. But on measuring one bank that works fine, the other bank requires 0.040” longer valves?

Re: 8BA Valve length
 

Question: Did somebody do a valve job and set the SEATS to be the same height (to the deck) on both sides? New seats installed by chance?

Re: 8BA Valve length
 

What B&S said, sounds like someone ground the seats incorrectly.

Re: 8BA Valve length
 

Hi Kev, you may want to figure out what you'll be doing for your installed spring hgts while your mocking that up??

Am assembling 2 units right now, they actually also could have used slightly longer valves, due to the 1.000" (nominal) cam base circle, but it definitely interferes with the spring hgts when you get up to that point!

Thanks, Gary in N.Y.

P.S. On both these builds we opted to stay with the std long valves and the more conventional spring package. We're using 16 lash caps on each one, fixes the small base cam problem and doesn't affect the spring numbers! We do have adjustable lifters on both and the adjusting nuts are in "deep" (more thread contact), exactly where we like to see them.

Re: 8BA Valve length
 

Hello again, I’ve been chatting to you Re lifter radius via PM
Yes the valve seats have been cut for three angle and set so the valves are equal to the deck height on both banks, so not incorrectly done.

Re: 8BA Valve length
 

I’m off to sleep now in the UK
Please post your replies and I’ll catch up tomorrow.
Thanks
Kev

Re: 8BA Valve length
 

RE: "so not incorrectly done" . . . let me expand on that a bit . . .

Just to get into the details . . . due to the offset of the camshaft and crankshaft in the block, and the different corresponding valve angles, the actual valve seat to deck height is different side to side - by roughly .040 or so.

You can see this on a stock flathead - as on one side of the block the valves are above the deck and on the other side they are almost flush.

So - if somebody decided to make the valve seats the same height (to the deck) side-to-side, then one side will be shorter than the other by about .040.

I can check my 3D model to give you the exact numbers . . . but if I remember the last time I checked the actual number was .043.

If this is your case (somebody "trued them up"), then you now have one side that is about .043 shorter than the other. This is why I pay particular attention to the top-end valve work that I have machine shops do (or I do myself). A typical performance shop will try to make both sides the same - not knowing that the flathead block/engine has design differences side-to-side.

When somebody tries to "fix it" - they are actually doing exactly the opposite. :eek:

Let me know the situation . . . just so we can all know the cause of your side-to-side valve length differences.

Best of luck,
B&S

Re: 8BA Valve length
 

[QUOTE=Bored&Stroked;1818940]RE: "so not incorrectly done" . . . let me expand on that a bit . . .

Hi B&S, thanks for the reply.
I checked a stock 8BA block I had against mine and as you said the valves are indeed recessed aprox 0.040" on one bank.
So my valve seats have been cut to equal the heights on both banks.

When you say "When somebody tries to "fix it" - they are actually doing exactly the opposite.", would it not be a good idea to do this normally as it would set compression ratios etc closer on each bank?
I suppose it's not normally an issue if you're running adjustable lifters, only a slight problem when you run non adjustable like I am.

I hope my wording doesn't come across like I'm trying to argue, I really do appreciate all input and advise given.

Thanks
Kev

Re: 8BA Valve length
 

[QUOTE=GOSFAST;1818879]Hi Kev, you may want to figure out what you'll be doing for your installed spring hgts while your mocking that up??

Hi Gary. That's what I was trying to work out when I came across the issue.
I'm going to drop Manley Valves an email to see how much for custom valves at the length I require with the collet (lock) ring groove set at the height I need to get my 2" installed height.

Re: 8BA Valve length
 

I just suspect that a custom valveguide would be less costly then making custom valves...
Or you can make a sleeve/spacer to fit the guides you have now...

Re: 8BA Valve length
 

[QUOTE=61Klassic;1818969]Hi Kev, A few years back I fabricated some valve guides that are able to carry up to 5 .060" shims under the springs, the springs sit on "locators" and the shims "stack" between them and the guide, this allows for up to a .300" adjustment on the overall spring hgts. The intakes are machined for the "Viton" stem seals, the 8 seals come in the pkge! (Photos below)

These will most definitely solve your spring problem but they aren't inexpensive. The guides also have the bronze liners already installed.

I have a few shots of them below here.

On a side note if you decide on custom valves I would strongly suggest speaking with the guys at Ferrea (located here in Florida) instead of Manley. Ferrea's are all we use here, much better quality than just about any other valve mfr including Manley's!

Thanks, Gary in N.Y.

P.S. This guide setup will allow you to use your existing valves, plus you'll end up with the bronze liners and stem seals. We use these lined guides on every build we do. I would have to give you the cost later today, the pricing is at the shop. I also need to make certain I have a set in stock?

Re: 8BA Valve length
 

Hi Gary. Those guides would certainly solve my problem on one bank but not on the other where I need 4.945” length valves.
How much are a set of those lifters Gary?
Thanks
Kev

Re: 8BA Valve length
 

Hi Gary. Sorry I didn’t read the end of the your post re pricing later.
Also thanks for the heads up on Ferrea valves

Re: 8BA Valve length
 

Gary can answer better than me on this topic, but think you can use lash caps on the side that requires a longer overall valve length.

Re: 8BA Valve length
 

Hi "J", the lash caps are .080" thick, not sure this will help in Kev's predicament??

Kev, keep in mind you can also work with the valve locks to raise or lower the I.H.'s. Also, I would be concerned about "grinding" any substantial amounts off the stem ends?

(Add) We also have some Ferrea SBC 1.600" x 4.960" on the shelf here (8 pieces at the moment), we stock them for the Chevy's at all times.

Thanks, Gary in N.Y.

P.S. We stock the "adjustable" valve locks here also, they come in -.050" or +.050", we use these often on all type builds! Without actually having the job before me I suspect between our adjustable guides and the "adjustable" locks it will end up "fixed"??

Re: 8BA Valve length
 

If all you're worried about is that on one side the valve is a bit longer (as far as installed spring height), just shim the spring to the correct installed height you're looking for - or use offset valve keepers.

You were only talking about .040 . . . which is obviously less than one .060 spring shim. I can see no need for custom guides - though Gary's guides are good to use regardless of the perceived spring stack height issue (his regular ones).

First of all - just measure your current installed spring height - how many shims do you need to get to 2.00"? Also, you might just consider some lash caps for the "tall" side.

Re: 8BA Valve length
 

The stock Ford machining and valve angles were the method Henry used to accommodate the shaft offsets and make it possible for identical valve parts to be used throughout the engine.

There was two different lifter lengths(height) utilized between 49-53 with the longer pieces coming sometime in 1951.