356" Y-Block - This isn't a FE, but it's a Ford cousin and another "dinosaur"

[JC-427Stroker]

 
(IF the Mods want to move this to "non-FE discussion" I understand )

Back in early February I got to spend the afternoon at Westech with a couple friends and their 356" Y-Block.  Engine has Mummert Alumi heads and a Mummert Y-block tunnel ram and rockers system.  (Maybe I can get some  FE rockers out of them ... ? ? )

Geoff Mummert has my 427MR stroker parts at his shop,  and before the year is over we hope to get things bolted together and have some dyno time with a couple of manifolds.  He's ported the Survival MR heads I got from Barry some years back.  We'll be working on the cam selection here before too long.

This 356" Y-block made 1.42 lbs ft per cubic and 1.7 hp per cube.   Intakes flow 275 cfm with a 1.97" valve, so 2.18 hp per cfm.
The engine is 14:1  and was running on Q-16.   Pk power 608    Trq  508.

She's a good running little engine.








Spec's Geoff posted on Speed-Talk:
https://www.speed-talk.com/forum/viewtopic.php?f=84&t=64715

- 3.860" bore 3.800 stroke
-14.25:1 compression
-268* @.050 263*@.050 .630" lift
-1.97" 1.51" valves
- CFM 275 int 195 exh
-1.7 roller rockers

[JC-427Stroker]

Dyno video ...   Check out the AF readings.

https://vimeo.com/673498812


Tuned with 8 -02's
Steve at Westech said this engine just might have the most consistent A/F across the board of any carbureted engine he's had on the dyno. I think my 565 is pretty close though.

The video is of a "lash loop" run.  We loosened up the Int (pulled duration out) and it picked up over the baseline.

[BattlestarGalactic]

Pretty cool stuff.

[frnkeore]

This is a good example of not needing thick cylinder walls to make big power.

[JC-427Stroker]

This is a good example of not needing thick cylinder walls to make big power.

 I believe this block is 3/4 filled.

[4twennyAint]

Awesome.  What vehicle will this be going in?

[blykins]

This is a good example of not needing thick cylinder walls to make big power.

 I believe this block is 3/4 filled.

Isn't a 3.860" bore just a .060" over 312 anyway?

[frnkeore]

Brent, yes, it is but, the 312 is built on the same block as the 292 with just larger mains. So at 3.860, it is a .110 over and Geoff used a 292 block. Geoff used a, in his words "filled a little over 1/2 way".

Ford's spec on cylinder walls for both the 292 and FE's for at least the first 3 years is .170 with a max over bore of .060. The spec for the 312 is .145 with a max over bore of .040. Ford may have payed special attention to the castings, after 56 when the 312 came out, because a .040 over 312 wouls be a .080 over 292. Geoff's cylinder walls should have a nominal thickness of .115.

I have conflicting specs on the .170 wall, one just list it as .170 (nominal assumed) and one says min .170. My Edsel block, with it's sonic map, would fit into the min .170, with it's 4.050 bore, now 4.110.

[JC-427Stroker]

Awesome.  What vehicle will this be going in?

Here's the ride:

[blykins]

Brent, yes, it is but, the 312 is built on the same block as the 292 with just larger mains. So at 3.860, it is a .110 over and Geoff used a 292 block. Geoff used a, in his words "filled a little over 1/2 way".

Ford's spec on cylinder walls for both the 292 and FE's for at least the first 3 years is .170 with a max over bore of .060. The spec for the 312 is .145 with a max over bore of .040. Ford may have payed special attention to the castings, after 56 when the 312 came out, because a .040 over 312 wouls be a .080 over 292. Geoff's cylinder walls should have a nominal thickness of .115.

I have conflicting specs on the .170 wall, one just list it as .170 (nominal assumed) and one says min .170. My Edsel block, with it's sonic map, would fit into the min .170, with it's 4.050 bore, now 4.110.

I'm sure that's why Geoff poured the block.  Block fill goes a long way to stabilize the bores and help the rings to seal.   It's a good trick for Cleveland blocks too, where the cylinder wall thicknesses are thin to start with. 

[frnkeore]

I started a thread, three weeks ago, on Speed Talk, regarding wall thickness and what might be to thin as well as, at what point it will cause hp lose:

https://www.speed-talk.com/forum/viewtopic.php?f=1&t=64800

I know that TODAY, it's commonly accepted, that you shouldn't bore a block more than .030 and the main reason seems to be that, it's because you will loose hp, if you do. I started the thread on ST because there is a wide variety of engine builders of all common American V8's. I also, checked what wet sleeve tractors use.

In my day, we didn't have  sonic testing and everyone bored, at least .060 and many 1/8" but, I don't recall anyone splitting a cylinder wall because of it. So, in those days, if you bored a 352, FE 1/8", you had a basic .107 cylinder wall. My best friend had a 303 Olds, he bore 1/8" to 324 but, 56 Olds heads, then put in a 280 duration, Herbert roller cam and mounted a 4-71 blower, w/2 AFB's and drove it for 8 years and 2 years before that, w/o the 4-71 but, 4 x 2's instead.

My own opinion is that you should have a min wall thickness of .120 but I found some wet sleeves at .115. Those are even, all the way around and not thicker in some/most areas. But, my main interest was at what thickness do you start loosing hp. There was no answer to that! I was hoping to find a few builders that said "I freshen this engine, X number of times and dyno it, each time. When it got to .X over, it lost power and I had to replace the block".

The diameter and length of the unsupported cyl wall make a difference, too but, there wasn't any input on anything that showed lose of hp.

Sorry, JC-427Stroker for taking this a little OT but, with that much power per ci, it does seem some what relevant to Geoff's engine.

I know the 351C had a problem splitting blocks but, don't remember them says they lost hp until they found a split.

[JC-427Stroker]

No worries It's all relevant to the discussion.   

[blykins]

There is an absolute that I truly believe in, that a thicker cylinder wall (or a better supported cylinder wall) will always be better than a thinner one.   

I understand that sometimes there is a desire to open up the bores to unshroud the valves, but that's where experience comes in, to see which trade-off is more detrimental.   Obviously, Geoff knows the Y-block stuff better than most of us here, so to offset opening up the bores to help with shrouding, he went back and filled the block to get back ring seal and cylinder stability.  In this case, a thin wall really didn't make big power, as he essentially increased the cylinder wall thickness and stabilized the bores with block fill.

On an FE, which I have a ton of experience with, I know that my 4.080" bore 445 strokers are not hindered by bore size when it comes to making horsepower and will make the same hp/ci as the 428 strokers, given the same parts combinations (of course changing cam specs per displacement).   Experience has also shown me that you can ruin a 390 block very quickly by boring them to a 428 bore (or close to it), even when a sonic test says it's ok, just because of manufacturing voids, pits, etc., on the backside of the cylinder.   It's not feasible to map out every 1/8" of landscape of a cylinder wall. 

On a Cleveland, which I also have a ton of experience with, they were thin when they were first cast.   I have sonic tested many standard bore Cleveland blocks and have seen .060"-.080" cylinder wall thicknesses.  You are not going to see a loss in power on subsequent builds because you (tongue in cheek) started out with junk to begin with.  One of the best things to do to help a Cleveland block live is to fill it. 

The biggest example of horsepower per cylinder wall stability can be found in aluminum engine blocks.   An aluminum block will be down in horsepower right off the gate in comparison to an equal iron-blocked combination.  The reason for that isn't really the sleeve thickness, but it's the material supporting the sleeve.  I have built all-aluminum FE's, dyno'd, then tore them down, to see shadows in the cylinder walls where the bores were distorting.

I just went through and read the SpeedTalk thread.  Seems like you got a lot of well thought-out responses from a lot of guys who build and they all reflect the "thicker is better" way of thinking as well.

[My427stang]

So your earlier parrot comment was a bit whiny and maybe rude Frank, which am never to you, but it’s simple….many of us say the same thing because we have walked this path and have seen the indicators of cylinders deforming.

If a cylinder distorts, rings seal gets worse, power goes down……..that’s it, like it or not. Vacuum and power stroke are affected.

Not using torque plates, thin walls, bore dimensions, internal support, thick rings, lots of reasons. You won’t find a number because cylinder pressure, temp, and even thrust loading isn’t even a constant in one engine, never mind different engines

We didn’t realize it either in the old days, not me or my father in our shop, and we built some hot stuff for the period.  However we also didn’t have the technology, tools or information we have today.

[Joe-JDC]

First, the C1, C2 292 Y block cylinder blocks are the best for most performance applications.  If you can find a standard bore block, then do a sonic map, and offset boring can be accomplished to +.130-135" in many instances.  My own 292Y is +.132" in the 375Y stroker.  Also, John Mummert has his own aluminum heads cast by Edelbrock that have improved combustion chamber shape and allows for porting to flow near 280 cfm on the intake side with 1.970" intake valve.  Valve position is such that they don't hit the cylinder walls like stock heads do above .535" valve lift, so a camshaft with much more lift can be used.  Also, on the race heads, he angle mills them .125" to get the intake valve even better position in the bore.  The heads are CNC'd and use 1.7 rocker arms on their special stands.  He sold several sets to racers, including myself a few years ago.  John M also has intake manifolds, front timing covers, valley covers, valve covers, thermostat housings, etc., cast for the Y for sale on his site.  The Y block is a side oiler, pre FE.  The blocks are very sturdy when minimal bore is accomplished, and can support upwards of 750hp with turbos or blowers.  The 289 SBF has same bore spacing, and the Y crankshaft can be machined for use in the 289 block for a stroke increase.  I have ported dozens of the aluminum Y block heads and intakes over the last 13 years for folks.  A simple head change can increase the power 70 hp on a 292/312 Y with the matching intake.  Joe-JDC