Deck plates?

[Mike DC]

(Just blue-sky thinking about motors lately.)

Anyone know anything about deck plates?  I've seen it on a few high-end drag motors.  They're basically custom-made items in between the block & the heads to dramatically extend the deck height on a motor. 

Does that work in a street motor?  Any side-effects to having a small seam line in the middle of cylinder like that?

.

[Chryco Psycho]

can`t help ring life + drag motors are rebuilt far sooner than anyhting street driven

[Roth68rt]

Deck plates are used during the boring process to replicate the clamping force of the heads on the deck.  This preloads the bore to get an accurate roundness as if the heads were installed.  Only used during the boring process.  You cannot extend the deck height, instead you increase the stroke. 

Steve

[Rolling_Thunder]

Deck plates are used during the boring process to replicate the clamping force of the heads on the deck.  This preloads the bore to get an accurate roundness as if the heads were installed.  Only used during the boring process.  You cannot extend the deck height, instead you increase the stroke. 

Steve

not true...   they do use them to extend deck height....     not very often but i have seen it done...   Chryco - what if you added the plates and bored the block and sleeved the cylinders...   would it then effect ring life at all ?

[68ChargerJMP]

Hey Roth, I think u are thinking of torque plates. In my latest Mopar Muscle, there is a procharger build, where they use some 1/8 thick steel shims between the head and block, which lowered the compression to 8.1 from 10 something to 1. It added like 30cc of volume.

[Mike DC]

I'm not thinking of "torque plates" that you use while machining the block.  I'm thinking of thick "deck plates" that you run while the motor is assembled & being driven.

The deck plates aren't very common, but I've seen them on a few high-end drage motors of various kinds.  They're basically saying "I want the deck an entire 1-2 inches taller" so they fabricate a block of metal to go between the block & heads.  (Think of the metal intake spacers that you would need to run a 383/400 intake on a 440 block.  Now imagine them for the cylinders instead of the intake passages.)

---------------------------------------------------------------

I was originally thinking it would be a pretty cool way to add 100 inches to a modern Hemi motor if you could somehow overcome the streetability problems.  (Sure it would be a lot of work, but trying to get a significant displacement increase on that motor by a conventionally stroking it would be at least that difficult.  And probably result in bad geometry anyway.)

Just a bull session thought.

.

[Ghoste]

Since it's just a bull session... I tend to think that if you could afford all the custom work to accomplish, then ring life would be less of a concern.  Unless we're talking about an engine that needs a rebuild after 50 passes or some crazy number like that.
In my own convoluted way, I guess I'm trying to say that the cost of doing one is up front and the other it could be after the initial build.

[Roth68rt]

I misspoke, I was thinking of torque plates and not deck plates. 

Steve

[Mike DC]

I dunno whether any of it is feasible or not.

I was thinking about the modern Hemis.  The motor is great in most ways right off the junkyard lot but it's just too small.  Finding a way to add 1-2 liters would REALLY make that thing a fun setup.  The heads are probably big enough, the block & rods & pistons are probably beefy enough, and the machining work is better than the muscle-era stuff as it is.

It might not have a whole lot more horsepower at the top end than the current 6.1L motor, but you'd bring up the torque curve drastically everywhere else in the powerband.  That would really make it a street motor from hell.

---------------------------------------------------------------

You'd basically just need the deck plates, some matching intake plates, a good stroker crank, and some longer pushrods.  The only part of that stuff that sounds difficult would be the stroker crank itself.  (No way to offset-grind that much of a change in the stroke length.  And a longer factory crank with the same rod journal sizes would allow you to re-use the same connecting rods in the bigger motor too.)

.

[Chryco Psycho]

if you ran a sleeve inside a deck plate & went to the top of the deck plate ther would be no problem at all

[Mike DC]

That might work pretty well.  I don't know enough about sleeving blocks though . . . wouldn't that distort the block pretty badly to press sleeves into all eight cylinders?

The whole idea might not be feasible to do as a one-off deal (not with the crank issue), but it might get a lot more feasible if some company decided to produce a small run of the necessary parts.  It probably wouldn't make converts out of anybody in the dedicated drag classes, but it might make for a lot of fun street cars.

.

[Chryco Psycho]

sleeving, especially all 8cylinders , will improve block strength

[Rolling_Thunder]

the only downside is you would never be able to remove the deck plates at the point correct ?

[Chryco Psycho]

true