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DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

authors avatar
Re: I think I found a Unicorn!
Posted by: DiDueColpi
Date: March 23, 2018 02:55PM

Got 4.6 block stripped down and pulled all the liners.
It's off to the machine shop on monday.
Going to use 5.3 ls pistons and rods. That gives me a nice modern piston and 6+ inch rod combo at a reasonable cost.
It also lets me destroke the crank slightly to 03.096" to get a 0 deck.
That stroke with the 96mm bore still works out to a 4.555 L engine.
You could also use the 4.0 crank with this combo and deck the block very slightly to get the same result.
Fingers and toes crossed.

Cheers
Fred


mgb260
Jim Nichols
Sequim,WA
(1894 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: I think I found a Unicorn!
Posted by: mgb260
Date: March 23, 2018 04:43PM

Fred, Wow! 3.78 bore! How thick is the remaining liner? Do you have to mill the rods big end on one side like the SBC rods to get the right offset? What is the compression height of the piston and rod length?


DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

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Re: I think I found a Unicorn!
Posted by: DiDueColpi
Date: March 23, 2018 05:45PM

The liners are 3.920" od. so I'm pushing the limit a little I think.
The 4.6 liners measure out at 0.072" so based upon that I should be ok.
Yep the big end needs to be milled. Will do 0.050" per side so that the Chevy bearing will still fit.
Compression height is 1.3140" and rod length is 6.0980".
The difference between the Rover rod journal and the Chevy is 0.0850" so I have 0.170" stroke variance to play with.
You could even get away with the Rover 4.6 rod as the pin is the same @24mm.and the length is close @ 6.110" but it would mean milling the piston and until I have one in hand I don't know how feasible that is.
I know that the compression ratio is a little whack but the heads are the 300 ones so not too much work to cc them. The pistons have an 8cc dish and should be up to at least a little massage as well.


mgb260
Jim Nichols
Sequim,WA
(1894 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: I think I found a Unicorn!
Posted by: mgb260
Date: March 23, 2018 06:31PM

Thanks, Fred!


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5567 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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Re: I think I found a Unicorn!
Posted by: BlownMGB-V8
Date: March 23, 2018 07:04PM

Sounds like a pretty good combination.

Jim


MGBV8
Carl Floyd
Kingsport, TN
(3434 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

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Re: I think I found a Unicorn!
Posted by: MGBV8
Date: March 24, 2018 10:04AM

You're killin' me, Fred!

"The liners are 3.920" od. so I'm pushing the limit a little I think."

Considering there is really not enough meat in the block with the stock liners, I would think the same.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5567 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: I think I found a Unicorn!
Posted by: BlownMGB-V8
Date: March 24, 2018 12:00PM

That's possible. Sometimes we go too far with these engines. That reminds me of a certain ill fated wet liner project awhile back. But, if we don't try we'd never know would we?

Do you suppose there is any reason why we couldn't use a higher quality metal in the liners, such as for instance a chrome-moly steel?

Jim



DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

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Re: I think I found a Unicorn!
Posted by: DiDueColpi
Date: March 26, 2018 03:25AM

The red block that I'm using should leave me with at least a 0.100" min. cylinder wall thickness. And yes it will be checked.
That along with the 0.070" liner wall thickness should be more than adequate for the power level that I'm looking at.
If I were using power adders or winding it up hard, this would be a different build. But I think that this will be a comfortable 250hp 6500 rpm engine that should stay together for a good while.
So I'm really hoping that you're wrong Carl. :-)
I am open to constructive criticism and inspired opposition. But I'm also a stubborn old @#$%&, so I've got to give it a go!

Live like you mean it.
Fred


MGBV8
Carl Floyd
Kingsport, TN
(3434 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

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Re: I think I found a Unicorn!
Posted by: MGBV8
Date: March 27, 2018 11:01AM

Got my fingers crossed for ya, Fred!

I have used the calculators for hours & hours juggling the 3 different Rover strokes with different rods & off the shelf pistons attempting an easy bolt together engine. I have finally decided custom pistons is the easiest route. And, maybe not any more expensive if it offsets some machine shop work. Seems there really is no such thing as cheap when building a Rover V8.


DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

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Re: I think I found a Unicorn!
Posted by: DiDueColpi
Date: March 27, 2018 05:35PM

Yah, I know Carl. My brain is still a little fuzzed out from that exercise.
It may still get custom pistons as the measurements on the world wide interweb are all over the map.
Won't know for sure until I have the parts in hand. Hopefully by the weekend.
The good news is that the block has been tested and there is nothing below 3.0mm for bore thickness.
The bad is that they have to make a counterbore tool for the top of the cylinder. And that might take some time.
Oh well, no rush. I don't even know what I'll put it into yet.

Cheers
Fred


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5567 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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Re: I think I found a Unicorn!
Posted by: BlownMGB-V8
Date: March 27, 2018 07:35PM

3mm is 1/8", should be OK with the liner. Can't wait to see how it turns out.

Jim


DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

authors avatar
Re: I think I found a Unicorn!
Posted by: DiDueColpi
Date: March 28, 2018 01:56PM

Found another piston option if the LS ones don't pan out.
It's right back to the good old 305 chevy
Wiseco has an off the shelf piston that will work with the 4.0 rover rod and 4.6 crank.
Part # K0137X3 is a forged piston 3.766" bore, 0.927" pin with the near perfect 1.250" compression height.
A little spendy @ around $650.00 per set but probably cheaper than all the machine work that I'm staring at.
And it buys me another 0.034" of liner thickness.
Just have to bush the rover rod.
Still going to try the LS stuff first as it's paid for and shipped. But we'll see.


pcmenten
Paul Menten

(241 posts)

Registered:
10/08/2009 10:40AM

Main British Car:


Re: I think I found a Unicorn!
Posted by: pcmenten
Date: March 28, 2018 07:16PM

I have been watching this thread to see how things turn out. I still have a 4.0 engine. I was researching the use of Sodium Silicate as a block sealing solution, possibly even a block repair solution; mixing aluminum shavings with Sodium Silicate and applying it in eroded or cracked spots.

I would want to use Fred's 305 liners to make a 4.9 (or bigger) stroker motor.


DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

authors avatar
Re: I think I found a Unicorn!
Posted by: DiDueColpi
Date: April 12, 2018 04:03AM

The LS pistons, rings and rods arrived today.
Didn't have time to measure anything. But will check it out and post pics tomorrow,
Here's hoping!


roverman
Art Gertz
Winchester, CA.
(2899 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: I think I found a Unicorn!
Posted by: roverman
Date: April 12, 2018 07:29PM

Fred,
You might want to double-check the LS rod offset, in the RV8 bore ? SBC needs different side/side to center in RV8. Too bad you don't like hyd. roller cams..... Good Luck,( probably won't need it).



DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

authors avatar
Re: I think I found a Unicorn!
Posted by: DiDueColpi
Date: April 13, 2018 04:15AM

Ok, so pulled out the old measuring stick.
The rods are exactly as expected with an average 6.0988" center to center.
The pistons look good with a 1.318" compression height. All eight are exactly the same which is impressive for the white box units that I purchased.
IMGP7331.JPG
The pistons are cast and look decent. With a projected 32hp per hole and 6500 rpm ceiling they should be more than adequate.

IMGP7332.JPG
They also have a 70 thou dish. Which means that I can reasonably shave 80 thou off the piston and use the 4.0 rod with no mods!

IMGP7333.JPG

If I can gain enough chamber in the 300 heads this might just work.


Cheers
Fred


MGBV8
Carl Floyd
Kingsport, TN
(3434 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: I think I found a Unicorn!
Posted by: MGBV8
Date: May 08, 2018 11:46AM

"The pistons are cast and look decent"

Yes they do. Not plain ol' cast pistons. Hypereutectic, right?


DiDueColpi
Fred Key
West coast - Canada
(1259 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
What if the Hokey Pokey really is what it's all about?

authors avatar
Re: I think I found a Unicorn!
Posted by: DiDueColpi
Date: May 08, 2018 12:50PM

Yes you're right Carl they are HT.
Patiently (sort of!) waiting for the liners to get fit into the block.

Cheers
Fred


roverman
Art Gertz
Winchester, CA.
(2899 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: I think I found a Unicorn!
Posted by: roverman
Date: May 16, 2018 07:46PM

FWIW, Smokey Yunick, never would have made sbc's live at Indy, without sodium silicate(egg keep/old school).
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