Unforgiven Project

That music is not to bad.. But I like this style:

Been working alot of OT these past few weeks. Almost made enough to cover the transmission rebuild.
I was talking with Rick and he suggested that I to a separate th400 build thread. I thought it was a good idea, so in a few weeks I will start one.

I just ordered some billet parts and shafts for the build. I still have to save up for a new direct drum and a intermedeate shaft.
I am waiting to gather all the parts I need before I open the case.

The engine is still sitting in the crate, in the back of the diesel truck bed. Being that we don't drive it in the winter... I figure the engine is in a good place until I get ready
to install it.
 
Yep.. I poured some anti freeze into the thermostat housing and opened the drain valves on the bottom of the block. The garage is heated also.
 
Grumpy asked for a quick rundown of the final motor specs for members to maybe duplicate.

I must state that I am not totally sure if this engine would work well on the streets. (More on this later.)
It was purposely built for my strictly off road truck and was specifically built for E-85 fuel.
The engine does idle very well at 850 RPM's, But .... on my first test hit, when I had the motor in the truck, (before dyno testing),
The acceleration was very violent, and instant,to say the least.
This may be overcome by installing a progressive linkage on the throttle. I think..
Also , the steep gearing (6.17:1 ) is a main factor in the jumpyness the truck exhibited as it started to roll forward. This would get very old fast in a street car, But it's damn fun in an off road truck!!
Being that no street car runs that steep of a gear, I am quite sure the jumping off the line could be tamed.

Those are a few issues that really could be over come , and are not really the engines fault.

So.... for those who are interested... here are the parts I used..

385 ci SBC
Bow-Tie Block with a 4.040 bore
Scat rotating assembly
5.7 forged rods
11:1 forged pistons

cam specs: .507/.530 lift .243/.253 dur on 112
anti pump up flat tappet hydraulic lifters
1.6 roller rockers

Promaxx 200 heads (slight porting)

177 Weiand blower with extensive porting (8.5 lbs boost)

Holley Super Sniper EFI
Hyperspark ignition system with 9mm wires

M77 oil pump
Canton 8 qt oil pan

ARP hardware

1 7/8" headers
 
thank you for posting the details,
its sure to help others if they are interested in duplicating something close to your project
 
Note to self: PAY THE EXTRA $600 FOR BETTER PISTONS !!!!
 

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yeah the heat and potential detonation that can result plays hell with pistons,
and yes forged pistons and probably higher octane fuel and maybe water injection to cool the combustion temps may be warranted
 
You had forged pistons, so what would another $600 have gotten you ?

Maybe it wasn't the piston fault, maybe even high dollar pistons would have failed. You might need to
back down the boost or lower your compression. If you lower the boost, that would also lower the
air temp.
 
Well... the pistons were forged 2618 Weisco and the fuel was VP C85
Going to rebuild AGAIN with Diamond brand pistons
 
I agree Rick... Pistons were 11:1 , but the formula I used with the fuel supported the compression. I am only runing 10 psi.
there are guys out there running as high a 30+ lbs.
My thinking is that the fuel (C85) may have clogged the injectors somewhat from being quarentined in the barn too long.

I got the dyno/tuner guy looking into it.
The A/f was tuned power rich. (7.1) on the E85 scale.
At an idle you could see a slight spray of fuel coming out the collectors. I thought that that might have an issue of washing the rings and cylinder down.. It's all speculation at this point.
We are installing a back up motor this weekend and going to go through this evil motor afterwards.
 
 
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Grumpy said:
think about adding water or alcohol injection as its a reasonably priced way to reduce potential detonation
Click to expand...

I think I proposed that idea earlier in the build thread ... we determined that it might no benifit because I was already running ethonal.
But I am open to anything.
 
you should not be having these issues with e85 unless your jetted too lean,
or you had a injector fail or the fuel delivery system can,t keep up with the engines demand,
remember alcohol; you must supply about 40% more fuel volume,
that may require a different fuel pump or injectors and with a supercharger you effectively need to boost fuel pressure,
to overcome boost pressure,
so if let's say you have 10 lbs of plenum pressure,
your 60lb of fuel pressure is effectively reduced by 10 psi to 50 psi at the injectors,
just like your valve springs that generally require a bit more spring seat pressure to seat the valves art higher RPMs,
as that 10 lbs of boost resists the valve closure.
let's say you have a 2.02 intake valve, that's roughly 3.17 sq inches of surface are fighting 10 lbs of boost resisting its closure.
so you've effectively lost or need an extra 30 lbs of valve spring pressure to close the valve at higher RPMs
Id also cut back a few degrees on total ignition advance, if you're experiencing symptoms of detonation

http://garage.grumpysperformance.com/index.php?threads/how-big-a-fuel-pump-do-you-need.1939/

http://garage.grumpysperformance.com/index.php?threads/calculate-fuel-injector-size.1200/
 
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Unforgiven said:
Pistons were 11:1 , but the formula I used with the fuel supported the compression. I am only runing 10 psi.
there are guys out there running as high a 30+ lbs.
Click to expand...
They are also running 11:1 with 30 lbs
of boost ? What is your theoretical CR when you consider the boost ?

Unforgiven said:
My thinking is that the fuel (C85) may have clogged the injectors somewhat from being quarentined in the barn too long.
Click to expand...
So you only had a problem on one cylinder ?
 
Indycars said:
They are also running 11:1 with 30 lbs
of boost ?
Click to expand...

I dont know their compression.. the formula I had used supported MY set up.
I was just making a point that 10psi is not that much. I believe my compression under boost was 16:1
The cooling effect is what allowed me to obtain the higher CR.


QUOTE="Indycars, post: 97364, member: 2753"]So you only had a problem on one cylinder ?[/QUOTE]

No... All 8 pistons are destroyed. Pics are from my bore scope. I havent pulled the heads yet. At first I thought the rings closed together and
broke the ring land.
I had them gapped at .026
Then I seen the melt on #1 piston and seen it was a lean condition .
But... I have seen pistons with wiped out ring lands because of over rich conditions also.

I have been researching the Holley forum today and I am discovering that The Sniper system is known for injector problems .
Now the posts where from 2018 so they may have fixed these issues, such as injectors lifting , connectors coming loose , and ECU's
going bad...which If you recall, I had to send my Sniper back because of an ECU failure.
 
Grumpy said:
you should not be having these issues with e85 unless your jetted too lean,
or you had a injector fail or the fuel delivery system can,t keep up with the engines demand,
remember alcohol; you must supply about 40% more fuel volume, that may require a different fuel pump or injectors and with a supercharger you effectively need to boost fuel pressure,
to overcome boost pressure,
so if let's say you have 10 lbs of plenum pressure,
your 60lb of fuel pressure is effectively reduced by 10 psi to 50 psi at the injectors,
just like your valve springs that generally require a bit more spring seat pressure to seat the valves art higher RPMs,
as that 10 lbs of boost resists the valve closure.
let's say you have a 2.02 intake valve, that's roughly 3.17 sq inches of surface are fighting 10 lbs of boost resisting its closure.
so you've effectively lost or need an extra 30 lbs of valve spring pressure to close the valve at higher RPMs
Id also cut back a few degrees on total ignition advance, if you're experiencing symptoms of detonation
Click to expand...

I have to agree with you Grumpy..
My focus is going to be on that Sniper Unit when I tear it down.
Lucky for me.......when it let go, it just died in the pit. I tryed to restart it and it wanted to fire for a split second , but I could tell the motor was cranking over like the plugs were removed. So... The motor turns over , and it was building 25 lbs oil pressure while cranking.
Nothing else seemed hurt except for the piston rings and cylinder walls. Remember... This is a Bow Tie Race block and has cylinder walls 7/16" thick.
So... I can bore to the next size safely.

As far as the fuel pressure... I have the A1000 fuel pump. It flowed more than what I needed.
The holley pressure gauge is connected to the return side and reads 60 psi all the time.
 
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Just heard back from my tuner. He stated that everything should have been fine. If he had to guess, he thinks the A1000 pump may of not been abls to keep up. He said he believed it was borderline too small. Well Damn... I coulda swore that from the research I did on pumps, that it was more than enough to supply the engine. What I did not take into consideration was the fact that I am under full throttle for 30-45 seconds at a time if I am in some deep stuff. That may have something to do with it too. I also never thought that motor would produce the power it has either! And that may be the problem.... The HP numbers I used for calculating the pump size were alot lower than the actual HP numbers. That is some really good food info for thought right there!!!! I am going to try and recalculate some numbers to verify.
 
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