Engine durability strategy

[CTX-SLPR]

Howdy,

The engine is starting to come together and I am now formulating the little details. Here's the combo so far:
Production 8484 4.1 Block with front 3 billet caps
Big valve home ported 8293 heads
twin IHI .48/.63 turbos
1.65 T&D's
72's and modded ECM
LS6 MAF and Trans+
TH400 with 1800/4200 switch pitch
3.07 rear gears
PAC Alky Kit

What I need advice on is in light of the weaker 4.1 block and the 3.07 rear gears I would like to make the power at as slow of engine speed as possible. What
1: Compression
2: Cam (Ductile Roller)
3: Fuel Pump (Walbro)
4: Any other tricks besides a girdle to make this thing more durable

Thanks,

 

[bruce]

Originally posted by CTX-SLPR
The engine is starting to come together and I am now formulating the little details. Here's the combo so far:
Production 8484 4.1 Block with front 3 billet caps

72's and modded ECM
LS6 MAF and Trans+

PAC Alky Kit

Unless this is a race car, 60s with the PAC should be plenty enough for the street.

You ought to get out to say Greenville sometime. I have one of em flaky 4.1L's. 206/206 hydral roller cam. By not means a race car but it's fun.

 

[Nick Micale]

You asked, so here are my opinions!

The 206/206 cam is a great choice for street, low end power, and still pulls nice at higher RPM's.

I would put about 1" of hard block in around the bottom of the cylinders. Will not block coolant flow and stiffen the bottom end.

The combination of the 3.07 gear and the high first gear of the TH 400 will make this a dog off the line even with the switch pitch, for as long as it will last.

For a comp ratio, 8.75:1 or 9:1 is where I have gone. Watch the boost at top end especially with alky and pump gas.

I would not be comfortable with one 340 pump, duals would be my choice unless there is a 5000 RPM cut off.

Good luck.

 

[CTX-SLPR]

This is all going into a 67 Skylark so that might have some effect on advice. The tank will be a Rock Valley custom stainless tank and he is a dealer for Walbro so I've heard some stuff about using a 355 instead of a 340 to supply this beast. I do want to get an S1 4.1 in the future so many of the pieces are there for thier transferablity. That compression seems a bit high, I would like to run 20 psi or so on pump gas and alky. You trust an inch of hardblock to not compromise the cooling of this motor in a street car? Oh well its getting a mammoth radiator anyway. Oh and I forgot to add, twin Ford Probe intercoolers front mounted.
The rear gear is what is currently in my Dana 44 IRS, I don't really have any idea whats in the BOP 8.2" 10bolt thats in the car right now but I'm sure its low with only 2 speeds in the SP300. Without an OD I'd like to keep the rear gears low to keep the cruise RPM. I'm having PAE build the tranny so I'm pretty confident that it will hold up. What about going low first in the 400, how expensive and effective is that option?

Thanks,

 

[Nick Micale]

Originally posted by CTX-SLPR
....... That compression seems a bit high, I would like to run 20 psi or so on pump gas and alky. You trust an inch of hardblock to not compromise the cooling of this motor in a street car? ...... I'm having PAE build the tranny so I'm pretty confident that it will hold up. What about going low first in the 400, how expensive and effective is that option? Thanks,

You are right, would not go that high on compression when planning 20 psi on pump gas and alky. With better gas, it would have great low end power.

If you hardblock only one inch, make sure the water passage holes in the block for the pump are left open.

The tranny will be more than stout enough, not sure about the converter? PAE has lots more experience with switch pitch than I do. He will also know about a lower 1st gear for the TH 400 if wanted.

 

[jastrckl]

Poking around on http://www.forcedinductions.com/help.htm (thanks ken mosher) and plugging in numbers for different turbos at different rpms vs boost levels. Your strategy turned out pretty well with a t66, but poorly with a gt35r. On the gt35r, the lower rpm and higher boost wound up putting you way higher on the compressor map. Just something to think about when you are selecting a turbo (go big).

 

[fast eddie]

CTX-SLPR

check how Jim or one of his boy's wired the solenoid on the switch pitch mine went out after a short time because the solenoid shorted out ,wired with speaker wire directly to the windings ,still havent got my timmer or new solenoid back yet
Ed

 

[CTX-SLPR]

jastrckl,

I'm not exactly sure what you are talking about since I'm going twin turbo instead of single turbo. By going to turbofast.com.au it recommended a pair of Garrett T3 with roughly the same A/R's on the early small turbos on Ford 2.3 I4's which were replaced by near identical IHI units in 87 which have the advantage of being water cooled and are easier to find and cheaper to get. A pair of those will set me back about $200.
Well I'm going with a switch pitch, either PAE's or someone elses. I will need a nice big converter but with no overdrive I don't want to be drinking fuel like a Russian drinks vodka and the car orginally could have come with an SP400 so all the mounting stuff is there.
Does anyone have any beef with the cam recommendation or 8.5:1 compression or any other comments?

Thanks,