Engine build efficiency mods

[oil pan 4]

So its time to put together my new engine. I will break it down into each group.

Compression:
Right now I am have tighter gaped piston rings to allow less blow by past. I wanted to run 0.02'' gap piston rings, the machine shop said I needed to be at 0.028 minimum so I put them at 0.024''.
Then I bumped the compression from 7.9: to 11:1
Higher compression should give more power and better fuel economy.
Had to have the machine shop bore out the engine 0.03 over because some of the cylinders were badly tapered from a leaking cylinder head gasket allowing coolant to wash away the oil from the cylinders.

Preheating:
I left 2 open freeze plug spots for 600 watt engine block heaters. Then once I have the oil pump pickup connected and installed I am going to cut a hole in the oil pan to install a oil sump heating element.

Bearing clearance:
Right now I am working on the rod and main bearing clearance. The main bearings are on the loose side of .004 that would work but I would like to get a little tighter closer to .003 inches. Tighter bearing clearance will allow me to run thinner oil which will make starting easier and give better fuel economy and will allow the engine to wear more before its warn out.
The most correct way to fix that is go buy a set of -.001 undersize bearings and mix and match them with the standard bearings to get the desired clearance.

Roller conversion:
The old cam used flat lifters. I have gotten a comp camps roller conversion set. The roller cam also creates about 16 more foot pounds of torque through the entire operating range. The benefits of that are easier starting, better fuel economy and now I wont have to look for much more expensive SH and SJ rated oils I can use cheaper normal oil. The depleted additive package in SN and SM passenger car motor oils can cause a flat tappet lifter to wipe a cam lobe off the cam shaft. GM claimed the roller cam made a 1.5mpg improvement on their small block powered vehicles with the roller cam compared to the same engine with flat tappet cams.
I also picked up a set of full roller rockers, because why not?

Stroker:
Went from a 4 inch stroke to a 4.25 inch stroke crank to give more torque on the low end. I would like to get the cruise RPM down to between 1,200 to 1,400 RPM at 75mph.
The boring and the stroking should bring the engine displacement up to 489 cubic inches or right about 1L per cylinder. So it will have plenty of power to putt a long at 75 to 80 MPH at unusually low RPM even in thin air found at high elevations here in NM. In texas or new mexico all the speed limits are 75mph. I would have to drive at least 8 hours before I got to a state that didn't allow 75mph highway and interstate speed limits.

Weight reduction:
I tossed the 77 pound each cast iron heads, the 55lb cast iron intake manifold for aluminum and tossed the 20lb each cast iron manifolds for tube headers.
Saving nearly 120 pounds.
I have a light weight mini starter in my parts collections. It replaces a 25lb factory starter with a 10lb permanent magnet gear reduction starter. Plus the factory starter was never intended to turn over an 11:1 compression stroker engine.

Valves:
I still need to look at the exhaust valves in my old cast iron cylinder heads to see if my lean burn tune was burning up the exhaust valves. If so then I need to buy some high tech more heat resistant exhaust valves.

Less oil:
I am replacing the truck oil pan with a chevelle oil pan.
That means 1 less quart of oil to add each oil change, 1 less quart of oil to warm up, so the engine oil will come up to operating temperature that much faster and there is less chance of damaging the oil pan because it sits about 1 to 1.5 inches higher off the ground.

Clean:
I am putting the engine together on the engine stand in a spare bed room to keep the dirt and moisture out of it compared to assembling it out side and storing it in the garage.

[Daox]

Sounds like a nice build.

What vehicle is it going into?

Any plans to use ceramic coating or thin film coatings on engine internals?

[serialk11r]

I dunno if you're up for the expense, but a regrind to move the intake cam lobes so they open and close later would get you some fuel economy, as well as enable a higher compression ratio.

[adam728]

What's the piston/ring manufacturer recommend for end gap? That's who you really need to listen to. You definitely do not want to end up too tight.

Too loose and you end up with 0.25% more leak down. Never notice.

Too tight and score/gall/seize bores the first time it runs, or is run hard. You'll cry about an expensive lesson learned for a long time.

[Frank Lee]

The mfg's have bazillions of hours of dyno test time. They probably explored the minimum gap limits then backed off just a smidge to allow for all the assembly variables out in the real world. No doubt they've also tested leakage at about all possible gaps and combinations. IMHO a person could go under the recommended minimum but not by much and also keeping in mind how hard the engine is loaded and how hot it might get i.e. if I was building a highly loaded engine I'd consider staying in spec.

[oil pan 4]

This is going back where it originally came from, the 2wd tan 3/4 ton suburban.
Yes I know the suburban has a 3 speed auto with 4.11 gears, but last year I bought 3.21 gears and an air locker and I have not had time to mess with it. But the machine shop that machined my engine block also does axles and drive shafts. I am going to have them install the gears and show me how to do it since it sounds like the guy running the shop wants to retire some time with in the next 12 to 24 months. He wont be around to do it next time.
Obviously the 1:1 top gear of the transmission and 3.21 gears wont but should be a good improvement over the previous cruise speed of 3,000+ RPM at highway speed but wont be anywhere near what I was talking about it being 1,200 to 1,400 RPM.
To get the cruise that is where the firebird come in.

Anyone who reads my posts is thinking "what firebird?"
I just bought a 1987 firebird with a six speed T56 installed. I think I am going to put it in the firebird with a ford 9 inch rearend with a relatively numerically low rear end gear, a 3:1 or more likely a 3.25:1. (Depending on if the T56 has a 0.5:1 or 0.6:1 top gear)
Problem is the stock T56 is only good for 450 foot pounds of torque. This 7.4L turned 8L engine will make a size appropriate 600+ foot pounds of torque. Posts on the chevelle tech forum say that an engine like this will snap the input shaft right off a stock T56. So I might have to get the upgraded "T56 magnum" which can handle 750 foot pounds of torque. Eh its only money.

[oil pan 4]

I run 0.018 inch top ring gaps and 0.014 inch 2nd ring gaps on my diesel which uses 22:1 compression and will run 5 to 6 PSI of boost sustained for hours on end. I think 0.024 is way on the safe side.
The cylinder bore diameters of both are with in less than 1/4 inch of each other.

[Frank Lee]

Run skinny tires so it can't hook up hard, then things shouldn't break.

[pgfpro]

Sounds like a cool build. I'm confused, is this engine going in the Suburban or the Firebird or both?

[oil pan 4]

First one then the other.
I want to drop the engine back into the suburban as soon as I can so I can get some use out of it right away. That's where the engine came from so it should drop right back in and go. Putting it in the firebird will take some work and will need to be done later on. I am not worried about taking that engine back out of the suburban because the first time I pulled it by my self in less than 5 hours.

Then while the engine is in the suburban I want to use the cavernous under hood area to work out mods and tuning.
For example I am going to start using the engine with premium gas, but I would like to wean it off premium gas on to regular by using water/methanol at anything more than part throttle. It should be able to cruise down the road and accelerate gently just fine on regular. Why burn premium all the time when I really only need premium like 2% or 3% of the time when hard on the throttle?
All that room would allow me to work out the water methanol stuff with ease.

Another roomy mod will be the carb heater. it will make the carb and air cleaner sit up an inch taller, need to decide if its even worth using in the car. Because an inch taller under the suburban hood is nothing but an inch under a car hood can complicate things a lot.

The suburbans vast under hood room and huge ground clearance will help me work out tuning, possibly automating the exhaust cut outs.

The car currently has 275mm wide ultra high performance summer only yoko tires on the back.
To me launching hard is kind of risky for the 7.6 inch stock limited slip rear end (the weakest link) with the stock "L98" high output 5.7L engine.