Seeking advice for a budget iron block build

[RainyP71]

Hello,

Looking for advice to finally put together a short block. I have been acquiring parts for a long time now for an all out Aluminator block build, but figured before I go building a high dollar engine, it would be best to cut my teeth on something more budget friendly to avoid the heartache of destroying much more expensive parts on my first go round if things go awry.

Currently these are the parts I am planning on using. I don't have a hp goal, just looking for a good and reliable NA pump gas 4v setup to build out of a hodge-podge of left over parts I have acquired over the years while gathering parts for a bigger build. Figured id start with the short block. I have multiple sets of heads I could use, but I think I want to go with a set of 99 cobra heads I have laying around with 96-98 intake cams, Mach 1 intake, accufab tb, 47lb/hr ford racing injectors m-9593-lu47

Short block:
03/04 cobra iron block, currently at 20 over with scuffed bores, hoping a 10 thou cleanup will make it usable.
2006 3v STD/STD cast steel crank
Brand new set of CR3Z-6200-B "boss" coyote connecting rods
ATI balancer
ARP main studs
I have both a ford performance high volume OR Melling M360HV I could use.
Ford performance 4v timing kit, I also have TFS billet crank gears and L&M secondary gears.

I need advice on selecting pistons for compression ratio and bearings. I was planning on going with 1-FX 4032 alloy DSS racing pistons because that is the price point I am looking for and I do not plan on needing the benefits of 2618 alloy.

Any guidance would be appreciated, thanks in advance.

Robert

 

[01yellercobra]

Is the 3V crank 6 or 8 bolt? If it's 6 bolt add a flywheel to your list of parts. But isn't there something different about the 3V crank from the 2V/4V? Or am I thinking of the Coyote crank?

If you're going for budget skip the forged pistons and go hypereutectic. Aim for 10-10.5 since you're staying N/A. You might be able to do 11:1 and live on pump gas. Plus the hyper pistons tend to be lighter than forged.

These engines don't really need a high volume pump. All it'll do is empty the pan quicker.

 

[RainyP71]

6 bolt crank, and I think you are thinking of the coyote crank, there shouldn't be anything different from my understanding.

And you know you may be right about going hypereutectic pistons, that was something that never crossed my mind. All I really am trying to build is a slightly stronger stock motor.

 

[01yellercobra]

I believe the cast stuff is a little lighter than the forged stuff too. That might get you a couple extra horsepower.

 

[52merc]

Using the following specs and the DSS 1-FX piston:

Bore Dia.=3.582"
Stroke Length=3.543"
Rod Length=5.933"
Compression Height=1.210"
Piston Bore Clearance=0.005" (approximated)
Top Ring Down Distance=0.300" (approximated)
Head Gasket Bore Dia.=3.622" (OE stock)
Compressed Head Gasket Thickness=0.036" (OE stock)
Combustion Chamber Volume=3.17 in³ [52 cm³]

Displacement=285.6 in³ [4.68 L]

With -4 cc 4V Notch Flat Top CR is 9.88:1
With -12 cc 4V Notch Dish CR is 8.92:1
With -21 cc 4V Notch Dish CR is 8.06:1

 

[RainyP71]

Thanks for the calculations! Rather disappointing results as I was hoping to be able to get closer to 10.5.

 

[52merc]

You would need to go with a piston that is -1 cc or less. There are a few around but may be too costly for what you are trying to do. My calculations are for stock block deck height. Decking the block 0.020" will get you to 10.34:1. There was some variance on combustion chamber size from the factory so the only way to get a good CR number would be to volume check the heads. A combustion chamber volume of 51 cc along with the 0.020" decking would yield 10.5:1.

 

[RainyP71]

Seeing as this block is already at 20 over, the deck may have been cut pretty well already. It was a Jasper rebuild so I wouldn't be surprised. I'll get the block over to the shop and have them check it out and I'll start getting things ready to have the heads refreshed then I'll measure the combustion chamber. Thank you for the help!

 

[RainyP71]

When it comes to bearing selection and clearances for the crank, what should I be asking the machine shop? Both my block and crank are in good condition on the mains and standard sized currently. Any advice on bearings to use and oil clearance targets?

 

[Badaz01]

Seeing as this block is already at 20 over, the deck may have been cut pretty well already. It was a Jasper rebuild so I wouldn't be surprised. I'll get the block over to the shop and have them check it out and I'll start getting things ready to have the heads refreshed then I'll measure the combustion chamber. Thank you for the help!

I had Manley flat tops in my 01 cobra that put me at 10:67.1. It was a little to hot even for e85 on 15# of boost. But would probably to good in an na build. I’m currently rebuilding myself for 9:1 compression but mines a whole different animal. Sometimes I wish I kept it simple and stayed na.

 

[01yellercobra]

I had Manley flat tops in my 01 cobra that put me at 10:67.1. It was a little to hot even for e85 on 15# of boost. But would probably to good in an na build. I’m currently rebuilding myself for 9:1 compression but mines a whole different animal. Sometimes I wish I kept it simple and stayed na.

Wut? I know of builds that ran 11-12:1 with boost on E85. One of my Cobros here is running a built engine with 11:1 and a Whipple 3.0 at 28 or 29psi. He's close to 900hp. I'm beginning to think your tuner might be your issue.

Op, what about looking for Mach pistons? I don't remember how much difference there is between the chambers in the 99/01 vs 03/04 heads. But the Machs were 10.3:1 from the factory. Well, thereabouts.

 

[Badaz01]

Wut? I know of builds that ran 11-12:1 with boost on E85. One of my Cobros here is running a built engine with 11:1 and a Whipple 3.0 at 28 or 29psi. He's close to 900hp. I'm beginning to think your tuner might be your issue.

Op, what about looking for Mach pistons? I don't remember how much difference there is between the chambers in the 99/01 vs 03/04 heads. But the Machs were 10.3:1 from the factory. Well, thereabouts.

Yea idk driver side bank ran leaner than the other for some reason. Idk.

 

[Blkkbgt]

When it comes to bearing selection and clearances for the crank, what should I be asking the machine shop? Both my block and crank are in good condition on the mains and standard sized currently. Any advice on bearings to use and oil clearance targets?

You're not building an all out race engine, keep the bearing clearances within the oem spec.

I personally am a fan of King SI bearings. They are considered a stock replacement and they've always measured properly for me.

Make sure you triple check every clearance. If you don't have access to a dial bore gauge buy one especially if you plan on doing this again.

If you use T-gauges or snap gauges and a standard micrometer don't snap them into the bearing, guide them in slowly or you'll dimple your bearings.

For your rods and mains plastigauge is actually a decent final check. I've tested it against a dial bore gauge and it was darn close and showed I was at least within the clearance limits. Just make sure your using the correct one for the dimensions your dealing with.

 

[RainyP71]

Great advice, thank you!

Also, I think I decided to just stick with the DSS forgings. Realized I have basically everything needed to do a eaton swap, so they cant hurt. Ill just stay N/A for a while until I put the bracket set and intercooler together.