2001 Cobra: Newbie Engine Build Thread

[SlowSVT]

Will the Trinity pan fit our chassis? It's a popular upgrade in the S197 community. I've been curious if it'll work for us.

It won't clear the K-member. I modified one to fit an Terminator for a fellow SVTP member but it was a lot of work. A cast oil pan makes me a bit nervous so I replaced the vulnerable spots with 3/16" and 1/4" aluminum plate. It came out real nice but next time I'll fab one from scratch which will be soon.

 

[SlowSVT]

To clarify, i am going to get the shop to check the block flatness, bores and hone as neccessary, line bore which ensures the crank lies straight, and clean and check the block for cracks....anything else i am missing?

Good first move. Ask the machine shop if they have a toque plate for boring and honing the cylinders (which will be "no") if you get to that stage with this block. If this was me I'd go to someone who does or you can rent one from MMR. This simulates the clamping load imposed by the heads and studs which distorts the cylinders so the boring bar can make a hole that will be "round" when the cylinders heads are torqued to the block. This goes "doubly" for an aluminum block do not skip this step!

 

[OW99]

Any good machine shop should have torque plates.

 

[CJK440]

The car will never be forced inducted. If anything we may do some work on the heads but need a running car first, or with the advice of forum users, to do worthwhile upgrades while the motor is dismantled.

Maybe I missed it but I think you need to elaborate on the goals for this car now and for the future.

 

[6mtsedan]

Goals are quite simple....
Retain factory power, if cheap and feasible upgrade power as the engine is apart. First and foremost is reliability. If building the motor from fresh, we dont want another spun bearint

 

[bzoli]

I'm also in the same shoe, planning my 99 cobra engine rebuild. Last summer I measured the compression end pressure and it was fairly low, pressure increase once I put oil in it. I will do a leak down test before I disassemble. Anyhow I find such threads as this one very informative.
So here is the question: once the engine is taken apart would it makes sense to fix the spark plug threads before I spit one out? Timeserts or LocknStitch?

 

[01yellercobra]

Are you planning on a lot of boost? I have the 4 thread heads and they've been ok at 19psi. I did spit a plug a few months ago. But it was my own fault. It didn't feel like it went it right, but I was in a hurry and ignored it.

 

[SlowSVT]

So here is the question: once the engine is taken apart would it makes sense to fix the spark plug threads before I spit one out? Timeserts or LocknStitch?

Ask yourself: "how paranoid was I when torqueing new plugs into a hole with only 4 soft aluminum threads?" :uh oh:
Then ask "what would be my reaction be if the engine spits a plug knowing I could have addressed this when the heads were off?" :cuss:

 

[bzoli]

Ask yourself: "how paranoid was I when torqueing new plugs into a hole with only 4 soft aluminum threads?" :uh oh:
Then ask "what would be my reaction be if the engine spits a plug knowing I could have addressed this when the heads were off?" :cuss:

If I read between the lines correctly that is a definite yes ...:rollseyes

 

[6mtsedan]

Update: Not much of an update. Engine is at the machinist right now. Its going to require some work to the block but the project pricing came in just under our budget.

I need to replace the lower door hinge. I got the nuts off but cant seem to get the hinge off. Is there a secret? Should i also replace the upper hinge while i am in there or just leave it?

 

[6mtsedan]

Todays Update:
Went by the machine shop to get an update on everything. They've completed the block and now waiting on the pistons, rods and bearings. The block itself was straight and unwarped. The cylinders needed boring and honing.

The short block will have forged wiseco pistons/rod and clevite bearings. The oil pump will be a high flow unit.
Should I really be upgrading the bolts to ARP or are the stocks fine? This car will only be seeing 300rwhp. I have until the end of the month to decide.

Also, these motors from what i gather make about 280ish to the wheels. Whats the cheapest and most effective way to bump up that extra 20hp keeping in mind car is stock and a fresh rebuild?

Thanks for all the help guys, you rock!

 

[bzoli]

Todays Update:
Went by the machine shop to get an update on everything. They've completed the block and now waiting on the pistons, rods and bearings. The block itself was straight and unwarped. The cylinders needed boring and honing.

The short block will have forged wiseco pistons/rod and clevite bearings. The oil pump will be a high flow unit.
Should I really be upgrading the bolts to ARP or are the stocks fine? This car will only be seeing 300rwhp. I have until the end of the month to decide.

Also, these motors from what i gather make about 280ish to the wheels. Whats the cheapest and most effective way to bump up that extra 20hp keeping in mind car is stock and a fresh rebuild?

Thanks for all the help guys, you rock!

What clevite bearing? Aluminium backed stock replacement or steel backed bearing? Why?
What is your rod bearing choice?

 

[6mtsedan]

What clevite bearing? Aluminium backed stock replacement or steel backed bearing? Why?
What is your rod bearing choice?

I am not sure if they were aluminum or steel but will find out in a few days. Which one is better and why? is the failure rate significant if they are aluminum bearings? I would hope the machine shop wouldn't have cheaped out on that!

 

[soccerman002]

A cold air, exhaust, and tune will get you right around 300rwhp.

With just an exhaust and cold air I dyno'd 292rwhp - I've since uploaded a Steeda tune and installed their underdrive pulley kit, should be well over 300rwhp at this point. Once I get my longtubes and new mid-pipe installed and get a new Steeda tune, I expect another nice bump.

 

[01yellercobra]

I am not sure if they were aluminum or steel but will find out in a few days. Which one is better and why? is the failure rate significant if they are aluminum bearings? I would hope the machine shop wouldn't have cheaped out on that!

One is more race oriented. I think it's the steel that's more race oriented. IIRC it has a soft upper layer that wears down quickly. It's for engines that are opened up a lot for rebuilds. You want the aluminum stock style replacement.

 

[6mtsedan]

One is more race oriented. I think it's the steel that's more race oriented. IIRC it has a soft upper layer that wears down quickly. It's for engines that are opened up a lot for rebuilds. You want the aluminum stock style replacement.

Hopefully it aluminum then!

 

[ashleyroachclip]

I have a 91 coupe, has an 01 drivetrain, trekked block,3650 trans, IRS with 3:27 gears.
Over the winter the iris will get re built with 3:73 gears.
New centerforce dual friction clutch .
Engine runs.strong.as is, but I have been picking up parts for a year or so.


To date I have a set of cp pistons that came on the factory 03-04 rods .
I don't plan on using these pistols, as my goal is forced induction.
Plan is is to use all arp hardware, rods already have the 2000 version , and forged pistols, billet oil pump upgrade, vintage tray , upgrades timing setup.

Goal is to build a short block, while still driving the car, then the heads once I pull the engine.

Along with the turbo, at least a single ,maybe twins, I don't want to spin this engine more than 6800,maybe 7000.
I don't have e85, would do nitrous before that, in fact I plan on using nitrous to help spool and keep IAT temps down , so it,will be 93 and 110 race fuel.
Sorry for the long wind.

And since I want the same as the OP whose thread I have hacked, relliability and a sleeper with power , can,you guys give a compression ratio that will work with the 01 heads, and the aforementioned power adders.

also the IW dampner
Long tubes a d fuel upgrades.

 

[bzoli]

One is more race oriented. I think it's the steel that's more race oriented. IIRC it has a soft upper layer that wears down quickly. It's for engines that are opened up a lot for rebuilds. You want the aluminum stock style replacement.

Tend to agree, plus the stock main cap bolt toque will have the right crush of the aluminium backed bearing without putting more stress on main cap.

 

[6mtsedan]

Tend to agree, plus the stock main cap bolt toque will have the right crush of the aluminium backed bearing without putting more stress on main cap.

I wonder why it was recommended in the parts list (previous page) to get the steel backed bearings? Is there any parts that should absolutely not be reused?

It appeared that the heads were fine and undamaged but they will be getting cleaned up and worn parts replaced. I'll be popping into the engine shop at the end of the month to see how they build this.

One thing that I have not been able to figure out in case I ever want to build an engine like this in the future.

Now for the ELI5:

When sizing the pistons, you have the dimensions of the cylinder say its 90mm. How do you order your piston because then you have rings too... would you get an 89mm piston and then the 1mm difference is taken up by the ring or is there a standard space that you need to have between i guess the ring to cylinder wall or is it more important to have a certain spacing between the piston and cylinder wall?

When sizing the bearings...this crank was .2 and .1 on all the other areas. This would mean that I would need a .02" oversized bearing on the one area and a .01" on the rest?

If someone is building up the shortblock, how do you get more power? I would assume that this is where the displacement and overboring the cylinders come into play? When they talk about stroke, how does this come into play with power production? What about compression ratios?

 

[01yellercobra]

I wonder why it was recommended in the parts list (previous page) to get the steel backed bearings? Is there any parts that should absolutely not be reused?

Because a lot of people want to make a race engine to drive on the street. They don't realize a race engine needs a lot more maintenance. I have stock style replacement bearings in mine. I'll know the condition in a couple weeks when I tear the engine apart. You need to reaplace all torque to yield hardware. Head bolts, cam bolts, and main bolts. You can go with ARP, but for a stock rebuild I'd just get stock replacements.

It appeared that the heads were fine and undamaged but they will be getting cleaned up and worn parts replaced. I'll be popping into the engine shop at the end of the month to see how they build this.

One thing that I have not been able to figure out in case I ever want to build an engine like this in the future.

Now for the ELI5:

When sizing the pistons, you have the dimensions of the cylinder say its 90mm. How do you order your piston because then you have rings too... would you get an 89mm piston and then the 1mm difference is taken up by the ring or is there a standard space that you need to have between i guess the ring to cylinder wall or is it more important to have a certain spacing between the piston and cylinder wall?

There is a standard space between the piston and cylinder. Usually called piston to bore clearance. This differs with different pistons. Forged pistons need more clearance than cast pistons due to expansion. The rings are there to completely seal that small space. They're not there to take up room. If the piston is too small it can cause issues. Such as rocking in the bore which will damage the piston and cylinder wall. What should happen is if you need oversize pistons the shop will tell you. Then either you or they order the pistons. When the new pistons come in they will bore each cylinder for the correct piston to bore clearance. The reason it needs to be done this way is because pistons aren't always the exact size stated. So adjustments in the boring size need to need to made.

When sizing the bearings...this crank was .2 and .1 on all the other areas. This would mean that I would need a .02" oversized bearing on the one area and a .01" on the rest?

Yes it would. This might mean having to buy two different sets of bearings though. I haven't seen mixed sizes in the same box. On the bright side you'll have some spares.

If someone is building up the shortblock, how do you get more power? I would assume that this is where the displacement and overboring the cylinders come into play? When they talk about stroke, how does this come into play with power production? What about compression ratios?

The easiest way to get power while buiding the shortblock is raising the compression. Any gain from the standard overbore is negligible. To really gain power you'd need a big bore set up. Longer stroke increases displacement. Which usually increases torque and leads to more power. But that requires either offset grinding the crank or getting a new crank. If you offset grind the crank then you need different rods. It's a snowball effect. If you need pistons then I'd bump the compression. Unless you absolutely need a new crank I'd leave it as is. If you need a new crank then I'd shop for a stroker set up.

Replies in red.