Lets talk engine packages

[CDW6212R]

The stock pistons have a large deck height measurement, which is what makes the strokers so easy to do. There is a lot of room to alter the heights. For a 302 it makes getting the chamber as small as possible desirable. You can remove volume with shorter pistons. I wonder if any used stroker rods might be available, to go with shorter pistons. Having longer rods can help some with efficiency, but shorter pistons would have to be matched with them.

What do you think Rob, could a better aftermarket piston with correct rod length be found reasonably? If they could be had for under say $500 that could be a good choice for a 302.

 

[Dan Whitaker]

I want to go forged pistons & rods. Is it worth the extra $ for this?
I plan on keeping the stock crank.

Right now I'm looking at Scat for the pistons & rods. JE & Wiseco are more than I would like to spend.

Should I have everything balanced?

 

[CDW6212R]

Definately have it all balanced, there is a little bit of art to the process of doing the assembly, find a trusted machinist to do that.

Most of Ford's cranks have been very strong compared to most other car makers, especially Chevrolet. They always have to hunt for special forged cranks, Ford's are usually great for moderate use, say below 7500rpm.

 

[chriswells78]

I've always heard that any 5.0 crank will hold up to 450HP no problem.

 

[rocket 5979]

The stock pistons have a large deck height measurement, which is what makes the strokers so easy to do. There is a lot of room to alter the heights. For a 302 it makes getting the chamber as small as possible desirable. You can remove volume with shorter pistons. I wonder if any used stroker rods might be available, to go with shorter pistons. Having longer rods can help some with efficiency, but shorter pistons would have to be matched with them.

What do you think Rob, could a better aftermarket piston with correct rod length be found reasonably? If they could be had for under say $500 that could be a good choice for a 302.

I would not see much advantage in doing this with the smaller pistons and longer connecting rods. It will possibly save weight on internal rotating mass but that is about the only benefit I can think of off the top of my head. Of course being that the crank would be stock then the stroke would remain the same so no advantage would come of that either. It seems like it may make for a slightly harder process while only giving minimal gain. I believe this what what you were asking Don. Let me know if I am not quite following what you are meaning.

 

[CDW6212R]

Well any real high quality pistons can be had in any deck height. The stock height leaves room for about 1/4" of shortening of the piston, so a light as possible piston with a rod of the same amount greater length would be better than just a longer piston(stock).

I know, I've gone beyond the basic piston replacement with that. I figured if new high quality pistons were a possibility, then look to see what rods may be better to match a shorter piston. I do not mean to suggest that they or anyone should buy new $600 rods just to gain a tiny power increase.

The only way that changing rods would be feasible for this lower cost project, is if rods could be found cheap, say used from some previous stroker engine. I don't know what kind of parts are now available, strokers have been very popular for a long time, some quality parts may be available. I wouldn't suggest hunting or buying them for an expensive or high powered engine, but a budget engine can benefit from that type of part.

I was just thinking okay, a little out loud and out of the box. Regards,

 

[Dan Whitaker]

Are stock pistons pressed fit?

 

[CDW6212R]

Yes, I think all non modular Fords have all been pressed in. I'm not sure about the modular engines though, Rob?

 

[chriswells78]

Welp, went to this place tonight...

I talked to one of the sales/product reps who was VERY knowledgable about Ford truck motors.

He suggested the Trick Flow stage 1 kit or some sort of Stroker bottom end kit. As far as a cam, he suggested sticking with the stock cam but moving to 1.7 rocker arms and better springs.

 

[CDW6212R]

In my not-so-humble opinion, by your description, that guy doesn't know enough about truck engines to be giving advice. The engine compression wasn't mentioned, or was it, the Trick Flow kit is a higher rpm kit than Explorer's(trucks) need, was rpm even mentioned, and cams are made to work with 1.6 rockers. Meaning that any cam is made to produce the lift intended, with the stock ratio rockers, which is 1.6:1. That advice listed above sounds like it's coming from an average Mustang guy, other than it not including some big rpm cam.

Look harder, find experts who comprehend making power under 5000rpm, maximizing efficiency(compression), and the importance of matching a cam to it. Skip the roller rockers, unless you have an extra $200 after the project is over, it isn't worth the 5hp gained. Regards,

 

[chriswells78]

Actually, he's an off road guy, runs F-150's from what he said. He was sayint the 1.7 rockers will make the valves open wider and for longer. I told him that trick flow didn't even suggest the stage 1 kit but he said it was probably just some guy cutting and pasting from a script. He said the trick flow stage 1 is advertised as 2000-6000 but there would be considerable gains below that as well.

Those Pics are of the Summit Racing store in Tallmage Ohio BTW.

 

[Dan Whitaker]

A 1.7 rocker will give you more valve lift but not more duration.

 

[chriswells78]

The more you lift it the longer it's going to stay open. Just a fact of mechanical engineering.

 

[Dan Whitaker]

If the trash talking & name calling does not stop imediately I will close this thread!

 

[Turdle]

The more you lift it the longer it's going to stay open. Just a fact of mechanical engineering.

Yup--this is correct

 

[Dan Whitaker]

I stand corrected. However a 1.7 rocker arm is not going to significantly increase duration & lift.

The stock cam has .430 I & 4.50 E
With 1.7 rockers you would have .456 I & .478 E

 

[chriswells78]

So that puts it about halfway between stock and an E cam. So it should keep the current power band but add some oomph. Especially with better springs and lighter rockers.

 

[chriswells78]

So I started looking at rockers, lots of choices and prices. A few questions...

What does a roller tip do? Less friction I take it between the tip of the valve shaft and the rocker arm?

What size is the stud in GT40P heads? 3/8 or 7/16?

What size are the springs?

 

[Turdle]

So I started looking at rockers, lots of choices and prices. A few questions...

What does a roller tip do? Less friction I take it between the tip of the valve shaft and the rocker arm?

What size is the stud in GT40P heads? 3/8 or 7/16?

What size are the springs?

ok--think with your engineer cap on and bear with me--

As the cam lobe increases, so does the "arc" of motion between the rocker tip, and valve stem. With a stock rocker arm this is a crucial adjustment, as the rocker can "drag" the valve stem out of alignment, and wear the seal ( guide) very quickly.
In extreme cases, the repeated slight bending of the end of valve stem and heating it, over and over, can make it break. I saw an article in the March '06 hot rod magazine, where they diagnosed a grenaded engine, and this was the cause. This engine was in fact their 302 test mule---BTW
The engine swapped a valve between cylinders--at 6000 rpm's, the pistons hit it 100 times each in a second---
yeah--there was a hole in the oilpan,along with a bunch of scraps, and pieces of metal on the dyno room wall, shot out of the headers--
Nothing was salvageable

stud size (stock) is 5/16"

 

[Turdle]

Ok--yes it is a mopar reference--but it illustrates my point--

http://www.moparmusclemagazine.com/howto/38620_rocker_arm_upgrade_install/