procharger 300 in 66 mustang coupe

This project started back in 2013 with the start being a 240 head done by Jerry Arnold. He worked his magic on porting and put in larger valves and 1.6 roller rockers. The head was still in the box until last week. The block is now out for a thirty overbore, new cam bearings . The crankshaft has the counterweights shaved off. I hope to spin it in the 5000-5500 range This will be balanced once the rods and pistons get sorted out. I mentioned the procharger in the header and hoping to run 8pounds boost. The idea with this project is for 90% use on the street, 9% autocross and once a yr to the dragstrip at Brainerd ,MN with MSRA. Hell maybe do the ice drags in Merrill WI this coming Feb.
My questions to you learned forced induction wizards are: what rods and pistons make sense? I've seen the speedpro and silvolite piston along with the molnar , compstar and LS rods, but nothing points to what 's the better way. What numbers for the cam? Again all over the place .
It's these decisions(for me, not having the knowledge and experience) that are the hard part. Doing the actual physical part is the easy stuff.

The straight six crankshaft doesn't normally need the rod and piston weight to be balanced.
Without the counter weights on the crank the rods and pistons need to be as light as possible.

Since you are only looking at 5500 rpm the 1965 to1968 240 six rods and custom forged pistons are a good combination.

For the same rpm range a camshaft with the .050" duration in the 230s will give you a wide power band and make good power to 5500 rpm.

Run more than 8 lbs of boost.

Are you going to use an intercooler with the Procharger?

what about LSA? In some of your other post in a crower cam I see you are liking 114. what does 114 do versus say 108

yolocah":2mzkikwf said:

what about LSA? In some of your other post in a crower cam I see you are liking 114. what does 114 do versus say 108

Click to expand...

The 114 LSA and shorter exhaust duration is more specific to turbocharging especially where a log exhaust manifold is being used.
Under those condition there is no exhaust scavenging but high exhaust pressure instead so it is beneficial to reduce the valve overlap period.

In the case of the supercharger it helps to have more exhaust duration than intake duration to help evacuate the extra exhaust volume.
There are varying thoughts about LSA with a supercharger for street use but for a centrifugal supercharger I would keep the LSA moderate at 112 degrees.

Omit what I said about the 240 rod and custom piston combination for your application. I should have asked some questions first.

Do you know what the chamber volume is in your 240 head?
Are you going to use an intercooler?
Carburetor or Fuel injection?

OUCH!!!
I bought the 240 connecting rods from a 1966 engine this morning. tell me what you are thinking and maybe I'll put them up for sale.
I told my engine builder to order the pistons ,that I can probably change.
65cc chamber volume
yes on the intercooler,hopefully make room.
Holley sniper fuel injection.
I want the engine to run on premium pump gas.

The 240 rod and custom piston gives you a very light piston.

The problem is the piston only has a 1.2" piston pin height which doesn't leave much room above the top of the connecting rod for a deep dish for a low compression turbo engine especially considering your head only has 65 cc chambers.

You would need a 30 cc piston dish just to get a 9:1 compression ratio.
You may be able to get there if you remove most of the pad that extends beyond the top of the connecting rod providing there is enough to balance the small ends of the rods.

Where is your engine builder ordering pistons from?

the pistons will come from JE ,If not those initials it was something close to that. Only 2 letters for the name.
The rods I purchased were cheap to buy. What is the better way to go?

Do you know what the dish volume will be and what target compression ratio is?

Omitted

the target ratio is 8:1 with that said it was picked based on what I've read is usual for a forced induction motor. It can be changed to what works best and runs on pump gas.
I do not know the dish volume

If you are going to run on premium gas with only 8 lbs of boost an 8.5 compression ratio would be sufficient.

That would require a 37 cc piston dish volume.

here again the 8psi was pick for the purpose of having the engine be reliable for a long period . I have no real goal for HP or torq numbers , it 's a build to drive and have fun with.
is there a better choice for rods that will make a piston selection easier?

The 2.100" small journal BBC rods (Molnar and Compstar) have the same big end width as the Ford 240/300 rods.
All other rods mentioned are narrower and would float back and forth on the crankshaft rod journal unless they are piston guided. Too much trouble.

The Molnar and Compstar rods are 6.385" long and require a little heavier pistons than than the 240 rods but there is room above the small end of the rod for any size piston dish and the rods will let you run any amount of boost you want.

https://www.summitracing.com/parts/cpi-b6385ds3b4ah

There has been one 240 rod failure under boost recently.
viewtopic.php?p=625838#p625838

the next step for the build is to select the cam,so I"ll be looking for a lsa of 112 and at .050"duration in the 230's.
I'll talk to the builder and find out what JE said about the pistons ,if they can build them for use with the 240 rods
PMULLER you have been fantastic in guidance,thank you

There aren't any catalog hydraulic cams with a .050" duration in the low 230s for the 240/300 six.
I went to Jones Cams to get a 232/232 duration cam on a 112 LSA.
Since you are supercharging it wouldn't hurt to have extra exhaust duration, something like 232/236.

FYI This is what the piston looks like for the 240 rod on the 300 crank compared to the stock 300 piston.
Custom piston and pin on the left weigh 574 grams. Stock piston and pin on the right weigh 819 grams
https://www.dropbox.com/s/h5rwpzcctzeew ... 8.JPG?dl=0

Here is a close-up of the piston. It has a 10 cc dish. Your piston will need around a 37 cc dish.
Notice how high the piston pin sits in the piston with a 1.2" CH
https://www.dropbox.com/s/0a5olnskn79m1 ... 2.JPG?dl=0

Don't know if this is possible, but am throwing it out.

If you can't find a piston with enough recess, could you increase the 240 head chamber volume to help reduce the CR?

Is there a thicker head gasket available for the 300 to help decrease the CR?

At best you may be able to pull 5 cc out of the chamber by removing material off the chamber walls around the sparkplug but it's not worth the effort.
This is what the finished chamber would look like.

[image]https://www.dropbox.com/s/inzdax63ixm9rrm/240%20chamber.jpg?raw=1[/image]

You can make it work if you remove most of the tab on top of the rod's small end during the process of making all the rod's small ends weigh the same.

[image]https://www.dropbox.com/s/i1jab6zfctu37t1/240%20rod%20small%20end.JPG?raw=1[/image]

my engine machinist(Tim) contacted his piston supplier (JE) and they were not that familiar with this application and said they would have to develope it through a modeling process. We talked yesterday and he suggested that I ask here who to use to have the pistons made.
I gave all the 240 head information from Arnold to him and now I need to get it back to finish filling out the paper work at Jones Cam. I hope to have both of these issues resolved before the weekend.

Racetec/AutoTec Pistons.
http://racetecpistons.com/wp-content/up ... 020_05.pdf

In order to fill out the order form you will need the following information:

Finish the connecting rods so you know how thick the top of the small end is after the tab has been machined down.
If you can get it down to .300" it would be good
This is for "Material thickness above pin"

You will also need to know the actual finished center to center rod length after they have been resized with ARP bolts.

You will need to know what the actual block deck height is.

The rod length and block deck height is needed to calculate piston CD.

You already know the finished combustion chamber volume is 65 cc.

The finished cylinder bore size.

The head gasket is .039" compressed thickness with a 4.18" bore size. 8.77 cc gasket volume.

Knowing the chamber volume, gasket volume, cylinder bore size will let you calculate piston dish volume at a 0 "Piston to Deck Height" for your target compression ratio.

You will need to decide which aluminum alloy you want the piston made from.
The AutoTec pistons are forged 4032 alloy and is a good all around piston.
The RaceTec pistons are 2618 alloy and contain almost no silicon, are much more malleable and will withstand more abuse but they are much more expensive.

You will need to decide who is going to supply piston rings.
If you are going to supply the rings they will need to know the ring dimensions.
Fill in the ring info is at the bottom of the page.

In the "Notes/Special Request" in the lower right section of the form put the following;

No valve reliefs.
No pin offset.

yolocah":nrfoxkxg said:

I gave all the 240 head information from Arnold to him and now I need to get it back to finish filling out the paper work at Jones Cam. I hope to have both of these issues resolved before the weekend.

Click to expand...

Let me know what Mike Jones recommends for cam lobes and Lobe Separation Angle before you buy.

Sometimes the cam suggestion is too conservative for a 300 six.
The 300 has the same cylinder size as a 400 V8.
He needs to know that you want peak torque at 3600 rpm and peak horsepower at 5500 rpm.