Putting 92 pistons in 93 460 w/F3TE heads

[DoctorD907]

IM doing a 460 build in my 1993 F350 w/C-6 Trans. It still has the OE SD control system. So far I have punched the block out .030, picked up some new aftermarket castings for the F3TE heads and doing some light porting and sticking with OE valve sizes. I have a Comp cams Xtreme 4x4 cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,000-5,000
Intake Duration at 050 inch Lift: 210
Exhaust Duration at 050 inch Lift: 218
Duration at 050 inch Lift: 210 int./218 exh.
Advertised Intake Duration: 256
Advertised Exhaust Duration: 262
Advertised Duration: 256 int./262 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.514 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.514 in.
Valve Lift with Factory Rocker Arm Ratio: 0.514 int./0.514 exh.
Lobe Separation (degrees): 111
Computer-Controlled Compatible: No
Grind Number: FF X4 256H-11
Valve Springs Required: Yes

So my question is, if I install 92 pistons with the smaller dish will I have any valve/piston interference problems with this setup? I know ill likely have problems with the SD system and likely need to go to the MAF conversion. Any advise would be appreciated,
DrD

[fatdan460]

go here and sign up. they will know everything you need to know.
http://www.460ford.com/forum/

[DoctorD907]

go here and sign up. they will know everything you need to know.
http://www.460ford.com/forum/
__________________

I signed up but have yet to be confirmed by the moderator.

[fatdan460]

Originally Posted by DoctorD907

I signed up but have yet to be confirmed by the moderator.

well boofawkinghoo! sorry you couldn't get your instant gratification. nothing is stopping you from searching the site as an unregistered member. i'm sure there is already info there about your particular situation, look for it

[DoctorD907]

Originally Posted by fatdan460

well boofawkinghoo! sorry you couldn't get your instant gratification. nothing is stopping you from searching the site as an unregistered member. i'm sure there is already info there about your particular situation, look for it

I have done some research but hoping someone with some common sense would reply to my question in a helpful manor.

[dieselboy740]

That's not that big of a cam. Looks like it a touch bigger than a rv cam.

[DoctorD907]

Yes, pretty mild cam. Not the comp EFI cam. Has overlap which can cause problem with the SD system. Just wanted to put the specs out there so we know what kind of lift I am talking about. Mainly concerned about driving a valve into a piston. And wondering if anyone has been there or could send me to the right spot for info. Went to 460.com but found limited info.

[82F100SWB]

I run that cam in a 97 bottom end with e6 heads. No issues.
If you are planning on running the early efi pistons for a compression bump I hate to burst your bubble but the pin height is different and you end up with the same compression with either one. The 93+ pistons will give you much better quench.

Sent from my Galaxy Nexus using Tapatalk

[DoctorD907]

Originally Posted by 82F100SWB

I run that cam in a 97 bottom end with e6 heads. No issues.
If you are planning on running the early efi pistons for a compression bump I hate to burst your bubble but the pin height is different and you end up with the same compression with either one. The 93+ pistons will give you much better quench.

Sent from my Galaxy Nexus using Tapatalk

You didnt burst my bubble, you gave me just the info I was looking for. Thank you! So stock, the 92 must have a lower compression ratio then the 93+ from what I can figure since the older heads have a larger combustion chamber. Anyway, I am going to use the pre-93 fractional pistons since they are available locally and cheaper. Thanks again all for the help. I will let you know how things go.

DrD

[82F100SWB]

Effective compression is the same between the 87-92 and 93-97 engines. Putting the early pistons with the later heads is going to keep compression the same but ruin your quench.

[DoctorD907]

Originally Posted by 82F100SWB

Effective compression is the same between the 87-92 and 93-97 engines. Putting the early pistons with the later heads is going to keep compression the same but ruin your quench.

If compression is the same then I guess I dont understand why the 93+ wouldnt be higher since the combustion chambers are smaller. I understand that you are saying my quench will suffer, I am just counting the cost versus the performance improvement.

[82F100SWB]

Depending on casting variance you are looking at 3 to 10cc difference between the heads. For the gain in compression vs the gain in torque I personally would stick with the better quench and torque.

[metalmacguyver]

What is quench? How are the mods that the OP is doing going to affect the quench and what does the quench affect after it has been changed? Thanks.

[82F100SWB]

The 93+ pistons sit within .010 to .015 of the block deck while the earlier ones sit at .030 plus. The tighter clearance creates a tighter quench area which forces more of the mixture into the combustion chamber and creates a cool spot in the quench area. This increases combustion efficiency and the cool spot it creates in the quench area increases resistance to detonation. The better burn by nature provides better torque and it is helped by the minutely longer dwell time provided by the taller pin height.
The difference in detonation resistance is enough that I can run my iron headed hoopty at 10.25:1 on 87 octane. Hopefully that somewhat makes sense for a 4 am response from my phone while I contemplate pulling the meter off of the neighbors apartment so I don't have to listen to their shit music...