2002VertGt

So I have a extra 5.4 3v sitting around now that I had to replace the motor. I also have a set of wiseco forged pistons that I took in a trade. I need to know if they would work and what I would have to do to the motor to get them to work? The pistons are for a 5.0 modular motor. I know that the 5.0 modular motor bore is bigger than the 5.4 so I would have to bore out the 5.4 to get them to work. the pistons are +17 dish pistons.

Wiseco/Roush #CA-R8540-3893 Custom Ford SB Forged Pistons
3.700" (94mm) Bore, 1.155 C/D, 1.00mm, 1.200mm, 2.800mm Ring Grooves, Dished (17.00cc's)

Full Floating .927" x 2.500" Pin, Piston Weight: 354g (nominal)
Will Work with 6.00" Length Rods
Includes Rings, Pins & Locks



Above is the info on the pistons. Any help would be appreciated on how much work I would have to do in order to make this work if possible. I know I will have to get forged rods as well.

jamie930

I pretty sure the 5.4 bore is 90.2 mm (3.552 in) so that would be almost a .15 overbore.
Can the cylinder walls handle that much?

2002VertGt

don't people normally do .30 over?

screamineagle

Yes, that has been the norm for as long as I can remember...

2002VertGt

I know very little about building engines. That's why I'm asking if this can/will work

Blackpony

I would not suggest boring the block that much. There is not enough material there for it to hold true under heavy cylinder pressure. Not to mention the pin height is not correct for that engine.

PerryB

NO, absolutely not. A common overbore is .030 not .30 -- .060 is usually considered a max. overbore for most domestic vee blocks.

screamineagle

Ok wise guy, please forgive us for leaving out the zero. Pretty sure anyone with half a brain knows what we meant. Thousandths not hundredths!

PerryB

Maybe you knew what you meant, but between post #2 and post #3 a critical mathematical error was made and you apparently agreed with it. I should have used the post above yours as my quote source since that's where the error originated. I'm sorry for any offence taken by you, but certainly not for pointing out a 10 factor mistake. Its simple little thing like this that cause huge engineering blunders. The Hubble telescope comes to mind. It went into space nearly blind because some lens radius/curvature figures were improperly converted from metric to english. I imagine those guys were sure of themselves as well.

papa tiger

Since .15 mm is about .006" it gets confusing for some to not be explicit with thousandths measurements when talking machining a block. The Pistons probably will be a very bad idea although some have machined pistons down in the past to fit a specific project and probably will in the future. Maybe sell them and get the new ones after the block bore cleans up. It would be a waste of money if it doesn't clean up to buy them first.