Are These a direct swap?

[Venom351R]

Will I need to do any type of machine work to use these pistons?


Trick Flow Specialties TFS-51404221 - Trick Flow® Forged Pistons - Overview - SummitRacing.com


Been talking w/ Trick Flow and these pistons will get my compression up to 10:0

One of my biggest problems currently is my lack of compression. Ive been going over all kinds of ways to pull more power out of my combo and I think this is the best way to start out. I know I need LT's and I really do want to do a set of 205cc Trick Flow heads to go along w/ these as well.

 

[revhead347]

Usually you put new pistons in when it is machined. I would have the clearances checked, but if they work out it shouldn't be an issue. Never heard of anyone running Trick Flow pistons before.

Kurt

 

[Venom351R]

I wanted to go w/ TF pistons to avoid any PVC issues w/ TF heads which I would also like to do too. Having the entire engine torn down and machine work being done is what Im trying to avoid so is it something you have to do when swapping pistons or do some do it and some dont?

 

[revhead347]

No, the biggest thing is the checking the piston ring gap, which you can do yourself.

Kurt

 

[Venom351R]

by that you mean how much gap is between the ends of the piston rings? I was also going to get new rings as well.

 

[nmcgrawj]

TFS isnt the only company who makes valve reliefs that match their heads.



And also, wouldnt balancing be a problem too? Or is that ok and u are just tyring to avoid having to have the block itself machined?

 

[Venom351R]

TFS isnt the only company who makes valve reliefs that match their heads.



And also, wouldnt balancing be a problem too? Or is that ok and u are just tyring to avoid having to have the block itself machined?

That's another thing, will it have to be balanced? Im keeping the same crank I just want higher compression pistons but what Im not sure of is if I really do need to have the block machined or not b/c if I have to then I dont want to do it b/c I dont want to have to pay the cost of having the entire engine torn down to the bare block and then pay for machine work.

Im trying to pull more power out of this thing N/A and I know I'll need more compression to do it. I can do a stroker kit but that means machine work + the cost of a stroker kit.

I dont want to do LT's yet but Im not sure which head I'll end up going with, whether I'll keep the AFR's or go w/ bigger Trick Flow heads so that's on hold for now. If I have to do the machine work maybe I'll just go w/ bigger heads and keep the internals the same but then Im still stuck w/ the same compression.

Does anyone know what machine work usually costs anyway? I was thinking around $700. One of the Local Napa shop does machine work and I know there are some engine builders around here too.

 

[nmcgrawj]

That's another thing, will it have to be balanced? Im keeping the same crank I just want higher compression pistons but what Im not sure of is if I really do need to have the block machined or not b/c if I have to then I dont want to do it b/c I dont want to have to pay the cost of having the entire engine torn down to the bare block and then pay for machine work.

Im trying to pull more power out of this thing N/A and I know I'll need more compression to do it. I can do a stroker kit but that means machine work + the cost of a stroker kit.

I dont want to do LT's yet but Im not sure which head I'll end up going with, whether I'll keep the AFR's or go w/ bigger Trick Flow heads so that's on hold for now. If I have to do the machine work maybe I'll just go w/ bigger heads and keep the internals the same but then Im still stuck w/ the same compression.

Does anyone know what machine work usually costs anyway? I was thinking around $700. One of the Local Napa shop does machine work and I know there are some engine builders around here too.

The balance comes from the entire rotating assembly. I suppose you could weigh each piston and see how far off they are from eachother....but even then im not sure i would cut that corner.

Why dont you just slow down and wait until u know what your final combination is going to be before picking a piston? How far out do u imagine having your ideal heads?

 

[79'293stang]

You have to tear down the entire engine anyway for the piston swap. You may as well have it all balanced while its apart. I didnt balance my first engine and thought it was great. When I rebuilt my engine I put on bigger heads and a much larger cam, had it balanced and it ran much smoother even with the larger cam. I will never not have an engine balanced after that!

 

[Venom351R]

The balance comes from the entire rotating assembly. I suppose you could weigh each piston and see how far off they are from eachother....but even then im not sure i would cut that corner.

Why dont you just slow down and wait until u know what your final combination is going to be before picking a piston? How far out do u imagine having your ideal heads?

Its not so much that I dont know what the combination is going to be. Im keeping the TFSR intake and the FTI cam and if I change heads Im going w/ the TF CNC 205cc heads but the kicker is that even if I swap heads and do LT's Im still stuck w/ my 9:0 compression so Im faced with either upgrading the pistons for more compression or doing a stroker it. If I have to have the machine work done just to swap out the pistons then I might as well do a stroker it and stroke it to a 393 or a 408 but it comes down to what the machine work will be. I suppose I could always wait on doing the head and put that money on those toward the machine work & Stroker kit?


I could make this really easy and strap on a Vortech w/ 10 PSI and have more power then I know what to do with but thats not really what Im trying to do. I just want a really strong running N/A 351 based engine.

 

[GT_green_GT]

My friends mustang has a 351w in it. stock crank. aftermarket rods and pistons. although he did not get his balanced. revs to 6800. the motors ran over two years putting his car in the 12.0-12.20 range. But you also have to remember. its gotta be tore down anyways. why not get it balanced. it wont be that expensive. more than likely all they will do is remove weight. its the adding of lead that gets expensive. trick flow pistons arent the only pistons designed for their heads.

 

[Venom351R]

I understand the balancing aspect as far as it should be done since its torn down anyway but what about the machine work aspect? If Im just going to drop in aftermarket pistons and not increase the cubic inch's then can I skip the machine work part? The Engine only has about 50,XXX miles on it.

 

[79'293stang]

You just never know until you get the engine apart and have the bores checked for wear really...

 

[revhead347]

The pistons don't get balanced like that. The crank, flywheel, and harmonic balancer is balanced on a rotating balancer, just like you balance a tire. Then they drill certain parts of each piece to remove weight. Balancing the pistons just means they are all relatively the same weight. Same goes for the rods. If you want to check the balance of the pistons, all you need is a gram scale. But honestly, high end pistons like that are generally machined well enough from the factory that they are well within tollerances. You really shouldn't have to do anything.

Checking the ring gap means checking the gap between the ends of the ring. Definately recommend putting new rings in there. Don't waste your money on those total seal rings or anything like that. The rings with the most longevity are the basic cast iron rings. The HP gains by going to a gapless ring is negligible on an engine like yours.

Machine work for a bore and hone should be about $25/hole. If you just do a hone, it's probably $15/hole. If you want to really spend the money to make it perfect, you can go .010" overbore, and have it honed with a .010" over piston. The pistons should be about the same price, and that comes out to about $200 in machine work.

Kurt

 

[revhead347]

Oh, and the engine doesn't have to come completely apart to change the pistons, you can still leave the crank in, and the oil pump on, but it's honestly not a whole lot more work to take the crank out.

Kurt

 

[Venom351R]

Machine work for a bore and hone should be about $25/hole. If you just do a hone, it's probably $15/hole. If you want to really spend the money to make it perfect, you can go .010" overbore, and have it honed with a .010" over piston. The pistons should be about the same price, and that comes out to about $200 in machine work.

Kurt

Well that's a lot less then I thought. I was expecting something in the 500+ range. I know that's not an exact price you spit out but its a lot lower then what I was thinking.

With that being said I think I would probably be better off going w/ a stroker kit(that comes balanced) and having the machine work done for a 408 I would assume?

 

[revhead347]

Well that's a lot less then I thought. I was expecting something in the 500+ range. I know that's not an exact price you spit out but its a lot lower then what I was thinking.

With that being said I think I would probably be better off going w/ a stroker kit(that comes balanced) and having the machine work done for a 408 I would assume?

Now you are probably talking more a long the lines of $500, probably more in machine work. They will most likely want to magnaflux the block, line hone the mains, and check all the clearances. If you go to a stroker kit, then you are going to have to get the crank balanced which is another $150 at least. Plus, stroker motors usually need the cylinders notched, which is at least another $100. They will also want money to press out the old cam bearings, and press in new ones.

Kurt

 

[Venom351R]

well at least gives me something to think about. The cost of the work to balance and bore/hone the block is probably more in the price range I want to be in. That way I can at least up the compression and balance the engine.

 

[revhead347]

If you just change the pistons out for bigger ones, and keep the same crank and rods, then you are looking at the $200 range in machine work. You also have to transfer the rods to the new pistons, and those wrist pins have to be pressed out. Probably better to have the machinest do that that for you. You won't have to rebalance the crank or anything like that.

Kurt

 

[The O.G.]

Those are made by arias still?