440 Piston options......need some help please

[BLK 68 R/T]

So, I have a 440 short block that was built in the early 90's. It has never been ran and has been on an engine stand ever since. It came with my Charger when I got the car. It has a 4.15 stroke crank, stock rods from what I can tell and 2371P flat top pistons installed (no valve reliefs) and from what I can find on the internet they are .020 over 400 mopar pistons, forged aluminum. They sit .047 below deck. I put a head on to check valve clearance and the valves hit the piston. So I have a few questions.

1. Can the pistons be notched for valves while they are installed - and is that even worth doing since they sit .047 in the hole?
2. Should I just pull the whole assembly and have it bored .030 over so the piston selection is greater - I did not find anything other than cast or hypereutectic in .020 over size.
3. I did find some KB 237 hypereutectic pistons from Summit that looked pretty good - would these be a good option with out having to have the block re-bored?

Ideally I would like to end up at a zero deck height on the piston to maximize compression along with 2 valve reliefs correct? I will be using 440 source aluminum stealth heads on the motor.

I would really appreciate some help on which way to go with this. Thanks in advance!

[Challenger340]

So, I have a 440 short block that was built in the early 90's. It has never been ran and has been on an engine stand ever since. It came with my Charger when I got the car. It has a 4.15 stroke crank, stock rods from what I can tell and 2371P flat top pistons installed (no valve reliefs) and from what I can find on the internet they are .020 over 400 mopar pistons, forged aluminum. They sit .047 below deck. I put a head on to check valve clearance and the valves hit the piston. So I have a few questions.
First off, the stock bore for the 400 engine is 4.340", and for the 440 it is 4.320". So a bone stock "std" Bore 400 Piston is already a .020" oversize for a 440 Engine.  So then, if you have a .020" over 400 Piston in your Engine(4.340" + .020") would be 4.360" Bore or .040" over 440 Bore(4.360")

1. Can the pistons be notched for valves while they are installed - and is that even worth doing since they sit .047 in the hole?
It can be done, ISKY used to make a cutter tool that went in the Valve Guide of a dis-assembled Head, which you could then use a drill to flycut the Piston, but very messy with cuttings inside the cylinder, plus not very accurate to keep them all the same. Just NOT a good idea ! and NOT recommended.

2. Should I just pull the whole assembly and have it bored .030 over so the piston selection is greater - I did not find anything other than cast or hypereutectic in .020 over size.
Again here, first you need to figure out if you have a .020" over 400 Piston, which is a .040" over 440 Bore, or a "std" 400 Piston which is a .020" over 440 Bore.

3. I did find some KB 237 hypereutectic pistons from Summit that looked pretty good - would these be a good option with out having to have the block re-bored?
Nope, the KB237 is for a 3.75" Stroke 440 Engine, and will NOT work with a 4.150" Stroke Crank and stock length 440 Rods at 6.76".
You would need a "Stroker" Piston with a Compression Distance around 1.87" for the 4.15" Crank and stock 6.76" Rods(NOT Recommended anyways)

Ideally I would like to end up at a zero deck height on the piston to maximize compression along with 2 valve reliefs correct? I will be using 440 source aluminum stealth heads on the motor.
Not really. Keep in mind the 4.15" Crank makes the 440 into a 493 to 496" Stroker(depending upon bore), which has alot more CC Swept Volume(~1010 CC's) and changes Compression Ratio substantially. Generally speaking, a "Flat Top" Piston at 0 deck with the 4.15" Crank and 80-83 CC Stealth Heads will be well into the 11's Compression Ratio-wise, too high for pump gas with most Street type Camshafts.

I would really appreciate some help on which way to go with this. Thanks in advance!

IMO, Best advice at this point, is to dis-assemble the Engine and start identifying exactly what you have currently ?  Bore size for sure ? Stroke for sure? Rods for sure ? etc., etc., and figure out exactly where you are now first..... before moving ahead with anything and plans.

[John_Kunkel]

It can be done, ISKY used to make a cutter tool that went in the Valve Guide of a dis-assembled Head, which you could then use a drill to flycut the Piston, but very messy with cuttings inside the cylinder, plus not very accurate to keep them all the same. Just NOT a good idea ! and NOT recommended.

I've done this numerous times, a tool bit silver-soldered to an old valve makes an excellent cutter and a stop collar on the valve stem assures consistency. Cleanup isn't all that bad, a vacuum gets most of it and the tiny shavings that remain will vaporize on the first combustion cycle.

[BLK 68 R/T]

So, I have a 440 short block that was built in the early 90's. It has never been ran and has been on an engine stand ever since. It came with my Charger when I got the car. It has a 4.15 stroke crank, stock rods from what I can tell and 2371P flat top pistons installed (no valve reliefs) and from what I can find on the internet they are .020 over 400 mopar pistons, forged aluminum. They sit .047 below deck. I put a head on to check valve clearance and the valves hit the piston. So I have a few questions.
First off, the stock bore for the 400 engine is 4.340", and for the 440 it is 4.320". So a bone stock "std" Bore 400 Piston is already a .020" oversize for a 440 Engine.  So then, if you have a .020" over 400 Piston in your Engine(4.340" + .020") would be 4.360" Bore or .040" over 440 Bore(4.360")

1. Can the pistons be notched for valves while they are installed - and is that even worth doing since they sit .047 in the hole?
It can be done, ISKY used to make a cutter tool that went in the Valve Guide of a dis-assembled Head, which you could then use a drill to flycut the Piston, but very messy with cuttings inside the cylinder, plus not very accurate to keep them all the same. Just NOT a good idea ! and NOT recommended.

2. Should I just pull the whole assembly and have it bored .030 over so the piston selection is greater - I did not find anything other than cast or hypereutectic in .020 over size.
Again here, first you need to figure out if you have a .020" over 400 Piston, which is a .040" over 440 Bore, or a "std" 400 Piston which is a .020" over 440 Bore.

3. I did find some KB 237 hypereutectic pistons from Summit that looked pretty good - would these be a good option with out having to have the block re-bored?
Nope, the KB237 is for a 3.75" Stroke 440 Engine, and will NOT work with a 4.150" Stroke Crank and stock length 440 Rods at 6.76".
You would need a "Stroker" Piston with a Compression Distance around 1.87" for the 4.15" Crank and stock 6.76" Rods(NOT Recommended anyways)

Ideally I would like to end up at a zero deck height on the piston to maximize compression along with 2 valve reliefs correct? I will be using 440 source aluminum stealth heads on the motor.
Not really. Keep in mind the 4.15" Crank makes the 440 into a 493 to 496" Stroker(depending upon bore), which has alot more CC Swept Volume(~1010 CC's) and changes Compression Ratio substantially. Generally speaking, a "Flat Top" Piston at 0 deck with the 4.15" Crank and 80-83 CC Stealth Heads will be well into the 11's Compression Ratio-wise, too high for pump gas with most Street type Camshafts.

I would really appreciate some help on which way to go with this. Thanks in advance!

IMO, Best advice at this point, is to dis-assemble the Engine and start identifying exactly what you have currently ?  Bore size for sure ? Stroke for sure? Rods for sure ? etc., etc., and figure out exactly where you are now first..... before moving ahead with anything and plans.

Thanks for the input.

I inspected further and verified the crank is a 4.15 stroke, I found the engine build receipts in the paperwork that came with the car. The pistons are std. bore 400 pistons, which equates to a 4.34 bore on the 440. I measured the bore and it measures 4.345 Rods are stock 440 LY rods. According to the paperwork the rotating assembly was balanced before installation as well.

I hate to tear down a perfectly good bottom end, but want to do the right thing. I guess the next questions are a) is there a good .020 over 440 stroker piston available? or b) should I tear it down and have the block bored to .030 over? it seems the piston selection is far greater in the .030 range vs the .020

Suggestions?

Thanks,
Wes

[BLK 68 R/T]

It can be done, ISKY used to make a cutter tool that went in the Valve Guide of a dis-assembled Head, which you could then use a drill to flycut the Piston, but very messy with cuttings inside the cylinder, plus not very accurate to keep them all the same. Just NOT a good idea ! and NOT recommended.

I've done this numerous times, a tool bit silver-soldered to an old valve makes an excellent cutter and a stop collar on the valve stem assures consistency. Cleanup isn't all that bad, a vacuum gets most of it and the tiny shavings that remain will vaporize on the first combustion cycle.

Thanks for the input. I am not completely opposed to this but I don't think I have the proper skills or equipment to perform this accurately. I thought maybe if this was a common practice for machine shops I would check into it further, but it sounds like it is more of a DIY type of job??

Thanks,
Wes

[BSB67]

.I put a head on to check valve clearance and the valves hit the piston. So I have a few questions.

What size and type of cam?  Must be pretty big.  How did you measure/test for clearance?

There will be a large price difference between cutting some notches yourself, verses new pistons.

I think you will need a dished piston if you want a reasonable compression ratio.

If you are going to get into this hobby, you will either need to figure things out for yourself, and do the work yourself, or you will need a lot of disposable income.

[BLK 68 R/T]

.I put a head on to check valve clearance and the valves hit the piston. So I have a few questions.

What size and type of cam?  Must be pretty big.  How did you measure/test for clearance?

There will be a large price difference between cutting some notches yourself, verses new pistons.

I think you will need a dished piston if you want a reasonable compression ratio.

If you are going to get into this hobby, you will either need to figure things out for yourself, and do the work yourself, or you will need a lot of disposable income.

So, I think I need to do some re-measuring on my issue. I was not measuring correctly. After doing a ton of reading over the last few days, I know where I went wrong. The cam I have is not super high lift by any means, .545 intake and .551 exhaust.

Appreciate every ones input and suggestions. Internal motor work has never been my strong suit and I need to get a few additional tools to make the proper measurements.

[BSB67]

.I put a head on to check valve clearance and the valves hit the piston. So I have a few questions.

What size and type of cam?  Must be pretty big.  How did you measure/test for clearance?

There will be a large price difference between cutting some notches yourself, verses new pistons.

I think you will need a dished piston if you want a reasonable compression ratio.

If you are going to get into this hobby, you will either need to figure things out for yourself, and do the work yourself, or you will need a lot of disposable income.

So, I think I need to do some re-measuring on my issue. I was not measuring correctly. After doing a ton of reading over the last few days, I know where I went wrong. The cam I have is not super high lift by any means, .545 intake and .551 exhaust.

Appreciate every ones input and suggestions. Internal motor work has never been my strong suit and I need to get a few additional tools to make the proper measurements.

You could have one of three conditions:
1) No clearance issues
2) No valve to piston contact, but still not enough clearance, or
3) Valve contacts piston.

1 or 2 are reasonable to expect, but 3 seems unlikely, but possible.

Good luck