Piston & connecting rods

Firepower354

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One I keep thinking about:
5.4L Ford rods are 6.657 w/2.086-.866 available from stock, to Speedmaster, up through Oliver et al
LQ9 6.0L GM CH is 1.328 with .945 pin, dead-flat top, 1.2/2.5mm rings, cheap, hyper, coated, anodized.
Or, custom slugs with .866 pins. CH should allow plenty of dish if needed.
.025 in the hole, minus any offset grind during journal reduction
Biggest issue, the 22mm to 24mm pin difference.
Either machine rods, or put sleeves in the piston bore.
A "tophat" type bushing installed from the inside of a heated piston, could also locate the rod.
 

CNC-Dude

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The best choice is to take advantage of the group buy for some Molnar rods for $200 a set as was mentioned in another thread. I have found most all piston companies offer a piston with a compression height of 1.425" in a 4.000" bore in dish, flat top and dome. So a wide selection of piston choices from many manufacturers. A rod length of 6.585" would be used, and Molnar can make it to fit the stock Ford 300 journal size and width. The rods would be correctly chamfered on both sides for an inline and the wrist pin size would be the standard SBC .927 size. No more speculating about having to regrind the journal smaller to a Chevy journal, which machine shops will charge you extra to perform. No more narrow rods on the B/E and having to monkey around trying to make spacers to center the rods that will also be an extra charge. No more worrying about anything other than making it fit a Ford journal and using standard replacement Ford bearings and having the proper offset,B/E width and ready to go play....
 

guhfluh

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CNC-Dude":101cgjh2 said:
The best choice is to take advantage of the group buy for some Molnar rods for $200 a set as was mentioned in another thread. I have found most all piston companies offer a piston with a compression height of 1.425" in a 4.000" bore in dish, flat top and dome. So a wide selection of piston choices from many manufacturers. A rod length of 6.585" would be used, and Molnar can make it to fit the stock Ford 300 journal size and width. The rods would be correctly chamfered on both sides for an inline and the wrist pin size would be the standard SBC .927 size. No more speculating about having to regrind the journal smaller to a Chevy journal, which machine shops will charge you extra to perform. No more narrow rods on the B/E and having to monkey around trying to make spacers to center the rods that will also be an extra charge. No more worrying about anything other than making it fit a Ford journal and using standard replacement Ford bearings and having the proper offset,B/E width and ready to go play....
I haven't seen anything quoting $200 a set for Molinar rods in a group buy?
 

CNC-Dude

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Someone must have misquoted the price or had a typo then, but that is what they posted. The Slant 6 guys have been using Molnar rods for about 10 years and $600 is what they are paying for them. No complaints either, and many of them are turbocharged and pushing close to 600 HP with them. Most of the N/A Slants are around 300 HP. So they are a good choice!
 

Firepower354

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CNC-Dude":3an1wrb3 said:
Someone must have misquoted the price or had a typo then, but that is what they posted. The Slant 6 guys have been using Molnar rods for about 10 years and $600 is what they are paying for them. No complaints either, and many of them are turbocharged and pushing close to 600 HP with them. Most of the N/A Slants are around 300 HP. So they are a good choice!


It's a little over $600/set for the 10 or so in at this point.

But, they're insisting on having them in stock length and pin size...
 

CNC-Dude

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Firepower354":hdm98fvt said:
CNC-Dude":hdm98fvt said:
Someone must have misquoted the price or had a typo then, but that is what they posted. The Slant 6 guys have been using Molnar rods for about 10 years and $600 is what they are paying for them. No complaints either, and many of them are turbocharged and pushing close to 600 HP with them. Most of the N/A Slants are around 300 HP. So they are a good choice!


It's a little over $600/set for the 10 or so in at this point.

But, they're insisting on having them in stock length and pin size...
(Quoted from Firepower354 post in the LS rod thread)

Over on the popular social media site, they're talking of a Molnar group buy of custom rods. 4 sets of these rods, making 5 sets of 300 rods (and a pair to spare), at $240/set, seems like it would be worth the little effort of centering up the rod at the top. Wiseco 383/5.7 1.44ch and Eagle 6.560 rod, comes pretty close to perfect. Having the crank guy set it at 2.100 and 4.00 stroke, she's purtnear on target.
A fella could do a lot worse, and spend a lot more money, but besides having to get after the chamber a little harder, these seem legit. Several other dish sizes available too.

The above quote was where I found the mention of a $200 something dollar price tag for the Molnar rods for the 300's. But anyway...
The stock length Molnar rods you are saying they have in stock may appeal to some people, but they only check one or two boxes of what a rod like this will benefit the user. You still will have a relatively poor rod length to stroke ratio, minimal piston selection and maybe only the benefit of having floating wrist pins. While a better rod itself is a plus. If the price is the same for a custom rod and a stock rod length, why not get the rod made that truly checks all the boxes instead of just one or two?
 

guhfluh

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CNC-Dude":exrt66d4 said:
Firepower354":exrt66d4 said:
CNC-Dude":exrt66d4 said:
Someone must have misquoted the price or had a typo then, but that is what they posted. The Slant 6 guys have been using Molnar rods for about 10 years and $600 is what they are paying for them. No complaints either, and many of them are turbocharged and pushing close to 600 HP with them. Most of the N/A Slants are around 300 HP. So they are a good choice!


It's a little over $600/set for the 10 or so in at this point.

But, they're insisting on having them in stock length and pin size...
(Quoted from Firepower354 post in the LS rod thread)

Over on the popular social media site, they're talking of a Molnar group buy of custom rods. 4 sets of these rods, making 5 sets of 300 rods (and a pair to spare), at $240/set, seems like it would be worth the little effort of centering up the rod at the top. Wiseco 383/5.7 1.44ch and Eagle 6.560 rod, comes pretty close to perfect. Having the crank guy set it at 2.100 and 4.00 stroke, she's purtnear on target.
A fella could do a lot worse, and spend a lot more money, but besides having to get after the chamber a little harder, these seem legit. Several other dish sizes available too.

The above quote was where I found the mention of a $200 something dollar price tag for the Molnar rods for the 300's. But anyway...
The stock length Molnar rods you are saying they have in stock may appeal to some people, but they only check one or two boxes of what a rod like this will benefit the user. You still will have a relatively poor rod length to stroke ratio, minimal piston selection and maybe only the benefit of having floating wrist pins. While a better rod itself is a plus. If the price is the same for a custom rod and a stock rod length, why not get the rod made that truly checks all the boxes instead of just one or two?

The quote from the LS rod thread for $240/set is for Eagle LS rods, not Molinar. It reads poorly and should be a separate paragraph.
 

CNC-Dude

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Yeah, I just wanted to show evidence to support the post I made about this earlier in the discussion so people wouldn't think I had lost my mind or anything. LOL
 

Firepower354

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Awkward prose notwithstanding,,, :eek:opsie:

But, yes, the ringleader of the custom order (still in design stage at Molnar) was borderline offended at the suggestion to consider even switching to a .912 pin to allow 351W's better slug selection.

He's convinced that since it's only another $80 to make the $800 custom FE-based slugs in 4.030, it's the way to go.

I even showed the 1.165 shelf DSS pistons that are available in multiple dish volumes, at half the cost, if the rods were made in 240 dimensions.
[highlight=yellow]And the SBC slugs that they could have 6.560-6.575 rods with 300 crank end and .927 pins.[/highlight] Not my ship, not my anchors.
 

guhfluh

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Firepower354":268pk6sw said:
Awkward prose notwithstanding,,, :eek:opsie:

But, yes, the ringleader of the custom order (still in design stage at Molnar) was borderline offended at the suggestion to consider even switching to a .912 pin to allow 351W's better slug selection.

He's convinced that since it's only another $80 to make the $800 custom FE-based slugs in 4.030, it's the way to go.

I even showed the 1.165 shelf DSS pistons that are available in multiple dish volumes, at half the cost, if the rods were made in 240 dimensions.
And the SBC slugs that they could have 6.560-6.575 rods with 300 crank end and .927 pins. Not my ship, not my anchors.
I agree, I argued against stock 300 rod dimensions. A common size (LS or other) long rod with 300 big end width as the only change would make more sense to me with plenty of shelf piston options and seem like a much easier engineering and machining "change".
 

CNC-Dude

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While a 240 rod length may realistically only be beneficial for probably one out of ten people, a better solution is something in the means of 6.585-ish that gives a broader, more dependable build. A compression height required for a 300 with a 240 rod has few advantages and more disadvantages unless you are strictly building a drag engine. The SBF guys realized this when the 5.0 Mustang craze happened and they all jumped on the stroker band wagon. While on paper and the drag strip, a 347 stroker looked attractive until guys started trying to drive them on the street and found ring life suffered severely because the really short compression height just wasn't conducive for expecting longevity for street driving. Yes, you get a really light piston, but that is something you will never measure the benefit of on a dyno or even at the race track. Many downsides, poor ring stack make it incompatible with even light boost or nitrous because the top ring is too high on the piston to be protected from the added heat created by forced induction. Also, the rings are too close together to let each ring do their job effectively. And pistons with that short of a compression height rock too much in the cylinders which upsets the rings staying in contact with the cylinder walls firmly to give any longevity to warrant the expense of either the pistons or rods. Great for drag racing, but not so much street driving or forced induction, which is what seems to be most enthusiasts intentions.

So the best advice would be to forget the 240 rod ever existed, and take advantage of being able to get a rod length that truly provides better alternatives from Molnar. The reason the 240 rod for some reason was revered as the "holy grail" was simply that's all that was financially available to the masses, but not always the best choice. Also, trying to adapt an off the shelf LS rod to a 300 crank isn't going to be as cheap as you think it will. While the cost from Eagle or Scat may seem cheap, the cost of the extra work to grind the crank smaller to fit(most shops charge more to regrind more than .010"), making the gimmicky spacers to center the rod to the piston isn't going to be without problems as far as function either. So by the time you mess up a few pistons from the spacers galling them and the excessive side clearance you end up with, you still will only end up with a combo that will be considered "make shift" at best. While for a few more dollars can have a truly custom tailored fit rod and piston that will last as its intended to.
 

clintonvillian

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Ok my head hurts...

So what piston are you going to run with these stock sized rods? From all the comments here I am gathering once again a custom piston set is required?

So we are looking at $1600 for a piston and rod combo?

AND where/who do I talk to about getting in on the group buy? Does anyone have a direct contact?
 

CNC-Dude

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Ok, I guess you haven't been following closely, but on the last page I posted a rod length of 6.585"-ish would allow a piston that is a shelf item for the SBC to be used that is configured in a dome, flat top or dish. Giving you many options from many piston companies to buy a quality piston that is not custom.
 

pmuller9

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CNC-Dude":r96falfr said:
Ok, I guess you haven't been following closely, but on the last page I posted a rod length of 6.850"-ish
don't you mean 6.585"-sh
 

clintonvillian

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Is there a Molnar group buy?

Is there someone specific you are talking to at Molnar? I need to call them and see where this goes. I hate having to ask a new person the same questions someone else knows the answers to.
 

pmuller9

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Is there a Molnar group buy?

Is there someone specific you are talking to at Molnar? I need to call them and see where this goes. I hate having to ask a new person the same questions someone else knows the answers to.
That would be Tom Molnar
 
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