2.5 liter HSC rods

hi all,

I did some research on the forum and some math and more research with my local machinist. I'm not the first to want to do this but I want to use the 2.5 liter hsc rods in the 250 I'm building this summer. I know they will work with a stock 250 piston because that's what I found out on this forum and from measurements I took myself and from my local machinist. My problem is finding an aftermarket performance source for these rods. I can't find anyone:x I am at my wits end.
I did find some reconditioned rods locally that would cost me $100 American for the set and thats with polishing, arp bolts, and bronze bushings. But I am affraid of using modified reconditioned parts the place that sells them is a reputable one but I only have that on word of mouth.
I also talked to Scat and they said that if I could get a 160 interested people they would make 160 forged H-beam or I-beam sets to what ever spec we wished but then they told me the cost; over 500 dollars a set! I don't think many of us will be making the power level that would require such an expenditure. But if you are we should start a list :
my bottom line its this:

does anyone know of an aftermaket source for these rods?

secondly;
I plan to have the rods bushed for floating pins and I can get custom pistons made but they would be forged aluminium. Would I have to get them coated (SDF, TBC)? this is going into my daily driver '66 mustang coupe next year I just wanna finish this short block this summer.

Thanks
and Keep Six'n

Dan

Camel Jockey said:

"I want to use the 2.5 liter hsc rods in the 250 I'm building this summer. I know they will work with a stock 250 piston because that's what I found out on this forum and from measurements I took myself and from my local machinist. My problem is finding an aftermarket performance source for these rods. I can't find anyone I am at my wits end.
I did find some reconditioned rods locally that would cost me $100 American for the set and thats with polishing, arp bolts, and bronze bushings. But I am affraid of using modified reconditioned parts "


THere are a number of forum members working on 250's. I picked up a 250 that was built for performance in JAck Cliffords' shop. The pistons were a mystery because I could see STD stamped on the top and a deep depression in the Piston. These were supposed to be JAHNS 10:1 pistons but the STD marking eliminated that. Using a dental mirror I found the pistons also read 470NP . I googled this and found out they are TRW pistons for AMC 258 cid engine. The STD bore amounts to @ .070 overbore on the 250 and the piston compression height gives an almost approximate zero deck height : Meaning the compression ratio would be through the roof, but the piston depression adds up to @ 21 cc's and with a "new composite" gasket being about .050 - I've been told it adds up to @ 8.8:1 compression ratio = suitable for street/daily driving.

http://fordsix.com/forum/viewtopic.php?t=34610


I just want to share the alternatives for the adventurous engine builder - which your ideas fit into well.


Powerband

cameljockey":1zfr66ch said:

I did find some reconditioned rods locally that would cost me $100 American for the set and thats with polishing, arp bolts, and bronze bushings. But I am affraid of using modified reconditioned parts the place that sells them is a reputable one but I only have that on word of mouth.

Click to expand...

as long as the shop has a good rep, the rods are going to be fine. what is the address to this place? likely there are going to be a number of us that will contact them about getting rods from them.

Why would you want full floating piston pins over pressed pins?

No real advantage on a street motor. Friction gains are negligible compared to conversion costs at your machinists.
Also, please consider forged pistons have some drawbacks too - like different heat expansion and heavier weight than stock pistons.
However, if you plan to hook up a blower or turbo, or even dinitrogen monoxide (to them: NOSSS), stick with the forgings.

Coated piston skirts are a different story - depending how easily, and for how much green, this service is available to you, ptfe-based SDF coatings are good precaution even on a daily commuter.

ok long post forgiveness please:

Well, I visited the shop to day. It looks like a clean opperation (as far as machine shops go) it turns out this particular shop, L&B Machine in Anaheim, only does reconditioning work on con rods.
It's the only thing they do. However because they are a smaller shop they only take the $green$ other that that there is a system of invoices and they even do recon work for some of the local autoparts stores and other machine shops as well. The owner of the shop claims to have enough rods when I told him of other enthusiasts that were interested; but he wouldn't divulge exactly how many sets he could procure if you wish to call him before 5:00 Pm PST 714-634-9119.
As for the price I quoted earlier it may vary based on what you ask for:
I got a more explicit qoute today for what I wanted: for the set of 6
ARP rod bolts: $45
re-size: $36
polish & shot peen: $36
that adds up to $117 but I have to find out what core charge will be
so this could all tally up to $150 easy for the set and the bushings will also cost more. These are recons after all; is it worth it?
thoughts anyone? I'll be contacting him again on Monday.

I also found a place in Atlanta Georgia that is selling the same con rod for $15/rod reconditioned, they are:
Atlanta Performance Motorsports
1-800-282-9319

I chose to do full floating pins from a durability stand point. As I understand it full floating pins keep the connecting rod from experiencing side loads I do intend to pounce on this motor on ocasion even though it's just a daily driver.

The pistons I was thinking of are forged aluminum from Venolia I am unsure of the benefit, durability, or feasability of such pistons in a street driven applicaiton. I don't know if the coatings will help. I know that I must run larger clearances with aluminum pistons as they have a higher coefficient of linear expansion but such is the case with any forged piston. If the forged pistons are heavier will that effect the balace and RPM potential of the engine : If the aluminum turn out to be a bad Idea can I machine the stock pistons for floating pins and the associated locks

I do need some one to double check my math though.
Hsc rod: 5.99 in
Deck height: 9.469 in
Stroke/2: 1.955 in
Compression dist (from pin center to piston face): 1.5 in
I get the piston face being down the hole only .024 in at TDC

Assuming the block hasn't been decked a substantial amount that's about as close to zero deck I am willing to go I am waiting for the new FSPP Head to come out because I intend to finish the short block this summer minus the cam in anticipation of the release. With any luck I hsould have all the short block parts including bearings in the next two to three weeks. Wish me luck!

Thanks again and Keep Sixn'

Dan Hanna

Thanks Dan for this post, I'll make some moves towards those rods. Great timing indeed, I still can change plans. Thanks for the contact info too...

8)

I would count on a custom balance regardless. Going with forged or cast pistons either way I would get a custom balancing done.

If you're going to put longer rods in your 250 why not go with 300 rods and use KB pistons for a 305 cheby with a 1.261" comp. ht. You would also get a better rod to stroke ratio at 1.59.

Howdy Dan:

Wow!!! Thanks for sharing this source. I'd just about given up on solving 250 problems. HSC rods are scarce!!!!

"Assuming the block hasn't been decked a substantial--"
Don't assume anything. The block crankshaft centerline to deck dimension is a FoMoCo engineering specification. It does not relate well or often to the real world of block castings. You must measure what you have to be certain.

FYI- In doing more research on this elusive 2.5 HSC engine I found a FoMoCo engine data page that specifies this engine to 1986 -'90 Taurus and 1986 Sables- and not to the Tempo line as previously thought.

Do a weight comparison of the stock 250 rod and an HSC rod before assuming balancing needs. The Venolia forged pieces may be more of a weight/balance concern. Heat barrier and friction coating are always a good idea with either cast or forged pistons.

Hexhead- thanks for the 300 rod thought. I had not found the 305 pistons. I'll be checking that out too.

I'll be anxious to hear a final price on this source for the HSC rods. Thanks for sharing.

Adios, David

I bought a set of recon 2.5L HSC rods for $65..
If I had cores it would have been $30..

I'll be adding Arp rod bolts later..

A person could use the Tempo 2.3L rods if they wanted to short stroke a 200 or 250..

2.5L HSC Taurus engines are hard to find.. out of the billions of tauruses sold, only 10% were 4 cylinder cars..

Nathan

heXhead Posted:
If you're going to put longer rods in your 250 why not go with 300 rods and use KB pistons for a 305 cheby with a 1.261" comp. ht. You would also get a better rod to stroke ratio at 1.59.

wait a sec. what are the dimmensions on the 300 ci rod:
pin dia
bearing housing
c to c length etc
and what is the bore on a cheby 305
the 300 rods could be beefier and they are stock forgings like the hsc no?
thanks for oppening my mind to that posibility I don't like making un-informed decisions I will do more Home work before proceeing.

as for sharing all the contact info for the sources on the con rods Think nothin of it. it is only throu sharing info that we will all benefit from this forum and learn from each other in order to build better engines.

Thank's again and Keep Sixn'

Dan Hanna

I talked to my shop today the 305 pistons are too big they would require too much over bore and make the wall to thin. this block has been bored over once already thin cylinder walls are nothing to sneeze at especially in a street motor. please let me know if there are any numbers.

Thanks and Keep sixn,

Dan Hanna

Howdy All:

FYI-

Use a longer 300 rod with the Keith Black 305 Hypereutectic pistons (Part # KB 153) with a 1.26" deck height. This combo has the advantage of reducing the deck height .120" and giving a slightly better rod/stroke ratio.
Rod Length & weight;
250 =5.88" 592 grams
300 =6.21" ??? grams
Difference = .330" grams

Rod Length to Stroke ratio;
250 = 5.88" : 3.91"= 1.5:1
300 = 6.21" : 3.91"= 1.58:1

Deck the top of the block to achieve zero deck height. Use a FoMoCo composite head gasket with a compressed thickness of .037".

Use with a Chevy 305 Keith Black (KB 153) Hypereutectic piston in a standard bore of 3.736" with a 1.26" pin height. This would require an overbore of .056". Plans would include milling a recess into the piston top which mirrors the combustion chambers. The goals will be to create a higher quench-to-bore ratio, lower CR, lighten the piston, reduce knock tendency, and maximize combustion efficiency.

Mill the head only enough to ensure it's flat. At this point it is critical to measure all volumes to assess CR. Reshaping the combustion chambers to reduce CR, unshroud the intake valves and match chamber volumes is critical.

The advantages of using the 300 rods are- longer, for a slightly improved rod to stroke ratio, likely tougher than 250 rods. The 300 are designed for higher load truck application and the same rod and main journal dimensions as a 250.

The only extra machining would be to rebush to accommodate the larger Chevy .9273" wrist pin. The 300 rods small end measures .9122".

This combination will have a more ideal deck clearance, likely have a lighter reciprocating weight, and be able to tolerate CR in the 9.5:1 range, at sea level, with 91 octane gas.

Additionally, plans are to use ARP rod bolts, polish the rod beams, balance the whole rotating assembly, and polish the piston tops and the chambers.

Adios, David

So I did some math if the 305 pistons will work then I calculated stock the piston is 0.135 in down from deck with my original plan using hsc con rods I get 0.024 a difference of .110 in from stock. with the 300 ci con rod combo I get .044 in down from the deck at TDC a difference of 0.090 from stock height. I think my combo will yeild the higher CR no? But the question remains will it be too high?

Thanks Again, and Keep Sixn'

Dan Hanna