H-Beam Rod By Frank's TDI's

September 2016, New Offering! Improve your Connecting Rod Bearings with Polymer Moly Coatings


I have the ALH/AHU 50.6 H-beam 4340 rods that are accurately made by our design engineers at Molnar Technologies. The owner’s pedigree extends 45 years in connecting rod design and is well-known in his field of expertise. We also have contracted to have the 53.7mm connecting rod for the BHW, 140+ hp Pumpe Duese and Common Rail 2.0 liter TDI engine. The same quality and rod design as our 50.6 rod will be incorporated in the larger 2.0 liter, 53.7mm connecting rod.

The rod is finished with the ARP 3/8" bolts with assymetrical thread design. The Assymetrical thread design is 'The Best, From The Best'. The pitch of the thread allows the holding strength of the bolt's threads to be extended over more of the threads in the rod.

The big end is finish honed using the ARP bolts, installed and correctly torqued. The rod bolts should always remain with the same rod, as honed. The parting line is correctly manufactured, by relieving the sharp edge at the internal mating point between the rod and the cap. This is a nearly universal mistake made on about every single 4340 rod we have examined. Center-to-center, sizing, parallel and balance are the highest precision accuracy with the work performed on a Sunnen AG-800, accurate to .00005" (yes, that's 5 hundred thousandths!). Our goal is to have the best TDI rods that money can buy.

Our initial offering is $525 per set

We also will precisely balance your pistons to our rods for the best overall engine smoothness.

For our initial offering, the first 10 sets of rods we will perform rod/piston balancing, normally $80, as a free service.

We also can provide many of your performance mod upgrades, including oil galleyed pistons, cylinder head porting, upgrade cams, injector upgrades, turbos, cylinder head and block builds, South Bend clutch kits and more.

Impressive pricing. If I had not just completed my wagon project - largely due to your assistance, I would jump on a set of these rods. Best wishes on these Frank. Way to go!

I'm in for a set! I'll give you a call later in the week.

Hi Frank,

"accurate to .00005" (yes, that's 5 hundred thousandths!)"

To me that's half an inch or 1/2" Did you mean 50 millionths?

I know I'm splitting hairs, but as a machinist, I'm picky.

Back on topic, the specs look awesome and I commend you for bringing an affordable rod to market. I hope these sell well for you.

Heh...Thank you for the input. Clarity counts.

My rod guru said," 50 millionths..."

I said, "You mean 5-hundred thousandths?"

He said,"50 millionths sounds more impressive."

50 millionths = .00005" or 1.27 microns. Our tolerance for these rods is .0004" or 10.16 microns...roughly .01mm.

It is splitting hairs. The thinnest human hair is 17 microns (.00067"). The finest Alpaca hair is 13 microns, or .00051". That Alpaca hair is wider than the total tolerance for our rod's big end.

To properly hone rods, you better have good equipment and you better know what the heck you are doing. If you are going to work with tolerances of 4-ten thousandths (.0004"), you must have measuring equipment that will measure one more decimal place. Our rods are finished by experts using the Sunnen AG-800 rod honing equipment.

For clarity I will be sure to say 50 millionths from now on.

Coolvdub, I am ok with you splitting hairs. My rod guru and I do, too. Really, it's quite necessary.

Here are some images of the current crop of rods. Front to Back; Top to Bottom, excellence is the hallmark of the product.

Note the attention to detail with the parting line between the cap and body of the rod. This is how it is properly done:

Wrist Pin End Detail shows small Phosphor Bronze bushing size.

Detail of wrist pin bushing. There are several rods with wrist pin bushings that have a radial slot cutting through the center of the bushing. The intention is additional oiling. However, it has the negative effect of reducing the total area of support on the wrist pin.

We were given a choice between the 'standard' ARP 2000 5/16" bolts or the asymmetrical ARP 3/8" bolts. After seeing the advantages, the cost difference was negligible. The next pictures detail the difference between the two bolts.



Clamping force is much superior for the 3/8" bolt and the asymmetric style spreads the thread load across 5-6 threads compared to standard thread design which has almost the entire torque load applied to the last couple of bolt threads.

This last picture shows the ARP threads for what they are; a thing of beauty.
The threads are formed with rolling dies, heat and extreme pressure, making a work-hardened thread.

When comparing genuine ARP's to forgeries, there are several points to inspect. Note the texture of the bolt, contact point of the bolt head has a relief ring against the shaft of the bolt, dimple on the threaded end and in general, a high quality look about the bolt.

We appreciate a good thing and know the value of parts well-made.

Good stuff, those rods are things of beauty. Wish I needed to build a engine. They are pretty enough for gearhead wall art.

If you appreciate my desire to offer well-made and competitively priced products for the TDI marketplace, please make your vote... Thanks.

I've been asked what is an asymmetrical bolt and what does it do?

The asymmetrical bolt design was patented by a Company, ESNA, now purchased by SPS, a high-end bolt and fastener company. I believe the patent has expired and ARP is one of the companies that uses this thread design.

Basically, there are two causes of bolt fatigue. One was a failure due to concentration of stress at the root of the sharp corners of a bolt's cut thread. The universal cure was to make rolled threads, which have a radius at the root of the thread, reducing the stress raisers.

The next weak link in the fatigue chain is the non-uniform load distribution among the engaged threads. The conventional 60 degree thread pitch, while mating well in the unloaded state, will cause the female threads to compress and the male threads to stretch. This does two things. It bends the threads, creating high stresses in the bolt and concentrates the point of contact in the last few threads at the bottom of the bolt and the end of the nut.
The following illustration exaggerates the effect of a standard pitch thread and how the asymmetric bolts differ.

The contact points of a standard thread at rest, will match up along the flanks of the thread. Once loaded, the nut (in this case, the connecting rod's female threads) will compress and the bolt will stretch, causing uneven contact between bolt and thread. The concentration of stress is at the bottom of the bolt and nut. This is demonstrated in this illustration, showing standard threads and the compression of the nut and expansion of the bolt.


Also, the bolt is given very high stress at the top of the thread, bending the threads of the bolt. As the strength of the bolt is near the root of the thread this is fatigue stress for the bolt.

The following illustration show a photo-elastic imaging of the difference in loading for standard threaded bolts and asymmetric bolts.

This picture illustrates the stress difference between the picture on the left; asymmetric threads and the right, showing standard pitch threads. Spreading the stress over a larger amount of threads is a vast improvement in holding ability, stability and durability.

The ability to spread the loading over a much larger area, over the life of the connecting rod, is obvious. As we have indicated earlier, the accuracy of the rod's bearing surface is critical. Any method to improve and maintain the concentricity of the big end and it's bearings will improve overall life-expectancy.

There are two methods that can be used for asymmetric bolts. One is to change the thread lead, longer at the end of the bolt and compressing shorter toward the head of the bolt. This is a complicated design and only cures half the problem. The other method is the alter the thread pitch, which is the more common method and the one that ARP uses. The thread angle toward the head of the bolt is at a steeper angle, causing the bolt thread to enter deep into the threads of the nut and as the bolt's thread distort, a longer contact area throughout the bolt is achieved.

I have copied the portion of the handbook, published by ESNA in a more complete form in my photos, if you care to read in greater detail and more in it's entirety. The content is in my photo section.

What size is the small end on these rods? ie. will they work with BHW pistons?

GoremanX said:

What size is the small end on these rods? ie. will they work with BHW pistons?

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iirc, small end pin size the same on all tdi's from 96 up ...someone please correct me if i'm wrong

huh, you're right. I must be on some kind of crack. Not the good stuff, either.

Let me rephrase my question: will these work on a BHW engine? I believe the LARGE end is a different size.

edit: In the OP, it states these are 50.3mm. I was under the impression the big end was 50.85mm or 50.6mm. Am I looking at the wrong thing?

bhw engine has large rod journals same as pd130/150 ... there are performance rods made for your application

We are working on the 53.7's and will have them before very long. The BHW, or basically any and all PD motors above 130, plus all the Common Rail 2.0 engines have the larger big end journal.

Too much can be made of how round a rod can be made, as we now see that a competitor thinks 50 millionths isn't close enough and how perfectly round they can make them. And I was told I'm splitting hairs...

Anyone with 1/4 mile experience knows that the kind of crazy hp claimed from some rods requires that the rods' big end better be OVAL. Otherwise, you will splatter your bearings all over the track. It helps to have a little experience in these matters. Perfectly Round is not always 'perfect' for the job.

Also, despite 'expert' opinion, we know the single biggest reason that I-beams are popularized. THEY ARE CHEAPER TO MAKE... same reason that cracked rods are popular with auto manufacturers. The cost is reduced by about 30%. Here is a YouTube of forged steel rods and just how quickly a billet can be turned into a nearly finished piece.... note ear and eye protection for employee: https://www.youtube.com/watch?v=feXzMFxpyu0

Honestly, when I boil all this down, I contracted a premiere rod design engineer to build a rod for me. If anyone else thinks it's good, I am happy to share it. Otherwise, I'll just do my own builds with one less fly in the ointment. I'm building with a connecting rod that I trust.

Franko6 said:

We are working on the 53.7's and will have them before very long.

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Unfortunately I need rods now... or at least in the next couple weeks. So, no go then?

Oh well

Frank, how do I go in on this?

Sorry to leave you wondering. We have sold all of our initial offering and have reordered.

There is an unfortunate lead time of over 3 months due to the backlog of work our chosen company is faced with. We have to deal with it. We are going to double the order and order two types of rods for the TDI's. We are making purchases for the 50.6mm big end ALH/AHU rods and the 53.7mm big end rods, which fit the BHW, 140+ hp PD engines and the Common Rail engines.

We also are going to offer a group buy. Those who make a pre-purchase will, of course, be first in line to receive our next order. Also, any advance order will be made in addition to those rods we would purchase for our own stock.

The cost is mandated to go up, as there was an increase at the first of the year from our supplier. The new cost is $475.

We will accept 1/2 payment down on the rods to reserve your purchase and balance to be paid before delivery.

Based on interest and volume, we will offer discounts on our initial group buy. For the first 15 sets, we will discount $10. Thirty total sets and we will discount $20 on each set. The larger the volume, the deeper the discount, up to 100 sets

I will close the initial offering on the evening of June 15, 2015 at Midnight. Orders will be placed in blocks of ten sets. Cumulative discounts will apply. I will hold the order open additional days if it appears that another level will be met, so as to allow for the best discounting for each member of the group buy.

Please PM your interest.

A second set of rods is ordered. 5 more commitments and all participants qualify for $10 discount.

is grinding of the block and intermediate shaft gear required to use these rods in a 1Z/AHU/AFN ?

Jim,

The design is 'drop in' as far as clearance to the block, but the intermediate shaft requires about a 1/16" clearancing. It's not much, but unavoidable. We will clearance the intermediate shaft for those who will send it along with pistons or any other work.

Four sets to go for first discount level.

Frank, I sent an email a few days ago regarding your BEW cam replacement kit. Did you get it? (I put my username and real name in the email)

We have been swamped... it's a usual problem, but yes, I saw your email... finally. You are included in the group buy JDS...

We are getting a good response. First discount level met for $10. Rods are now $465 per set.

I will report progress as it occurs.

Please remember, we also stock all items for assembly of blocks and cylinder heads.

We recently made an order of BRM 79.5 oil gallied pistons and the BHW 81mm STD pistons, which is a great add to the 1.9 rods for additional displacement. We will balance pistons to your rod sets in group buy sales for FREE! PM or email for details.

Hi, Frank.
Any updates on your current order?

Hey Frank, I am looking for a set of H beam rods for my alh build. You have any extras?

We now have our rods in stock. The length of time for reordering is basically, huge. I hope people think a good thing is worth waiting for.

hmmm these sound like a good deal....

Franko6 said:

We now have our rods in stock. The length of time for reordering is basically, huge. I hope people think a good thing is worth waiting for.

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Are all of the rod sets spoken for? Or do you have extras?

We are stocked up at this time. We have the 50.6mm big end rods that are used for US models: AHU/ALH/BEW and BRM.. Basically all the 1.9 diesel ecu operated engines work with that rod.

We now have expanded our inventory to include sets of our 53.7mm tang-less rods, intended to replace any of the 2.0 liter engine connecting rods. This includes all common rail engines and the US Passat BHW motor from 2004/2005. With some of the scary large builds that we are anticipating for the Common rail engine, the 4340 rods will be an important part of a large build. We also will be stocking sets of the sputtered rod bearings for the 53.7mm big end. As we see the big advantage of the sputtered rod bearings, we are considering some of the slick coatings either applied to our conventional bearing sets or buying prepared sets that are coated.

The common rail wrist pins are nitrided. These wrist pins are identical in diameter to all TDI engines with 1.9 liter designations available in the US/CAN, except the AAZ. We are examining this improvement for high end builds.

Franko6 said:

We are stocked up at this time.

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Fantastic! I sent you an email this week asking about rod & piston options, good to hear you have rods in stock. Get back to me when you can, I know you guys are busy

Cheers,
Andrew.

I think I may have overlooked the info I'm looking for, but do the 50.6mm big end rods have a tapered small end? Apologies if I have.

If so, would you ship overseas?

Cheers,
Law.

The rods we are working with are the tapered small end, as we feel that limits our production line to keep with the most popular pistons intended for the greater horsepower of the H-beam rod. Every piston beginning 2004, at least in the US, are tapered wrist pin design and have oil galleys. We know that those two designs are improved loading and heat dissipation.

On the other hand, the only piston we have used that has the straight wrist pin design are the ASV. For limited applications, at or below 150 horsepower, we have no particular issue using the stock rods used in the ALH/ AHU engines against those particular pistons.

We will and have shipped overseas. Payment options are more limited. We do have a transfer agent in the UK we can work with.