The Dodge Challenger Message Board

i am in the market for new con rods for my 340 build up (+0.040, Forged TRW heavy slugs, 2.02 J heads and small solid cam, expect about 320-350HP). It is a build on a budget as my expenses are stretched with too many projects at the moment. There are some cheap conrods on the market - but with good names - SCAT, Eagle, CAT (maybe not so good there) -of course, all made in China, so how good are they? My mechanic said he didn't like H beam because they increase oil windage. This makes sense to me, he said the groove acts to scoop the oil, thus throwing the balance out and increasing windage, like a spoon. The oil dripping down from the top end also gets held by the groove he says. He reckons I beam are a better design. Whats others thoughts?

Also, he reckons these cheaper aftermarket rods have just as cheap rod bolts, even though they look good, he replaces them with ARP bolts, which coincidentally, so does Mancini, with the cheaper Eagle SIR rods. Maybe they have also experienced returns from rods with the pre-installed bolts...?

Lastly, which steel is better, 5140 or 4340...? 8740 Chrom-moly for the bolts, there are all these advertised.

My budget is around US$300-350 for some aftermarket rods, which is still cheaper than working up some stock rods to that level. I have some 340 rods, but they are heavy, and with ARP bolts, shotpeening, resizing and rebushing and balancing,, would be expensive.

Any suggestions from people who have been in the same situation. thanks.

Ive been very impressed with these folks and Tom Molnar's place www.k1technologies.com their rods are very reasonably priced, I think they only offer according to their 2008 catalog which I have, MoPar Smallblock Rod 4340 H-Beam, ARP 2000 fasteners, around 400.00 bucks a set, a bit less than most, reportedly made in the USA, I think the H-Beams versus the I-Beams is blown out of proportion regarding the oil control problem, if there were that much oil windage it would result in other noticable problems such as oil temperatures higher, frothing, ect but I havent heard of any issues regarding this. Also if you insist on I beams for the smallblock the only choices I know of are the eagle's SIR rods and the, "Custom RACE-- Lentz, Carillo(A subsidiary of K-1 Technologies), Oliver forgings, and these are VERY expensive but come in any style you want even Titan and alloy. Maybe for a class racer wanting to squeeze the last ounce of power might consider this but I think it's not that important. Since you are using a solid cam and possibly overrevving the engine, I would consider the 4340 rods with ARP 2000 fasteners. It will blow your budget a bit Steve but only by 75 bucks or so. maybe you can find a set from someone wanting to upgrade or has an extra set??? As far as the 'overseas' rods,, as long as they are carefully checked by a competent machinist,,they should pose no problems and I havent heard of any and have built at least 2 engines of other brands with them and NO failures as of yet and they are drove hard and put away wet!

Thanks for that quick reply Ed, i do think $400 is a bit out of my price range (have to consider around $50 for postage as well), even though i am sure it is a great price for what they are. Made in the USA too - that is a big plus for me. I notice Eagle and Scat chinese I beams are very well priced, have been on EBay and perusing these, have a look: http://cgi.ebay.com/ebaymotors/ws/eBayI ... &viewitem=

they have the bigger ARP cap bolt 7/16 Vs 3/8 for the Eagle. And a great price for 500HP rated rods that are very light, as long as they can ship US Post Office. I have dealt with this company before - they are very friendly. Mancini are very big and they often 'surprise' you with a high postage cost, which you have no control over. I think you are right about the H beam oil windage - i think it has been exaggerated. If there was such a big problem, people would not be buying them. But i have to keep the cost in proportion to the rest of the build and its for a street motor. i definitely do not drive my cars as hard as you!

Thats a nice rod for the money Steve! I wasnt aware of those, and with the 7/16--190k psi ARP capscrews I think it's plenty strong enough.

gday steve ive bought from that seller they are good to deal with
cheers ian

Oh yes. i much prefer a company that send you an invoice which you can pay by PlayPal or Credit card, rather than, like Mancini who take your Credit Card details and then charge you what they like for postage. My mate asked for USPS (Post Office) - so then they sent it BAX Global, which was then taken by FedEx -huge cost including $300 extra for GST and Import Duty. Surprises like that i don't need! Steve

airfuelEddie wrote:Thats a nice rod for the money Steve! I wasnt aware of those, and with the 7/16--190k psi ARP capscrews I think it's plenty strong enough.

thanks Ed, glad i have your tick of approval - so i will hopefully get them if they send USPS. I will have to ring and request that though as they say they only ship UPS for orders over $299.

I'm sure they are very good quality Steve, but, check em out to be sure. Measure the length of the fasteners before you do anything and make sure they send you a spec sheet of fastener torque specs. Write all this down in your "Engine BuildPlan Book"--My old supplier didnt include anything like this and I had to contact the Engineer at the place where they made the parts. But now I have a wonderful supplier who does everything I ask of him. I would also measure the width of 2 rods placed together and measure the width of the big end in regard to your crank rod journal. This will give you you're rod side clearance. But it's checked during mock-up and assembly. After each rod is installed you can measure the length of the rod bolts to insure the proper amount of fastener stretch if you wish to install the bolts at the proper stretch or pre-load. But you can forgo this procedure and just use a known accurate Beam Torque wrench. The first way is a bit more accurate. (These are all things you can do at home without the builder,, or if you are building it)

The quality of the rod bolts is FAR more important than the quality of the rods themselves.

X2

Thanks for that great build advice -i have cut and pasted it into my Tech notes!! Anyway, i have bought them last night. Well actually, early this morning, tried ringing KMJ about 7 times,no answer, no answer, so i thought it must be a public holiday over in Iowa. Well at 2am, i tried for the last time -finally got a guy there - yes, it was a public holiday! He was very helpful, i paid by CC there and then and he said he would unpack them all and put in a USPS Flat Rate box for me. That's service! Only Fifty Bucks postage Ed, All up cost of only US$338 !

Yes Dave, I would not have bought them if they didn't have the ARP cap screws, but we'll do Ed's checks as well just to be sure. Well they are still "cheap" rods. What i like is that they are light : 595 grams. As opposed to 750+ for my stock 340 rods. My old school TRW 340 Forged pistons are quite heavy, so a lighter rod will help rotating mass there.

Thanks, S.

Glad you enjoyed the 'Tech Tips' Steve. Just make sure you use an anvil tipped micrometer. This way the tip of the mic,opposite of the handle, will have a pointed end and will fit in the 'divit' on the end of the fastener bolt which can then be easily measured with the mic. If they are both flat the mic slips all over the place and an accurate reading is difficult.. After rod installation on the rod journals, the fastener height can then be re-checked and compared to the free standing height of the fastener which you measured before installation. Any discrepency beyond the fastener stretch spec. will then be noted by the engine assembler/blueprinter. The fasteners shouldnt 'stretch' beyond a certain point. If they are then you can conclude that they have been over-tightened and should be re-placed. This exact same scenario happened to me. Some idiot tightened my rods with an impact wrench and I had to use a breaker bar to remove my fasteners on my 'New' rods. I measured the fastener height and they were all over the place. I replaced my fasteners with ARP 2000 capscrews. I measured them as soon as I recieved them. They were ALL spot on! New ARP Con Rod fasteners arent cheap, the ARP 2000 series are 150.00/16 Or you could say screw all this and use a clicker-type torque wrench

airfuelEddie wrote:Some idiot tightened my rods with an impact wrench and I had to use a breaker bar to remove my fasteners on my 'New' rods.

you gotta be joking! I thought they only did things like that in the back yards over here!

Thats good advice - i have been meaning to invest in a micrometer for a while now. Good 'ole Ebay...looks like i will fast track that purchase.

BTW, you didn't say what the 'stretch' should be after tightening to torque specs. You say they were all spot-on, but should they stretch at all? I know the whole reason for resizing rods is mainly due to the higher clamping force of new or hi performance bolts. So after torquing to specs, what is the allowable percentage of stretch for your 2000 bolts for example?

Goldenblack440 wrote:You say they were all spot-on, but should they stretch at all?

Yes. Bolts only stay tight when stretched. The amount they have stretched is a better measurement of how tight they are than torque. But you need to be able to measure them accuratly and of course you need to know how much is just right.

Goldenblack440 wrote:

airfuelEddie wrote:Some idiot tightened my rods with an impact wrench and I had to use a breaker bar to remove my fasteners on my 'New' rods.

you gotta be joking! I thought they only did things like that in the back yards over here!

Thats good advice - i have been meaning to invest in a micrometer for a while now. Good 'ole Ebay...looks like i will fast track that purchase.

BTW, you didn't say what the 'stretch' should be after tightening to torque specs. You say they were all spot-on, but should they stretch at all? I know the whole reason for resizing rods is mainly due to the higher clamping force of new or hi performance bolts. So after torquing to specs, what is the allowable percentage of stretch for your 2000 bolts for example?

Dave's right! Sorry Steve, I should have explained it more clearly. First take the bolts that are in the rods when you get them. Remove the bolts from the rod and measure them directly. Now take that measurement write it down and put the new fasteners back in the rod,,go on to the next rod and record it until you get all 16 values. When installing the rod, torque the bolts using a 12 point offset if it's a big block and standard if it's smallblock boxed end wrench that is at least 10-12" long. I had to go thru at least 5 tool suppliers before I found a long enough box ended 12 point wrench with an offset. and then I had to order the whole set to get 1 wrench! You will need it this long to place 65 foot pounds on the fasteners,,which is what my rods called for..Yours will be different I'm sure. The extra offset on the big blocks is needed due to the fact the oil pan rail is much higher or lower depending on how you look at it. If it's not long enough you will have to use a breaker bar and this may slip busting your hand and cutting you badly! Dont ask me how I know this Then take the stretch gauge and place it between the fastener points and tighten away until the gauge reads the amount of stretch,(pre-load). This is the 'proper' way to place torque on a con rod fastener using the stretch method. If you dont have the wrench and stretch gauge you can do a great job with using ARP's lube, tightening the bolts to the required foot pound/newton meters using a torque wrench. Just make sure you use their lube and tighten them 5 times or cycle them tighten/loosen 5 times to place an accurate torque on them. The tighten/loosen technique ensures the bolt friction is reduced enough to get an accurate torque on the fastener instead of measuring the friction from the new parts. I've never used the 'angle method'. I have a torque wrench thats very accurate. Richmont Sturtevant 0-150 lb. Beam style Torque Wrench. BTW, when I said they were spot on I meant the new fasteners I ordered were spot on as far as initial height measurement out of the box. This indicates they are all within spec. The old bolts were all over the place as far as a relaxed height measurement with the micrometer. Con Rods are actually a little larger,(I.D.) opposite the parting line. This helps with the crush at higher rpm's The fine quality tools arent cheap either,,the ARP stretch gauge accurate to .0005 and the wrenches,,,or an accurate torque wrench is also very pricey,,so the proper tools, knowledge and experience come into play here. Sorry for the winded reply,,hope this helps.

wheew-ee, that is an involved process for correctly tightening con rod bolts. I wish i lived closer, i'd gladly pay you well to build my engine! Here is a picture of the SCAT conrods - are you sure it is necessary to remove the bolts to measure them? These look well and truly pressed in. My mechanic reckons it is quite involved to press them in and out without damaging anything. Cannot they be measured with a micrometer while in the rod? I see the necessity of tightening loosening etc 5 times to get an accurate torque reading - initial friction is a big factor. i will enquire about the ARP lube, i may have to get it from the States.

Here also is a picture of my 30-150 Ft-lb torque wrench. It is a quality Sidchrome made in Australia (before they were shipping off stuff to get made in You-Know Where) using a British patent and a French made bar. It is the clicker style ones and is almost new.

I groaned when i read about your hand slipping. Arrrgh. Thanks again. S.

Sure you can measure the length in the rod while the fastener is a 'relaxed state' no torque placed on them. Write this measurement down, then after attaching the rod to the journal measure them again after final torque. But if you are going to use a Torque wrench you wont be able to use the stretch method anyways. The wrench must fit in the middle of the gauge, thats why a box ended 7/16-12pt. wrench must be used. It's really not necessary Steve. I would use the 5 torque/loosen method before final atttachment as long as you use ARP moly lube it will be very close in accuracy as long as that clicker wrench of your's is accurate. You would probably need another couple hundred dollars in tooling to do it correctly,(The stretch gauge and a 12 point long handled wrench) and I know you are on a budget. It will be fine as I know you are very meticulous. BTW, did they include a torque spec or length measurement included with those rods,(Spec/Tech/Installation sheet)?

airfuelEddie wrote:It will be fine as I know you are very meticulous. BTW, did they include a torque spec or length measurement included with those rods,(Spec/Tech/Installation sheet)?

That's good to hear! Also too, i really do drive on the gentle side of fast, with the occasional squirt to blow out the cobwebs and hear that exhaust 'music'. So i think that method will be fine for my driving style. And i am using the factory rocker gear if i decide on a hydraulic.

I have not received the rods yet, only paid for them a few days ago, so can't say if they have the spec sheet. I hope so! Then again, if the specs are there, they would most probably be written in You-Know-What. !!

BTW there is a guy in the Charger Club over here - he runs a street driven Aussie Charger with a Fuel injected 360 and under-bonnet supercharger. He runs flat 11's (11.0) on street Hoosiers, small diff and standard rocker gear!

Goldenblack440 wrote:

airfuelEddie wrote:It will be fine as I know you are very meticulous. BTW, did they include a torque spec or length measurement included with those rods,(Spec/Tech/Installation sheet)?

That's good to hear! Also too, i really do drive on the gentle side of fast, with the occasional squirt to blow out the cobwebs and hear that exhaust 'music'. So i think that method will be fine for my driving style. And i am using the factory rocker gear if i decide on a hydraulic.

I have not received the rods yet, only paid for them a few days ago, so can't say if they have the spec sheet. I hope so! Then again, if the specs are there, they would most probably be written in You-Know-What. !!

BTW there is a guy in the Charger Club over here - he runs a street driven Aussie Charger with a Fuel injected 360 and under-bonnet supercharger. He runs flat 11's (11.0) on street Hoosiers, small diff and standard rocker gear!

Well, if they dont have it,,you can get it at SCAT. I also have a spec sheet for H-Beams but they are the Eagle H-Beams for A/B/RB engines. That blown 360 is stout. (blowers&Turbos turn reg. engines into beasts,,that cylinder pressure thing Dave always rants about!!)

I'll just give this topic a quick kick in the guts again to post some pictures of the SCAT 318/340 I beam rods i just received. And to say that everything Eddie you said about the rod bolt measurements was right - as you can see there are full instructions and places to log the measurements and how to check for throw-away condition after use. They even include a satchet of the ARP Moly lube Eddie described. The rods are all individually wrapped and sealed in a generous amount of anti corrosive stuff. They look great, very light, and only US$287 plus $50 postage.

Thanks for making me aware of those Rods Steve. They are very nice for the price. Dont forget to clean them completely with solvent then lightly oil them. Make sure the pin bores and big end or spotless, use paper towels never shop rags. The small lint can plug up oil passages but paper fibers dissolve. Then after you are done put them back in a new plastic bag, dont re-use those that came with the rods, they probably are contaminated with grease and metal shavings.. Good Luck!! Keep us posted on the build.

Good advice, thanks, i will. !!