ALFAGTV6.COM

Mats · Post by **Mats** » Thu Jul 12, 2007 12:15 am

The pauter units are heavier??

tectoteam · Post by **tectoteam** » Thu Jul 12, 2007 3:22 am

x-rad wrote:I'm curious if anyone has had stock rod failure below 7,500 rpm with natural aspiration w/ S-compressioin values (V6 12)??

during the 80' in the supertourisme champ.
The gtv6 2.5L from race cars produce output beetwen 7500 to 8000 (depending year) driven by STOCK RODS (stock 2.5L ones).
polished ect....but stock ones !, and he says that they get no noticeable failure.
Got this from the man that build theses engines at the sodemo, that guy is working now alone...he is an old guy.
This is for 2.5L in ~12/1 cr 6ITcarbs...., probably in a more than 8-8500, and more over than 2.5L rods can fails.

i'm running 3.0L 24v with stock 24v rods (lightened on ends to 510gr each), in a 290° 7800rpm, but not enough kilometers to feel any reliability. no fail upon today.
but i am afraid each time i went a few over 8000

.
these rods can perhaps handle it well, but there are also OLD to, the whole engine as at least 150.000 km when i start the project, this is a very important factor to.

Foreground: 3.0L 24v 164 based, polishopeened, and lightened on ends. (a few less than 510gr)
1st ground: 2.5L from a gtv6.

Of course, polished..ect are pretty but when they are hidden in the block:
ligthnening these stock rods, are somewhere a non senses; it take SO MUCH (especially in regard of balancing all the ones) A Fcking consuming time, then it will paid for new ones, like pauter style or other...

Mats · Post by **Mats** » Thu Jul 12, 2007 3:47 am

8k in the V6 should be a walk in the park I think, the issue as I see it is the silly pushrod in the head. Have anybody ever heard about rod failure in a V6 in a sound engine (i.e. serviced and no other issues)?
If you compare the geometry with a 4 cyl it looks like a walk in the park.

x-rad · Post by **x-rad** » Thu Jul 12, 2007 4:20 am

Thanks guys...I think for my other engine I will polish/peen/balance the stock rods and (maybe) save some cash...

junglejustice · Post by **junglejustice** » Thu Jul 12, 2007 6:47 am

Mats wrote:The pauter units are heavier??

We have developed several iterations (one with European M5 journal sizes to undercut a crank and run longer rods), then we have an NA rod, a turbo version etc...

The one on the scale in this picture is the heavier turbo rod WITH bearings and WITH bolts. Not bad at all and the overall weight including a 100mm piston, rings, wrist-pin and retainers is below that of a stock 93mm assembly!

With a shift in conversation to revs, it is worth mentioning that there are other issues with the 24 valve; hydraulic lifters that float at some point! In the 3.7 we went solid - see pic...!

In the 12 valve, (other than stronger 164 rockers and heavier springs), you can't really do anything else about float and you already have solid lifters, so we go after weight - see pic...!

But back to the topic of rods; my street/interim track car is (right now), just a stock old 12 valve 3.0 "Milano Verde" that has NEVER been opened - I know the previous 2 owners. I run the 50mm intakes, headers, AFM removed and a GoTech, but it is otherwise bone-stock! I have left my rev limiter set at 7,250 for the last few years and routinely run it up there...

Just the other day though, I dialed it back to about 6,800 - just to be safe - until the rebuild/24 valve replacement! The thing pulls strong to 7, at 6,800 it just wants to keep going, but I won't be pushing my luck much longer - with 200 kilos (Canadian car) on the odo - she is due for a rebuild here soon!

My opinion; while revs are the enemy of any rod in general, some stock rods are better than others. These rods are good for 7K all day long and maybe 7,500 with some treatment (but it costs so much that buying a set of the THS/Eagle/Pauter/Farmdon-whatever makes more sense.) 8K for the stock rod - even with shot-peening and polishing prep - is pushing it, but still!

I'd be more concerned about the stock rods with boost, but then again, ol' Greg has proven otherwise...

tectoteam · Post by **tectoteam** » Thu Jul 12, 2007 8:23 am

JJ, funny lightened ones

everythings is lightened i like it

nice trick...dismantle the hydraulic one to make it solid...

for the guy tooled its a good way to reduce costs.
very very good trick...never heard about even so easy.

easy easy......how did you dismantle the hydraulic part of the lifter ?

i remenber theres just a few room to work/grab/pull/explode the thing

junglejustice · Post by **junglejustice** » Thu Jul 12, 2007 9:02 am

Nice flat, hard, solid surface - cup your 3 middle fingers and hold the back of the follower (between 2 & 4, with your middle finger on the back of the lifter - whack the open end on the steel surface REAL hard and FLAT 2-3 times! (Do not use pliers etc - you may want to use them again...) Make sure to hit FLAT! After the 10th/11th/12th one the joints in your fingers start to ache. After 18 gout sets in! By number 24 you're done with that hand for a week!

Now you need a HUGE variety of forged steel, chrome molly "bullets" to set the clearances - just like shims in a 12 valve shim-bucket/cam-follower - cams in and out, in and out - the same "old" story...

On the 12 valve rebuild I am also toying with the idea of some bushings on the shaft that holds the rocker-arms (in place of the springs that retain/space the shaft!) The lightened/relief of tension is sure to reduce the "drag" on the valve-train.

tectoteam · Post by **tectoteam** » Thu Jul 12, 2007 11:19 am

junglejustice wrote:Nice flat, hard, solid surface..................

i just try it on an old tappet, works fine...

so easy in fact to dismantle the thing.
also i'm running on 0.5mm cam/hydraulictappet when collapsed. dawie says that this can handle something like a solid tappet below 8000 rpm, but after..solid really required, to keep things solid instead of soft hydraulic, and also because of the weigth of hydraulic tappet.
blabla....
well, i stop now this became a huge outsubject.

Greg Gordon · Post by **Greg Gordon** » Thu Jul 12, 2007 1:44 pm

I go to sleep for the day, wake up and we are way off topic.

Stress on rods is a combination of power and rpm. I feel pretty comfy with supercharged power within the stock rpm range. However 100 horsepower above stock AND another 1000rpm above redline...that does scare me.

The only person I know of that did extensive testing to the point of rod destruction was Tom Zat. In the 80's Alfa gave him some engines to test to destruction which he did. He found that on the 2.5 the valves would start to float around 7500rpm. Once that was fixed the rods would suffer catastrophic failure just over 8000rpm. I am pretty sure that was with stock or near stock power levels and I don't think he ever did this with the 3 liters. I think we can safely assume that on the 3 liter with its higher pistons speeds and piston mass that the limit would be a little lower.

Having the stock rods preped is always an option. It does save some money vs replacing the rods with the THS units. Just how much money it saves probably depends a lot on where you are.

From my point of view the additional cost of the THS rods vs stock rods is pretty minimal compared with the increase in capability.

grant · Post by **grant** » Fri Jul 13, 2007 10:21 am

Greg, what other cool things did Zat do? Did Alfa give him those engines because he was racing at the time? I"m awware of the products tha the sold but I had no idea he worked with Alfa.

Greg Gordon · Post by **Greg Gordon** » Fri Jul 13, 2007 2:34 pm

Hi Grant,
Tom Zat himself told me this story. This was a couple years ago when I called him up to purchase some stuff from him.

I don't know the details of Zat's relationship with Alfa Romeo. It probably had something to do with his racing program. I know he owns a couple championship winning Alfas.

Greg

tomp · Post by **tomp** » Mon Feb 04, 2008 5:57 pm

Greg, beautiful rods sir! Can you steer rod purchasers to a v6 balance man worthy of them?

Tom P.

Greg Gordon · Post by **Greg Gordon** » Mon Feb 04, 2008 6:14 pm

Sure thing, Csaba at Vick Autosports can help you out. They are in Ft. Worth. Or Carbone's in Tulsa seems pretty good. I will know more about them soon.

Greg

PietereQ · Post by **PietereQ** » Wed Feb 06, 2008 11:51 am

I know this is a lame question, but, do you need to rebalance crankshaft after putting these in?

Greg Gordon · Post by **Greg Gordon** » Wed Feb 06, 2008 5:27 pm

I suggest balancing the engine anytime parts in the bottom end are changed. That means with new rods, the rods, pistons, crank, front pulley and flywheel all make a trip to the machine shop. Balancing the whole deal is pretty inexpensive, usually under $300.

Greg Gordon,
www.hiperformancestore.com