Jump to content
SAU Community

Recommended Posts

spool rods looks pretty chunky. although abit of unused wieght in them. sact and eagle are similar too. either way for the money, who cars.. all capable of the same power.

and all made from 2 seperate bits.. not a tru billet. but then again for the money, all the same.

Hey Paul how do u rate the cp ring sets? i pulled my motor down after the initial dyno tune to check pistons etc and noticed a couple of the ring gaps had lined up with each other, any ideas why? i've not had any issues since reassembly but not something i want to happen if possible. I used to run Jun cosworth pistons and never had any issues, but since my bore is bigger than 87mm i cant use the jun ones anymore :)

CP rings are too thin in my opinion...0.8mm top ring and 1.2mm second ring...CP have since addressed this with 1.0mm top ring and 1.5mm second. The earlier versions were permitting too much blow-by for high boost applications as they had a small contact patch with the cylinder wall and sealing was an issue.

Dave the rods look great...im a fan already...I beams FTW!

I like your thinking paul... rb26 2.8 stroker would be nice :)

I was more thinking of a stroker crank for the CA18 engine. Im a big fan of them as they are basically the same design as an RB26 missing 2 cylinders. SR's have significant problems with rocker arms, oil pumps and their open deck block design has issues at high horsepower. A tough CA engine is a great option and in my opinion an often over looked prospect for performance.

and im itchin' to build one to prove it.

Edited by DiRTgarage
I was more thinking of a stroker crank for the CA18 engine. Im a big fan of them as they are the same design as an RB26 missing 2 cylinders. SR's have significant problems with rocker arms, oil pumps and their open deck block design has issues at high horsepower. A tough CA engine is a great option and in my opinion an often over looked prospect for performance.

too bad they sound worse than an sr :)

CP rings are too thin in my opinion...0.8mm top ring and 1.2mm second ring...CP have since addressed this with 1.0mm top ring and 1.5mm second. The earlier versions were permitting too much blow-by for high boost applications as they had a small contact patch with the cylinder wall and sealing was an issue.

thanks Paul, when did they switch to the better ring sets? i bought my pistons around october last year do u think they were old or new ringsets? i might pull it down and redo them with another set if ive got the old versions

Paul,

I can get CA cranks, changing the stroke shouldnt be too much of an issue.

Cheers

I was more thinking of a stroker crank for the CA18 engine. Im a big fan of them as they are basically the same design as an RB26 missing 2 cylinders. SR's have significant problems with rocker arms, oil pumps and their open deck block design has issues at high horsepower. A tough CA engine is a great option and in my opinion an often over looked prospect for performance.

and im itchin' to build one to prove it.

Scat are manufactured in america.

or is their website full of it?

http://www.scatenterprises.com/

All Scat's forged parts are "forged" in china, but much of the machining is done in america aparently. What isnt clear is exactly what is US machined and what is Chinese machined. Scat has been a major player in the VW aftermarket parts scene for years. I cant remember where i read it, but it was from one of the top VW drag engine builders in the US.

Clearly where the comments were going were to do with concerns about parts quality from china, because we've all seen the ebay parts that are available these days. Well there is some reason to be concerned. While im sure SCAT is working to improve quality controls on their chinese manufactured products, demand for cheaper product seems to be not helping improve that quality.

There have been issues with some parts that were machined with terrible tolerances such as lifters not hardened or radiused properly resulting in camshaft and lifter lobe failure, pushrods with the ends rattling loose, high ratio rocker assemblies that have too much clearance and the ratio's differ from one rocker to the next (when measured with a dial indicator) because they arent machined the same.

Good news is though i've not heard much of people reporting crankshaft or rod failures in recent years. There was some quite a few years back though and for a while Scat had a an australian reputation of "scatter" when some of their crankshafts were breaking, though that was unconfirmed whether they were the forged or the cast cranks.

Seems to me that its not often you hear of an engine breaking solely on power. Its usually an oil system issue, or at worst a rod bolt letting go.

On topic again...

Great build progress... love your work!

Cheers,

Ian

spool rods looks pretty chunky. although abit of unused wieght in them.

? I want your "in head" FEA app :)

I'm a big fan of them as they are basically the same design as an RB26 missing 2 cylinders.

:) CA18's are wicked little motors that ppl don't seem to pay much attn to. A capacity nudge would make them a real SR killer.

Shanef ur deaf! - full house CA's sound wicked imo!

EDIT: Dammit, limpus beat me to it.

Edited by GeeTR
All Scat's forged parts are "forged" in china, but much of the machining is done in america aparently. What isnt clear is exactly what is US machined and what is Chinese machined. Scat has been a major player in the VW aftermarket parts scene for years. I cant remember where i read it, but it was from one of the top VW drag engine builders in the US.

Clearly where the comments were going were to do with concerns about parts quality from china, because we've all seen the ebay parts that are available these days. Well there is some reason to be concerned. While im sure SCAT is working to improve quality controls on their chinese manufactured products, demand for cheaper product seems to be not helping improve that quality.

There have been issues with some parts that were machined with terrible tolerances such as lifters not hardened or radiused properly resulting in camshaft and lifter lobe failure, pushrods with the ends rattling loose, high ratio rocker assemblies that have too much clearance and the ratio's differ from one rocker to the next (when measured with a dial indicator) because they arent machined the same.

Good news is though i've not heard much of people reporting crankshaft or rod failures in recent years. There was some quite a few years back though and for a while Scat had a an australian reputation of "scatter" when some of their crankshafts were breaking, though that was unconfirmed whether they were the forged or the cast cranks.

Seems to me that its not often you hear of an engine breaking solely on power. Its usually an oil system issue, or at worst a rod bolt letting go.

On topic again...

Great build progress... love your work!

Cheers,

Ian

Excellent post Ian, Yes Scat are a major supplier of VW performance parts (thats where they started from). As their are about a dozen grades of 4340 id say the cheaper products are made from the inferior grade that just meets the SAE or ATM standard. The Spool rods although being Taiwanese made are of such a standard in regard to their finishing tolerances that they would be up to the task in all but the wildest street application.

Im unaware of any RB26 engines standard rods failing due to a weakness in their construction. Its always the bolts or the oil supply (or lack of). I made over 450KW at the tyres on STD rods and raced the car for over 3 years and when checked after pulling the engine down they could have been reused as they were in perfect condition. RB26 rods would be adequate in this build but i leave the final choice of rod selection up to the customer. Some people just like new shiny stuff :)

RB26 rods would be adequate in this build but i leave the final choice of rod selection up to the customer. Some people just like new shiny stuff :(

Mmmmm SHINY!!! :P Get some pics up of the new rocker covers on the head Paul.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...