Race engine problems and TS considerations
Rather lengthy, and some info might aggravate, but as Jack Webb said, "only the facts mam"
Dear Richard,
I allways read with interest your comments on the AlfaBB concerning engine preparation.
At the moment I run a Nord with 85mm JE pistons and EFI (DTA computer , Jenvey ITB).
Since this engine is at the border of its power, and we have regular problems with it I am contemplating building a TS .
I would like some advice on cams, and headwork to be done (or not to be done...). The cams you design are working nice (a fellow racer has them in a nord and is very happy with them).
Hope you can take some time to inform me, it is for a full race engine.
Regards,
Walter xxx xxxxxxxxxxxx
The Netherlands
In a message dated 8/28/2014 10:30:34 A.M. Central Daylight Time,
AlfaR7@aol.com writes:
Walter,
Some questions, but I also have to think you might be missing the point by considering building a TS after all the extensive work done on your Nord motor.
I and all, know well the "advertised" power being made by certain British builder/supplier. However these expensive engines checked on "honest" and "calibrated" dynos by unquestionable builders here in the USA are only making about 85% of the "guaranteed output".
Not knowing your internal build info, or problems with the Nord I wouldn't jump into that without serious thought.
What are your problem issues with the Nord? What are the internals? Head mods and cams used? What HP are you getting on your dyno?
About the only thing I would want from a TS is the crankshaft from a 155 to get the longer stroke. This will fit in the Nord block.
As for TS cams I would suggest the RjR575 intake and RjR1291 exhaust. These will require head mods to clear the lift including short guides set deep, race springs, notches to clear lobes in the cam follower bores etc. Smoothing out the intake runners and reshaping the seats will improve flow, however don`t get caught up in the large intake valve, small exh valve mods.
See attached PDF file of full lobe profiles.
A successful race engine isn`t about high RPM power, It`s about power made over a useful power band to make an easily driven race car.
If you are having issues because of high rpm failures, you will have the same with a TS.
Rj
---------------------------------------------------------------------------------------------------------------------
Hi Richard,
Problems we had are somewhat related to overrevving , own fault, but issues with leakage test since. Engine is now apart, almost in the car again and will be dynoed in the next few weeks.
Internals are a knife edged crank, 85mm HC pistons (spruell supplied these), H beam rods, 45 mm intake valves (reading your comments we shouldn`t have bothered) also Spruell, as are his valve springs, highest rate he has. stock exhaust valves
CB cams intake 12.9 lift and exhaust 11.3 (diagram I have not at hand at this moment).
Long aluminium intakes (Alfaholics) and off course the DTA EFI.
Rear wheel HP when engine was just run in 171 at 7000 rpm`s, torque 180 nm also at the wheels, I do however not have the dyno print at hand now for the curves.
Reason I am contemplating on a TS is that engines (especialy the 155 and 164 2nd series which also has the 90 stroke crank) are more available overhere than a 105 2 liter, and I am building a FIA car (GTAM replica) that can get the 2 liter fitted, with carburators (I have 45 mm dell orto with 36 venturi).
I will need in the end a second engine when that car is finished (almost on its axles by now) and have to go from scratch, no spare parts to mention.
I am told by several engine builders the 155 block is stiffer than earlier blocks, with also stronger main bearings (I am aware of the tales AH , Formula GT and so on tell on HP , but I also know I am with my current engine just as fast on Castle Combe, their home and main testcircuit as Max with his 215 HP TS). And torque on any TS I seen and drove, and experienced has way better torque at lower rpm`s , better on the more twisty tracks overhere than just the high HP at high RPM.
I appreciate your thoughts on this.
Regards, Walter
---------------------------------------------------------------------------------------------------------------
Walter,
Several things caught my eye.
The knife edged crank to start.
Alfa Nord 2 Liter cranks have inadequate weight in the counter throws to correctly balance an engine for use over 6000 RPM even with light Carillo rods and light pistons. Knife edging compounds the problem.
If you are having crank/bearing issues blame the knife edging. (I do assume the block has been drilled for direct oiling on #2 & #4 main. If not it should be.)
There are light billet 2 liter cranks being made by Marine in Calif. Will send you an email with the info. These light cranks have adequate designed counterweights for higher RPM use.
The camshafts. I am unaware of any 12.9mm lift cam made by C&B for any Alfa. None at all on their website. Never heard reference to such.
Regardless the C&B`s typical designs are high overlap designs and the exh cam has to be another C&B "intake" cam by design and incorrect for the exhaust side.
Correct cams will both make a more powerful motor and do it at reasonable RPM. As well the power band will be much larger/longer. Again those cams I suggested for the TS are what the serious engine builders over here are using. There are no TS cars (even the 2 with AH motors), running competitively against well built Nord motors. Typical baseline rear wheel HP on these is 190 and above....
If your head hasn`t been "High Ported" it should be. See my intake at post 179 at:
http://www.alfabb.com/bb/forums/motorsports/146464-old-alfa-racer-pics-so-west-div-4.html
Don`t use Delorto carbs. They won`t flow as well as Webers. As well you should use 48mm carbs if racing with carbs at a minimum. I`m using to 50 DCO carbs but they require a custom manifold due to width.
48mm DCOEs can be modified at the middle shaft ends to fit a stock Alfa intake opened up to fit big runners.
The "Torque" you mention is not the TS design, but cams being used. Those are the engine`s brain. (As well the engines are most likely using the longer stroke crank, legal or not...)
What is the Throttle body size? Shouldn`t be any smaller than 45mm and preferably larger. Hopefully fed from a cold air box, not airhorns in the engine compartment.
Rj
---------------------------------------------------------------------------------------------------------------------
Hi Richard, thank you very very much for putting me back on my feet concerning the possibilities of the old nord engine.
Few question still :
First price of the camset as you adviced?
Second the crank, you know a price of the firm you mentioned? And the 90mm crank 155, use eith its own shorter rods to prevent protruding pistons? Or use longer nord rods with changed piston pin location?
And last what is your opinion on the " apple bite" pistons from Spruell?
O and one more: do you plan any CR gearboxes in the near future, might be interested in one if shipping to holland is no problem for you?
Regards Walter
---------------------------------------------------------------------------------------------------------------------
Walter,
-Cams (a pair of any lobe design) shipped to Europe is $xxxxx USD.
I keep a pair of the RjR575/RjR1291 cams in stock because of demand. If you catch me out of stock build time is normally about 2-3 weeks, but I order as soon as stock ones are bought.
-Billet Crank by Marine. I don`t know for sure but I think it`s about a $3,200.00 item. Jon Norman, Alfa Parts, Berkeley, Calif. is the Distributor (
ALFA PARTS - Alfa Romeo Parts, Spares, Accessories 800-890-ALFA)
-155 crank : I think using it and the 155 rods would fit on your pistons.
-The Apple bite Pistons. I`m no fan. I bought a set and they measured 84.5mm at the skirts!! Had to bore new liners to fit as skirt clearance was .024 (.55mm) in the 85mm liners. I`m not the only one with size issues with these pistons. See Bill xxxxxxxxx`s mail I cut and pasted below.
In my opinion (?) the dome design is good for fitting in a 2 liter Nords 4 different shaped combustion chambers, but the "applebite" and with the really big valve reliefs are not appropriate re compression increase. And that's why they only produce about 11.5 CR in a full thickness head.... If the existing uncut dome design was simply flat cut about .050 off the peak, and valve reliefs sized correctly and not as deep they would be more effective. The dome of the pistons will still fit a head (that is stock thickness 4.410") with .020(.5mm) milled off of it to improve the combustion ratio.(to 4.390 thick )
-I keep at least one CR box built on the shelf. Right now there are two. Both with the rear tower shields to prevent spray into the shifter tower.
One is a 1.99/1.59/1.25/1.0/.92
the other is a 1.85/1.59/1.25/1.0/.92
Cost $xxxxxx complete box or gearset complete with syncros $xxxxxx plus shipping (gears only about $130.00-$150 to Europe.
An entire trans I suspect will be $350-400.00 at least since everything goes by Air from here).
Thanks, Rj
Hi Richard,
I now have sympathy for what happened to you with Spruell’s CP pistons. I finally got them with the bored out sleeves only to find out when I measured the skirts that 2 of them were 0.004” oversize and the other 2 were on the money. See data I sent to Spruell below. I have to put the sleeves in a block with my torque plate and remeasure when I get them back to verify accuracy, but the static measurement is close.
I called CP myself to find out what was going on and talked to the general manager, he didn’t have an answer. Spruell insisted that I send the pistons back to him for return to CP. They went to Spruell then to CP, who has subsequently made a new set and sent them to Spruell who should have them already if not by Tuesday. (I called CP to verify their return). So my situation sounds similar to yours, which wasn’t Spruell’s fault (other than he didn’t measure the pistons when he received them and he told me that the liners were match bored to the pistons, which is obviously bu!!****.) Hopefully I`ll be able to build the new motor before the end of the year.!!!!
BTW: the OSG CR gear set is still performing beautifully. I still have oil leaking at the exit of the shift tubes on the front / top of the gear box. Any thoughts on how to stop this.???
Any new cam revelations I should know about for the new motor. With the: 31 lb. billet crank, 360 gram CP pistons and light weight Carrillo rods my plan is to run the engine up to 8500 rpm. I’m putting 46mm X 8mm lighted Ferrara intake and 38mm X 8mm lightened Ferrera exhaust valves in the head with new seats, springs, etc.
Hope all is well, see you're back on the BB so that's a good thing?
Forgot to provide raw measurement data.
bill xxxxxxxxxMeasuring Instruments:
Mitutoyo 3-4” micrometer Model #013-218 / .0001” per increment resolution, calibrated to the national bureau of standards.
Mitutoyo Dial Bore gauge Model #511-753 / .0001” per increment resolution
Raw data:
Coated CP Pistons:
#1 = 3.3491+/-.0001”
#2 = 3.3445+/-.0001”
#3 = 3.3453+/-.0001”
#4 = 3.3497+/-.0001”
Sleeve #1 = 3.3497 +.0016" (top) +.0024" (bottom) of measurement area.
Sleeve #2 = 3.3497 +.0016" (top) +.0023" (bottom) of measurement area.
Sleeve #3 = 3.3497 +.0012" (top) +.0021" (bottom) of measurement area.
Sleeve #4 = 3.3497 +.0012" (top) +.0021" (bottom) of measurement area.