Nick from Modern Performance
"I would balance the motor. I have found the pistons to be off as much as 6 grams. The rods are also off and sometimes as much as 5-7 grams. The cranks seem to be right on the money. The front damper and flywheel are also real close. Make sure when you do the rods you also peen, grind, polish, replace the bolts and resize the big end."
Here is my perspective on pistons,rods and balancing when rebuilding a 2.3 .
Step one: throw the stock pistons and rods in the trash ! why you ask? By the time you polish,shot pean,resize,replace the rod bolts,balance and press the pins in for the new pistons,you could have bought a set of new,cap screw,floating pin,high performance rods that are way stronger than any redone stock rod
As far as balancing, every stock 2.3 crank I have had checked has been in balance from the factory all the performance rods and pistons have been within 1/2 gram right out of the box.
So in my opinion buy new high performance rods and pistons and forget balancing,you will save time money and have a very strong bottom end.
Total seal rings don't hold up well under detonation due to the thin two piece upper rings. They will crack under detonation, and that's not what you want in a turbo car. If you must have a zero gap type ring, go with the Childs and Albert ones, they use a single upper ring with machined ends that fit together for a zero gap. A friend of mine runs them on his 8 second nitroused Fairlane and swears by them. The Speed Pro rings work great for most 2.3 turbos, and are much cheaper than the zero gap style.
The stock rods have oiling squirter holes to allow for cooling and lubrication of the piston skirts, that's why the engine will last longer with stock rods.
First a very brief response because you listed them so well
and you seem to be
putting a lot of thought into the rebuild. This is a subject that has had a
lot of coverage and there is lots of info in the archives, but I think we
cannot stess enough NOT to go overboard with an engine build. Especially to
make the kind of power you have indicated.
>With your permission I will publish this also to the list. With membership
changing I'm sure there are a number of people interested.
> Balance 130 YES
> High Vol Oil pump 18 NO
> Adj Cam sprocket 46 NO
> Better Head gasket 19 YES but only Fel-Pro wire ring
> Face flywheel 35 YES
> Additional things I'm considering are:
> High strength fasteners 80 NOT NECESSARY @250
> Bronze valve guides 50 NO
> Lightened Flywheel 55 NO
> Match manifolds/head 50 NO
> Port head 100 YES
> Roller Cam 348 NO
> My intention with this engine is for it to last 100K miles and
> probably get to around 250 HP once I get the better exhaust, Intercooler,
3"downpipe, and maybe a mild chip in place, and not spend a ton of money.
You can make 250 HP with a basically stock engine with lots
of boost and good
intercooling. Everything stock with mild modifications.
Some details......this is very similar to an engine I am helping with in the
Detroit area for an SVO Must. Objective, 271 HP (same as 289 HiPo)
Hi volume oil pump is not necessary. The stock pump is about
the same flow as
a 460 V8. (No data....your gonna have to trust me on this one)
Going to hi volume only puts more stress on the auxillary shaft and this is
the big weakness in our 2.3.....If you want to increase bearing clearances and
use oil flow for cooling, then you need more capacity, and Esslinger has a
really nice heavy duty Aux shaft with distributor gear, and hi volume pump.
but again, if the bottom end is stock and power is below 300 dont worry, be
happy..........you have a really strong structure.
Adjustable cam sprockets look great, but if you dont have to
cut more than
.010" from each surface, it is not really necessary. But cheap enough that if
you really want it why not.
Better head gasket. Everyone does not agree, but the Fel-Pro
gasket, while not cheap is the very best that money can buy for the 2.3. I
know Nick likes one of the Detroit gaskets, but they do NOT have the wire ring
and CANNOT provide the same combustion sealing "unit load".
This is the same gasket I had installed when we went 11.53 ET and the same
motor, head, and gasket went 186 MPH at Bville.
Studs and nuts help a lot, but at the levels you are talking,
they are not
necessary. Nice, but not necessary. If you have the money budgeted, go
ahead. Use the studs that neck down. These provide more recovery and less of
a necessity to retorque. I do not use these but then I have retorqued heads
regularly when using gaskets.
Bronze valve guides have proven to be as much problem as anything
you do not have excessive valve guide clearance, do nothing. Use the NOK
valve stem seals (production 87/88) and a little more exh clearance than
intake (they run a LOT hotter)
The problem with bronze is that some alloys will shrink with high temperatures
experienced under Highly boosted conditions. I run a lot hotter than most,
and have had exhaust guides sieze the valves so they had to be driven out. No
damage to either valve or guide, but the size permanently became smaller. If
you must put guides in the engine, ask again, because there are some alloys
that will be affected less. I cannot remember which alloys and need to go
into my own archives and I'm running out of time today.
Lightening flywheel is debatable. Most of us feel that the
mass of the
production wheel helps the launch of our relatively heavy cars.
The aluminum wheel provides a better transient response, but also have a
tendancy to vibrate loose unless driven with pins in addition to the 6 bolts.
The problem I have is the original wheel was engineered and tested to not fail
at speed much in excess of what you can run at on one of our engines. By
machining away material you will create a component that may behave in an
unpredictable manner. If you must have a light weight wheel, buy a light
weight steel wheel or go to an aluminum. I would not run a modified cast Iron
wheel in my worst enemy's car.................(well maybe one guy)...........
PORT head................YESYESYESYES..........and the intake
upper & lower
The valve throat and valve pocket respond very nicely to a little massaging.
Keep stock valves, (the exhausts are inconnel) (and yes you do need them for
durability), port, modify the chamber for more volume, extending the chamber
toward the exhaust side thereby making the spark plug more centrally located.
(Not much but a little helps.)
Save money where you can and spend it on the best air charge
cooler that you
can find and the 3" exhaust system.
Nicks pipe and intercooler are probably the single biggest improvement you can
do. The engine probably has to be redone, but be conservative with the engine
modifications. You can make the power with the stock valves and cam. If you
need to change a cam, one that most on the list have overlooked is the Lunatti
.500" lift that used the stock events. This is not a roller cam, but is
hydraulic and when installed with the correct valve tip heights works well.
It idles and is streetable. As with almost all aftermarket cams, we loose
bottom end and somewhere in your plans should be a lower ratio rear axle. It
really makes the package wake up and makes it feel like a super car.
I hope this helps.......................its just a small consideration.
Do not go overboard, and remember that air flow, boost pressure,
charge cooling are the main things to work with.
Can you tell me where I can get this cam?
> Is there a wear problem due to the high lift and
> non-roller configuration?
Lunatti Cams in Tenn. I do not have a number but they advertise in most
publications. Hot rod, Street Rodder etc.....
Russ Harness at Rapido also has carried them in the past. I think Esslinger
may have them in stock also. The deal is do not accept a substitute. As has
been said in the past, this deal wants to be as little overlap as possible.
Lots of lift but otherwise pretty mild and conservative.
Slider followers are not new, and they are really not bad. They are just not
as good as the rollers we have now. The key to long life is the iron alloy
and the heat treatment the finished cam goes thru for hardness. I suspect
that the aftermarket is a little sloppy about alloys and heat treat. Very
cost driven, and heat treat is hard to control. The roller cams are almost
all billet or powdered metal and hardness is easier to control. Actually we
tried nodular cams for rollers when we did the first one for the 2.3 and ended
up with the powdered metal (more expensive) because of a few failures.
If you assemble a slider follwer cam with all new components
and keep the
springs conservative. You don't need 400# @.500" but thats another story...No
actually its an important part of this one. Most of us choose springs that
are too heavy. With the engine calibrations we use and fuel shut off being at
6250 or if a chip I'll bet no one runs higher than 7500 RPM, we dont need
super heavy springs, especially with stock valves.
(would you believe that Esslinger now runs the midget motors over 10,000 RPM
(and they live)). Dwaine really does understand the geometry of this valve
At any rate, use lots of MDS lube (the ugly black stuff) in assembly and break
in like Jon Welsh described in the archives. (20 Min at 2000 RPM)
dump the oil, filter, fill it up with fresh good oil, the slipperier the
better, and take off. (I use Mobil 1) The used cam I sold a guy had 65 1/4
mile passes and 2 years at Bonneville on it. (about 16 passes)(2 records) 186
MPH fastest, and it looked good. Speed limited to 7500.
The cam is all done at 7000 anyways.
I know a number of guys that ran this on the street, and were happy. Consider
though that some bottom end is lost and the gear I mentioned earlier is a good
idea. Powertrain matching is soo neat.............
and we all overlook it at one time or another......