Engine rebuild.
Here I will post information about my "engine rebuild" for the 2006 season

It is time to put together the engine for 2006 season, and there is some modifications compere to 2005. The engine will get a new set of heads, new camshaft, new nitrous oxide system and possible new exhaust. I will in this post, try to describe how I put it together, and the information in this text is based on personal experiences. This is not a new build, but a rebuild, so some part of building will be left out. This is just an example, and NOT the answer on how to do it. If you should decide to follow this information, it your responsebility and do not blame me if your engine blows up.

THE CASE is a new item from Brasil (AS41 with 4 % Alu). Following modifications is done to the case:
Full flow oilsystem, 94mm stepped bore, clearenced for 84mm stroke,removed casesavers, tourqe-change of the 8mm studs, "steelbacked" split-bearing on #3, longer oilpicup.



This picture shows the cow-magnet on the pickup. Every time I change oil, this magnet is "hairy" with metal particles. It does an exelent job helping to keep the oil clean.

I always start the assembly with a good old cleaning of the case. Small brushes, some solvent and a lot of time will do the trick. Old gaskets are remowed with Aceton. Finnish up with cold water and pressurized air.

Then I'll check the bearing clearences, to verify if I need replace bearings. Mesure ID of the bearing, and the OD of crank, then subtrackt and you have the clearence. Crankbearings was in good shape, and will be reused.


I'll check the small end of the rod, mesure ID on rod, OD on piston pin. The clearance should be 0.03-0.04mm (info from carillo).

The big end clearence is very important, it must not be to big (so it ratles), and not to small, so the oillayer is not "strong" enough to support the pressure. You need to have some oilflow "trough" the bearing for cooling of the crank. I my setup, the clearance need to be 0.06-0.1mm.

This is a rebuild, so I do check the rodbearings really close to see if I can spot some "problem areas" from last season. I do messure the width of the bearing to see if the engine has experience detonation or pre-igniton. Bearing #4 was 0.05 wider than the rest, and it can indicate that sylinder #4 have had some "issues". The rest of the bearings was in good shape (within spec 53.06-53.08), but they will not be reused due to the amount of "dirt" stuck in to them.


The rodbolts have a "mission impossible", and I am really carefull when it comes to tourqing the bolts. The length of every bolt is messured before assembly, and I check the messurments up against the files from "last" assembly. If any of the bolts are longer, it can indicate "overstreching" and if so, I'll replace them. When mounting the bolts, I do not use a tourqewrench, because it will only messure friction between the bolt and rod, and not the actual strech in the bolt. So I use a caliper to messure the correct strech. The correct strech of carillo 5/16 SPS bolt is 0.15-0.20mm .


This picture shows the Gene Berg 84mm vedgemated crank. The oilchannels are taped and plugged. Makes cleaning easy!

Here I am polishing the crank. Hard use (abuse) of the engine often leads to some "scratches". What I do is removing the "tops" of the scratches with a very fine sanding paper. Be careful not to remove any material, just polish the surface.


Here is the clutch setup. Its based on a black magic disc from Ron Lummus, and a KEP stage 1 pressure plate.


Messuring for "straightness". Both flywheel, disc and pressurplate needs resurfacing. The flywheel had "hotspots".

Checking for "endplay". I like a tight 0.10mm. It's important to use 3 shims, the outer shim follow the speed of flywheel, the inner shim follow the trustsurface of the bearing and the middle shim funktion as a "slide-bearing"


The crank is a Gene Berg 84mm. Porsche-journals (dia. 53mm), and T4 center. According to producer, this is one strong combination.


I am running close side-clearance rod-crank (0.15mm), this clearance is to tight to get oil out of the bearing (to cool down crank and bearing), so that is why we have maschined 4 "oiltracks" on each side of the rod. Keeping the clearance tight, reduces the side-movements and the stress on the piston pin.

Messuring of cam-bearing ID, they was almost out of range, so they will be replaced.

Messuring OD of "no-named camshaft"

The picture shows that the camshaft have been milled down, to clear the crank and backside of rods. Need min. 1.0mm radial clearance.

RESURFACING OF FLYWHEEL
The flywheel was "marked from battle" and needed some grinding. The flywheel and crank is wedgemated together, so we put the complete package in to the lathe. The picture shows Mr Ingar "Pro Mod" Gveserud doing what he does best. It is important to have experienced people helping, on this kind of project. I would say Mr Gvesrud qualify in that class. On a daily basis he is responsible for the engine in Terje Håkonsens ProMod (2000 Firebird, 6.45@351km/h) and he will for the 2006 season tune a "methanoleating, firebreathing" 2500HP Brad Anderson engine. In my opinion that qualify to help out on a old Volkswagen engine.

"Hotspots". The heat develope by the clutch is tremendous.





This weekend I fokused on tourqing down the rods. I use loctite as antifriction, and I strech the bolts 0.15mm. Pay attention not to overstrech the bolts.


Homebrewed headbolts, they are made out of 2541 steel, and is 8,5mm dia. They are equiped with M12x1,5 lower end, and 3/8 unf at the top. I drive the M12x1,5 direct in the case (without casesavers). The nuts are ARP (180.000psi tensile). The headbolts is calculated to keep in the "planned" cylinderpressure (2000psi)


I use Permatex as gasket. Let it dry up, before you put the casehalves together


This is how I adjust the oilpressure. Easy and simple, works every time. My setup needs 60-65psi of oilpressure at 3500rpm (hot oil)


On the lifter, I have done the Gene Berg trick, providing better oiling of the lifter with high lift cams.


I like to use camlube, when I put in new camshaft and lifters. I do the following break in routine: Prime the oilfilter hoses with oil, so you are shure you will get oilpressure quick. Remove the rockers and pushrods and crank the engine for at least one minute after the oilpressure light is out. Put in the pushrods and rockers, and only the outer spring. Make shure everything works, then fire the engine and keep it running on 2500-3000 rpm for some minutes. All the time I do not have any cooling, I pay attention to the oiltemp and headtemp. I performe this routine 3 to 4 times (letting the engine cools down in between). Then I put in the inner spring, and repeat the routine a couple of times. After the engine has cooled down, I check the oilfilter and cowmagnet, and if it's okay, change the oil and you are good to go.


I put some grease on the oilpump gears, so it will not pump air.




I have had the case mashined for bigger washers and 15mm headnuts. With this change I tighten the nuts to 28nm (std 18nm), and the big six bolt to 46nm (std 35nm). According to Gene Berg this will improve case life. I do not have the experience to question this, and it is really cheap to get it done, so I like to have this on my case.


Shortblock completed.


According to producer of the cylinders (JayCee), the will not handle the planned cylinderpressure (2000psi). We needed to develope a "powersleeve", but before we started, all cylinders was X-rayed for defects. One of the cylinders had some small pores in the cast.

X-ray pictures

This pictures show the top of the cylinder computerized and put under pressure in a simulator. 2000psi make the cast deform and crack (note the red part).


This show the same computerized cylinder with a powersleeve on it. The powersleeve is made out of 2541 steel, and the calculations show that the cylinder will keep up with 2000psi without any problems. We did also some pulsating calculation, simulating the stress of 7000rpm over time simulating 2 seasons of racing.


Here are the ready made powersleeve mounted on the cylinder. The cylinder is taken down to 99mm OD, and then the 2,25mm thick powersleeve is shrinked on with 0.05mm shrink. The inner lower part of the powersleeve has a radius of 1mm, that will fit to the radius made in to the cylinder.




With a OD of 103,5mm and 8,5mm thick bolts, it is a tight fit, but I have clearence.

Messuring for deckheight. I run "zero deck", but adding a copper gasket of 1mm make the total deckheight of 1mm.


Always clay up the engine, to check the clearance of valves to piston. With this combination, I needed to add valvepockets to the pistons. I run 2mm on intake, and 3mm on exhaust.


This is how I like the pushrod to line up with the rockerarm adjusting screw at half lift. The adjusting screw is 1,5 turn "out" and the pushrods are cut to length (Manton pushrods)


With a permanet marker I color the lashcaps to get a "print" of the rockerarm on to the lashcap. The mark was slightliy of center, so a shim is added to the rockerarmstands.


Checking the height of the valvestems. Due to some valveseat work the intake valves are sunk 0.5mm in to the heads. I just shorten them in a lathe, and problems is solved.


The rockerarm setup is completed.


Location of nitrous oxide nozzles.


Inside view of the nozzles.


This pictures show the Pro Race Fogger system mounted on to the engine. I have stand alone fuel system for feeding the NOS system. The pictures show fuelfilter, fuelpressure switch, fuel solonoid, nitrous solonoid and purge valve. The mid-mounting location of solonoids and the length of the tubes, will probably soften the hit from the "juice" and reduce the tirespin.


I'am not proud of the way it looks, but is hard to squeeze in all the "equpment" I "need". I will work on the "looks" later in the season.


On Johannes Perssons Dyno. (JPM motorsport Sweden).


The engine combination was simulated on Engine Analyzer before we vent to the dyno. My goal for the dyno session was to exceed the 250 mark N/A. We managed to get 253hp@7440rpm and 256NM@5660rpm, and the curve from the dyno looks like the computerized curve from Engine Analyzer.

When it was time to hit the "juice", we decided to go for the 18/20 NOS/Fuel setup. We did a power run, and the engine misfires at 6000rpm. We where afraid of detonation, so I increased the fuelnozzle to 22. WOW.... The engine misfires at 6000rpm, but it made an impressive 275hp at only 5500rpm with over 340NM of tourqe and the curve was aiming for the sky. After close look at the setup, we found out that the ingnition system did not handle the pressure, and the sparkplugs was "blown out" like a candle in the wind.

We reduced the nitrouspressure, and did a power run of 278hp@6500 and with 305nm at 6300rpm without any misfireing. Until we have improved the ignitionsystem, this is the setting we will run.
Thats all folks.....
Any questions, please feel free to contact me.
posted 5/1/2006 by Roar.