Category: Engine Services

This is another service we offer here at Pavel’s Racing Engines. We can weight match, aka balance, your engine’s connecting rods and install ARP rod bolt. As a sample of our work we have a set of Nissan SR20DET connecting rods. We can provide this service for any set of connecting rods; motorcycle, automotive, truck, industrial, import, domestic, marine, we can do it all. We have precision scales to weight match every connecting rod to within 0.5 grams of each other. We weight match the small and big end of the rod. We identify each bolt and provide rod bolt log sheet with every connecting rod order. This way you can monitor rod bolt stretch and replace worn bolts before catastrophic engine failure occurs. All connecting rod bolts replaced with appropriate application kit for one of the best hardware manufacturers in the world, Automotive RAcing Products (ARP).

We performed the following services on the connecting rod:

• -Check for bend and twist, and correct if necessary
• -Check piston pin bushing
• -Weight match small and big ends of connecting rods
• -Install ARP connecting rod bolts
• -Engrave each bolt for identification, measure it’s free length, and record in the “Rod Bolt Log Sheet”
• -Compare “torque” vs “stretch” methods for bolt validation
• -All bolts torque using ARP Ultra-Torque Moly Lubricant

Pictures of completed set:

Here is another SR20DET cylinder head we rebuilt at PRE. This cylinder head came to us in very poor condition. Customer wanted a OEM style rebuild. Upon complete disassembly and inspection it became obvious actual condition of the cylinder head. Cylinder head gasket mating surface was slightly warped, exhaust valve guides worn beyond factory limit, valves pitted, and valve seats showed unacceptable wear. Since this cylinder head is going on a performance engine intended for high speed auto cross and drifting we had to make sure every specification was better than factory. This is what separates engine builders, attention to detail.

Work performed:

Cylinder head gasket mating surface checked using precision straight edge
Valve seats checked for out-of-round using precision seat concentricity gauge
All valves checked for bends and out-of-round using v-block and dial indicator
Exhaust guide clearances checked using Sunnen P310 valve guide gauge
Exhaust guides replaced with manganese bronze units
Exhaust guides honed to spec using Sunnen P190 valve guide hone
All valves refaced using IDL/Sunnen valve grinding/refacing machine
All valve seats recut using Serdi 100 valve seat cutting system
All valve hand lapped using grinding compound and checked for seal using machinists blue
Cylinder head gasket mating surface deck milled and hand stoned to prepare for metal head gasket
Viton valve stem seals
All valve springs, retainers, spring seats, and keepers checked for rust, pitting, and cleaned
All valves springs checked for pressure at install height and full lift using Rimac valve spring tester
Cylinder head carefully assembled and bagged for storage awaiting customer pick-up

Pictures of the cylinder head during the rebuild process:

This is a custom cylinder head repair we did at PRE. Spark plug on cylinder 6 was not torqued down properly, vibrated loose, and finally ripped out all the thread. Heli-coil spark plug thread repair kit was of no help in this situation; too much material was torn out. This kind of repair cannot be done with the cylinder head installed on the block. We removed the head from the block, completely disassembled it, and inspected all components for wear. Cylinder head was checked for cracks with a Magna-Flux system. BWM M50/M52/S50/S52 head are notorious for cracking into the water jacket near the exhaust valves. After passing crack inspection the head was cleaned and valve seats checked for concentricity. Cylinder head was also checked for straightness of the deck mating surface. After passing all of the above tests we began the repair process. Cylinder head was mounted in a Bridgeport style mill and spark plug hole counter bored to a specific size. Additional counter bored “step” was machined and 4 spots for laser welding of the fitting. An aluminum fitting was precise machined in a lathe with a standard M14x1.5 spark plug thread pitch on the inside and a precise side on the outside diameter. Aluminum fitting was machined to have a 0.002″ inch interference press fit into the head. Also a pilot tool was machined to ease fitting installation. After all machining work was done the cylinder was heated up, fitting cooled, and pressed in with a light coat of green “sleeve type” Loc-tite. Afterwards the fitting was laser welded in 4 designated spots in the head. Combustion chamber was vacuum checked for seal and volume checked to make sure all cylinders maintained same compression ratio. Cylinder head was deck mill faced and hand stoned to ensure perfect mating surface for a factory or performance multi layer steel head gasket. All valves were cleaned and refaced using a Kwikway valve grinding machine. Valve stem seals replaced with genuine OEM BMW parts. All valve springs we examined and spring pressures checked using a Rimac valve spring tester.

Pictures of individual machined components and finished work:

Today we started a new project. Customer submitted a Hyundai Genesis Coupe Theta 2.0T engine for us to disassemble, assess build quality, and suggest upgraded parts for increased performance and reliability.

Initial observations: the new engine is an all aluminum inline 4. The block is lighter than the old 4G63. Contrary to the old 4G63 found in the Lancer Evolution 7-9, the new engine has the exhaust/turbo on the left side and intake on the right side of the engine. New engine uses bucket-style direct valve activation, compared to the 4G63 using rocker arms. Oil pump is not a separate unit driven by a chain off the crankshaft and located in the oil pan. 4G63 oil pump was timing belt driven and located in the front engine cover. 4B11 does not have balance shafts like its predecessor. Crankshaft is forged and fully counter-weighed. Pistons are cast with friction coated short piston skirts. Connecting rods are “broken” or fracture style. This means the connecting rod is made of powder steel as one piece and precise “broken” during manufacturing in order to separate it. We this being the weak point of the engine. While being adequate for its designed performance duties, the rods become a weak link when increasing engine performance. This can lead to catastrophic engine failures. Our suggestion is replacement of connecting rods in all performance-oriented applications. Main caps are independent on the 4b11 contrary to the 4G63 which has a single cast-iron girdle. Before disassembly we though the engine had the upper oil pan and main caps act as one unit, common practice in racing and even modern engines such as the F20 in the Honda S2000, but this was not the case. The main caps are not tied into the oil pan, nor are they connected together with any type of girdle. This is an area of development we will take on at Pavel’s Racing Engines.

Shortly we will be performing further disassembly of the cylinder head and testing valve springs. We will also provide all component dimensions and weights.

Enjoy the pictures. Most pictures have descriptions. Click to see the details.