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High Horsepower SR20DET Engine Build…Done Right!


Out of state customer called us to inspect and quote an engine rebuild. This is an S13 SR20DET engine. Originally purchased as a “built motor”, this was nothing but an exercise in fixing and making right what someone else could not and did not do. Upon initial disassembly and inspection it was obvious the previous engine builder did not know what he was doing. Piston to cylinder clearances were 0.006″ inch plus. Not only were the bore clearance almost double than recommended, the bores were also tapered and out of round. This “500hp” engine still used factory main stud bolts which showed signs of wear and main cap walk and fretting. Due to heavy damage of the main stud threads, the block was mounted in a 2-axis CNC machine and all threads repaired using Time-sert thread repair system. Engine bearings were heavily worn and most likely reused during engine rebuild. Engine was advertised with a set of Brian Crower 272 degree camshaft and they turned out to be Brian Crower 264 degree camshafts. Stock valve springs and retainers used with high lift camshafts. Cylinder head was completely stock with worn intake and exhaust valve guides. All valve guides were replaced and exhaust converted to 6mm stems, in lea of standard 7mm stems. Valve guides honed using a Goodson diamond hone and seats recut using a Serdi 100 cutting system. All valve springs validated using a Rimac valve spring tester. After final assembly camshafts were degreed as per manufacturer instructions. This is critical to do since both the block and cylinder head were machined, affecting final valve and ignition timing.



  • Darton Sleeves
  • CP 86.5mm forged pistons
  • New CP piston rings
  • Eagle H-beam forged steel connecting rods
  • ARP 2000 1.5 inch connecting rod bolts
  • ACL Race series main, rod, and thrust bearings
  • ARP main stud kit
  • ARP head stud kit
  • Silicone bronze intake and exhaust valve guides
  • New 6mm stem intake and exhaust valves
  • Brian Crower 272 degree intake and exhaust camshafts
  • Brian Crower single valves springs
  • Brian Crower titanium retainers
  • Fidanza adjustable camshaft sprockets
  • Apexi 87mm head gasket
  • Rocker arm stoppers
  • Install Darton sleeves
  • Bore/hone block to size
  • Deck mill block with oil pump front cover and hand stone to prepare for metal head gasket
  • Align hone crankshaft main bearing bores
  • CNC repair main stud threads
  • Weight match pistons
  • Weight match connecting rods
  • Measure and record connecting rod bolt lengths in log book
  • Balance and micropolish crankshaft
  • Disassemble, clean, and inspect oil pump
  • Measure all bearing clearances using micrometers and bore gauges
  • File fit piston rings using Childs & Alberts piston ring grinder
  • Replace front and rear main seals
  • Measure piston deck height
  • Measure piston dish volume for compression ratio calculator
Cylinder Head
  • Replace intake and exhaust valve guides with silicone bronze units
  • Hone valve guides using Goodson diamond hone
  • Recut valve seats using Serdi 100 machining system
  • Hand lap all valves and check with machinists blue for seal
  • Deck mill cylinder head and hand stone to prepare for metal head gasket
  • Check valve spring pressure using Rimac valve spring tester
  • Check rocker shim thickness and adjust for proper fit
  • Bleed hydraulic lifters
  • Degree camshafts using degree wheel and dial indicator
Pictures of engine build:
Posted on 12 Comments

VW ABA 2.0 stroker motor build


This is an engine build for a local customer. He is a VW fanatic and likes doing things just a little different than most. After collecting parts for the last 8 years he finally decided to go ahead with this engine build. The goal is a reliable, torquy, naturally aspirated engine to power a 1989 VW Cabrio. This engine will use an 8 valve SOHC cylinder head and an OBD2 conversion.


  • JE SRP Autotech 83.5mm forged piston kit with piston pins, lock, and rings
  • Cunningham I-beam forged steel connecting rods
  • VW TDI diesel 95.5mm stroke crankshaft
  • Audi 80 2.o liter block with piston oil cooling jets
  • New Bosch distributor
  • Blueprinted oil pump
  • OEM main and rod bearings
  • ARP main stud kit
  • ARP head stud kit
  • Dual valve springs
  • Titanium retainers
  • 268 degree camshaft
  • OEM metal head gasket
  • OEM oil baffle shield
  • New OEM oil pan
  • All new seals and gaskets
  • Bore/hone block to size
  • Deck mill block and hand stone to prepare for metal head gasket
  • Weight match connecting rods
  • Measure connecting rod bolt length and record on log book
  • Weight match pistons
  • Check main and rod bearing clearances using micrometers and bore gauges
  • Check piston to cylinder clearance using micrometers and bore gauges
  • Balance and micropolish crankshaft
  • Install Mallory heavy metal into crankshaft for balancing
  • Measure piston dish and combustion volume and calculate compression ratio
  • Disassemble, clean, and inspect oil pump
  • File piston ring gap to size using Childs & Albert piston ring grinder
Pictures of the engine build in progress:


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Nissan SR20DET connecting rod weight matching service

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
We offer connecting rod weight matching, balancing, and ARP rod bolt installation for the following engines:
  • -Toyota: 2JZGE, 2JZGTE, 1JZGTE, 4AGE, 4AGZE, 1UZFE
  • -Nissan: SR20DET, SR20DE, SR20VE, KA24E, KA24DE, VG30DE, VG30DETT, VQ35DE, VQ40DE, RB20DET, RB25DET, RB26DETT
  • -Subaru: EJ205, EJ207, EJ20T, EJ22t, EJ255, EJ257
  • -BMW: M50, M52, M54, S50, S52, S54

Pictures of completed set:


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Nissan SR20DET cylinder head rebuild process

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:

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BMW S52 cylinder head spark plug thread repair

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:

Posted on 15 Comments

Hyundai Genesis Coupe 2.0T Theta engine disassembly, evaluation, and comparison to the Mitsubishi Evo X 4B11T

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.