What is a LS/VTEC?
The hybrid Honda engine known as the LS/VTEC takes the displacement of a 2.0 liter B20 engine and combines the DOHC VTEC head from a GSR or B16. This unique combination has been around for quite some time, as the LS/VTEC build is nothing new. You can also take the non VTEC shortblock from the Integra LS, giving the LS/VTEC one half of it’s moniker. However for some people, building a reliable LS VTEC is still somewhat of a mystery, but it doesn’t have to be!
Today we’ll be discussing the benefits and drawbacks of the LS/VTEC engine build, and showing you how to build a reliable LS VTEC motor. These builds are popular with both naturally aspirated enthusiasts as well as boosted ones. Providing more low end grunt and displacement, while being able to rev as high as 8600 RPM in stock form.
What you will need to complete a LS VTEC Hybrid Build
Non VTEC engine – B20 or B18 Engine
LS VTEC Kit – Either Golden Eagle / BLOX / SKUNK all make complete kits
DOHC VTEC Cylinder head
GSR Timing Belt
New Timing components – water pump, tensioner, etc
ARP rod bolts – part number 208-6001
ARP head studs – part number 208-4306
Benefits of LS/VTEC
- Easy to build
- More Displacement
Drawbacks of LS/VTEC
- Not legal – Cannot BAR or smog this Honda swap if you are using a B20 shortblock. Because the B20 is classified as a light truck this will never pass for California emissions. You will be limited to using the stock 1.8 displacement. For more information check our How To Smog your Honda Swap guide here.
- Need a mismatch of parts to make this swap work
How To Build a Reliable LS VTEC
Locate a VTEC cylinder head – You’ve got a few choices when it comes to the cylinder head for your LS VTEC engine build. You can select from a B16 cylinder head, a B18C5 cylinder head or B18C1 cylinder head. If you are sticking to stock components, the obvious choice would be the Type R cylinder head, with upgraded valvetrain and more aggressive cam profile.
If you are going to be upgrading some parts in your cylinder head regardless, you can do simply pick a PR3 head (B16) or a P72 cylinder head (GSR). There isn’t much difference between the two cylinder heads, but if you don’t have your intake manifold lined up yet you’ll want to match the intake to the VTEC head.
You can also opt to port or build your cylinder head through any number of machine shops or upgrade facilities. If you are having your cylinder head ported or blueprinted, you will also want them to replace your old springs, retainers and valve stem seals. Upgrades like dual springs or titanium retainers will help your engine last at very high RPM.
Modify Your VTEC Cylinder Head – Once you are done with your VTEC cylinder head and have installed, modified or tweaked it to your liking, you will need to install the 1/8th inch NPT fitting for your VTEC oil pressure solenoid.
After you’ve installed the 8th inch NPT fitting as shown above, you must then remove the dowel pins in your cylinder head and install the LS VTEC dowel pins included in your kit. Depending on the kit you are using, you will also need to plug holes in the cylinder head as these passages are not used in your LS VTEC conversion. Have questions about install or procedure? Leave them for us below!
The next part of the LS VTEC kit to be installed is the oil sandwich adapter and the lines to supply your VTEC head with oil pressure. Because your factory LS or CRV shortblock did not come with the proper lines or oil passages, we’ll be installing a oil filter sandwich adapter and teeing a 8th inch NPT fitting from it.
If you want to go the cheaper route and build your own VTEC oil fitting, check out our guide here on how to build your own VTEC oil pressure tee.
There’s an existing allen plug in your VTEC head, that must be removed for the set screw. Remove the plug and use a 8th inch NPT tap to retap the cylinder head so that your set screw will turn in nicely. Teflon tape the set screw and screw it into your VTEC head so that you can begin mounting it.
You will need to install the set screw in your LS VTEC conversion kit into the oil ports of your cylinder head. Because these oil passages do not match your non VTEC block, this set screw blocks the port. Install your set screw by sinking it just a bit further in the cylinder head to properly clear the cylinder head mating surface.
Check your Lost Motion Assemblies – The VTEC LMA is also known as the Lost Motion Assembly. This preloaded spring is part of your VTEC cylinder head and it’s meant to hold on the big lobe of your camshaft up when VTEC is not engaged. If you are planning a LS VTEC build, it’s a good idea to check or upgrade your lost motion assemblies.
Modify Your non VTEC shortblock – There’s a few things that should be done before making the LS VTEC jump. First off is the rod bolts, which should be upgraded to avoid your rod bolts stretching at high RPM. When taking your non VTEC engine apart, many swappers simply decide to toss the stock rods and pistons for OEM casts or even forged units.
ARP Rod Bolts – If you are planning on keeping your stock rods and pistons, install your ARP rod bolts now. You will need a machine shop to properly install them, as the rod end holes must be enlarged to take the ARP rod bolts. While the machine shop has them apart, have them shotpeen your LS rods to strengthen the rods for higher abuse.
As a general rule of thumb, you never want your piston stronger than your rod. Whereas piston failure or piston ring land failure is not a whole lot of fun, it’s much more easier fixing or repairing a cylinder wall, as opposed to possibly replacing your entire motor when a rod fails.
Because the non VTEC DOHC engine from Honda was never meant to rev as high as the VTEC versions, the stock rod bolt will stretch and ultimately fail. Rod failure is not a pretty thing, don’t let this happen to you.
ARP Head Studs – Head studs are a great choice for keeping things together under boost and at 9000 RPM. ARP is of course the stud kit of choice for most Honda and Acura enthusiasts. The part number you will want from ARP is 208-4306, and if you happen to get a LS motor or CRV motor with ARP studs in it already, you don’t need to waste money on an entirely new 208-4306 kit from ARP.
Simply switch the two middle ARP bolts from ARP part number atp8.000-1LUB to ATP6.000-1LUBA which is two of the 11mm hex bolts from ARP. Two of that part number will transform your LS ARP head stud kit, into a LS VTEC ARP head stud kit.
With the correct ARP cylinder head stud in tow, install your cylinder head bolts carefully into your non VTEC block. When installing your head bolts, clean the holes with an air compressor or chase it with a bolt by hand slowly first to remove debris and oil.
Use our How To Torque a B18 Guide to bolt your cylinder head to spec and in the uniform order required. Clean holes and thread the rod bolts fully and back off a half turn. Always use the provided ARP lube and tighten to manufacturer specification.
If you need replacement washers from your old ARP cylinder head studs, use the ARP part number of 200-8530. If you need replacement cylinder head nuts, use the ARP part number 300-8303 for a replacement 13mm ARP multipoint nut.
If you are planning on building a LS VTEC engine meant for turbocharger or supercharger use, it may be a good idea to switch to forged pistons and rods. The added strength and rigidity of these parts can help your LS VTEC last the test of time and fight off dangerous detonation.
Turbo, supercharger or naturally aspirated, if you are buying aftermarket pistons make sure to always do the math when it comes to compression. Never blindly follow the manufacturer’s claims of compression, as you’re almost always guaranteed to have a different result when testing. Giving your tuner a true compression value will only increase your engine life and performance.
Things to Plan
1. Mechanical Differences – Water Pump differences between GSR and LS
How To Change your B18 timing belt
Depending on the water pump you are using you will need the timing belt to match. The differences between the VTEC water pump on the B18C1 and the one on the non VTEC B18 is three teeth. You can use either of these pumps but make sure your timing belt matches. The part numbers for these belts can vary greatly depending on the application.
For ease however the 1997 Acura Integra B18C1 timing belt is part number 14400-P72-004 or 14400-P72-014. The non 1997 Acura Integra VTEC LS with the B18B is part number 14400-P7J-004 or 14400-PR4-A01. Match your year and OBD generation to the USDM version of your motor if you happen to have a JDM swapped engine.
Your intake manifold will have to match your cylinder head of course, make sure your intake manifold is for your intended head.
2. Engine Management – ECU Choices
This is a big step for your Honda engine swap, unless you don’t care about wasting money or time. Depending on the ECU you decide on and a combination of your local smog laws, your choice of ECU and OBD will obviously play a big role. Things like knock sensors and crankshaft position sensors may or may not be required depending on what you are doing and what your goals are.
B18C1 ECU Pinout
Any VTEC ECU will work just fine here and if you need a guide on wiring VTEC, check our how-to here or our How To Troubleshoot VTEC guide here.
If you have the choice to pick whichever ECU to use, the best idea is to try and stay within your OBD range for your car. For example if you are building a LS VTEC in a OBDI vehicle, use a OBDI engine, and a OBD1 VTEC ECU so that you don’t have to convert anything. If your are OBDII, you’ll need additional sensors, like your knock sensor and crankshaft positon sensor.
OBD1 ECU’s to choose from are : P28, P30, P61, P72, and P73. If you are chipping your ECU, make sure to plan ahead so that you aren’t wasting any money or time. Check here for our How To Chip your Honda ECU guide, and a Guide to Aftermarket Tuners for more information.
3. Engine Bearings
Here’s where your personal preference comes into play as a truly reliable LS VTEC build demands that you install OEM or aftermarket rod and main bearings.
We’ve built more than our share with stock bearings and had them last for a while, but for truly best results it’s worth your time to take this extra step
4. Intake differences
Make sure you don’t paint yourself in a corner if you have a ECU that requires a in pipe IAT sensor and have the appropriate intake to match your LS VTEC build. Not having the proper intake and trying to figure out a solution for your air intake temperature sensor is a hard thing to tackle this late in our How To build a Reliable LS VTEC guide.
5. Cam Choices
If you have the ability to upgrade your camshafts, now is the perfect time for any number of camshaft upgrades for your LS VTEC swap.
What TDC should look like
Trying to give your LS VTEC a healthy upgrade when it comes to the bumpsticks but don’t want to break the bank? Look into a ITR or CTR stock cam combination, which can provide a increase on the cheap. Cams that are more aggressive will require further cylinder head upgrades, like dual springs, titanium retainers and possibly some valve guide work or seal work, depending on the condition of your VTEC head.
Engines like the B18C1 need grounds to start properly
Learn how to Tune your VTEC
After you are done with your cylinder head prep, you’ve got to install your LS VTEC head gasket. Make sure you have the right bore and thickness you desire. Because you’ve followed our guide on How To Build a reliable LS VTEC engine and done the math as far as your compression is concerned, you should have a target range for your headgasket.
Once you have your cylinder head installed and valve cover on, the next step is to install the timing belt and water pump. Check out our How To on Installing a timing belt on a GSR for more instructions on how to complete this step.
Our parts list of things you need in order to know how to build a reliable LS VTEC are as follows ;
GSR or B16 Cylinder Head
LS VTEC Conversion Kit
Engine Bearings – OEM Honda or ACL/ King
Valve cover gasket set
LS VTEC Dowel Pins
OEM P72 Timing belt to match P72 water pump or LS version (See water pump notes)
Have any questions about our How To build a Reliable LS VTEC Engine guide? Leave us a message below!