Assembling an LS/VTEC

We may earn a small commission from affiliate links and paid advertisements. Terms

Building an LSVTEC​

Building an LS/VTEC is not for the feint of heart or shallow of wallet, but it is worth all the time and money that it will take. In this article I will assume that you have read our recommended parts list, you have an understanding of engine building, you own a Helm's (or equivalent) manual, and you have the parts you need for the minimum (in my opinion) build. An engine stand is a nice tool to have, it is not necessary but it is very helpful. You can get them at any major parts store; I got mine from AutoZone for $65.

Our LSVTEC parts list gives several options, here is the list (beyond block and head) that I would call a minimum:
  • Pistons from any B16 because LS pistons do not have large enough valve reliefs for VTEC intake valves. Forged pistons would be better, but if you can afford them B16 pistons will work well.
  • New piston rings. Honda rings work well, or you can use your preferred aftermarket.
  • Cam gears (brand is up to you, some folks have had trouble with AEM gears slipping, after replacing the bolts, I have had no trouble with my AEM gears).
  • A B series DOHC VTEC distributor. An LS one will work with some serious modifications, but this is not a good idea.
  • An ECU that matches the OBD of your engine and that is setup to run a DOHC VTEC engine. I run a P72, but a P30, P61 or a chipped P28 would work fine for an OBD1 car. Also, if you are using a GSR head, and the stock intake manifold, you are going to want a P72 from the GSR in order to control the IAB butterflies.
  • Water and oil pumps from a GSR or ITR. I don't consider using the LS water pump an option as it is likely to cavitate at high RPM. This means you have to run the GSR timing belt.
  • ARP rod bolts. If you are using LS rods this is not a must, but it is a damn good idea. The stock LS bolts were not designed to handle the forces of 8000 RPM. $55 is not much to pay for peace of mind.
  • ARP head studs. They hold better than stock and you don't run the risk of destroying the threads in the block every time you pull the head. You want the studs for the B18C1.
The Block

First, the modifications that you will need to perform on the bottom end. You won't actually change anything in the bottom end, just the normal steps that you would take if you were rebuilding the engine. Once the bottom end is disassembled you should take it to a machinist to have the cylinder walls honed, make sure that you keep the piston to wall clearance within spec for the pistons that you are using. It's a good idea to bring your pistons and rngs to the machine shop with you so that they can perfectly spec them to match. Have your crank polished, and have the rotating assembly balanced. When you are reassembling the bottom end make sure to check all the bearing clearances with plastigauge. I am not including any pictures of the bottom end rebuild because they can all be found in your Helms manual.

The Head

There are several modifications in this step; first you will need to have a machinist open the holes on the intake side of the engine to accept dowel pins. Pictured here:


One dowel pin has my finger and a red arrow pointing to it, the other is on the opposite side of the picture with just a red arrow. This is where they need to be, when you first get the head the pins will be on the exhaust side of the head.

Next you will have to tap the VTEC oil passage and plug it using a set screw. This passage is in the picture above, it is below my hand and has a red arrow pointing at it. If you bought a kit for your oil line it most likely came with a set screw to plug this passage. 3/8" NPT to either a -3 or -4an line, depending on your line/kit. It HAS to go into the head far enough so that it does not affect the way you head sits on the gasket! Make sure to apply a little thread lock to this set screw.

Next you need to decide where you want to run your oil line. There are two spots where the line can attach to the head. Shown here:


My finger and the red arrow are pointing at the first; this is where the LSVTEC kit from InlineFour will run the oil line. The other spot is at the bottom of the picture with a blue set screw in it. Either place will work, it depends on what fittings and line you can acquire. Make sure to use Teflon tape on all of these connections except the two connections to the external oil line, as they will be self sealing.

Make sure to clay your engine for proper clearances if you are running aftermarket cams and/or aftermarket pistons. When you are assembling the engine, make sure to use generous amounts of assembly lube on any metal to metal contact area except your piston rings. Use regular, non-synthetic, engine oil on them. This will protect your engine for the first few seconds that it runs before your oil starts flowing.

If you bought a VTEC conversion Sandwich adapter, you can skip the next step.

Now you are ready to install the oil T on the block. Next to the oil filter will be your oil pressure sending unit. Remove the sending unit from the block. This is where you will be installing the oil T. Shown here:


Install the T before you install the oil filter.

First, apply some Teflon tape to the adapter that will be threading into the block, make sure to apply the tape to the side that will thread into the block and the side that will thread into the T. Start the adapter threading into the T, then thread the T into the block. Make sure it is snug, but be careful not to over tighten.

Next, apply some Teflon tape to the oil pressure sending unit. Then thread the sending unit into the T. It does not matter which spot on the T that you use. I chose up because it made routing the oil line more simple. Apply some Teflon tape to the end of the fitting that will thread into the oil T and install it. Again, make sure everything is snug, but be careful not to over tighten.

Now install the oil line. If you are using the InlineFour or a similar kit, your assembled engine should look something like this:


Now install the engine and tranny. Procedure on this is out of the scope of this article, however, wiring it up is not.

Finishing Touches

You will have to run 2, 3, or 4 wires through the firewall to the ECU. Two to the VTEC solenoid, one to the knock sensor (if your ECU requires one), and one to the IAB (if you are using the gsr head with the stock intake manifold for the butterflies). Where you run these wires to on the ECU depends on your OBD version and which ECU you are using. You can ground the VTEC switch to the engine or any good ground source, so there is no reason to run that wire through the firewall.

As long as you have everything hooked up properly your engine should start.

Put her on the Road

Onto the break in, there are man theories on how to properly break in an engine. Here is the method I used:
Make sure the floor beneath your engine is clean, or lay some newspaper down. On the first start up, turn the idle up to about 2000 RPM and let the engine come up to operating temp. Make sure that you are flowing water and that your fan(s) kick in when they should. While your engine is warming up check for any leaks; this is where the clean floor comes in handy. If you don't have any leaks take you car out and do a couple of 1st gear pulls at 1/2 to 3/4 throttle stopping at 4500 or 5000 RPM. This loads the rings to help them seat to the cylinder walls. Then do a couple 2nd gear pulls the same way, then some 3rd gear pulls. Now change your oil. Drain the oil into a clean open pan. Check the oil for metal. There will be some, but make sure you don't have a lot of metal floating in the oil. If you have a lot of metal in the oil you should disassemble the bottom end and check all your bearings for excessive wear. You probably have a rod or main bearing that does not have enough clearance. If everything is clear then drive your car for about 1000 miles. Try not to exceed 4500 RPM for the first 150 to 200 miles, and then increase the revs that you use as mileage increases. I would not drive it really hard until you are finished breaking it in, but you can use the full rev range after about 600 miles (assuming that you haven't developed any problems). Change the oil again at 1000 miles. It is now safe to run synthetic oil (in fact I recommend it). I used this break in method on my car and the engine is running very well. Not burning any oil and it is not smoking at all.

I hope you found this guide helpful. The normal disclaimer applies: Neither (including its owner, and staff) nor myself are responsible for any damage you do to your car. I have written this guide to the best of my ability and these steps are the same I used when building my engine. If you are unsure about any step or feel that this guide could be improved in any way please contact me. Thanks for reading and good luck.
Last edited by a moderator: