Some interesting and potentially helpful EFI conversion info
 

So, I just wanted to say hey to everyone as a first time poster of this community.

I've been through some interesting things with my 4runner project and thought I would share them.

First of all, it is an 84 4runner. My father in law gave it to me after it set for 5-6 years in a field. Frame is in good shape, body so so, and motor had bad front and rear mains and a bad fuel line. The engine started out as Carb and I wanted it to be EFI. I figured if I'm rebuilding the motor (which I wanted to do as it was setting for 6 years) then I may as well get rid of the carb. So I buy all of this EFI stuff from a guy parting out his Toyota truck.

I get everything going, get my motor pulled, replace the rear main, clean it up a lot, paint the block, replace the head bolts and head gasket, replace the timing set, put a nice cam in it, replace the oil pump and water pump and timing cover gasket, replace the oil pan gasket, and taboot go through the terrible ordeal of pulling my crank pulley bolt, everything is going great.

So a week or so ago, I go to bolt on the intake runners for the EFI manifold and the bolt pattern is completely different. My stomach sinks to my feet. I start digging through all the info I can find and then I find out that the motor that is in my 84 4runner was a rebuilt motor swap about 8 years ago and obviously not the original motor. I'm looking through everything I can find and frankly quite angry because as far as I was concerned, either my entire motor was a wash or I had to find an 83-84 head (due to the open combustion chamber, dual row timing, and intake bolt pattern). Then it hit me!

I go out in my garage with a vengeance. I compare the intake runner to the bolt pattern. AHA! There's four out of ten holes that match up...and then something else strikes me. The mating surface on the head has all of the flats for where the other six holes need to be...just no holes. I confirm that all of the ports between the head and the runners mate correctly and the two water passages mate up. After making sure of this, I knew I was in business!

I take a trip to Advance Auto and pick up their 40pc. tap and die set (the only tap I needed was the M8x1.25) and picked up some machining lube. I confirmed that a 1/4" drill bit was the best size to drill with. So I put my intake gasket in place and sharpie all of the holes that are not drilled. Then I took my drill bit and sunk it down into an all ready drilled hole and marked the depth with electric tape. Here is the most important of what I did. I checked to make absolutely sure that there was enough meat in what I was drilling into to make sure that I did not drill into a valvestem, water passage, or oil passage. Basically, this was really meant to be. Plenty of room.

I went through every mark, starting with a small pilot hole dry down to about an 1/8" and then well lubed the rest of the hole. Cleaning out all of the shavings from every hole as I went along and then filling the hole with lube and lubing the tap. The head tapped VERY cleanly!

As of now, the entire intake is on the head and every one of the holes took the correct factory torque specs. This has saved me in a huge way, both in tons of work and quite a bit of money. It cost me essentially $28 for the tap and die set and the lube. The drill and drill bit, everyone should all ready have.

I will warn everyone though! This is not for the faint-of-heart to do something like this. I was ready and willing to trash my head in attempting this. It was an absolute last resort as it was going to EFI no matter what!

The reason that I thought I would share this is I have not seen anyone else give any information whatsoever about doing this and it working. Everyone just says "Just go buy an 83-84 head...you're screwed."

If I have a chance, I'll post pics of my abomination later. :banger:

i converted my 84 also, but mine has the original engine in it so the head was already drilled, the wiring is the fun part

And the fuel tank and fuel lines :D

Nice work on tapping the head, more courage than I have :banger:

hehe, i cheated and used the original carb tank, and just put a in line pump on the frame, eventually I'm going to a fuel cell, since my factory tank seems to be loosing capacity every time i get squirrelly in big rocks :think:

I have a feeling I'll be going to fuel cell as well. My stock skid is trashed but the tank is still good so far. It won't be long :saw:

Nice. that's very ballsy drilling into the head... much cheaper than a new head..
Did you take the head off the engine to do it, or did you do it with it under the hood still?

You might be a the first to try this method to do a R to R-E conversion!

The head was still on the block but it is on an engine stand.

No substantial update as of recent. I have been (ensuing laughter) working on my wiring and working on dropping/replacing my tank and fuel lines.

well, I just ran into this. I bought an 87 runner with a blown head gasket, a guy I know had a 22r for sale for a steal, with a double roller chain and had been rebuilt at some point. well, I put it in, and my exhaust manifold I had to drill a center hole cause the 2 center holes didn't have any where to thread into on the head.

Then the intake has about half the holes that don't line up, except mine doesn't have the flat spots to drill. looks like a new head, but I am still looking for other options...

I just got done converting mine to efi, it was really easy and runs great. no codes started right up. The hardest part of the convertion is the tank. Junkyards just dont have them. If I had to do over, it be the ford fuel pump on the rail.

I got a 84 efi head sitting in the shed, bought it at a yard and found out its a 84, mine is a 85