EF head onto CB, possible?

Questions and Answers
1

Been comparing a few things lately between the CB and EJ motors with the thought of cheap 12 valve head conversions on a CB as the heads seem virtually identical fit wise, and re-read that Fortis is using an EF 12v head on an EJ, just wondering if anyone has tried an EF head onto a CB Block at all? Would it be worth the hassles with any better perfomance or economy do people think? Any problems apart from gaskets and timing belt that anyone can think of? Just pondering really

2

I hav pondered this also b4 but never looked into it. I also just considered an inlet efi manifold from an e series to get rid of carb but never went any further than a thought really. I think maybe the best way would be to hold a e series head gasket and a cb headgasket up against each other to see how close they are as the cb looks tom like it would be bigger physically

1 Like
3

Best way to get EFI on a cb is get the CB-90 inlet manifold which is factory EFI :wink:

1 Like
4

yeh but if you have all the ef stuff eg head etc. and it fits then???

5

Yeah then that would be easier lol.

6

More thinking for the 12 valve than the injection side really

7

i think the 6 valves on a cb head would almost be the same size as all 12 valves on an ef/el. lol

8

True but better breathing with a little porting work. Is mainly just a curiosity but yeah could be interesting with the injection side of things. Is that really all the ecu controls, injection?

9

well I have an ef head hear on a block and cb engine on an engine stand and the head has to come off the ef and also with the cb so it will be the perfect time to see. Wont be for a little while though I think. When i do take them apart i will let you know if they look like they will fit.

1 Like
10

thanks bloke :smile:

1 Like
11

I think if it looks possible you should definitely go for it, even if 2 valves on the 12v head are the same size as 1 valve on the 6v head the different combustion chambers, ports, squish, and manifolds will change the power and torque characteristics, either for better or worse. But having a chance to do something that hasn’t been done before and breaking new ground is an awesome thing even if you don’t get any improvements you havnt failed, you have just learned something new :smiley:

1 Like
12

I actually getting tempted to try this and use it in my mira.

1 Like
13

really the interest for me would be a cheapish 12 valve efi cb60 type conversion in a g11 for something different :wink:

1 Like