my 4/6 engine swap,and other mods....

[scooby4/6]

yea EC thats 1 option if it was the only engine i had,but as i still have the other as a spare (it's for racing/trackdays) it will maake it difficult to swap over if it goes bang.looking at the cradle it wont effect the frame mounts so can just do a straight swap if needed.

will be having a chat to a guy that fabs bits up for me to see what he thinks will be the best route.


will keep the thread updated when something happens.

[Kayla850]

yea EC thats 1 option if it was the only engine i had,but as i still have the other as a spare (it's for racing/trackdays) it will maake it difficult to swap over if it goes bang.looking at the cradle it wont effect the frame mounts so can just do a straight swap if needed.

will be having a chat to a guy that fabs bits up for me to see what he thinks will be the best route.


will keep the thread updated when something happens.

You should be able to use your knackered engine to mock some stuff up for the 3HE engine, I'm sure the 4JH and 4TV still have the bottom mounts in the same place to fit in an earlier frame. Once you have the measurements you can just make some bits up.

[scooby4/6]

the knackered engine isn't,errr knackered,it could very easily go back in,but that would be far too easy

it's not the measurements that the problem,its the "gettiing someone to fab it up",tbh i didn't try to mount or even offer up the 1wg engine yet,i just had a quick look at the rear frame mounts and they look the same (famous last words i know),so on my next day off will put it in,take a few measurements and see where we go from there.

the only other thing that concerns me is that looking at it,the 4jh head is used as a stress member to the frame,so is this going to make it lose some of it's stiffness,or more to the point enough to change drastically change the handling.i guess thats a more "time will tell" question.

[scooby4/6]

reet time for a bit of a revival,been tied up with buying a new bike and breaking my cbrr superbike (if anyone want s any parts let me know )

so,theres a few diferent options i can do.

make a frame/harness for the 3jh engine.....

put the 4jh back in.....but no point doing that really.

have a chat with a man that can about welding on some lugs on the head to take the frame mounts.(i'm liking this option but can be tricky with the heat in the head).

or,which is the easiest option as it stands,is to put the head off the 4jh onto the 3jh block.most of the engine work has been done to the block (pistons/crank/rods etc..)the cases look the same,but the question is are they?

if anyone knows the answer to the above iwould be most gratefull,dont want to take the head off only to find it doesn't mate up properly.

cheers

[Evilchicken0]

The barrels are 20mm higher on the 4JH and I seem to recall there's a volumetric is difference between them too.

[scooby4/6]

20mm higher? on a same CC engine,thats huge,or at least would be....


i've measursed the barrels from gasket to gasket and there is a 2mm difference,but thhat could just be and my measurng skills

or do mean the engine itself sits higher through the mounts?

[Evilchicken0]

Maybe it's the overall engine height then.

2mm in the barrels is interesting. How much do you reckon could be skimmed on the head to raise compression ???

[rockTJ]

Mention of the 20mm difference in this article here, cylinders & head 20mm nearer the front apparently?....

http://homepage.ntlworld.com/xploiter/f ... R4-6.2.jpg