x16xe bottom end with 8v head

[jonn]

Is it possible to fit a 1.6 8v head to a x16xe block and get it running ok. Want to build a cheap engine and put it on R1 carbs.

I all ready have a very good x16xe block so just need a head carbs dizzy and make my own manifold.

[philip]

my mate has the 16v bottom end with 8v head, not sure if need to machine the top of the pistons slightly to check clearance, im trying to get him to strip engine to have a good nose at it, as its ment to be pushing decent power. i know chris astley isnt trading on here now but iirc it was built by/for him so may be worth dropping him an email..........sure can find him on ebay with 'yeltsa' as his new business name.

[jonn]

Thanks, I read somewhere that chris built one but was not sure where to contact him.

[burgo]

Why not keep the 16v head?

[jonn]

I want to run it on bike carbs but I will need megajolt for the 16v head, and with a 8v head I should be able to use a dizzy. I just need to buy 1 bigger cam and vernier pulley for a 8v head.

If it is going to cost to much I will just try and get a good 1.6 8v engine and put it on carbs.

[Graeme]

Brett did it on his sr without any problems iirc

[burgo]

The cost of having the pistons machined is going to be about the same as megajolt and with rhe 16v head it'll probably make about 20bhp more

[mowgli]

i'm with burgo on this.

if you really want a dizzy, you could try to fit the manta dizzy drive setup, if you can find one.

but a 16v on megajolt & carbs will be way cheaper than sticking a cam in an 8v & then sorting out the pistons.

[thegingerwhinger]

I run this set up on some stock cars and there is no need to machine pistons, even with the head and cam box skimmed it still works.

[mowgli]

/\ but not with a higher lift cam, surely??

[jonn]

Might be right to go the 16v route. Was just going to see what I can get together cheap for my corsa b. Driving a 1.0L 12V can get boring after 2 years!

Will also be building a 1.6 for the kadett so just finding out my best options.

[thegingerwhinger]

Not tried a high lift cam as thats not permitted in our formula hence why the cam box is skimmed to give more valve lift

[mowgli]

mr thegingerwhinger, please explain how this works again, cos, in my mind, moving the cam nearer the valves simply squashes the followers, by my way of thinking, as you haven't changed the size of the cam lobe, or changed the rocker ratio, it stays the same overall

[thegingerwhinger]

Whats the followers also touching aswell as the lifter? The valve, through a lash pad and onto the valve, maybe wont give you loads of power, but ive found it does help.

[mowgli]

ok, but the valves still have to close & the hyd lifters still take up the slack. i think the gain must be from the lifters not moving so much under load

[staggy_gsi]

Am i being stupid??

Because i thought it was obvious that moving the cam closer to the valve would give you more lift, because fitting a cam with a higher lift is effectively the same.

[mowgli]

Am i being stupid??

Because i thought it was obvious that moving the cam closer to the valve would give you more lift, because fitting a cam with a higher lift is effectively the same.

the bottom of the cam lobe (as in the bit where the valve doesn't lift) is still the same distance from the top of the lobe, thus no extra lift has been generated. it you fit a higher lift cam(fast road), the top of the lobe is no further from the centre line of the cam, but the bottom of the lobe is closer to the centre line of the cam, then the slack is taken up on the lifter, which gives higher overall lift.

[staggy_gsi]

Im with you now. It just means there wont be as much oil in each lifter due to the cam pressing it down further, right??

[mowgli]

yes.

[meritlover]

you would have to run an adjustable cam pulley then? as if you move the cam closer to the rocker, the valve will open earlier and therefore have advanced valve timing.

[mowgli]

you will get more cam timing advance from the skimming causing the timing belt to be out of line.

[meritlover]

that and the fact that the valve will start to run up the slope before the ramp and flank earlier.

[thegingerwhinger]

Im using solid lifters here mr mowgli, i maybe should have said.

[thegingerwhinger]

And the std pulley is drilled and doweled. No aftermarket pulleys allowed im afraid

[meritlover]

what valve clearance do you run?

[thegingerwhinger]

10 and 6 thou

[mowgli]

i'm still at a loss as to how it increases valve lift.

i can see the point in solid lifters to get bigger revs though.

[thegingerwhinger]

Its ok, news travels fast on here as a competitor i race with has been on here and seen what im posting and now ive had a few calls from scrutineers! Tut tut

[thegingerwhinger]

Moral of the story an 8v head will fit and run on a small block xe.

[mowgli]

its a subject that's been on here a few times. the head & cam carrier both have a minimum dimension iirc, so i guess it covers skimming & refacing. if you've passed scrutineering before, then you should be fine. people usually suspect engines of being tampered with, yet way more can always be found in the suspension set up.

[jonn]

What will the compresssion ratio be like? I could machine the pistons cheap enough, I know a lad
that is very handy on a lathe and milling machine.

Which head gasket should I use and timing belt?
Might try it and see how it goes.

[meritlover]

i'm still at a loss as to how it increases valve lift.



me too, thats why i asked about valve clearence

[thegingerwhinger]

What will the compresssion ratio be like? I could machine the pistons cheap enough, I know a lad
that is very handy on a lathe and milling machine.

Which head gasket should I use and timing belt?
Might try it and see how it goes.

I use a qtb192 cambelt quinton hazel and a se1.6 headgasket