Valve guides
Turbo Mini Forums

Hi
Just wondering if anyone can help iv just had my stage 2 cylinder head converted to 36mm inlet and 31mm exhaust from 33mm and 29mm, iv also had bronze guides fitted but i think the engineer has reamed tham out to much thay have a bit of play side to side, should thay have play or should thay be a nice tight but loose fit if you know what i mean!!?

thanks
Rich

how much movement, , lift the valve 1" off the set and measure sideways freeplay,

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You should be able to feel some movement, yes. But it shouldn't be excessive.

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just had my dti on it and its 0.4mm to 0.6mm on inlets and exhausts

is that too much, i think it might suffer from smoking?

was that at 25mm off the seat,

Edited by fastcarl on 31st May, 2009.

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I tend to prefer having a bit more play in exhaust guides, to let the valve expending.
0.4, 0.6 is ok, a bit tighter and you could kiss your cyl head and pistons.
A series tend to be smokey on overrun, try the last vuitton valves seals

when the cylinder head was on engine the engine would smoke when accelerating just a puff of smoke then clean up, and also if you had the engine ticking over for a long time, this is why i had the head done in the frist place, i just don't wont it to be the same

Put stem seals on the exhaust valves too...also what oil were you using ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Stevie I've going to have to disagree with you on this one. The Ex valve gets very hot as we no, and putting a stem seal on them isn't a good idea imo as it needs some oil to lubricate it to help stop it seizing.

Yes better to have a little paly in the ex valves them be tight i've found.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

And, as previously discussed on this forum, oil is highly unlikely to be sucked down the exhaust valve guides - there is suction is on the inlets on a closed throttle but I cant see how the exhaust has anything but positive presure except for VERY brief intervals due to pressure waves bouncing up and down the exhaust.

Your turbine suck thru exhaust guides when your closing your throttle,
secound Matt, doesn't use exhaust seals, to keep a bit of oil going to the guide, prfer to have a light smoke on overrun than to keep my guides dry and tight on stem.

I agree, I never fit them on the exhaust on any of my heads.

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thanks people il keep that in mind, but the oil im using is 15-40 is that ok?

Thank you fab - I was thinking N/A not turbo so was quite wrong about exhaust suction.

10/15w50 motorbike oil, or 20w50 millers cv, what else?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I didn't know that about moden engines Stevie. Emm, some thing to thing about then maybe??

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

i run sprung plastic seals on both ex and inlet ,and also run tight clearances .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM