Thinking about doing some motor work(BT20v)

JyuRoku
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Thinking about doing some motor work(BT20v)

Postby JyuRoku » Tue Mar 24, 2015 3:07 am

I've been trying to find mild 20v builds but for some reason the search isnt working for me...

I've been looking at the Kelford 194 b(rally) or c(mild racing/top end) cams, but wanted to see if anyone else is using them and how the clearance is with a .5mm shaved head/.5mm headgasket.

if anyone could shine some light it would be really helpful.

yoshimitsuspeed
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Re: Thinking about doing some motor work(BT20v)

Postby yoshimitsuspeed » Wed Mar 25, 2015 10:09 am

I have not sold many of the B or C cams and I don't think I know anyone who has done this on stock pistons. Maybe you will get some input on this from someone with experience but otherwise your best bet is going to be mocking this up as much as possible. With the motor at TDC you can measure how much your valves can travel before hitting the piston. To do this you want a light spring on the valve and a dial indicator.
Using the cam cards you can also estimate crank location and valve travel and see if it should all clear.

Option b if you are willing to get new pistons if it comes down to it would be to get the cams that you want. Then you can put the cams and cam gears in, put some clay on the pistons, spin the motor slowly at factory cam timing, then advanced as far as you want to advance it, then retarded as far as you want to be able to retard it. Spin it really slow in case it makes contact.
If it doesn't then you pull the head and look at your clay to see how much clearance you have.

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oldeskewltoy
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Re: Thinking about doing some motor work(BT20v)

Postby oldeskewltoy » Wed Mar 25, 2015 10:22 am

JyuRoku wrote: how the clearance is with a .5mm shaved head/.5mm headgasket.

if anyone could shine some light it would be really helpful.



be careful with the .5mm gasket. You might check to see if you have a few thousandths positive deck (piston is below blocks edge), because a .5mm squish is very tight
OST Cyl head porting, - viewtopic.php?f=22&t=300

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