Author Topic: KA24DE camshafts.  (Read 2810 times)

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Offline Pure_Sincerity

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KA24DE camshafts.
« on: Mar 15, 2013, 08:40AM »
Looking into cams for the DOHC Andover had found out the following.

Factory 248 degree with a .367" lift
= 9.3218mm

BC 264 degree with a .375" lift
= 9.5250mm

If my math is correct of course.

So the BC 264 degree shafts are only 0.2032mm larger lift than factory. Now I know small numbers mean everything in engine work, but that's a fuck all difference, I reckon they would fit even with the flat pistons. Even if I do purchase them, and they hit while doing a hand rotation, than I can always go out and buy a slightly thicker commentic head gasket. Even if that was the case, I doubt it would drop the compression much.

Lift should not be an issue, more so the duration. But dialing them in right should allow them to work adequately.

I had sent an email off enquiring about clearance on a ka motor with flat top pistons and all I got back was "these camshafts are designed to clear when set at 0 degrees or on your stock cam gears"
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Offline Kranzy

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Re: KA24DE camshafts.
« Reply #1 on: Mar 15, 2013, 09:42AM »
They will never guarantee anything other than stock, otherwise if something doesn't work and there isn't enough clearance and you stuff the engine, they don't want you to come back at them blaming them.

It's all liability crap, or no knowledge.
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Offline Pure_Sincerity

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Re: KA24DE camshafts.
« Reply #2 on: Mar 15, 2013, 11:05AM »
Yeah, but in theory, if dialed in correctly with the adj cam gears, nothing should touch after a hand rotation test. Eg. Advancing 5 degrees.
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Offline squizz taylor

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Re: KA24DE camshafts.
« Reply #3 on: Mar 15, 2013, 11:18AM »
The clearance between the valves and pistons depends on a lot of things. Some of the info you have stated is correct, but a variable you have not taken in to account is the piston height in the block, or deck height, and the head height.
When we did the machine work on deviates engine, everything was fully blueprinted. The deck height was set to 0, and the squish of the head was .040" and then the head was decked to get as close to possible to 11.5 compression we could. All of this brings the valves closer to the piston when everything is setup and the cams are dialled properly. When the cams were installed,  they were less that .5 a degree out from the blueprint spec, so we left them as is.
If any of the steps are skipped or shortcut, there is only one outcome that will eventually happen. Mass destruction.
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Offline Pure_Sincerity

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Re: KA24DE camshafts.
« Reply #4 on: Mar 15, 2013, 11:37AM »
Nothing has been taken from the head, still factory besides intake (ITBS) and as for pistons, they are not complete flat tops, they have a 1.5mm flat dish, factory DOHC pistons are 6mm curved dish from memory.

So in theory, these cams with adj cam gears should work with the flat pistons. The gears can advance or retard 2.5 - 15 degrees. So dialed correctly with a hand rotation test should be good to go. And if they touch no matter how advanced than well, they go back in the box and in the cupboard for a future rebuild with forgies.

(Advancing closes the valve earlier in order to build more compression within the cylinder.)
« Last Edit: Mar 15, 2013, 01:44PM by Pure_Sincerity »
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Offline crazy2287

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Re: KA24DE camshafts.
« Reply #5 on: Mar 17, 2013, 02:13PM »
they only way to be sure is to pull the head off, Keep you used headgasket. Put some Plasticine  in each pot. make sure spark plugs are out and stick the head back with used gasket on and do an engine rotation 720ยบ.

Pull it off and measure the squish of the Plasticine with some calipers.

true, 8thou is fuck all but the duration may cause an issue. but you can use your new data to decide how much clearance you have. Ring the cam manufacturer and tehy should be able to tell you how far you can go. Remember you have to leave clearance for metal stretch at RPM and heat difference.

get the new cam and do ANOTHER plasti test.
This time don't bolt the head down hard. after head is assy and on, back the head bolts off a couple of turns. Do your test. if you have good clearance. Torque it down properly and test again so you know how much room you have to play with.

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Offline Pure_Sincerity

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Re: KA24DE camshafts.
« Reply #6 on: Mar 19, 2013, 09:37AM »
I emailed crower personally and explained the engine build and that I have only 1.5mm flat dished pistons etc and he responded with

Quote
Aaron,
You will not have any piston to valve issues with the stage 2 cams when
they are set up properly -Run with confidence.

So I will do as I said, buy them, fit, test by hand rotation engine, if they don't fit no mater how try are dialed in, than they will be in the cupboard for later.

Will be a good addition to the high comp and ITBS ^_^
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