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Old 07-03-2004, 05:14 PM
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Damn Guide plates!

Hi,
I'm New here, so first let me say hello to all G'Day All!

Now that the introductions are out of the way could someone please help with a prob i have??

Ive been building a 454 Chevy for quite some time now and made the decision to go with a pair of Merlin2 heads over the stock ones i have.

In order to get the valvetrain geometry correct i had to use longer pushrods, no worries there yet! However when the time came to install the guide plates,(the ones that came with the heads)the exhaust valve tip and roller rocker tip alignment is way off, i'm talking half the valvetip off, the intake is ok though.

Ive tried to move the guideplate fore and aft and sideways to get things better, even tried to bend one of them, but thats not a good idea as they crack real easially.

Elongating the mounting holes sort of helps but isn't the answer either.

The only idea i have left is to buy some 5/16th guide plates and grind them up to suite my 3/8th rods, is this feasable?? and will grinding the plate remove the hardening?? and render it useless?

Anyone have a better idea???

Cheers RobbieRat

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Old 07-03-2004, 05:29 PM
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You need the proper guideplates for Merlin heads I believe, I have cut the stock Chevy type at the joining strap and then brazed them back together in position with a short piece of 1/8" mild steel. It doesn't look pretty but it works and gives you the opportunity to align them perfectly. As long as your quick and quench them with a wet rag you won't remove too much of the heat treat.
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Old 07-03-2004, 05:51 PM
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I have the proper World Guideplates, there the problem?

I like your idea about splitting them in the middle and rewelding them, i have a MIG welder, do you thing i could use it? and would it be strong enough??

Cheers RobbieRat
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Old 07-03-2004, 06:31 PM
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Mig welding would work great. Cover the springs and seals to protect them from splatter.
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Old 07-03-2004, 06:37 PM
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Robbie, let me know how you go as I have the same problem with SB heads. You know they only send the junk down here don't you?
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Old 07-03-2004, 09:36 PM
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Thanx for the replys fella's,

I'll let you know how it turned out.

HQ
There are adjustable guideplate available for SBC's.

Cheers RobbieRat.
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Old 07-09-2004, 04:50 AM
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Hi All...........

Well i finally managed to sort these bloody guideplates out

After much cutting and welding and more recutting and welding i had to find a better way
Problem with all the cutting and welding is they still move into the wrong place when cool.I wasn't game enough to weld right on my brand new heads so i used old ones instead for the welding.Which is a bit hit n miss.
Even after torqueing them into place and welding them and then tranfering them to the Merlins, one would always be out a tad

So i decided to buy a new set, torque em in place and check tip alignment, interestingly things wern't as bad as with the World guideplates(bonus).
Only about half needed adjusting, i also found out guideplates crack real easy the hard way.
One major difference in the two brands of guideplates is the hole in the base, World have a huge hole, which tend to move around under tightening which is a prob in itself and the Pioneer i used are very tight on the studs and can't move period.

Now all i need to do is realign the misaligned ones, and thats pretty easy if you have an oxy set. I just heated the vertical part of the guideplate redhot and twisted it to suite the rocker tip. The result is perfect rocker tip alignment and now with 1/4'' longer onepiece pushrods the geometry is correct and the whole job only took a few hours so the rest of the afternoon was spent drinking beer and celebrating!
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Old 07-09-2004, 04:59 AM
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Here's a pic of the heads

Cheers RobbieRat!
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