Epoxy to fix excessive bowl cut

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vwchuck
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Epoxy to fix excessive bowl cut

Post by vwchuck »

Has anyone used epoxy to fix an excessively large bowl cut? The port bowl cut is larger in diameter than the valve seat so there is a step up from the port to the valve seat. Was thinking about using epoxy to fix it. Either that or find a different head. Thoughts?
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Re: Epoxy to fix excessive bowl cut

Post by David Redszus »

vwchuck wrote: Thu Jul 12, 2018 9:41 am Has anyone used epoxy to fix an excessively large bowl cut? The port bowl cut is larger in diameter than the valve seat so there is a step up from the port to the valve seat. Was thinking about using epoxy to fix it. Either that or find a different head. Thoughts?
On the inlet side, it might be possible to use an epoxy filler, if the surface is properly textured.

On the exhaust side, i have found welding to be necessary.
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Re: Epoxy to fix excessive bowl cut

Post by vwchuck »

Yes I was going to rough up the surface. I wonder how it will hold up as this is a daily driver. Not sure I trust epoxy to last that long. It has however held up on a set of air-cooled heads on my racecar and they see some very wild swings in temp.
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Re: Epoxy to fix excessive bowl cut

Post by MadBill »

If the repair formed a full 'ring' below the seat, it would be very hard to dislodge even if the bond was a little weak...
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Re: Epoxy to fix excessive bowl cut

Post by mk e »

Epoxy within an inch of the seat seems like a bad idea.....I would weld it.
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Re: Epoxy to fix excessive bowl cut

Post by Belgian1979 »

On my intake the epoxy came loose after a while. It didn't dislodge completely however.
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Re: Epoxy to fix excessive bowl cut

Post by vwchuck »

Yea I won't waste the money welding up this head. Easier to get one that isn't hacked up already.
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Re: Epoxy to fix excessive bowl cut

Post by gmrocket »

I've done it many times on heads that have a poor bowl to seat transition.

Make sure it's a good rough and clean surface...JB weld is the best.
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Re: Epoxy to fix excessive bowl cut

Post by user-30257 »

If it's aluminum, I usually heat the head a few times clean in a water based hot tank/parts washer. Until the oils stop coming to the surface. Then just isoalcohol and epoxy. Since the bowl is bigger than the throat, it can't come out except in pieces.

With cast I use phosphoric acid, iso.
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Re: Epoxy to fix excessive bowl cut

Post by F-BIRD'88 »

May be able to go to a larger valve, if the casting will allow.

Whats the general rule? bowl is 88%(ish) of the valve seat diameter..
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Re: Epoxy to fix excessive bowl cut

Post by mag2555 »

What head is this and how was it used, on a boosted motor?
For flat out top end power in a very very narrow power band some porters/ engine guys have been known to make the valve seat area the minimum port area .
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Re: Epoxy to fix excessive bowl cut

Post by grant6395 »

Splash zone has worked well on my heads. Don losito literally filled the existing intake port and created a new one. That was in 2005 I belive. Still there. 400 ci comp engine. Prep is obviously the key.
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Re: Epoxy to fix excessive bowl cut

Post by vwchuck »

Hmmm maybe I will epoxy this thing. It is a production daily driver 5 valve per cylinder head. This is on the tiny little intake valves.
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Re: Epoxy to fix excessive bowl cut

Post by SchmidtMotorWorks »

Bore a counter-bore below the seat.
Lathe turn a sleeve to press-fit the counter-bore
Press in the sleeve
Install the seat
Finish VJ as usual

2 hours work max, no worries about deteriorating epoxy.
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Re: Epoxy to fix excessive bowl cut

Post by JoePorting »

I'd get another head.
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