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Can I use Belzona to "shrink" manifold runners this much?

General engine tech -- Drag Racing to Circle Track

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BradH
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Can I use Belzona to "shrink" manifold runners this much?

Post by BradH » Tue Sep 27, 2016 12:18 pm

I put a lot of work into one intake manifold to use with a set of heads I have. In addition to plenum work, they also required opening up the manifold runners & exits a good bit to match the heads.

However, I may not end up using those heads after all, and the heads that would be used instead have pretty much the size of the runners which this particular intake started off having... naturally. #-o

With the proper surface prep, would Belzona 1111 be appropriate for "shrinking" the manifold runner exits this much to match the heads w/ the smaller port entries? I already have the Belzona on hand (unopened since purchase) thinking something might come up where I'd need it. Now I just want to get confirmation that I'm not expecting too much from an epoxy "fill job" like this.

Heads for which intake was modified to fit:
HECNC_intakes1_sm.jpg
Same heads with matching gasket:
HECNC_intakes2_sm.jpg
Small-port heads with their matching gasket:
PRH_intakes_SP_sm.jpg
Big-port gasket on small-port heads:
PRH_intakes_HECNC_gskt.jpg
Big-port gasket over small-port gasket:
HECNC_gskt_over_SP-Std_gskt.JPG
Thanks! - Brad
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V Remian
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Re: Can I use Belzona to "shrink" manifold runners this much

Post by V Remian » Tue Sep 27, 2016 2:14 pm

Before going to all that work, read this: viewtopic.php?f=1&t=38868

BradH
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Re: Can I use Belzona to "shrink" manifold runners this much

Post by BradH » Tue Sep 27, 2016 3:07 pm

V Remian wrote:Before going to all that work, read this: viewtopic.php?f=1&t=38868
Yeah, I'd read that thread before... not really an "apples to apples" comparison, IMO. No way I'd run mine w/ this big of a intake-to-head oversize mismatch.

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Re: Can I use Belzona to "shrink" manifold runners this much

Post by Powertrip » Tue Sep 27, 2016 4:22 pm

If anything will work, Belzona will. I like Belzona 1121 best, longer working time and longer shelf life. The 1111 only lasts about a year on the shelf.
I would not get carried away with shrinking the entire runner down, just use enough for a smooth transition.
Heck, I wouldn't even run the small port head on a BBM, unless the velocity profile was a lot better.
The price of progress is trouble.

Abbottracingheads
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Re: Can I use Belzona to "shrink" manifold runners this much

Post by Abbottracingheads » Tue Sep 27, 2016 4:45 pm

Yes it will work, will work well.
Abbott Racing Heads and Engines

BradH
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Re: Can I use Belzona to "shrink" manifold runners this much

Post by BradH » Tue Sep 27, 2016 5:43 pm

I'd hate to think my 1111 is garbage already without having even opened it, but I bet I've had it for close to a year, if not longer. That sh!t ain't cheap...

EDIT: Data sheets on both 1111 & 1121 say 5 years shelf life when stored properly. Mine has been in a room that's been between 68 - 72* F year around.

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Re: Can I use Belzona to "shrink" manifold runners this much

Post by mag2555 » Wed Sep 28, 2016 6:45 am

Balzona is overkill for that, in manifolds I have used a much more price freindly JB weld in the tube form, or a brick of Moroso or Manley epoxy, and have never had a issue .
I save my Balzona for use in heads and blocks !

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Re: Can I use Belzona to "shrink" manifold runners this much

Post by Carnut1 » Wed Sep 28, 2016 6:59 am

I might try that manifold just as it is. I have had 1204 heads that pickup flow using a 1205 or 1206 radius! True. Thanks, Charlie
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BradH
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Re: Can I use Belzona to "shrink" manifold runners this much

Post by BradH » Wed Sep 28, 2016 9:00 am

mag2555 wrote:Balzona is overkill for that, in manifolds I have used a much more price freindly JB weld in the tube form, or a brick of Moroso or Manley epoxy, and have never had a issue .
I save my Balzona for use in heads and blocks !
Manley A/B got soft & lifted due to ethanol exposure from using E10 pump fuel. That's why I bought the Belzona this time.

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Re: Can I use Belzona to "shrink" manifold runners this much

Post by BradH » Wed Sep 28, 2016 9:02 am

Carnut1 wrote:I might try that manifold just as it is. I have had 1204 heads that pickup flow using a 1205 or 1206 radius! True. Thanks, Charlie
My flow testing has always shown flow reduction if the radius plate entry isn't a good match for the runner. Can't imagine how that would change by using an intake manifold that leaves a step in the direction of flow.

Walter R. Malik
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Re: Can I use Belzona to "shrink" manifold runners this much

Post by Walter R. Malik » Wed Sep 28, 2016 9:09 am

BradH wrote:
V Remian wrote:Before going to all that work, read this: viewtopic.php?f=1&t=38868
Yeah, I'd read that thread before... not really an "apples to apples" comparison, IMO. No way I'd run mine w/ this big of a intake-to-head oversize mismatch.
No Way ???
If you already have all your own answers, then why are you even on here asking these kinds of questions... ?
Especially when total mass airflow is only a small percentage of what it takes to make power.

"When testing, if the results differ from your theory ... believe the results and invent a new theory".
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Re: Can I use Belzona to "shrink" manifold runners this much

Post by Frankshaft » Wed Sep 28, 2016 9:28 am

The other thing, think about how the air flows thru the manifold and head. The intake port of the head, is sucking the air thru the manifold, its not being pushed thru, unless its under boost, which, at that point, it just jamms it in anyhow. But, on a na deal, its sucking it thru, so, it really doesn't "slam" into the face of the cylinder head like most think. But, with that little difference, you could use the epoxy to shrink it down, no problem.

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Re: Can I use Belzona to "shrink" manifold runners this much

Post by Carnut1 » Wed Sep 28, 2016 11:10 am

BradH wrote:
Carnut1 wrote:I might try that manifold just as it is. I have had 1204 heads that pickup flow using a 1205 or 1206 radius! True. Thanks, Charlie
My flow testing has always shown flow reduction if the radius plate entry isn't a good match for the runner. Can't imagine how that would change by using an intake manifold that leaves a step in the direction of flow.
You would think. But it has happend to me a few times. Thanks, Charlie
Servedio Cylinder Head Development
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BradH
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Re: Can I use Belzona to "shrink" manifold runners this much

Post by BradH » Wed Sep 28, 2016 11:34 am

Walter R. Malik wrote:
BradH wrote:
V Remian wrote:Before going to all that work, read this: viewtopic.php?f=1&t=38868
Yeah, I'd read that thread before... not really an "apples to apples" comparison, IMO. No way I'd run mine w/ this big of a intake-to-head oversize mismatch.
No Way ???
If you already have all your own answers, then why are you even on here asking these kinds of questions... ?
Especially when total mass airflow is only a small percentage of what it takes to make power.

"When testing, if the results differ from your theory ... believe the results and invent a new theory".
Please re-read MY original post: I wasn't asking about whether to run the intake w/ the mismatch. My question was whether Belzona would be suitable for reducing the runner size. OTHER people brought up the idea of using the intake "as is" w/ the mismatched entry sizes, not me.

Also good luck at the EMC 2016.

ap72
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Re: Can I use Belzona to "shrink" manifold runners this much

Post by ap72 » Wed Sep 28, 2016 11:46 am

Frankshaft wrote:The other thing, think about how the air flows thru the manifold and head. The intake port of the head, is sucking the air thru the manifold, its not being pushed thru, unless its under boost, which, at that point, it just jamms it in anyhow. But, on a na deal, its sucking it thru, so, it really doesn't "slam" into the face of the cylinder head like most think. But, with that little difference, you could use the epoxy to shrink it down, no problem.

Can you explain the difference in the air flow, besides of course the density. In both cases you have a high and low pressure end, flow is going from the high pressure to the low pressure, it's not really being "sucked" nor "pushed", it's both.
LOL, according to the post count I'm an "expert." The only thing I'm an expert at is asking questions.

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