Re: Blocking the heat crossover in iron heads.
[Re: Porter67]
#2393637
10/27/17 01:00 AM
10/27/17 01:00 AM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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I like to keep the horse shoe openings in the middle of the head open to air & block the passages in the intake itself.
live every 24 hour block of time like it's your last day on earth
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Re: Blocking the heat crossover in iron heads.
[Re: Porter67]
#2393716
10/27/17 10:10 AM
10/27/17 10:10 AM
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Joined: Jan 2003
Posts: 1,792 Greer, SC
TooMany62s
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,792
Greer, SC
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If your car is primarily driven on the street and used during colder weather, I personally would leave the cross-over open. I blocked the cross-over in a 383 powered car I had. The change made it very "cold blooded." If the car is equipped with a factory type thermostatically controlled choke, the choke will take way too long to pull off. If you have an electric choke, it will pull off too soon. Plus, blocking the cross-over didn't make any noticeable improvement after the engine was "warmed up". I think this is one of those questions to which the answer is, it depends.
Last edited by TooMany62s; 10/27/17 10:11 AM.
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Re: Blocking the heat crossover in iron heads.
[Re: RapidRobert]
#2393719
10/27/17 10:18 AM
10/27/17 10:18 AM
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Joined: Jan 2004
Posts: 4,566 Motor City
6PKRTSE
master
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master
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Posts: 4,566
Motor City
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I like to keep the horse shoe openings in the middle of the head open to air & block the passages in the intake itself. This is what I have always done to any of my cars as well. They don't get driven in winter anyway.I just use a couple of small thin piece of sheet metal & sandwich them in with the gaskets. Never had any intakes leaks either.
1963 Belvedere 440 Max Wedge Tribute 1970 Charger R/T S.E. 440 Six Pack 1970 Challenger R/T, 528 Hemi 1970 Charger 500 S.E. 440 4 BBL 1970 Plymouth Road Runner 383 1974 Chrysler New Yorker 440 1996 2500 RAM 488 V-10 4X4 2004 3500 Dually Cummins 4x4 2012 Challenger R/T Classic.
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Re: Blocking the heat crossover in iron heads.
[Re: Porter67]
#2393758
10/27/17 11:48 AM
10/27/17 11:48 AM
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Joined: Mar 2006
Posts: 74 Stevensville, ON
Frank Raso
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member
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Posts: 74
Stevensville, ON
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As in the title im looking for opinions on if still blocking the heat crossover is a plus or if anyone figured out it might keep more heat then wanted in the inner cylinders. There is no benefit to blocking the intake manifold heating system on a street-driven engine. The hot-spot under the carb is necessary to vaporize any fuel that falls out of the air stream and to replace the heat from the vaporizing fuel's cooling effect on the intake manifold. See the Carter, Holley, and Rochester references in Intake Manifold Heat. Even with an al. intake wont it heat sync nearly as hot sooner or later? Nope. Without a working cross-over passage you won't have a hot-spot under the carb either.
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Re: Blocking the heat crossover in iron heads.
[Re: Porter67]
#2393879
10/27/17 04:51 PM
10/27/17 04:51 PM
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Joined: Jan 2008
Posts: 3,886 Lost and Spaced
bboogieart
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Lost and Spaced
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Not to high jack, but kind of the same subject... Would it be beneficial to remove the heat riser valve in the exhaust manifold? The reason I ask is mine are rusted in place. Usually partially open. Street cars, summer use.
I have mechanical Aptitude. I can screw up anything.
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Re: Blocking the heat crossover in iron heads.
[Re: bboogieart]
#2393885
10/27/17 05:02 PM
10/27/17 05:02 PM
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Joined: Oct 2015
Posts: 728 Michigan
BlueRacer69
super stock
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super stock
Joined: Oct 2015
Posts: 728
Michigan
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Not to high jack, but kind of the same subject... Would it be beneficial to remove the heat riser valve in the exhaust manifold? The reason I ask is mine are rusted in place. Usually partially open. Street cars, summer use. That's a reasonable suggestion. Back in the day we used to take a piece of wire and wire the heat riser open.
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Re: Blocking the heat crossover in iron heads.
[Re: BlueRacer69]
#2393896
10/27/17 05:15 PM
10/27/17 05:15 PM
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Joined: Jan 2008
Posts: 3,886 Lost and Spaced
bboogieart
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O.K. Open it will be. I will remove 'em and drill and tap for plugs. As well as the intake block-of R.R. recommended. Thanx.
I have mechanical Aptitude. I can screw up anything.
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Re: Blocking the heat crossover in iron heads.
[Re: Porter67]
#2394100
10/28/17 12:43 AM
10/28/17 12:43 AM
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Joined: Jan 2003
Posts: 1,760 Windsor, ON, Canada
Diplomat360
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,760
Windsor, ON, Canada
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I had to fill the cross overs with epoxy because one of the darn things sprang a leak...LOL, yeah, all iron heads, heavily ported, so it is conceivable that maybe this had something to do with it, although the machine shop did a pressure test first and there was NO air coming out of the ported exhaust valve area.
Anyways, to answer your question, on top of this I used FelPro 1213S-3 intake gasket, which has the passages blocked off.
This is on a street car, but not a daily driver. Car heats up just fine (I only drive it in late spring, summer and early fall months), no issues to report.
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Re: Blocking the heat crossover in iron heads.
[Re: Porter67]
#2394355
10/28/17 08:07 PM
10/28/17 08:07 PM
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Joined: Jan 2003
Posts: 14,497 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,497
So. Burlington, Vt.
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The aftermarket heads seem to work just fine without a heat crossover passage.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Blocking the heat crossover in iron heads.
[Re: Frank Raso]
#2394421
10/28/17 10:42 PM
10/28/17 10:42 PM
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Joined: Jan 2008
Posts: 3,886 Lost and Spaced
bboogieart
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Lost and Spaced
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There is no benefit to blocking the intake manifold heating system on a street-driven engine.
So block off the exhaust heat riser, but not the Intake cross-over? Good to know. Now I can use the pan gasket I already have.
I have mechanical Aptitude. I can screw up anything.
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Re: Blocking the heat crossover in iron heads.
[Re: fast68plymouth]
#2394474
10/28/17 11:58 PM
10/28/17 11:58 PM
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Joined: Jun 2014
Posts: 5,183
Porter67
OP
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OP
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The aftermarket heads seem to work just fine without a heat crossover passage. The smog heads I just did, they go up on both center exhausts unlike the older j or x for instance that just go up on one, thats why I asked about heat buildup.
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Re: Blocking the heat crossover in iron heads.
[Re: Porter67]
#2394541
10/29/17 01:32 AM
10/29/17 01:32 AM
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Joined: Jun 2005
Posts: 6,257 gulfport, ms, west mi
rowin4
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gulfport, ms, west mi
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Back in the 70'S I used tin foil which worked OK. Then some gasket manufacture had little squares of thin metal gasket material to place over the hole. Later race type gaskets were introduced that didn't have the crossover opening.
it's ok to butt heads, just don't do it with a butthead
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Re: Blocking the heat crossover in iron heads.
[Re: Porter67]
#2394646
10/29/17 08:34 AM
10/29/17 08:34 AM
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Joined: Aug 2007
Posts: 1,511 AZ
Mike P
pro stock
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pro stock
Joined: Aug 2007
Posts: 1,511
AZ
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I’ve also found exactly the same thing 2many62s describes especially on cold mornings.
“……If the car is equipped with a factory type thermostatically controlled choke, the choke will take way too long to pull off. If you have an electric choke, it will pull off too soon. Plus, blocking the cross-over didn't make any noticeable improvement after the engine was "warmed up". I think this is one of those questions to which the answer is, it depends…….”
While not as bad as eliminating the heat crossover, eliminating the heat riser will also slow the warm up period considerably. None of my cars have a heat riser valve and a few in the past have run manifolds and/or heads without the heat crossover. As I often drive my cars year around and during the winter and we get some pretty chilly early mornings I can say first hand it can be a real PIA.
The one band-aid I’ve found that really helps during the warm up period is to add an MSD box. The multiple spark during low RPM really makes a big difference in firing off the cylinders until the car warms up.
1957 Plymouth (Hemi, Dual Quads, A833 4 Speed 9 1/4 w 4.10) Sold 1937 Dodge Pickup (Hemi, 6X2 intake, 46RH, Dana 60 w 4.56) Sold 1968 Plymouth Valiant 2dr sedan (354 HEMI, 46RH w/4.30 gears)
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