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Author
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Topic: 351C 4V port plates
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Mark From Detroit
Journeyman Posts: 29
From:
Registered: APR 2001
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posted 04-08-2001 10:37 AM
 
I was wondering if anyone has used port plates on a 351C 4V engine. I was thinking of using them but was wondering if they really worked? Any info would be helpful.
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Mark from Detroit
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kid vishus
Gearhead Posts: 6220
From: middle of NC
Registered: OCT 2000
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posted 04-08-2001 10:54 AM
Welcome to M&M Mark, you should get lots of replies on this one.As for the port plates, I have used them and found them to be a pian in the a** and definately not worth the effort. On my drag car, they never helped one bit, and on the street I could never tell a diference either. And actually, the exhaust plates hurt the flow over .250 lift when I had acces to a flow bench and did alot of testing. I still have mine, but I will never use them again.
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MrXerox
Gearhead Posts: 348
From: Oklahoma City, Oklahoma
Registered: NOV 2000
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posted 04-08-2001 12:23 PM
Mine are going up for sale on Ebay as soon as I get them off my motor!
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SG236
Gearhead Posts: 416
From: Jasper, TN, USA
Registered: DEC 2000
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posted 04-08-2001 06:20 PM
Welcome to M&M Mark pull up and have a cool one!I never used the port plates but like kid heard they have no effect.
Russ Hood
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Clevo377
Gearhead Posts: 312
From: Blackburn, Victoria, Australia
Registered: NOV 2000
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posted 04-09-2001 08:04 AM
Mark I would advise against them as well. I currently have the inlet and exhaust ports installed. I can't give you a comparison as there were many other changes made to the engine at the same time I installed them. What I can tell you however is that they are marketed at bringing your peak torque RPM down, whilst not affecting top end flow. This makes sense as the cross sectional area of the port is reduced. I have heard of many people having trouble with bogging off the line and blaming the size of the ports for this (low velocity). I guess this is where makers of these plates saw an opportunity. I never had this problem with my 4V heads. I believe if you match up an intake, cam, carb and hedders to suit your application, the velocity in the 4V ports at launch will be ok.You may ask why I bought them then....well I don't really know now  I guess I just wanted more out of the 4V's. I am sorry I did though, as now with the amount of port work done on the heads and intake, to match everything up, they've become too non standard to use with anything else. I realise that the work involved with the ones I bought was probably more than others on the market. But with any of them you will have to bog up the bottom of the manifold runner so the air doesn't hit a wall when it gets to the plates. In summary...don't bother  Paul
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Moneymaker
Administrator Posts: 26513
From: Lyons, IL, USA
Registered: MAY 99
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posted 04-09-2001 02:04 PM
Welcome to M&M Mark  ! Glad to have you join us. In another thread we beat this topic to death. I did back to back track testing with port plates several years ago and found no improvements in ET or speed. ------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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SteveLaRiviere
Administrator Posts: 43793
From: Saco, Maine
Registered: MAY 99
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posted 04-09-2001 03:11 PM
Welcome to M&M, Mark. Here's the thread Alex was talking about:
https://mustangsandmore.com/ubb/Archives/Archive-000002/HTML/20000809-1-001383.html ------------------
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L Disposable Commuter
"Keep your driveway all Ford!"
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Gary Ferringer
Journeyman Posts: 59
From: Kennerdell,Pa.
Registered: FEB 2001
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posted 04-09-2001 09:05 PM
I built a set of these about 10 years ago,and had the same results as everyone else. No improvement at all. It did seem to make the engine free rev better,but it didn't translate into an improvement in E.T. I did do a little research on these on my homebuilt flow bench before I used them. The flow did decrease a little,but the velocity on the new raised floor increased tremendously. The velocity on the stock floor's sharp drop was non - existant before the port plate was installed. I was quite disappointed to see no gain in performance. As a side note,after I made 4 or 5 runs with these in, one of the tongues blew upward and covered 3/4 of the exhaust port. Even though the engine sounded a little ragged,it still ran the same times. Now THAT was a little strange. I took them out after that before I ended up burning an exhaust valve. ------------------
'85 Capri
Cleveland powered
carburetted '72 Pinto
CARBURETTED,draw thru turbo 4 cylinder. Runs good.
http://pub43.ezboard.com/blowdollardragracersassociation
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Mark From Detroit
Journeyman Posts: 29
From:
Registered: APR 2001
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posted 04-09-2001 11:03 PM
Im glad I asked this question before I spent my time and money to buy the port plates. There does not seem to be any good responses here from anyone. Mark
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Clevo377
Gearhead Posts: 312
From: Blackburn, Victoria, Australia
Registered: NOV 2000
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posted 04-10-2001 06:06 AM
Hey Alex, Do you think I should dump my closed chamber heads (with inlet plates) for a set of open chamber (non plated) ones. This is for my new Procharger assisted engine. What effect does the size of the port have in artificially aspirated applications?Paul
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Moneymaker
Administrator Posts: 26513
From: Lyons, IL, USA
Registered: MAY 99
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posted 04-10-2001 12:17 PM
Yes Paul, that's a good idea. You can reduce your static compression ratio that way and not worry about detonation. ------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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n2oMike
Gearhead Posts: 2499
From: Spencer, WV
Registered: JAN 2001
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posted 04-10-2001 06:06 PM
Open chamber heads offer zero quench... and therefore are not that resistant to detonation. Open chamber heads will unshroud the valves a little and decrease the compression ratio, but in my personal opinion, the total loss of quench kills the deal. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/motorcitymustang/cmml/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
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Clevo377
Gearhead Posts: 312
From: Blackburn, Victoria, Australia
Registered: NOV 2000
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posted 04-11-2001 06:11 AM
Okay Alex, how about if I used pistons that were .242 down in the bore (giving me a CR of 8:1). Given the large distance from chamber to piston, would the likyhood of detonation be worse than using an open chamber??Thanks Paul
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n2oMike
Gearhead Posts: 2499
From: Spencer, WV
Registered: JAN 2001
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posted 04-11-2001 07:06 AM
That would kill quench as well. Quench is produced when the piston surface comes -really- close to the head surface. In simplified terms, this "pinches" a pocket of air between the piston and head that is then blasted into the open part of the combustion chamber, mixing everything up and helping the mixture to burn.The closer the piston comes to the head, the greater this effect... hence the reason people shoot for a "zero deck" shortblock, where the piston comes right to the top of the cylinder bore. Depending on the head gasket thickness, engines are sometimes set up to where the piston actually protrudes above the deck. Your best scenerio is a dished piston with the closed chamber heads. A dished piston will still have a flat area around the edges to produce the quench effect, while the dished center will help relieve the compression ratio. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/motorcitymustang/cmml/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
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Moneymaker
Administrator Posts: 26513
From: Lyons, IL, USA
Registered: MAY 99
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posted 04-11-2001 10:28 AM
There are a few million pretty good running open chamber big block chebbies that would dipute that senario. Yes you do want the deck height as short as possible for compression and quench, but the open chamber principle has proven itself on canted valve engine repeatedly. ------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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n2oMike
Gearhead Posts: 2499
From: Spencer, WV
Registered: JAN 2001
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posted 04-11-2001 07:02 PM
The BBC's "open" chambers aren't really 100% open. They still have a flat area that provides quench. BBC closed chamber heads give new meaning to the term "valve shrouding".... hence the popularity of the open chamber big chevy heads.351C open chamber heads have no flat area to provide quench. They are truly 100% open. Chambers that are fairly open are great for eliminating valve shrouding, but chambers that are 100% open kill quench and promote detonation. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/motorcitymustang/cmml/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
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Jim Sams
Journeyman Posts: 55
From: Charlotte NC
Registered: JAN 2001
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posted 04-12-2001 08:04 AM
Back to the port plates, specifically the intake plates....
If they cause no change in ET does that mean that they do nothing? or does it mean that they could help in a power range below the lauch point?
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kid vishus
Gearhead Posts: 6220
From: middle of NC
Registered: OCT 2000
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posted 04-12-2001 08:39 AM
Here's my take on it Jim, and I may be out to lunch. The plates, by raising the floor should increase velocity and by doing so should increase flow #'s. And when you increase the flow numbers it should make more power all the way thru the power band, not just down low or up high. The little bit of flow bench work I have done showed that filling the floor of the runner with epoxy raised the flow #'s quite substantially, all the way thru the lift range. But, the port plates themselves on my car, on the track, showed no improvement at all. And, they worried me that they would leak due to just being permatexed to the heads and intake. I feel that #1, they dont raise it enuff, and #2, they dont potrude far enuff into the port to be affective.I may be wrong on the above, but I do know that they didn't help me at all.
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Moneymaker
Administrator Posts: 26513
From: Lyons, IL, USA
Registered: MAY 99
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posted 04-12-2001 11:18 AM
I personally think that they are a waste of money and effort. I, and many others have seen zero performance improvment from them. ------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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