Blocking Off Heat Risers

[Shadetree]

Originally Posted by Merc Cruzer

Pennies go in the intake or the block?

They go in the block. You may have to flatten (stretch) the pennies a little. I didn't have to do that in my younger days. The newer pennies may be a skosh smaller, but you want to use the older pennies anyway..

[Merc Cruzer]

Update....did mine this morning. Went the block off plate (.025) method. The first thing you realize is that it is a lot easier to install the passenger side plate (less around the base). The driver’s side has a lot more stuff that get in the way of loosening the bolts (breather pipe, choke, oil filter and fuel pump). OK so the real reason that I did this was for the sound, I got tired of it being so quite...I love the flathead sound and I wasn't getting it! Then there is the issue of doing it on a brisk Colorado morning (36 degrees). When I finished I started it up and it ran like crap, you would have thought I pulled half the plug wires off. As the engine got warmer and the ambient tempature got up to 40 degrees (high today is to be 51), it began to smooth out. When the engine temp got to 160 I was good to go. The sound at idle is awesome!!!! And my wife said as I pulled out of the drive way she could really notice the difference. Bottom line it took about 45 minutes to install the two plates. As to the increased noise, my car is a convertible the overall noise from the sounds through the convertible top will overpower it anyway. I can't wait for a nice day - 50 degrees (most of the snow is gone for now and the roads are dry - remember I am at 8300 ft.)- and the top will go down and then I will be able to hear her in all her glory.....and there there is that issue of a cooler carb. Pulled the plugs and so far I am not noticing any increase in running richer.Thanks guys for this posting.

PS: I do have duals on the car.

[dullchrome]

Originally Posted by Shadetree

I have a lifter starting to get loud in my `51 F1. It probably doesn't have 300 miles on the rebuild. Not sure if I'll use Red Locktite or stake the threads, but rest assured when the intake manifold comes off I'll be two wheat straws poorer when it goes back on. The Smithy's are just too quiet. My 2 cents worth.

Now thats funny!

[dullchrome]

Well its been approx. six or seven hundred miles now with the heat risers blocked off. There really hasn't been any difference in my warm up or drivability but keep in mind that I live about four feet above sea level in Southern California. The exhaust note sounds much more akin to a flatty with duals as far as I'm concerned. I've even had a few older fellas approach me and say " sounds like you blocked your heat riser." With that being said I am very happy with the results so far.

[Rand]

Man I've wanted to do this for a long time...My Dad used to tell me that the year of the penny had to match the year of the car...My question is? What if I block off the heat risers and install streight pipes too?? Will my neibhors hate me? lol
Randy

[Talkwrench]

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Yes you neighbours will hate you..! I have 1 3/4" straight pipes and its loud. I havent checked to see if the heat risers have been blocked, I'd hate to be near it if they wheren't....

[Shadetree]

Merc Cruiser, just wait until you get in town and hear the echo from the buildings~Sweet!

[Shadetree]

[QUOTE=Rand;645999]Man I've wanted to do this for a long time...My Dad used to tell me that the year of the penny had to match the year of the car.

I never heard that before but the pennies always should go in heads up for good luck!

[Talkwrench]

I forgot to add something funny: There is a family halfway down our short street and they have two young boys, as soon as I come around the corner the youngest always puts his hands over his ears with a very serious look on his face...

[Merc Cruzer]

Follow up question....first let me say I do love the new sound of the exhaust. Has anyone found any issues with blocking off the heat risers, other than the ruff idle at startup when cold and as one post stated runs richer?

[dullchrome]

Ive got close to one thousand miles on since blocking them off with no issues. So far so good!

[Mike51Merc]

Is is really necessary to block both sides? I was thinking I could accomplish the same thing by blocking only one side with a shim.

If you block one--- you've stopped the bypass.

[Merc Cruzer]

I did block off both sides. Did you notice any change in performance or idle after the car is up to temperature? Do your plugs seem to be burning the same?


I am trying a few test runs with different air cleaners. I have an original air bath that I converted to a K&N insert and I also have an original air bath without modifications. Also testing with different air temps: 40 degrees vs. 80 degrees

[Merc Cruzer]

Before and after temperatures...sorry for the blurry shots of the temp gun but digital cameras are not too good for depth of field...but I think you get the "picture". Car up to the same running temp:180

Just might resolve some of the issues on those hot days

[dullchrome]

Originally Posted by Merc Cruzer

Before and after temperatures...sorry for the blurry shots of the temp gun but digital cameras are not too good for depth of field...but I think you get the "picture". Car up to the same running temp:180

Just might resolve some of the issues on those hot days

Temps look good. Hows she been running?

[Merc Cruzer]

It has been runing great and love the flathead music! Recently I was told the gas mileage would be worse, it was explained that blocking off the heatrisers would result in un-burnt gas, with the possible result of washing the cylinder walls. With that in mind I took the car to the local state of Colorado emissions station and had the car checked, here are the results. All passed but the idel and that was fixed with a half a turn in on the screw. By the way the test was only $15.00 and the testing stations are easily assessable during the week....no need to invest in all
that equipment if you tax dollars already paid for it!