Thread: A log of my updates on my '32 Brookville highboy

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Nick, it appears that you're tailpipes are welded to the rear bar, which I assume is bolted to the frame.
If so, aren't you worried about that vibration (noise)?
Usually a rubber isolator is set between the pipe and frame, allows the system to move to prevent stress / flex - fatigue failures and help keep the vibration noise out of the cab.

Just curious how it acts once you get to drive it.

Originally Posted by 34_40

Nick, it appears that you're tailpipes are welded to the rear bar, which I assume is bolted to the frame.
If so, aren't you worried about that vibration (noise)?
Usually a rubber isolator is set between the pipe and frame, allows the system to move to prevent stress / flex - fatigue failures and help keep the vibration noise out of the cab.

Just curious how it acts once you get to drive it.

Yeah, I wondered about the welded pipes when I saw that picture, too, but I let it pass. Besides the vibrations exhaust systems grow with the every startup simply due to the thermal expansion through the system, so they are hung rather than being direct coupled. If it's welded all the way you're going to have some pretty good forces on that nerf bar weld.

Thanks for the comments guys. I'm seriously considering your suggestions and looking at what will happen as things flex and get hot and cold. I'm also wondering if I wouldn't rather have an exhaust I can quickly drop and run straight open headers ...if for no other reason that to scare away big bears that might come on my property. Whatever I do, you'll be the second ones to know.

I use just a harden rubber washer on mine, might be an easy out for you Nick. It acoustically decouples the exhaust from the mounting point and allows a fraction of the movement of a hanging rubber donut isolator.

If you look at the coefficient of expansion for steel and assume a nominal ten foot length for the pipes the movement from a 50F ambient to nominal 180F exhaust temp (higher with CAT's) yields over 1/4" of growth. It's proportional to the change in temperature, so going from a frigid winter day to operating temps is going to be more. Bob, you's will be flexing that vertical mount, and the donut provides very little for isolation with the bolt coupling both rigid parts.

Originally Posted by rspears

If you look at the coefficient of expansion for steel and assume a nominal ten foot length for the pipes the movement from a 50F ambient to nominal 180F exhaust temp (higher with CAT's) yields over 1/4" of growth. It's proportional to the change in temperature, so going from a frigid winter day to operating temps is going to be more. Bob, you's will be flexing that vertical mount, and the donut provides very little for isolation with the bolt coupling both rigid parts.

Are you sure a 1/2"? The table I use, the expansion is given 10 to the negative 6th in inches. Coefficients of Linear Thermal Expansion

Aw, you edited it to 1/4". Mine is a 5' run, so maybe 1/8" for my set up.

Originally Posted by deckofficer

Aw, you edited it to 1/4". Mine is a 5' run, so maybe 1/8" for my set up.

Yeah, I had looked earlier and missed the first digit. 1/4" is not nearly as much of an issue as 1/2" or more. Vibration & noise are more of a concern, and given the other noises on one of these that's not such an issue either...

Originally Posted by rspears

Yeah, I had looked earlier and missed the first digit. 1/4" is not nearly as much of an issue as 1/2" or more. Vibration & noise are more of a concern, and given the other noises on one of these that's not such an issue either...

I agree with you to rubber insulate the mounting. Before I did I had some audible resonant droning at certain rpm.

So Nick, when is the first drive planned?

While we are on a thread drift and waiting for Nick to fire up Super Mouse......

Support a BBQ Rib Joint that supports hot rods

It is that time again where the local TV station has the "best of" polls. Take my word along with Gilbert and Mary Ann, that Hog Wild has the best ribs in the area. Also if in the area (Placerville, half way between Sacramento and Lake Tahoe) stop by the 1st or 3rd Monday during cruising season for hot rod nights.





Please vote for Hog Wild here> Hog Wild Barbeque in the Sacramento area on the A-List

Bob, I just voted for Hog Wild. It said they're currently in 8th place but in my heart and stomach, I know they're #1

Btw, besides the locomotive valve I mentioned before and other associated industrial controls, we also make bbq controls (for wood and charcoal only, no gas or steam powered bbq for us) under The BBQ Guru name: The BBQ Guru temperature control barbequeing

Priming the oil tonight, checking the pre-crank checklist a couple times...but also busy with my boys since their school is playing in the state championship high school basketball playoffs tonight GO LOWER MERION ACES! I feel confident that we'll fire it up tomorrow, because unlike a well know deity many of us sort of know, I do not rest on Sunday.

Earlier this afternoon I was at the Northeast Rod & Custom Show and took about 130 iphone pics and some don't look too bad. I wonder is that fits into the "events" section here? Whatchu think?

I won't say it was the highlight of the show, but the Budweiser people had a free beer tasting booth and I finally got to taste their Black Crown. Pretty good if I do say so myself. I'm not a fan of regular Bud due to the rice taste which I can't get out of my beer tasting frontal lobes and it reminds me of bad times I had with sake (made from fermented rice). But I'm going to give Black Crown some more tries.

Originally Posted by Hot Rod Nick

Earlier this afternoon I was at the Northeast Rod & Custom Show and took about 130 iphone pics and some don't look too bad. I wonder is that fits into the "events" section here? Whatchu think?

Just toss a thread in the lounge and post them pics!

will do in a few!

In the meantime, fire in the hole!!! (click on pic and it'll play my photobucket video)