for those who have had their large log cylinder head machin

[hickorystang]

and the bore size increased, from looking at my large log, it appears to have a 1.75" diameter, whereas my small log has a 1.5" diameter.

Thanks to The Dude, I have a Webber 5200 carb, which as I understand it is the right one for this setup. The size of the primary and secondary combines is about 3". Is this what the size of the new milled hole will be?

 

[xctasy]

In the long run, a little less than 2 large means you bolt on 35 to 45 hp, and never have to deal with cracked log intakes again.

The area of the hole depends on if you use the open oval or the closed twin circle runners.
For strength, two holes with a bridge between is probably best

The centre spacings and bore size is designed for Webers 38 mm venturis, on something like a 46 by 93.5 mm bolt spacing and the spacing between the holes is 44mm. So it can be as big as 1.732*1.496*pi r 2=4.349 sq in, or as little as 3.516 sq in with two 38 mm holes

If its furnace braised and fully preped and reworked like this $1000 ebay item

http://www.ebay.com/itm/Ford-170-200-25 ... 62&vxp=mtr



Then it's less likely to crack like this...

Tue Sep 11, 2012

........

5) I'm almost positive I have a vacuum leak... I took everything apart.


The putty is separating, I've talked to mike and he'll fix me up, but in the mean time I got nothing... I won't be able to drive like this for ever.
FOR NOW, until I can take the time to fix it, I'm taking the ultra copper RTV silicon gasket maker, and apply'n it all over the area, hoping it seals it long enough for me to have time to take the head off to get it fixed. I have one layer on right now, I'll do more layers, but the one moved the idle from 1300rpm to 1050rpm, so there is a possibliliy this 'patch' can work temporarily. I'm not drving it right now, but it's raining and here it would rust in a day if I took the head off outside so I'll have to wait for a garage.

all this and the wedding coming up... I'm very stressed.






(I have asked about the O2 wide band system, they have it but it won't be 'tie(d) into the ECM' so I do have a narrow band, it's works so nothing too bad about it)

 

[aribert]

Greetings hickorystang

I modified my '78 head. http://i290.photobucket.com/albums/ll27 ... rface3.jpg You can still see the vestige of the original 1.75 dia port. I built up the surrounding area and then milled it flat and used a 1.5 inch end mill to slot the hole. I expect to redrill and tap new carb mounting in the future in order to be able to fasten the adapter easier. THat is why I added surface around the existing boss. I also lowered the boss for extra air cleaner clearance. I went for the bone stock look: http://i290.photobucket.com/albums/ll27 ... 300065.jpg

I use a custom carb adapter for my Weber 32/36 DGV that looks like this (grungy after a couple of years of use)http://i290.photobucket.com/albums/ll272/aribert/Falcon/fristweldedcarbadapter2.jpg THis adapter started out as a Clifford adapter (machined casting on the right) and a couple of 6061 aluminum chunks that I welded together. http://i290.photobucket.com/albums/ll27 ... chined.jpg My adapers has dual ports for the PCV. I have the origial '61 CA only (machined) PCV valve instead of a draft tube. At the moment w/ a '78 block I am unable to mount the special elbow for the PCV plumbing in the draft port (since it does not exist) so I am using a later valve cover w/ rear PCV port and the '61 PCV threaded into the rearward port on the carb adapter.

 

[roghax85]

In the long run, a little less than 2 large means you bolt on 35 to 45 hp, and never have to deal with cracked log intakes again.

The area of the hole depends on if you use the open oval or the closed twin circle runners.
For strength, two holes with a bridge between is probably best

The centre spacings and bore size is designed for Webers 38 mm venturis, on something like a 46 by 93.5 mm bolt spacing and the spacing between the holes is 44mm. So it can be as big as 1.732*1.496*pi r 2=4.349 sq in, or as little as 3.516 sq in with two 38 mm holes

If its furnace braised and fully preped and reworked like this $1000 ebay item

http://www.ebay.com/itm/Ford-170-200-25 ... 62&vxp=mtr



Then it's less likely to crack like this...

Tue Sep 11, 2012

........

5) I'm almost positive I have a vacuum leak... I took everything apart.


The putty is separating, I've talked to mike and he'll fix me up, but in the mean time I got nothing... I won't be able to drive like this for ever.
FOR NOW, until I can take the time to fix it, I'm taking the ultra copper RTV silicon gasket maker, and apply'n it all over the area, hoping it seals it long enough for me to have time to take the head off to get it fixed. I have one layer on right now, I'll do more layers, but the one moved the idle from 1300rpm to 1050rpm, so there is a possibliliy this 'patch' can work temporarily. I'm not drving it right now, but it's raining and here it would rust in a day if I took the head off outside so I'll have to wait for a garage.

all this and the wedding coming up... I'm very stressed.






(I have asked about the O2 wide band system, they have it but it won't be 'tie(d) into the ECM' so I do have a narrow band, it's works so nothing too bad about it)

Hello, do you know how was did it?

cause I am try to welding my intake to a base plate adapter for my holley 350.

I try whit bronze, but late of the welding its come to broke the welding

thanks

 

[bubba22349]

It can also be done by Arc Welding with a special nickle rod. Brass could work on the intake log but Cast Iron is quite difficult to do right. Skill level is higher, it is important that parts be cleaned good and first preheated and then after welding kept from cooling down to fast. Wrapped or insulated good or put in an oven slowing reducing the temp over about 12 to 24 hours other wise it just cracks again right next to the weld.

 

[roghax85]

It can also be done by Arc Welding with a special nickle rod. Brass could work on the intake log but Cast Iron is quite difficult to do right. Skill level is higher, it is important that parts be cleaned good and first preheated and then after welding kept from cooling down to fast. Wrapped or insulated good or put in an oven slowing reducing the temp over about 12 to 24 hours other wise it just cracks again right next to the weld.

:thanks: :thanks: :thanks: :thanks:

I will try it, do you have a video or pictures of this proccess?

do you know what is the numer or name about the welding electrodes?

thanks

 

[aribert]

roghax85:

I used brass to build up the area around the stock carb mounting pad and then milled a new flat surface (see my earlier message in this thread with photo links). I cleaned the area and then sand blasted the area to be brazed. I preheated the head by placing it over a kerosene heater (something you might not have in a more temperate climate) for about half an hour (slowly bringing the head closer to the heater) before doing the actual brazing. After brazing, I again placed it over the same heater for about 1/4 hour and then slowly reduced the heater temperature. My method was a low cost approach based on the tools / skills on hand. A welding shop with the ability to braze cast iron probably has some method(s) of preheating to get a faily uniform temperature in the head casting.

 

[bubba22349]

Here is one link that gets into the details of cast iron welding. It's better to find some junk parts to practice on first, good luck!

http://www.keytometals.com/page.aspx?ID ... kts&NM=185