Exhaust Manifolds (Page 2/3)
Patrick JAN 31, 04:12 PM

quote
Originally posted by WKDFIRO:

88's are the only one with the "Baked Potato" shield and concern has been made over the amount of moisture, over the long run, the Y-pipe cracks at the Y-welds along with the mount situation. Pre-88 Y-pipes are not the same length. I've taken into consideration removing the shielding and going to the pre-88 Y-pipe shielding. The lack of an air pump to the coil in 88s concerns me and I may fabricate additional layers of shielding or maybe relocation. We shall see. I'll be posting a question to the collective mind to see how many 88s took off the heat shield.



I've had my '88 Formula for eight years now, always parked outside (and we get a lot of rain here), and so far no problems with the Y-pipe cracking. When I ported my exhaust manifolds, I would've also liked to have done the modification to the Y-pipe, but eventually decided against it as I didn't wish to disturb/wreck the "Baked Potato" shield.
str8maxn JAN 31, 05:07 PM
Patrick ---

Are you drilling with a 29MM (1 1/8") hole saw all the way thru? down into the long pipe?

I've pickup a Milwaukee hole saw and was not able to punch thru before the teeth were gone.

[This message has been edited by str8maxn (edited 01-31-2021).]

Patrick JAN 31, 05:26 PM

quote
Originally posted by str8maxn:

Are you drilling with a 29MM (1 1/8") hole saw all the way thru? down into the long pipe?

I've pickup a Milwaukee hole saw and was not able to punch thru before the teeth were gone.



Porting of my manifolds was done 7-8 years ago, so details are getting a little vague, but... When I acquired my Formula, it required a lot of work (including a clutch replacement), so I had the car towed to a friend's garage which had a lift. We decided to port the exhaust manifolds while we had easy access, and it was a hole saw kit that my buddy actually owned which was used.

All I recall from the process was that the particular hole saw we used fit the inside diameter of the port perfectly... and yes... I admit to being rather surprised myself that the hole saw chewed through the "blockage" in the manifolds so easily. Perhaps there is a difference in quality of hole saws. Maybe some are only designed for use with wood. All I can say is that whatever it was we used had absolutely no problem cutting through metal.
str8maxn JAN 31, 05:58 PM
FYI-

a 1" hole saw can be used to cut thru the blockage. It slides thru the exhaust port and Cuts right thru with little effort. Just be careful that the drill bit does doesn't drill thru the bottom.

Patrick JAN 31, 06:45 PM

quote
Originally posted by str8maxn:

I've pickup a Milwaukee hole saw and was not able to punch thru before the teeth were gone.




quote
Originally posted by str8maxn:

a 1" hole saw can be used to cut thru the blockage. It slides thru the exhaust port and Cuts right thru with little effort.



Okay, you've now confused me.

[EDIT] I have to assume that you're talking about two different hole saws here, and that the first one was not designed to be used on metal.

[This message has been edited by Patrick (edited 01-31-2021).]

ericjon262 JAN 31, 07:12 PM

quote
Originally posted by Patrick:

Porting of my manifolds was done 7-8 years ago, so details are getting a little vague, but... When I acquired my Formula, it required a lot of work (including a clutch replacement), so I had the car towed to a friend's garage which had a lift. We decided to port the exhaust manifolds while we had easy access, and it was a hole saw kit that my buddy actually owned which was used.

All I recall from the process was that the particular hole saw we used fit the inside diameter of the port perfectly... and yes... I admit to being rather surprised myself that the hole saw chewed through the "blockage" in the manifolds so easily. Perhaps there is a difference in quality of hole saws. Maybe some are only designed for use with wood. All I can say is that whatever it was we used had absolutely no problem cutting through metal.



Bimetal holesaws tend to do a much better job on metal than the cheapies.

------------------
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

cognita semper

pmbrunelle JAN 31, 07:25 PM
Part of using hole saws successfully is to run them with a slow enough RPM and a lot of torque.

With a consumer-grade drill-press (that doesn't run slow enough), you need to take frequent breaks to keep the saw from overheating.
dremu JAN 31, 07:55 PM
Can't speak to the specific task, but in general, cutting metal, especially something like cast iron: yes, bi-metal holesaw, not those made for wood, yes, going slow with breaks to keep the teeth cool, and also, use cutting oil. There's a bazillion kinds; I like Sprayon LU208 and Rapid Tap, the latter being more viscous and might work better here.

-- A
Patrick JAN 31, 08:11 PM

quote
Originally posted by ericjon262:

Bimetal holesaws tend to do a much better job on metal than the cheapies.




quote
Originally posted by dremu:

...in general, cutting metal, especially something like cast iron: yes, bi-metal holesaw, not those made for wood.



Out of curiosity, I contacted my buddy a few minutes ago and asked him what was it about his hole saw that allowed it to cut through the blockage in the exhaust ports so easily... and yes... bi-metal was his response!
eti engineer JAN 31, 08:25 PM

quote
Originally posted by Patrick:





Funny you should mention this, because I was looking into this exact thing. I was in Harbor Freight the other day and saw one of these kits and it crossed my mind that I should check into using something like this for the job. A die grinder would take much longer. Thanks for bringing this up. If I do this, this way, I will let you know how it went.