Front cover question.

[TurboDave]

This is in regards to on-center work.

I have been told be several friends (whom I trust implicitly), that in order to mount up a front cover on either of these two on-center blocks, that the cover would have to be shaved .125 or so. So that the cam gear and cam sensor properly align.

OK, no reason to doubt this simply because the on center block is longer than the off center.

My question is, since Buick Motorsports made both on center and off center blocks, didn't they make front covers for on center blocks???? Or does everybody (on-center) have to shave their front covers??

P.S. Got the lifter bore lube holes drilled on "INDY1" turned out pretty good. Just had two intrusions into the valley which were easilly welded shut.

 

[S2V6RACER]

Mill cover, or space out cam gear(providing you use a roller), check pulley alignment. They did not make a production cover to fit the stage II on-center cover.

 

[TurboDave]

That's what I find so wierd. They made on center blocks, but not a front cover to use with them (at least none that I've been able to find).

 

[KendallF]

Well, they made a dry sump cover that works on the on-center blocks..that is what went on probably 90% of the late S2s. Since most everybody using them was doing their own cam thrust machining, the gear and spacer alignment was pretty easy for them to set up. Take a look at the pictures I posted a while back of my new gerotor front cover..it uses a top half of one of these.

 

[EightSecV6]

Not to doubt you Kendall but every NEW stage two cover I have ever had I had to machine.It didnt matter on the old or new versions, but that could just be my luck! You can only safely get about .080 off of a production front cover before you run out of material (oil pump mainly!). You can make the difference up on the dist. drive gear with shims. The factory belt alignment will be off about .045 on the water pump, this has not been a problem for us on engines spinning over 7000 rpms.
Bill

 

[Mac in SD]

I had .120 milled off of mine, but then had to clearance one screw boss for the oil pump housing to clear the block, and also grind a bit on the Duttweiller oil pump for the same reason. No shims on the cam gear, lined up perfectly with the cam-oil pump drive. The had .120 milled off the main accessory bracket, and all pulleys lined up perfecto.

 

[EightSecV6]

I've never been able to take a stock front cover that far Mac, I am pretty sure it will be into the oil pump, and the mounting surface would be paper thin, I know it will be into the furel pump mounting boss for sure. We've had good luck using .080 and shimming the dist. drive gear. I have milled the front of the block before as well but it is a Pain I.T.A
Bill

 

[KendallF]

Originally posted by EightSecV6
Not to doubt you Kendall but every NEW stage two cover I have ever had I had to machine.It didnt matter on the old or new versions, but that could just be my luck! You can only safely get about .080 off of a production front cover before you run out of material (oil pump mainly!). You can make the difference up on the dist. drive gear with shims. The factory belt alignment will be off about .045 on the water pump, this has not been a problem for us on engines spinning over 7000 rpms.
Bill

I guess what I was trying to say is that the Busch motors and the like that I've seen that were dry sump and cog drive didn't appear to have machined covers..I used one of those dry sump covers recently to make my gerotor front cover.

Speaking of machining the covers, how'd you set it up for milling? I was going to mill down the weld points on that one and there's nothing particularly flat on that stupid thing other than the water pump face and it wasn't exactly parallel to the mating surface of the cover on the one I checked. When it looked like I'd be screwing around with shimming it for a half hour to get it level, I took it to the belt sander.

 

[Mac in SD]

Bill, maybe I'm losing it... But I'm pretty durn sure that the machine shop took about .120 off it, maybe .110. I understand what you're talking about, but if you factor in that little rib on the mounting surface on an aftermarket cover (can't remember stock covers), you're probably only going .050-.060 into the cover itself.

Anyway, I did have to grind on the block side of the pump housing(actually one of the cover screw bosses), as well as the fuel pump block-off plate (forgot about that one), to clear the block. It IS close.

 

[EightSecV6]

Originally posted by KendallF
Speaking of machining the covers, how'd you set it up for milling? I was going to mill down the weld points on that one and there's nothing particularly flat on that stupid thing other than the water pump face and it wasn't exactly parallel to the mating surface of the cover on the one I checked. When it looked like I'd be screwing around with shimming it for a half hour to get it level, I took it to the belt sander.

Kendall,
I have always just let the water pump mounting face index the cover, I have never had one out enough to warrant shimming it in my opinion. I only use GM covers on the on center stuff because it requires the Dut. oiling system (wich requires a stock volume front cover)
Bill

 

[Mac in SD]

Okay, Bill. I eyeballed a front cover over at Neal's today, and I think I got it. You have to just mill the gasket surface: i.e.- the oil pump housing "hangs out." Then you just have to grind about the last 3/16" off the one oil pump cover screw boss that would interfere with the block face. On the DS, you do have to grind on the fuel pump block-off plate, but it will take .120-.110. That's how I did it anyway.