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G'day enthusiasts,

The previous owner of my '74 105 GTV installed these roll pins into the oil galleries of the block (see attached pic). Looks to me that they maybe too small in diameter. Anyone else want to offer an opinion?

To anyone that has installed the IAP/Centerline roll pin kit, did you have to drill out your oil galleries to make the pins fit? What diameter should these pins be?

Regards,
Axeman74- Melbourne, Australia
 

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The purpose of the roll pins, is not to align the O rings, but to restrict the amount of oil to the upper head area, and it improves warm oil pressures with multiviscosity oils.

No drilling is needed, nor wanted, to install the roll pins, just tap them in.

I believe the restrictors that Jon at Alfa Parts sells, are from the '91 and up Spiders.
 

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The current roll pins on the block are fine. That is the size that IAP sells and was Factory on 76 and later 4cyl. Blocks.

Check out this article on roll pins. Why they were installed and the arguments about what size.

Roll Pins

Good Luck
Dave
 

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My preference is for for the brass tube/o-ring kits that Jon Norman of Alfa Parts in Berkeley sells. My last choice would be the IAP version, which aren't tubes or rolls pins, but split pins. They've got two razor-sharp edges. I once pulled the head off a 2-liter with pins like that, and 2 of the o-rings were sliced through, I'm guessing from being "squished" as the head was torqued down.
 

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DaveC said:
The current roll pins on the block are fine. That is the size that IAP sells and was Factory on 76 and later 4cyl. Blocks.
***Warning***

Dean is quite correct, the split pin type roll pins are dangerous, in fact they are worse than running no roll pins at all. See photo by Rex Chalmers (used with permission) for illustrations of how they destroy o-rings.

There are several type of roll pins that work fine. One is the solid tube style Dean describes, the other is a spiral type roll pin that does not have these sharp edges. These spiral pins are what we sell at Centerline, along with square cut viton o-rings.
 

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Hi All,

Just while looking at all this I went to Wurth to get some goodies!

I got a catalogue from them and found out they have pins of a lot of sizes and o-rings of a lot of sizes. I guess I would need to get a sample and go there to get a part number and see if they are 100% the same thing.

Would those be compatible?? I need to dig more into John Norman and IAP, I guess I will now order a set from John.

If am not mistaken Jon Norman has Alfa-Parts. If so, his web iste is no longer running, any other way to contact him?

Regards,
 

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In my experience, it is not a mechanical fault that the o rings get damaged, or split, but one of improper installation. Technically, an o ring doesn't require, nor is it desireable, to have an inner mechanical support. The o ring is sealed by the fluid pressure on the inner diameter, and the contact on the top, bottom, and the outer diameter.

I have used the seal kits sold by Centerline for years, on street, and race engines, with NO failures or leaks. Only use the square seals, throw the round cross section seals away. And use their roll pins, to reduce oil flow to the head

I make sure the head gasket fits flat on the block. Sometimes one or more holes need to be "adjusted" with a round file to get it to lay flat. Then insert the seal in the hole in the gasket, carefully lay the gasket on the block, slowly set the head down, I SAID SLOWLY!!! Initially torque the head down to 20 foot pounds, then 10 foot pound increments to 60 foot pounds, for a 2 liter engine). Warm up the engine, after it has cooled down, retorque to 65 foot pounds.

This method also avoids blown head gaskets, even on 13 to 1 compression ratio engines. I use Centerline's stock head gaskets. No failures.
 

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JoeCab said:
***Warning***

Dean is quite correct, the split pin type roll pins are dangerous, in fact they are worse than running no roll pins at all. See photo by Rex Chalmers (used with permission) for illustrations of how they destroy o-rings.

There are several type of roll pins that work fine. One is the solid tube style Dean describes, the other is a spiral type roll pin that does not have these sharp edges. These spiral pins are what we sell at Centerline, along with square cut viton o-rings.

Joe. The article is correct. However at the bottom of Rex's writeup. He states that if you want to use roll pins to keep the orings from collapsing, use the ones supplied by Centerline, International Auto Parts, Etc. Remember, after 1975, all Alfas had split roll pins fitted into the block at the Factory. It was a neat solution for keeping the orings from deforming. That was the only reason they were installed.

Dave
 

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Dave,

Yes, the split roll pins were a factory item. However, I believe there are better options out there, and I would use them if it were my engine.

Some argue the split roll pins only cut through the o-rings if the o-rings are not properly seated when the head is installed. While this may be true, why not use one of the other styles of roll pins to completely eliminate this possibility?

Joe
 

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I've always thought Orings were the wrong way to seal those passages. To bad the aftermarket will never look into this particular problem. I've always felt that the head gasket should have the seal incorporated into the gasket. I know the wet sleeve design leaves little area for the sealing of the oil passages and a great deal of movement due to heat cycles. However, I feel a head gasket design of sandwiched metal with an oversized sealing rings chemically bonded to the metal would be the way to go.
 

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I got the roll pins from either IAP or Centerline (got so much stuff from both I don't remember who supplied what) that look like a little metal jelly roll. I couldn't fit them in! Do 1750s have smaller oil passages than 2 liter? I didn't want to drill, so I used split pins instead. I guess I'll find out eventually if I get a problem.
 
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