[76Alfetta]

Hi all,

On my Alfetta GT track car we're starting to get bubbles into the radiator overflow and we suspect there is compression leaking into the coolant. The compression on the motor seems very strong at 200-210 per cylinder and the last time I replaced the head gasket when it was doing this the machine shop o-ringed the head. I'm using Reinz head gaskets now.

Motor is a 2LTR with 1mm bored liners and JE 10.5 to one pistons. the head's been cut a bit so the compression is probably up to 11:1 now.

The bubbles start as the motor gets fully warmed up on the track and not when cold or only slighly warmed up. I suspect a leaking head gasket or maybe 1 liner not protruding corectly compared to the others. When it's done this in the past and I've replaced the head gasket it does not show where it's leaking.

Any other causes or sugestions on things to check?

 

[Alfar7]

Compression leak

There is liklyhood that there is now some tracking past the firering now that may require that the headgasket be replaced and surfaces cleaned.
But if it were my motor doing this I would 1st retorque the head to 70-72 ft pounds.
I would suggest running the motor until warm then drain the water level below the top of the heads. Then remove one nut & washer in the correct sequence, and clean& lube threads & washer with oil and retorque to 70-72 lbft. The manual calls for retorquing to 65 lbft, but combustion pressures are higher and the stud can easily take that torque value.
If that stops the leak you have to decide whether or not to replace the headgasket, as CP will be much higher at the track...

 

[76Alfetta]

Thanks Richard. is there any particular head gasket you prefer on the race motors?

 

[pillowmeto]

A trick I learned from a guy at work is to put a coolant pressure tester radiator cap on and start the engine, if the pressure jumps up quickly it is leaking compression into the coolant.

If yours does not leak until it is hot you could warm the engine up, shut it off, release the pressure, put the tester on, and restart.

 

[Alfar7]

Head Gasket

[QUOTE]Thanks Richard. is there any particular head gasket you prefer on the race motors?
__________________
[/QUOTE]

The Reintz 2 liter seems to work well for most. But, in trying to find a head gasket for my Ausca 1600 I found the Reintz to have a narrow width firering.
This was a problem for that motor as it was modified with the small "V" shaped grooves in the head (and I did them in the new liners as well) that allow the firering to expand into them when compressed. (discription of proceedure is in the CAS manual). This stops that type of compression migration, as well as "blowout" expansion,and is a good idea on the 2 liter as well. But with the Reintz the firering was too small. The "italian" (their term) brand sold by Centerline had a slightly larger firering, but still not as large as the Orig. ones "back in the day". (and the ID of all of them was too large even with .5mm overbore. Just another compression loss)
I have a box full of unused 2 liter gaskets & will look at the firerings if you want.
I think the Reintz was liked because of the sealants incorporated in their gaskets.
PS:
Looked at both the Reintz & "Guardinia"(? sp) gaskets. They both have additional sealing material around the block & passages area. I would chose the latter based on firering.
The Reintz firering was the same width on both sides. Measured without removing from packing it was 3.25 to 3.4mm wide.
The "italian" brand was 4mm wide on both sides.
I intend to call John Norman to inquire on the gaskets with wider firerings to see if available for the 1600.
Rj

 

[Alex]

Jon Norman sells 2L head gaskets with a particularly wide fire ring - and Alfaholics sells the Spesso gasket too. Not sure if the latter needs extra sealant at the rear though?

I've never seen a copy of the CAS manual so I've not heard of the V-groove modification before - do you have any photos?

Alex.

 

[Alfar7]

CAS info

[QUOTEJon Norman sells 2L head gaskets with a particularly wide fire ring - and Alfaholics sells the Spesso gasket too. Not sure if the latter needs extra sealant at the rear though?

I've never seen a copy of the CAS manual so I've not heard of the V-groove modification before - do you have any photos?
][/QUOTE]

Alex,
Do you or any of you have a ph. # for Jon?
I will pull my CAS & type it verbatim & take pics of my head & liners & post tonight.
Rj

 

[emr5503]

Richard,
Ph # (510) 525-9435. Just got some ARP rod bolts from him.
Ed

 

[Alex]

Richard,

This is a photo of the AlfaParts / Jon Norman Racing head gasket that I had on file. Hope this helps.

I had heard of some engine builders milling a circumferential groove in the top of the piston liner, but only in order to more securely locate a wire ring for high compression applications etc. It never occurred to me that a fire ring would actually expand significantly into a plain groove when the head is torqued down - unless the ring was specifically designed to crush in that manner. Seems like CAS knows otherwise!

Cheers,

Alex.

 

[Alfar7]

Sealing Grooves

This is from the AROC Competition Advisory Service Manual.
Section 1A / Cylinder Head 516 / page 3 / Issue 1 (about `68 I think)
paragraph D.
Machine sealing groove around combustion chamber. This groove should be 85.5 mm diameter. from center line of groove. Width .8 and depth .8 mm
(.032)
For 1750 or larger the diameter will of course be larger. I would suggest determining diameter for the "V" based on headgasket firering design. The grove should catch the outer edge of the metal firering but if a wide one is being used no closer than 3 mm from cyl.bore.

Section 1 / DETAIL / pg.2 / Issue 1
Details of the upper cylinder grooves are shown here. This can best be done by using a lathe and properly centered cut-off tool ground to the grooves dimensions. (same as above).
Drawing shows groove in center of liner top. Diameter 84.8mm.

These were never intended to use wire rings.

Pics of Ausca head below. Head was milled about 3 mm so combustion chambers are smaller than stock ones would appear.
Hopes this helps
Rj

PS will load pics later BB having issues.. PPS no I won`t, pics are too large...

 

[La Voce]

76 Alfetta I am experiencing the same thing, did the head gasket solve your problem?

 

[76Alfetta]

I ended up going with a thicker head that had not been cut very much and a regular Reinz gasket. Seemed to be fine when I sold the car last month.