Pitting on V6 block surface - Alfa Romeo Bulletin Board & Forums
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post #1 of 29 (permalink) Old 10-31-2011, 12:55 PM Thread Starter
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Pitting on V6 block surface

Hi, guys. I'm currently trying my first engine rebuild as part of the process of a (slow, too slow) GTV6 restoration. The engine didn't run for +/-10 years and both heads and block surface presented pitting along their surface as a result of that inactivity. After cleaning everything well, resurfacing heads... I need your opinon on the block.

After spending several hours of intense cleaning, the block surface is smooth when you slide your finger along it, except at the part along the six water passages (surrounded with red) that presents noticeable pitting.



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Measuring flatness with a straight edge, at those points I can slide the 0.05 mm gauge (0.002 inches) and not the next one (0.1 mm / 0.004 inches). Since 0.05 mm / 0.002 inches is the maximum recommended at the manual, it seems that the surface flatness is beyond spec just a bit. What can I do at this point? Several ideas come to my mind:
a) Throwing away the block. I don't really want to if I can avoid it.
b) Resurfacng the block is not an option since the machinist couldn't remove the studs without risking the block.
c) Using a very fine grit sandpaper / steel wool and, pressing it with some flat surface and extensive care, eating some 0.01 mm all around to keep it under specs.
d) Fitting the gasket hopěng that it will seal the imperfections. That's the easy one!
e) Using some sealant with the head gasket in the pitted area to help it.
f) Using some metal epoxy (JB Weld or similar) at the pitted area spreading it with some razon edge and fine sanding it until getting it perfectly flat. This doesn't seems a crazy option since the area doesn't support a great temperature or pressure, but still have serious doubts about it.

Too many options, too many doubts... Have you faced this situation before? Which way did you take? Opinions and experiences are really appreciated.

Thanks everybody.

Last edited by jabier73; 11-15-2011 at 10:45 PM.
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post #2 of 29 (permalink) Old 10-31-2011, 02:47 PM
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get a copy of BMW's S.I. Bulletin B 11 10 93.. Says to use J.B. Weld to fill pits in cylinder head sealing surfaces.

Might work for the block too.
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post #3 of 29 (permalink) Old 10-31-2011, 08:44 PM
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heads

Don't be to concerned about the pitting. We do not live in a perfect world. Use some copper spray sealant on the gaskets and providing everything is flat it will be fine. Don't sand the block with anything other than something like 1200 grit wet and dry to clean the surface.
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post #4 of 29 (permalink) Old 11-04-2011, 04:05 AM
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Don't worry about that, the zone you are indicating is in between the coolant jacket in both sides , so nothing is going to happen if a little coolant goes from one side to the other.

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post #5 of 29 (permalink) Old 11-04-2011, 04:58 AM
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I have noticed that some gasket sealant /material and/or certain non phosphate antifreeze will corrode the aluminum, especially at the water pump.

I have used mr gasket high temp sealant and checked the water pump area 3 years later, no corrosion/pitting.

Tis is a low pressure area. If you were to machine it, you would have to machine the liners or liner seat too.

so forget machining..

If concerned, use a THIN smear of high temp silicone sealant, staying away from the liner tops. Use very fine emory cloth to clean the liner seats. I use the rubber ring provided in the ccomplete gaskets sets AND a VERY VERY thin smear of silicone sealant at liner seal.

USe Victor Reinz head gaskets..well worth the little extra price. and I like Zerex phosphate free antifreeze.

I had a 3.0 block with much worse pitting and no problems using above techinques
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post #6 of 29 (permalink) Old 11-09-2011, 03:19 PM Thread Starter
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Thanks for your replies calming my novice fears, guys.

This past weekend I was doing some intensive cleaning at the block surface. After some thin (1000 grit) emery paper and scrubbing with acetone, now its pretty clean and even if the pitting is still there, your comments make me feel more optistic about the results. I think I'll try the headgasket alone, with no sealant and see how it goes.

Best regards

Last edited by jabier73; 11-09-2011 at 03:28 PM.
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post #7 of 29 (permalink) Old 11-10-2011, 01:44 AM
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pitting

Jabier 73. I work with three factory trained mechanics that have a combined exp (if i guess Conservative) of about 80 years. If you have pitting on the mating surfaces they/i would use copper gasket spray. Thats just something to consider. The pictures you have don't look that bad so I'm sure you will be fine either way however the extra sealant will fill the pitting.
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post #8 of 29 (permalink) Old 11-10-2011, 03:13 AM Thread Starter
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Quote:
Originally Posted by alfettaparts View Post
Jabier 73. I work with three factory trained mechanics that have a combined exp (if i guess Conservative) of about 80 years. If you have pitting on the mating surfaces they/i would use copper gasket spray. Thats just something to consider. The pictures you have don't look that bad so I'm sure you will be fine either way however the extra sealant will fill the pitting.
Thanks for the advise, Alfetta. That copper spray solution is pretty uncommon here but, since it seems it can't harm, I'm really considering it. Do you know which is the effect of the copper spray on the block/head surface after time? Does it keep the surface more protected or is it a pain to remove the sealant residue when you remove again heads?
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post #9 of 29 (permalink) Old 11-11-2011, 02:54 AM
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From conversations the spray does not cause any extra damage. Certainly the sealer will make the gaskets very hard to remove if you have to remove the heads again. The theory is if you use such a sealer you wont have to remove the head for a considerable time.
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post #10 of 29 (permalink) Old 11-11-2011, 05:42 AM Thread Starter
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Thanks, Alfetta. I think I can give the copper spray a try.
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post #11 of 29 (permalink) Old 11-11-2011, 01:00 PM
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if you use copper spray, tape off block and don't overspray into bores or bearing areas!..

hopefully, you won't have to remove the copper seal any time soon. It is a bear to get off.

..... you will be fine with dab of high temp silcone smeared thin with a finger. And the VR head gaskets also have a sealing ring built in to them for the water jacket..the biggest sealing problem is going to be with the bores and heads ...so make sure your heads a flat and bores are even

what does the head side look like, usually, it is worse there....
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post #12 of 29 (permalink) Old 11-11-2011, 01:08 PM
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Hi xray. You just hang the gasket with a bit of wire and spray a light coat on both sides. Shouldn't be anywhere near the car at this stage. Agree that you could also go with some sealant on the sides of the block.
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post #13 of 29 (permalink) Old 11-11-2011, 01:14 PM
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Here is a copper gasket ..it was a huge PITA to clean the block after taking it off. The VR gaskets work great. Here is a pic of one of my 3.0 rebuilds with Carillo rods and C+B cams, high compresion pistons..great engine. Notice the pitting on the block. no issues with smear of silicone and VR gaskets.....
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post #14 of 29 (permalink) Old 11-11-2011, 01:26 PM
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That gasket with the copper spray looks good. If its a long term usage road car hopfully you wouldnt need to remove the heads for a very long time. If its a race car maybe you wouldnt want the headache of the copper spray each time you pull the heads for what ever reason

Heres a thread of a similar issue i had with my engine.

http://www.alfabb.com/bb/forums/alfe...rain-plug.html
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post #15 of 29 (permalink) Old 11-11-2011, 02:02 PM
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Quite honestly I think you are worrying about nothing serious and my experience has lead me to recommend against the copper spray sealant due to the difficulty of removal in later servicing.- just use the Victor Reinz gasket set and all will be fine without any compromise to reliability. If you are really concerned use some J B Weld to fill those pores but again use the VR gasket set.

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