piston valve pockets 7A

[A1QSHIP]

oh.

Other than the issue of valves getting a bit too close to the pistons, are there any other problems that excess skimming causes?

If I had the valve pocket machined down by 1.3mm isn't it effectively the same difference as far as valve / piston relationship goes?

If enough material has been removed from the cylinder head then cam timing can be affected.

[steve briance]

Christmas out of the way and the block I have has now gone off to be bored / honed / decked. :-)

When it comes back i will be doing a dry fit of crank / piston / head to check on valve to valve pocket clearances. I will also use the assembly to check on how the cam timing marks line up in light of the skimming on the head. I anticipate that i will end up getting an adjustable cam pulley to bring cam timing back into line but that is another thread for another day.

I was for now hoping that someone could tell me how much the fibre composite head gaskets compress when the head is torqued down fully? Reinz / Goetze / Elring quote the 7A gasket as being 1.8 or 1.82mm thick new, i don't really want to use one and a set of head bolts just to find out how much the gaskets squash so was hoping someone might have an old one they have just taken off that could be measured or donated for cost of postage? I guess it doesn't matter so much if it is a 7A or 3B etc, it is the compression amount i am interested in so as long as i can find the new thickness of whatever gasket you might have lying around, i can do some sums...

[Mikes2]

I've got an old used head gasket lying around I can measure although it's from a 10v turbo. I'd expect compression to be similar

[steve briance]

is it the WR or MB engine? i'll have a look for new specs and see what they are pre squish.

Thank you very much - this is the sort of helpful information you don't get easily searching online.

[steve briance]

Because everyone likes pictures: epoxy primer - it does a proper good covering

[Error404]

WTF? Why is it sunny at your house?

Block's looking good

[steve briance]

It is sunny because this project has been bubbling away for quite a long time!

[twoqu]

Took a bit of head scratching to figue out what gasket was what (10V turbo/Tdi/ another) but helpfully I found a 4V marking on it . So if the 7A gasket has a bore spacing of 83.5mm then the firering is at 1.76mm for a used Elring carboard gasket. Obviously the carboard uncompressed is greater than that.
Not sure if that helps or not!

[steve briance]

that could help! If my subtraction is right, your squashed gasket at 1.76mm means it is actually only crushed by 0.04-0.06mm from what Goetze say a new one is. That is not actually as much as i thought considering how tight the bolts are torqued down to

what car do you think it came off?

selection from the excellent elring online catalogue:

2.1 turbo 10V WR engine - 1.8mm 81.5 hole.
2.2 turbo 10v MB engine - 1.75mm 82.7 hole
2.2 turbo 20v RR engine - 1.65mm (MLS) 82mm hole
2.3 n/a AAR engine A6 - 1.75mm 83.5 hole
2.2 turbo AAN engine - 1.65mm (MLS) 82 hole.
2.3 n/a 7A engine - 1.8mm

[twoqu]

Took a closer look and it is a Goetze gasket not an elring one!
It is an OE Audi gasket p/n 054 103 383B. It has the bore diameter stamped on it at 82.5. Apart from Goetze the only other numbers are 11516-043.
Seem to recall that I once had an 7A with a spun rod from which I removed the head. Don't think I have taken apart anything else with a 82.5mm bore so fairly confident thats a OE 7A head gasket made by Goetze!

[steve briance]

the cross over part number in the Elring book says 054 103 383 is for 7A so I'm going with 1.76mm squashed then!

My gasket set is an Elring kit but that has a Victor Reinz head gasket in it! What the hell??!!

[Mikes2]

Mine was from an MB. I'll dig it out or do you not need it now ?

[steve briance]

Thank you but the MB gasket was actually thinner than the 7A so actual figures would be a bit off, if it is to hand it might be worth measuring to see how much yours has squashed but don't worry too much if it is not to hand.

[steve briance]

Its picture time! (with a follow up question)

Finally picked up block today.

Looks lovely and the bores are plateau honed to exactly 82.51mm - spot on factory fresh for 7A. Deck has been skimmed till clean and no further.

At the next free opportunity i am planning on putting the crank in and doing some plastigauge measurements for bearing clearance and then a dry build to check the piston - valve pocket clearance. A Tommis adjustable cam pulley on its way as well to give me the most control in compensating for head skimming that has been done and make for meaningful measurements.

I've got some clearance figures i'm hoping to see and I shall use the Plasticine technique. What worries me is that i have read that hydraulic tappets can mess up the measurements if they are not pumped full of oil. I understand that in service the hydraulic tappet fills with oil and under pressure the plunger comes out to meet the valve stem and does the pushing. If it is not under pressure, how on earth do you do the dry build Plasticine method of checking?

Do i need to get hold of a couple of solid lifters and shim them up to check? I would only build up #1 piston so only need 4 lifters, can't see anywhere that sells them individually.

anyway, here are the pictures!

[S2 EDS]

Its picture time! (with a follow up question)

Finally picked up block today.

Looks lovely and the bores are plateau honed to exactly 82.51mm - spot on factory fresh for 7A. Deck has been skimmed till clean and no further.

At the next free opportunity i am planning on putting the crank in and doing some plastigauge measurements for bearing clearance and then a dry build to check the piston - valve pocket clearance. A Tommis adjustable cam pulley on its way as well to give me the most control in compensating for head skimming that has been done and make for meaningful measurements.

I've got some clearance figures i'm hoping to see and I shall use the Plasticine technique. What worries me is that i have read that hydraulic tappets can mess up the measurements if they are not pumped full of oil. I understand that in service the hydraulic tappet fills with oil and under pressure the plunger comes out to meet the valve stem and does the pushing. If it is not under pressure, how on earth do you do the dry build Plasticine method of checking?

Do i need to get hold of a couple of solid lifters and shim them up to check? I would only build up #1 piston so only need 4 lifters, can't see anywhere that sells them individually.

anyway, here are the pictures!

Nice one Steve.

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