cylinder head and head gasket holes

First... head gasket number of holes is determined by piston protusion. Nothing to ask here. I had a 2 holes head gasket. It blew. I have to replace it but have been told to "repair" the cylinder head. That is: changing valve seats, and making a slight peel (i mean less than .25mm or maybe even only .10mm) of the cylinder head surface contacting the head gasket.
This being said i don't know if i should have a thicker head gasket installed in orden to counteract the small difference in head gasket height.
Shall the answer be: "NO keep with your 2 hole head gasket" then i've gotta ask... should i do anything to counteract higher compression due to smaller space between pistons and head? And if so... what?

Thanks a lot!

The car is a Seat Cordoba TDI (well, obviously) "AGR" model year 2000. The car is chipped so turbo pressure is probably increased.
I had already had some issues with coolant dissapearing, but it is important to note that i advanced my injection timing (mechanically) from 1,1º to 3,7º BTDC before all this happen. Is it partially o totally related? Should i set a more conservative, let's say 2,5º of advance?

The heads are flat except for the valve pockets. How much compression increase would there be from removing a thousandths?

i don't know. i have been warned because of the already very high compression rate of diesel engines and therefore increased engine stress, especially in turbocharged ones.

But if you believe there is nothing to worry and that i should stick to my 2 hole gasket... i will believe whoever claims, and for good reason, to know more, and have more experience than myself.

thanks

stick with the 2-holer. You're not going to change your deck height so don't change your gasket. That's how I look at it.

I had the head on my car "peeled" due to some FOD and subsequent repair welding. Went right back in with a 2-hole gasket. Been running great for 120K miles since.

If what your asking is can you use a thicker gasket the answer is yes. keep in mind there are a few side effect of doing so. You raise the injectors up so the spray may not be perfect in the piston bowl. I had a pd150 block that came with a 1 hole gasket I installed a 3 hole with no problems other than a little smokier cold starts.

I just put another head on and I made an even thicker gasket. I bought 2 3 hole gasket and cut them both open and stacked a few extra layers.

KROUT said:

I just put another head on and I made an even thicker gasket. I bought 2 3 hole gasket and cut them both open and stacked a few extra layers.

Click to expand...

Understood KROUT thank you very much. I shall only ask... why would you do that? Your goal was to reduce compression beyond factory specs?

yes cause I run 28psi so I wanted lower cr and its only temporary in my case. I am building another engine with properly lowered cr(bigger piston bowls).

You wont notice any difference with that little bit of change. Just make sure you check the pistons and get the right gasket. I am sure you will need the same as you took off.

keep the 2-hole... the head gasket is determined by the piston protrusion which has nothing to do with the head at all.. you could shave 1/8" off the head and it won't change the compression ratio since the head is FLAT..

IIRC, VW says don't shave anything off the head. The main change is the valve relief. If you plane anything off the head, then you will want to make sure the valve seats are also cut so that the valves will maintain the proper relationship to the pistons at TDC. I.e. so they won't bang into each other. Then you'll want to make sure that the valves don't push the lifters too high and into the cam.

I think I'd send my head to someone that specializes in TDI heads and can therefore do the work you need done and have it work properly after. A guy who won't rape you on labor charges and does it right.

Very few of them out there. On this forum, ask for Frank. As in, Frank06.

Absolutely no reason to ship your head from Argentina to Missouri

Look people a cylinder head is a cylinder head. I have these redone all the time at a local shop I have been using for 20 years for half the cost of shipping anything to any one.

i'll stick with the 2-hole! thanks a lot! I already asked and they're also replacing valve guides, and recalibrating the lifters so valves won't hit the piston

any opinion about the injection timing stuff? could 3,7º have been resposible of the blown gasket?

It does increase peak cylinder pressure. If your car is modified and running over 20psi of boost you should get some of the new arp head studs they hold better than stock bolts.

car turbo is stock garret gt15 (waste-gate type) and it is chipped but nothing further. boost is 18psi or less (anything above that would have already blown the turbo, which is perfectly good shape)