Vilhuer

These have been discussed before and pics have been shown where these are used. Are there any sources for these? How much $, how diffucult to machine block and install them?

Vilhuer

Anyone have any experience of there? What material to use? Tolerances etc?

I'm looking few different S4 blocks for stroker engine build and they all have too thin walls. Narrowest point in two othervise best candidates is 115mm in one and 116mm in other. This meaning 5.5mm or 6.0mm thickness with 104mm pistons. Recommend thickness is at least 6.35mm.

Would need to decide in next few hours if I use one block or other. Decicion would be much easier if support rings were available or someone knows what it takes to make good ones. If they are, 115mm walled block would be feasible choice.

John Veninger

I think some have run strokers with less than the 6.35mm thickness without issue.
In the end sourcing a thicker block may be cheaper than trying to installing some sort of supporting rings.

SwayBar

The support rings used in Wisconsin were used with the stock-sized bores in the supercharged cars to prevent cylinder-ballooning at the top; it worked.

However, I do not think it would be a good idea to use the support-rings on a bored-out engine since the support-rings themselves require maching around the outside of the cylinders, making the bored-out cylinder-walls that much thinner.

I do not know any of the specs regarding the rings, just a little bit of the thought-process regarding their existence.

hacker-pschorr

I remember Todd saying he needs the block to make a set.

SwayBar

That is not true. He has them made to a certain spec including heat-treating, and then machining the block afterwards.

I know because to help keep costs down, a batch of several sets were made, one of which was mine. After they were done, he machined my block.

hacker-pschorr

True or not, that is what he told me when I questioned him about making a set for someone overseas.

Why are we awake? Are you on call too?

SwayBar

Maybe you misunderstood him. Or maybe 'he needs the block' because he has to do the machining on it so that it's done correctly for the rings; I bet that's what it is.

I'm always up early.

Too bad for you you're on-call!

I'm heading over to JL's for some lunch as there are left-overs from last night's party; yum!

Louie928

Check a 32v '85/'86 block. They are reported to have thicker cylinder walls.

Vilhuer

Thanks for the replies.

Todays block hunt ended up being wild goose chase. Went to see two '87-88 S4 blocks. One had 115,5mm towers and other 116mm. I could have lived it 116 but strangely both blocks had aluminum sleeves on all 8 cylinders. They were very well made and it was really difficult to see they were sleeved. So both of those are ruled out simply because removing sleeves would either make cylinders too wide or at least leave 2x2mm square ring at top.

32V S engines are really difficult to find in here. There is maybe three or four cars with such engine. Two or three US models and one '83 ROW S which has '86 ROW 32V engine in it. One or two US models might be for sale but I don't want to buy entire car just to get engine. There has been few blocks for sale in US in past year or two that I have seriously considered buying despite of $500-1000 shipping costs. Problem in these have been that towers were in usual same 116mm range. No point in bringing in something I already have.

What I currently have is early '87 S4 block with squrters and 116mm towers. Good point in this block is that towers are evenly centered. Its probably possible to keep maximum amount of towers in and achieve 6.0mm walls. Wouldn't want to use it as it there is enough oil in circulation without those squrters already. Obviously it's easy to take them out but that would be waste. Much better to turn it into low compression SC engine.

Other option is friends '90 S4 block with 115mm towers. Other problem with this is how uneven wall thickness is. Casting mould had been mm off center on three or four cylinders and wall thickness varies between 6.5 and 8.5 mm. Taking 2mm away from low point makes wall way too thin. Narrowest part is between 10 and 11 o'clock in narrowest cylinder. Machine shop can move cylinder center if I want to. So uneveness could possibly be sorted out. At least front/back direction could be centered. Not sure about up/down until block is checked if all towers on one side of V are narrow into same direction. I do realise some material needs to be removed from outside to make towers round for rings. Was hoping it would be so small amount there would still be enough left. This would obviously mean rings must be custom for this particular block. Was hoping outside support rings would make this block feasible option.

Deck plate is obviosly other option. Think Motorsport in Utah can supply those. Machine shop I'm almost forced to use (its only place which has needed experience and lapping stuff for Alusil) do not want to install deck plates. They have has some previous problems with unhappy customer(s) I think.

In all, have looked maybe 10 different 32V blocks and none has had thicker walls than 116mm. About half has had uneven wall thickness visible to naked eye. Luckily all walls get thicker pretty quickly on the way down. Just wish factory would have used little more material.

Ian928

Vilhuer,

Just checked my 85 block: 115,5mm towers. What is the largest diameter recorded?

Ian in Norway

atb

Errka,

If you find a piston coating you trust, or are willing to coat the cylinders, I'm having 103.80 mm pistons being made at ROSS in order to keep the walls thicker. In my case, actually to make room for the Nicom coating on the cylinders.

Vilhuer

I have seen consistent 116,0mm in one S4 block. There must be much thicker walled blocks out there.

Vilhuer

Adam, as good as it sounds there simply doesn't seem to be Nikasil coating available in here. Besided I have set of 968 pistons and other set of 944 S2 pistons ready and waiting. Don't know which ones I end up using yet.

Moldex crank spends the weekend at airport warehouse and monday its finally in garage.

Mike Simard

Did Moldex finish your crank? When did you order it? I ordered mine early October.