jeff spahn

That is a travesty Greg

Ricardo Vega

I left in the tank for about 30 minutes. Didn’t see any residue at bottom. I took out as soon as color changed. So that is what freaked out!




Okay. So after the realization that I’m not going to have much luck using my original engine with the state that my cylinders are in, is there any hope I can use it if I wet wall cylinder sleeve it?




Or is it possible I can take off 0.5 mm and use the engine?




Again, thanks for everyone’s comments!




RV

Wisconsin Joe

Yup. That's what happens when a supercar that originally cost as much as a small house becomes available for the cost of a cheap econo-box.

Fools and idiots think that their shade-tree mechanical knowledge is enough to work on them, do all sorts of very questionable things and do a ton of damage.

I don't pretend to be an expert mechanic, but with the info available on here I feel I can do a fair amount with the 928. But I always do a fair amount of research before tackling any project.

Junkyards are full of "ordinary" cars that were destroyed by incompetence and ignorance. There are more than a few "cheap" exotics there too.

How common is the "Idiotic PO" lament on here?

We've just reached the point where a select few (GTS, GT, OB) are worth retrieving from that sort of idiocy.
Or the owner thinks that they will be worth it in the future.

Ricardo, I have to ask:

Did you have any idea what the block of the 928 is made of?

Did you read the label on the ZEP cleaner?
Did you do any research on what that stuff does to aluminum?

Seriously, it took about 30 seconds to find a lot of info on what it does to aluminum.
Including this:
https://rennlist.com/forums/944-turb...-the-ugly.html

jeff spahn

Your post is harsh but true. Supercars were and are an expensive proposition, no matter what you pay for them they still have Supercar level repairs that need to be done, not bailing wire and goodntight torque on fittings.

Ricardo Vega

I made a big mistake so it’s time to move forward. Not going to walk around with my head down. I didn’t lose a family member, or a pet. I can get a new block since there’s cars around that can donate.

But before I give up the ghost on this one block is it possible I can have the wet wall liners installed and have the crucial part fixed? Looking at my block I would say it’s not dead. But that’s why I have my friends on Rennlist to help me.

Thank you.

RV

BC

I think the point some peeps are trying to make is that with the corrosive nature of the solution you may need to get an idea of what else was affected other than just the bores.

Ricardo Vega

So I must ask them. Is my block made out of Alusil? Or is just a coating? That would maybe help me get an idea and maybe I can ask metallurgist I know and see what they think?
Maybe they can find a mathematical equation to test strength of alloy before I go forward?

RV

jeff spahn

Your block is made out of Alusil. It is not a coating.

dr bob

For those playing along at home...

For quite a while we've been alerting users to the dangers of using "purple" degreasers for even casual engine cleaning. Most of them clearly state on the label that they are not suitable for aluminum, or at least they recommend that you try a test on an inconspicuous place to verify compatibility. For external engine cleaning folks gamble that they can get the chems on and let them work on oily deposits, yet get them removed before there's noticeable damage to the aluminum underneath. Maybe they can, or maybe the key word is "noticeable". Common chemical degreasers use some seriously alkaline chemicals to hydrolyze the oil and grease deposits. They do the same thing your great grandmother did before commercial detergents were available, when they made lye soaps with animal fat, fireplace ashes and rainwater. The resulting chemicals react with the aluminum, creating aluminum hydroxide. That's the dark grey runoff noted in some of the pictures. In the case of the silica-infused upper block, you can see where the caustic has leached the aluminum from the silica crystals, leaving what looks like grains of sand standing proud of the now-gray metal substrate. And that's exactly what it is. Unfortunately, losing the metal means the bores need to actually be bored again back to where there's no "missing" metal, then finished with the Sunnen honing paste process to get the correct silica exposure in the bores. A problem is that the soak in the cleaner has exposed every other surface and damaged precision machined faces for bearings and the girdle. You might be able to Blanchard-grind the girdle and block, then align-bore for new bearings. And re-machine the seal recesses, block plugs, oil relief passages where they are threaded or plugged, etc. Then hope you got everything correct. Bottom line is that you could easily spend more on just the machine work and oversized pistons/rings/bearings than another whole engine might cost.

--Please-- use extreme care when working on the aluminum stuff. There are more than a few horror stories around like Greg's, where aluminum engine blocks, heads, cases and cylinders were placed in a "hot tank" intended for steel/iron parts. I can confess to using Mr. Clean to degrease aluminum engine parts, only to find a telltale grey surface color when things dried. Once. This is stuff many people put their hands in while doing household cleaning chores. It dissolves fat cells in you hands the same way it does the target oil and grease you are trying to dissolve. Read The Labels on stuff you use. If you can't safely put your hands in it, you probably want to look even more carefully at using it on precious metal car parts. Look for something pH-neutral or at least close to it, or plan on diluting it so much it's safe but no longer easily effective.

Even common flavors of Simple Green are banned from use on aluminum aircraft surfaces and parts, due to extended corrosion dangers. Wonder why Vaseline is the "approved" surface protectant on your anodized wheels? So casual exposure to common corrosive substances have to chew through it before getting to work on the anodizing?

skpyle

Ricardo Vega, keep your head up! You are not alone. Meh, you made a mistake. You can recover from it. I have not screwed up majorly yet on the Red Witch. However, guess why I had to put a new crate engine in my little S-10. Hint: leaving cam and lifter break in lubricant in the oiling system for over 30 minutes was not good for the original engine...

Keep on going, you've got this!

Ricardo Vega

Thank you skpyle! Gotta keep moving forward.

RV

jeff spahn

I can tell you from experience from my youth that you don't want to defat your hands. My fingers constantly split at the cuticles now from using gas, oven cleaner and lye soaps to clean my hands. Bleed at the drop of a hat now at the fingernail, finger interface. Don't use stuff on your hands that says wear gloves!!!!

GlenL

You're a great candidate for a 1/2 price S4 short block from 928I. Are the heads still good? The pistons are custom-fitted to the block. Getting just a block will mean that , most likely, the pistons won't fit right.

The Forgotten On

The pistons can be swapped block to block so long as the tolerance groups are the same.

The tolerance group numbers are listed per cylinder on the block itself next to the head sealing surface.

Porsche did state that it was possible for different tolerance groups to be used in the same engine. Some even came out of the factory that way.

Rob Edwards

The '89 I'm working on right now has six Group 1 pistons and two Group 2 pistons.

All that said, with used blocks and used pistons, probably best to actually measure the bores and the pistons to ensure your piston to wall clearances are correct.