AO

Fuq me! Wow! A lot of people are going to learn from your mistake. I'll buy you a beer for posting this.

FredR

When I did my manifold 10 years ago I blasted the outside surfaces and plugged all the potential ingress points with rags and tape. Basically when it came to the internal coating I hit the chicken switch out of concern for problems like this.

Whether or not the original internal coating presents as much a problem as the blasting media if it flakes off and hits the inside of the motor I do not know. Presumably I am still trusting to luck- it still concerns me to this day. Obviously I do not have the inlet manifold off every day of the week but on the occasions I have removed it I look for signs of delamination of the internal coating- so far so good.

One thing you need to do with this metal is prime it within the minimum time after blasting [cleaning] as the alloy oxidises very quickly. I had mine primed within 1 hour of it being blasted.

Rgds

Fred

Imo000

Since Porsche cleaned it after casting, why chance it by contaminating it AGAIN and then trying to clean it. Paint flakes are alot more forgiving when they go through the engine than sand. This is not hysteria.

Speedtoys

Look...Im sort of an automotive hack. I dont do bad work, but I could do better work.


I was able to clean my intake.


Judge your own fears and ability against that. Don't place them upon others.


This is hysteria...perpetuated by the thought that it can't be done, but...my a multitude of others over time can be, has been, and still will be.


The simple process of ensuring something is scrubbed well and CLEAN, is not a PHD step in auto repair.


Again..some intake types are easier than others to scrub out..and those should have further steps taken during R&R to ensure they dont pack with grit. But The flaky S4 intake coating on the inside needs blasted out..and they are NOT hard intakes to get the grit out of.

Like I said.._I_ could do it.

I had -1- working arm when I did it too.

Those of you with two arms, carry forth.

Mark R.

It seems like some shades of gray here fellas. How clean is "clean"?
Is it likely that EVERY single granule gets removed? Maybe. Probably not.
Is it possible that some come loose later, once reassembled and running? I would think yes.
So let's say a couple grains do get in and do "some" damage. How severe is that?
The engine still runs, but perhaps at a slightly reduced performance level?
> Just wondering how many of us may have some damage and not realize it...

> A question for the experts:
Let's say an engine sustains some (small amount of) media related damage.
Will the damage continue to grow and eventually self destruct that motor?
Or might it live and operate for a long time, albeit at a less than optimum level?

> And a question for Van:
What were the driveability symptoms that drove you to investigate and seek this rebuild?
(just curious - I didn't see that mentioned in any of the previous posts).
.

Speedtoys

I don't see where the grey area here is.

Scrubbing out the blasting material, is clean.

Not most of it all of it.


And if you have an intake hard to clean in all corners, dont blast the inside of it..S4+ intakes get that mostly anyway, and are easy for the most part, to simply clean with brushes in a large cooler to hold warm slightly soapy water in.


For every 100 that get cleaned, 1 doesn't, and the hyperventilation starts.


Just...clean it. Brushes that get in the tubes, compressed air, no more grit comes out....clean.

Mark R.

Well, if you're certain that you can get every single granule out, that's great. I'm just not so sure how realistic that is, hence my previous question about what happens if a "few" grains remain behind, come loose later, and get ingested into the running engine. Not clumps of sand, just a few individual grains...
.

Speedtoys

I dont know why you feel it's unrealistic.

Many have had no problems, perhaps 100s to 1000s over the years.


_I_ believe it's likely that 1 in 100 people fall short of being able to do detailed work, or rush it.

That's colouring the perception here that it's 'unrealistic' to get the job done.

It's easy to screw up an oil change too, through lack of detail, is that unrealistic to get done right too?

Ducman82

i have done two intakes. no issues. just takes time and elbow grease.

Mark R.

OK. Let me agree with you (Speedtoys) about the cleaning, so we can move on.
I'm not trying to debate the cleaning effort. I'm interested in my other question.

I did mine over ten years ago, and have never had any problems since.
So I am one of the 100 successful cases to which you refer.

I had mine sand blasted inside and out, before repainting the outside surfaces.
I submerged it, and scrubbed it, and rinsed it. And I did this repeated times.
As far as I could tell, it was completely clean and free of any remaining sand.

My questions are/were:
> Could some people be driving around with some media damage, and not know it?
> What symptoms would one notice when the internal damage gets as bad a Van's?
.

James Bailey

I seem to recall that Sterling SG lost his original stock engine due to a beautiful powder coated Intake many years ago.....was done by a third party sent to him assembled and "complete" sadly was NOT clean inside. Ended up as part of the motivation to build a stroker....

vanster

Sorry everyone, I have to weigh in here since I was the one that did this. I agree with Jeff and I am a clean freak when it comes to anything automotive. This came from racing sports cars for 25 years. The only grey area here was the grey slurry that Greg found when he drained the oil. The intake on an 86.5 is a lot different than a 16v or I believe an 87 and up. There are many hidden pockets and I missed a few. I spent about 2 hours cleaning when I should have spent 4 or 5. Wrenching on anything is always a learning experience to some degree. This car is an exceptional car with near perfect interior and body, color combo etc. I see it as a keeper and with a new GB motor along with all the other issues, because of this, new clutch, motor mounts, water pump, PK chip, everything re-plated and pressure washed, updated motor, I now have a car that good for 100k or more. More grins per mile. Yeah, not cheap but now I can enjoy it for years to come. In someways I think this was destined to happen. I guess the really only down side is that it won't have matching numbers any longer. BFD

GregBBRD

Because the S3 intake system has velocity stacks cast into the plenum, they are really tough to get clean.

At least on the S4 intake systems, one can get dental pick style tools into the casting holes above and below the velocity stacks.

Mark R.

Van, what was your engine doing when this damage started to become noticable?

Down on power? Running rough? Wouldn't run at all? Making strange noises? Or? ? ?

vanster

The first sign was oil consumption then a rattle like a broken valve spring. It still had oil pressure and the temp was normal. The rattle was not a valve spring but the wrist pin banging around. It would easily start, it just hurt to listen to it. Greg thought at first it was a rod.