Compressor housing repair
Discussion
I've just got a cast aluminium compressor housing that has been machined to take a bigger wheel. However, I'm not convinced that the profile is accurate enough; the gaps between the wheel and housing may be too large.
When I get chance I'll check the clearance by putting a soft material such as paint on the housing and abrading it with the wheel. I had 0.3 - 0.4 mm as a working clearance.
Getting another housing isn't an option. Clearly, any form of filler is a poor substitute for aluminium, not least through the risk of it breaking off, and I have to take great care not to damage the compressor blades. However, if push came to shove, is it feasible to profile the housing, for example by using JB Weld?
When I get chance I'll check the clearance by putting a soft material such as paint on the housing and abrading it with the wheel. I had 0.3 - 0.4 mm as a working clearance.
Getting another housing isn't an option. Clearly, any form of filler is a poor substitute for aluminium, not least through the risk of it breaking off, and I have to take great care not to damage the compressor blades. However, if push came to shove, is it feasible to profile the housing, for example by using JB Weld?
Can you not take it to whoever machined it wrong and tell them to sort it ?
If it's been messed up and gaps are huge...IMO the only option is either replacement or welding.
I would not be using any sort of epoxy there, unless you were happy with the risk of destroying the turbo at some point.
That said, years ago Apexi used to offer turbos with some sort of carbon seal on the inside of the housing. The wheel effectively worse this away, which allowed absolute minimal clearance between the impeller and cover.
Never heard or seen it used anywhere else or since though
If it's been messed up and gaps are huge...IMO the only option is either replacement or welding.
I would not be using any sort of epoxy there, unless you were happy with the risk of destroying the turbo at some point.
That said, years ago Apexi used to offer turbos with some sort of carbon seal on the inside of the housing. The wheel effectively worse this away, which allowed absolute minimal clearance between the impeller and cover.
Never heard or seen it used anywhere else or since though
Thanks.
The machining wasn't done for me and, even if it was, I can't see an easy repair if they've machined too much away.
What clearances do you think there should be?
I had a quick look and saw that Belzona products are available (the name is for the manufacturer and individual products are specified by a product number), although to say any of its fillers/glues isn't cheap is a bit of an understatement.
That abradeable coating is interesting. I'm not surprised that no-on else followed suit; the cost is prohibitive for the competitive car turbo market and it does have disadvantages.
The machining wasn't done for me and, even if it was, I can't see an easy repair if they've machined too much away.
What clearances do you think there should be?
I had a quick look and saw that Belzona products are available (the name is for the manufacturer and individual products are specified by a product number), although to say any of its fillers/glues isn't cheap is a bit of an understatement.
That abradeable coating is interesting. I'm not surprised that no-on else followed suit; the cost is prohibitive for the competitive car turbo market and it does have disadvantages.
JLGsDad said:
is it feasible to profile the housing, for example by using JB Weld?
You haven't said how much you're trying to fill, and if you're looking for fractions of a mil then you might decide it's not worth the trouble, but if it's so close that you're seriously thinking of checking it with a later of paint, is there any reason not to have that layer of paint be your gap filler? Thanks. Paint would certainly be easy to apply and sculpt/abrade to shape, and if there is any interference then it would wear away rather than damage the compressor wheel lips.
However, I suspect it won't last or adhere for as long as I want at the temperatures I expect the housing to get to, particularly when heat soaking after use (I've not seen any figures though). If I use the housing then it will be buried away and removing it to reapply a coating isn't practical. That said, I may be wrong and will do some research tomorrow when I have more spare time.
However, I suspect it won't last or adhere for as long as I want at the temperatures I expect the housing to get to, particularly when heat soaking after use (I've not seen any figures though). If I use the housing then it will be buried away and removing it to reapply a coating isn't practical. That said, I may be wrong and will do some research tomorrow when I have more spare time.
JLGsDad said:
Thanks.
The machining wasn't done for me and, even if it was, I can't see an easy repair if they've machined too much away.
What clearances do you think there should be?
I had a quick look and saw that Belzona products are available (the name is for the manufacturer and individual products are specified by a product number), although to say any of its fillers/glues isn't cheap is a bit of an understatement.
That abradeable coating is interesting. I'm not surprised that no-on else followed suit; the cost is prohibitive for the competitive car turbo market and it does have disadvantages.
So some muppet machined a housing...then too much...then you dont know what tolerances your specific turbo actually needs...The machining wasn't done for me and, even if it was, I can't see an easy repair if they've machined too much away.
What clearances do you think there should be?
I had a quick look and saw that Belzona products are available (the name is for the manufacturer and individual products are specified by a product number), although to say any of its fillers/glues isn't cheap is a bit of an understatement.
That abradeable coating is interesting. I'm not surprised that no-on else followed suit; the cost is prohibitive for the competitive car turbo market and it does have disadvantages.
Why on earth are these people even tackling this sort of work in the first place ?
Tolerances would depend on a few things I'm sure, size of wheel, materials, bearing system and how much movement there may be there, etc etc
There are some spray metal systems available to build up worn parts. Not sure if they apply to aluminium though.
But really...if it's screwed up too badly the housing either needs replaced, or metal needs added. In some ways a real thick coat of paint isnt perhaps such a bad idea. But depends how much it has been screwed up in the first place. And no doubt the paint wont last forever.
Just how much clearance is there ? And how much was there with the previous wheel ?
Your first post mentions 0.3-0.4mm...IMO that sounds very small if anything. But again need more info
Edited by stevieturbo on Saturday 11th March 11:17
E-bmw said:
What I would use is a stuff called Belzona, but it is quite hard to come by.
There are other similar things around, they are generally epoxy metals that you mix together like Araldite.
Belzona is easy to find if you know where to look. Your best bet would be a plant parts shop that sells parts for crushers or a friendly plant mechanic who works on crushers may have some extra in his van. It's used for building up pits in crusher cones. There are other similar things around, they are generally epoxy metals that you mix together like Araldite.
Thanks.
I don't have a similar turbo to measure. It's for a journal bearing turbo with a new CHRA so I don't have to worry about sloppy bearings straight away.
I was using paint purely because it was softer and easier to remove. I'm building it up in several layers.
Unfortunately, getting another housing isn't an option; it's from a hybrid turbo that had a limited production run well over 10 years ago and has a large A/R unique to this application. I can get housings with the correct wheel profile but they all have A/Rs that are 15-20% too small; this is also true of the turbine housing, where the A/R is 25% higher than the standard turbo from which it was derived. .
Belzona is just the manufacturer's name and their products are defined by a 4-number code. The ones used for construction work are less suitable than the 1000 series, for example the 1131 used for bearing material (ostensibly a good choice as it is intended to wear, thus sacrificing itself to protect the wheel if rubbing occurs, but that may not be true for the aluminium of the wheel). I don't mind paying for quality, and, to be fair, per weight Belzona prices look quite reasonable; it's just that the minimum pack size is quite large so RRPs are all over the £100 mark. I can get some 1000 series at decent prices on eBay that may do, but not the ones that I think are best for the job. I've emailed them for a recommendation.
I don't have a similar turbo to measure. It's for a journal bearing turbo with a new CHRA so I don't have to worry about sloppy bearings straight away.
I was using paint purely because it was softer and easier to remove. I'm building it up in several layers.
Unfortunately, getting another housing isn't an option; it's from a hybrid turbo that had a limited production run well over 10 years ago and has a large A/R unique to this application. I can get housings with the correct wheel profile but they all have A/Rs that are 15-20% too small; this is also true of the turbine housing, where the A/R is 25% higher than the standard turbo from which it was derived. .
Belzona is just the manufacturer's name and their products are defined by a 4-number code. The ones used for construction work are less suitable than the 1000 series, for example the 1131 used for bearing material (ostensibly a good choice as it is intended to wear, thus sacrificing itself to protect the wheel if rubbing occurs, but that may not be true for the aluminium of the wheel). I don't mind paying for quality, and, to be fair, per weight Belzona prices look quite reasonable; it's just that the minimum pack size is quite large so RRPs are all over the £100 mark. I can get some 1000 series at decent prices on eBay that may do, but not the ones that I think are best for the job. I've emailed them for a recommendation.
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