MR2 Roadster Owners Club

The Workshop => Performance Related => Topic started by: jvanzyl on August 9, 2023, 09:07

Title: How close is too close?
Post by: jvanzyl on August 9, 2023, 09:07
Topic: clearance between turbo and engine block

Question: how much vibration (distance moved) can one expect the turbo and engine block to have independent of one another (I.e not moving in tandem)?

Reason: when mounting the turbo the clearance is definitely less than 5mm and more than 2mm between the turbo and the engine block. Is this ok? Or am I going to need to remove some material from the block?
Title: Re: How close is too close?
Post by: J88TEO on August 9, 2023, 09:18
How about bracing the turbo so no or very little movement?
Title: Re: How close is too close?
Post by: Joesson on August 9, 2023, 09:54

IF ( big IF) you had access to a milling  machine it could perhaps be possible to machine the vertical face of the manifold, removing, say 1mm at the top to nothing at the bottom, effectively tilting the Turbo away from the block.

But, where is this movement going to come from?
The manifold is bolted to the block and the manifold is bolted to the Turbo with a metallic gasket between the mating faces. Where is the opportunity for movement there?
Title: Re: How close is too close?
Post by: jvanzyl on August 9, 2023, 10:45
Quote from: J88TEO on August  9, 2023, 09:18How about bracing the turbo so no or very little movement?
Possible... will need to investigate.

Quote from: Joesson on August  9, 2023, 09:54IF ( big IF) you had access to a milling  machine it could perhaps be possible to machine the vertical face of the manifold, removing, say 1mm at the top to nothing at the bottom, effectively tilting the Turbo away from the block.

But, where is this movement going to come from?
The manifold is bolted to the block and the manifold is bolted to the Turbo with a metallic gasket between the mating faces. Where is the opportunity for movement there?

That's a very good idea.. I have no idea where I can find someone local that does that. But I do like the idea!

Well that's the thing, I don't expect "much" movement, but this is the first time I've worked with turbo's etc or done any of this. But I have no idea how "much" movement is possible. I guess worse case scenario I could put it all together and if I'm getting some kind of fouling or running I can deal with it? I think I'd start with taking a bit away from the block with a grinding tool.. 

Thank you both!

Title: Re: How close is too close?
Post by: Carolyn on August 9, 2023, 11:49
If it's all bolted up solid, there shouldn't be any movement.  Perhaps a few thou clearance to allow for expansion and you're good.
Title: Re: How close is too close?
Post by: Alex Knight on August 9, 2023, 13:10
As above, the turbo should move with the engine movement.

It does, however get very hot.

Metal expands when heated.
Title: Re: How close is too close?
Post by: jvanzyl on August 9, 2023, 13:55
Quote from: Carolyn on August  9, 2023, 11:49If it's all bolted up solid, there shouldn't be any movement.  Perhaps a few thou clearance to allow for expansion and you're good.

Quote from: Alex Knight on August  9, 2023, 13:10As above, the turbo should move with the engine movement.

It does, however get very hot.

Metal expands when heated.

Thank both - I'm guessing this might prohibit a turbo blanket - but we'll see!