engine mounts and turbros...

[herrods]

my '74 260z is getting an efi turbro conversion.

 

Its currently a 2.9L L28, and I just bought the appropriate manifolds for the conversion, and have also acquired a turbo slightly larger than a GT28.

 

Problem comes when one attempts to attach it to the manifold, it fowls on the engine mount.

 

to fix the problem, about 1 cm of the mount needs to not be where it currently is.

 

New custom engine mount? or is a little shaving not going to hurt anyone?

[zzzzed]

would a spacer plate between the manifold and the turbo help?

[herrods]

im not too sure on that one, at work at the moment, spacing it out means we may run into clearance issues on the chassis rail, not with the turbo itself but for the turbo to intercooler "hot" pipe connection

 

well worth the thought though cheers

[nizm0zed]

I think i get what your saying,

Part of the top edge of the mount needs to be clearanced for the turbo?

like so?

(the red section cut out)

 

Of so, then yes, you can clearance some of it out, i would probably look at strengthening it elsewhere on the mount to make up for it.

 

as for the turbo not clearing, is it a really long turbo? like a really long centre bearing assembly on it?

I have a GT3271 (big) on my motor on a stock manifold and no clearance issues.

[herrods]

hey nizmo zed that is exactly what is required

 

to be honest I dont know what the turbo is.

 

Its a GT28 front housing, and an unknown rear housing, and was made by airesearch.

 

I dont really know if it counts as long, but its only the front bolts that are hanving the issue.  not the acual housing.

 

to clear it do i need a certain amount to allow for flex or the fact that the engine and turbo all flex on the mount equally means it only has to clear by a bee's dick

[Scando]

Mine has a LOT of that section cut away to clear the turbo (3540R on a custom manifold).  It's done plenty of racing and hard launches with no issues.  You're right, you don't need much clearance at all from the turbo to the mount as they will move together.  I have about 2mm!

[herrods]

scando i must have looked at the photos of your car 100 times in the last few months, one of hte first to come up searching anything around L28 and turbo in the same sentence

 

have you reinforced the mount in other areas to compensate?

 

I was thinking to weld a thicker piece of something-or-other just underneath the dip of the curve, (see the diagram kindly provided in previous posts)

 

or is it not worth the effor for the amount to be cut out?

[Scando]

My mount has not been reinforced to compensate.  because the mount only needs to be cut away on the back side you still have the front side to provide the full support.  mine has a lot more cut away than in the picture provided by nizmozed.  I would say if it's only a very small amount like that it would have almost zero effect on the rigidity of the mount.  Some of the engineering minded people on the forum might be able to give you a better answer here.  Mine has been through a couple of the rubber mounts that sit below with no signs of damage to the part of the mount shown in the picture.

 

Hope this helps.

Shane