The 'E' Type Forum

Am I missing something or has anyone else had a problem with the SNG supplied units

I have been speaking with SNG about a set of updated mounts I bought quite some time ago..but only recently needed to use as I was finally trying to install the IRS

My original items were beyond salvation and sadly I discarded them some time ago...I say this as I can only guess that the new units are much wider than the old and require a far greater amount of shimming to fit tightly to the rear chassis legs

I had 7 original spacers in my assembly, but think to get the new ones to fit I will need double that

The rear chassis leg is some 55mm wide yet the inner faces of the new mounts are approx. 61mm

This means that my original 3” bolts are not long enough...

SNG are investigating but so far think that this size is correct..as it is what they have been making for some time

I would appreciate any feedback from others who have installed new mounts...so that both SNG and I can solve this puzzle

All the best
Jonathan

Hi Jonathan.....my IRS is currently sitting loose under my car ready to be fixed in place.....it has SNG mounts that are approx 10 years old.....will take some measurements tomorrow and post details it may help....Steve

They do close up some as you tighten them.

I will measure some original ones for you later.

For now I would be tempted to give them a squeeze in the vice.

Hi Jonathan.....chassis rail is 54.5mm.......spacer shims 3mm......width across inside of mount 57.5......the mount is bolted to the rail...unfortunatly i dont have a loose one to measure......this may help..
Edit..the mount is made from 2 pieces of metal joined by rubber....the top piece that fixes to chassis is approx 3mm thick......the lower piece that connects to irs is approx 6mm...so with your 61mm gap plus two thickneses at 3mm of mount your total width is approx 67mm.........so 3in bolts should have approx 8mm thread showing...Steve

Thanks guys for the speedy reply...

all those dimensions tally with what I have and yes I can squeeze them in a vice..but I was assuming the design of the mount would rely on not just the shear through the 5/16 bolts but also benefit from a friction resistance

When the mounts are squeezed together the inner mounting faces are no longer parallel..so friction is not so perfectly achieved..is this an issue...from the sounds of it I sense not...?

By the way please can any of you remind me if it’s the forward or rearwards pair of brackets which are best bolted to the chassis rails first (leaving the other pair fixed to the IRS first)

Many thanks
Jonathan

Hi Jonathan.....drawing shown in Jag service manual(rear suspension removal)....front mount on irs...rear mount on chassis....the mounts dont just rely on shear of the fixing bolts...they have shoulders that the chassis rails sit on.......Steve

mgcjag wrote: ↑

Sun Jun 02, 2019 1:35 pm

Hi Jonathan.....drawing shown in Jag service manual(rear suspension removal)....front mount on irs...rear mount on chassis....Steve

As Steve says because it's very difficult to get to one of the nuts on the rear mounts. Another useful tip is to have a couple of tapered punches handy that will allow you to line up one hole while you put a bolt through the other hole. They will not line up straight away and may even look like they never will but they will.

Simon

Just for anyone with a 2+2 that reads this i found it impossible to refit the irs unless the mounts were attached to the body first.....the irs then lifted straight up.....there is less room in front and behind the irs cage on a 2+2.. Steve

Thanks all..