38 replies to this topic

[davefitz]

Also ment to add that the I'm using RAC type sump guard which will surely make back up the strength and avoid issues with distortion?

[Broomer]

I might just cut out that front section and weld in some tubular across in its place?

Whilst your chopping the frame about you may as well mod it to fit a lighter engine.
More weight saving to be gained there than any hole sawing is going to achieve.

It does make me laugh when people carry out all this weight saving, which I totally believe in but then refit that boat anchor of an A series which weighs so much.

[Broomer]

Pick up all the holesawed bits and weld them back in?

[GraemeC]

Dependant on use, I would say the sump guard could make the situation worse - one good knock from underneath and it will simply bend the front cross member upwards.

You'd be surprised how much those sump guards will actually bend when used in anger, even when on a 'full fat' strengthened subframe.

[Will16]

Personally I'd say you'd be fine with it. Re: the front crossmember mine is all holey pretty much the same as yours and the RAC man used it to drag the car onto the recovery wagon and there's no distortion at all.

[carbon]

Also ment to add that the I'm using RAC type sump guard which will surely make back up the strength and avoid issues with distortion?

Make sure you fit an oil cooler, the sumpguard makes engine oil run a lot hotter.

[Spider]

Most of the stresses on loading of the subframe is in the suspension towers, where the engine mounts and everything in between. The front rail and sides between the engine mounts and the front rail carry little loading, most of that loading comes from the front caster bar mounts (and the caster bars themselves).

 

While it does have many and big holes put in it, there's little I see that has weaken it, even in respect of the fitting of a sump guard. Where the holes are located has left the members in a cross braced configuration, while this term implies added strength, in this case, it doesn't , but likewise doesn't take anything from it.

[mad mk1]

Hi Dave,

I would say you will be fine, as long as you have down some good welds.

I run a frame that's got a lot lot more removed from it, think it was 12kg the last time I had it on the scales the standard was 16.3kg.

As long as you have a good think about it and brace in the right place you will be sound.

[Carlos W]

I don't really understand the logic in making the subframe lighter, only to add a subframe.

 

What's the net weight saving?

[davefitz]

Ok thanks all! think I'll run with it and mount gopro in there to see how much it flexes if at all.

Carbon thanks for that tip I didnt think of that and will run oil cooler! does the oil get up to temperature or take too long to get up to temperature though if used as a road car also?

Mad Mk1 cheers also!

Carlos W the objective is to at least get it back to its original weight or lighter after you have added strengthening plates and additional welds etc.

GraemeC if i give the car enough of a knock to bend the sumpguard ill be giving it a serious once over anyway before putting the car on a jig to straighten it!!! :) I'll let you know if it happens.

Cheers all.

[Carlos W]

If you're fitting an oil cooler Minispares sell an oil thermostat

[Cooperman]

A sump guard will seriously bend if used for its intended purpose. Mine has been on the car for many years and shows the signs of that.
I don't think I would like to fit a sump guard to that sub-frame.

[carbon]

 

Also ment to add that the I'm using RAC type sump guard which will surely make back up the strength and avoid issues with distortion?

Make sure you fit an oil cooler, the sumpguard makes engine oil run a lot hotter.

 

The requirement for an oil cooler depends very much on how the car is used. I found out the hard way if you use a sumpguard and then go for long distance motorway trip of several 100 miles in the summer the oil gets hot enough to cause main bearing issues. And there was no obvious sign of engine overheating with radiator coolant temperature in the 80's.

[CityEPete]

You could just put half a gallon less petrol in it and save the same weight?

[Carlos W]

You could just put half a gallon less petrol in it and save the same weight?

 

Or go on a diet.

 

I could do with losing about 4 stone