Radiator selection for road car with race springs

[Rich Goddard]

Bought a 1.6K SS a few months ago and have since suffered 2 (very minor but annoying) rad weeps.  Had one professionally sealed and pressure tested, but now have another.

I notice the type of rad fitted is noted on CC Parts site as "not to be used on the road with race springs fitted".   (RADIATOR ALLOY TRIPLE PASS K-SERIES ENGINES. Ref 73159)

Obviously with stiffer springs make the rad want to shake itself to bits on cr@ppy roads.  Can anyone recommend a suitable rad for use on a (mainly) road car with race springs?

And/or more flexible bobbins?

Also, does the rad need to be bolted up tight to the frame, or would it be ok to leave a small amount of  movement in the mountings?

Cheers, Rich

[Jonathan Kay]

Where were the leaks?

Is there any mechanical stress on the radiator as the bobbins are tightened up? This is notorious for causing leaks. You might need to bend the supports or enlarge the holes to remove the stress.

Then the bobbins should be tightened so that there is no play in the fitting.

Jonathan

[Rich Goddard]

Thanks Jonathan.

It weeps at the top corner where one or two of the horizontal veins meet the vertical side tank.

After the first leak I read on the forum about his, and I've used various numbers/thickness of steel washers to take out any vertical-plane misalignment in the 4 chassis brackets so that it didn't "twist" the rad when I nipped it up. (Or so I thought)

[JonT]

I have a radtec radiator which had 2 possible mounting holes - I cut these into slots which gives more flexibility about how you mount it to minimise any loads from the pipes. And yes, was mounted on rubber bobbins too. 

[7 wonders of the world]

and space the individual bobbins to eliminate twist on the rad too.

what spring rates are you running...?

[Rich Goddard]

Thanks 7Wonders. 
They're 250 lb Eibach springs on SL wide track.  
Please can you explain what you mean by spacing the individual bobbins? Cheers.

I'm thinking of trying 'waisted' bobbins rather than the standard cylindrical type. Might absorb a bit more?

[Tazio]

250 fronts aren't what I'd consider a race spring, there are loads of us using them, helps prevents bottoming on compression.

I know of one enterprising owner who has replaced the bobbins with small pieces of cut down hoses, and inserted bolts through each side and suspended the rad that way, allowing it to move a little.

There are reports to of using the incorrect coolant in aluminium rads causing leaks, it should be coloured blue.

[Jonathan Kay]

"There are reports to of using the incorrect coolant in aluminium rads causing leaks, it should be coloured blue."

There's a lot on this in the archives. I'm not convinced about the causation.

What coolant are you using?

Jonathan 

[Rich Goddard]

I'm using the Comma Red stuff, same as what was in it when I got it.

[Molecular--Bob]

My thinking on coolant is engine expensive, radiator consumable, use what the engine needs.

[Jonathan Kay]

"My thinking on coolant is engine expensive, radiator consumable, use what the engine needs."

Agreed. And the evidence of harm caused by modern coolants to any radiator isn't strong.

"I'm using the Comma Red stuff, same as what was in it when I got it."

That's Comma Xstream G30?

Jonathan

[7 wonders of the world]

when you sit the rad on the bobbins sometimes you find a gap between 1 or 2 bobbins so you can shim these with washers so the rad can be tightening evenly onto all the bobbins.

As above 250lb s[rings are pretty standard for road use

[Wrightpayne]

My old style copper rad has two sets of fixing holes. When using the bottom set the bottom hose was hard against the chassis and top set the top hose fouled. I just drilled a set of holes in between the official ones and it sorted the problem.

Early on I did have a rad leak on the lower hose connection which I suspected was the hose pressing against the chassis so I altered the fixing points.

Like others, I had to put packing under the bobbins to level off the mounting points and avoid twisting the rad. If you put them on the chassis fixing side you dont have to worry about misplacing them if you ever take the rad off.

Fixing holes could be completely different on the ally rad but worth a check.