One for Rohan - Q55 valve spring ranges

[promotor]

I have just bought some Q55 valve springs and retainers - having checked the pressure range I found them to give very low readings on the gauge when compared to just about any other springs - is this right? 120 pounds at full lift figure was the reading I got.

I have your spreadsheet with valve spring load ranges in it and looking at your figures in there they also show low readings - the thing is I always presumed that they were a typing error/mistake!

So, have I got a rogue set of Q55 springs or are they as they should be? Only reason for posting on here is because QED are closed for the day now so thought I'd drag up your favourite topic!

[holywood3645]

I built a QED 420S spec motor and bought the QED, Q55 valve springs cotters shims etc to suits cams. I sent the head and parts of to Tony Ingram (here in the US to assemble)
Tony contacted me with exactly the same issue you have described in this post.
I opted for Tony to fit the stronger springs that he felt thet were more appropiate. I didn't follow up with QED for refund as I thought the same (maybe a bad or wrongly sorted set of items) and i could use on a standard twin cam spec' rebuild for another engine.
I'm interested in what answers you get from QED. Have you contacted Simon yet? Maybe it is part of new lotus twin cam rebuild theory

James

[rgh0]

The Q55 spring are a very light spring as you observe and my testing showed compared to all other high lift springs. Designed for a 6500 rpm bottom end I think as most of the rest are intended in 8000 rpm race engines.

They would be nice and gentle on the cam and bucket but too light on the nose of the cam for a high reving engine.

Plenty of people appear to have used them without issue

cheers
Rohan

[avro]

The Q55 springs although quite soft work well, especially with some of the more modern fast road profiles such as the QED420 and the Kent L14. As a soft spring well suited to high lift fast road profiles its design is limited to relatively low RPM , not much higher than what would be considered safe for a standard bottom end.
Early outdated fast road cams were generally low lift, longer duration units that required higher RPM to produce the expected power. Modern profiles such as the excellent QED420 and L14 are a fast opening ,high lift cam with shorter duration. As such they produce excellent power and torque at lower RPM ,well within the limits of the Q55 valve spring. I would not hesitate to use them.


Nick

[promotor]

Thanks to all of you that replied!

I suppose the purpose of my post was really to make sure I got what I was paying for - I trust QED that the Q55 springs are right for the spec of engine I'm building but just wanted to make sure I actually had Q55's!

I haven't contacted Simon but from the info provided it looks like I won't need to - I'm happy with fitting lower tension springs as it looks after cams and buckets much more.

When I've fitted Kent 224 cams in xflows I never like to fit the supplied double valve springs (as their load ranges are absolutely ridiculous) and I've never had any issues. I know crossflows require stronger springs on cams like-for-like due to more flex in the valve train but their springs are at least twice as stiff as 1600GT springs - i always want to fit the lightest springs possible for longevity.

So, the engine will be 7000rpm 420 spec with 10.5:1 and it looks like the valve springs should be perfect for that.

Can't wait to see what it turns out like!