Lotus Elan

QED Q55 valve retainers

PostPost by: Pfreen » Tue Jul 14, 2020 5:36 pm

Does someone out there know the distance between the top of valve spring and the tip of the an original spec valve for the QED Q55 retainers? I know the installed height for the Q55 springs is 1.15". I am trying to measure everything up on my head before I order all the parts from QED. I want to order once since I am in the U.S and shipping is expensive. Thanks.
Pfreen
First Gear
First Gear
 
Posts: 19
Joined: 27 Aug 2018
Location: Fort lauderdale, florida

PostPost by: rgh0 » Sun Aug 02, 2020 6:10 am

Just saw your post and did a quick check on a set of Q55 springs and retainers I have as spares.

With a standard valve, with a 1/10 th inch tip ( 2.54 mm) above the collet groove. The outer spring top on the Q55 retainer is 1.0 mm +/- 0.1 mm below the valve tip.

The Q55 spring pack has a low lb/in rate of around 135 lb/in and is forgiving of small changes in install height due to this and normally installs fine in any head with standard valve lengths and reasonable valve seat cutting.

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7513
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: Pfreen » Sun Aug 02, 2020 10:43 am

Thanks Rohan. I bought the q55 valves spring and retainers. Everything worked out fine. I just needed .015" valve spring shims on all eight valves to set the installed height to 1.15"
I bought thicker pad lifters, which I think go in the 910 engine, to reduce the valve shim thickness requirement since the L14 cams I bought only had a 1.029" base circle. Anyway, the largest shim I needed was .161.

I just need to time it, check valve to piston clearance, and torque it up.
Pfreen
First Gear
First Gear
 
Posts: 19
Joined: 27 Aug 2018
Location: Fort lauderdale, florida

PostPost by: rgh0 » Mon Aug 03, 2020 9:19 am

In a race engine I would not have fitted 15 thou shims as they are thin and can crack and break up under the hammering from stiff springs and high revs, you can get the spring seats machined in various thicknesses and i used these if needed in race engines. In a road engine probably OK though, especially with the Q55 springs which are low in load. Given the low spring rate of the Q55 springs that 15 thou equates to about 2 lb lower seat and nose load which is not significant so I would not have bothered with the shims either as the springs will change by more than that in the first few minutes of running.

Q55 springs do not suit above 6500 rpm so I presume you intend keeping to that limit with the L14 cam you have fitted. With that smaller base circle you have you normal fit longer "race" valves as your normally building a "race" engine but using the thicker followers works OK at lower revs for a road engine

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7513
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: Pfreen » Mon Aug 03, 2020 5:49 pm

I am building an under 6700 RPM engine. that is where my rev limiter is set. I have a stock bottom end (except for ARP bolts) and the HP for the L14 cam drops off over 6500 RPM, so no point in going higher.

I thought about longer valves, but I really did not want to change the valves, since what I have works just fine. I also did not really want to go with racing springs since I am not going over 7000 RPM.

As far as weight, the new alloy, thick pad lifter is 4 gms lighter than the stock iron one I had. Even with the thicker shims I saved 2-2.5 gms of valve train weight. BTW, the thick pad lifters(.246" vs .218") are taller (.986" vs .873") in height, so if anyone is interested, you have to check that the lifter does not bottom out in the lifter bore at full cam lift. I bought them from RD Enterprises.

My point of all this is to see what gains can be made on a stromberg head. I chassis dynoed the car before I took it apart to fit these cams. So, it will be a sprint cam vs L14 cam comparison. We'll see how it does.

Thanks again for your input.
Pfreen
First Gear
First Gear
 
Posts: 19
Joined: 27 Aug 2018
Location: Fort lauderdale, florida

Total Online:

Users browsing this forum: 69S4 and 14 guests