dcskinx

First up I have done a search and can't seem to find a definite answer.

I have just had my machine shop dismantle, clean and install my new springs and seals on my LS1 (241) heads. He thought the springs might have too much pressure, so I am hoping someone here can let me know if these specs sound about right or something has gone wrong.

The springs I am using are BTR Dual Spring kit with Titanium retainers (Part: BTR #SK001). The heads are factory, have not been milled.

Specs machine shop has given me are;

175lb @ 47.2 Installed (I am assuming this is mm, which works out to 1.858")

380lb @ 0.500" Lift

Any help would be greatly appreciated.

DietCoke

iTrader: (18)

Anything under 450 pounds is fine, you couldn't get there if you wanted to with the rate of the BTR duals. Looks like they set them up at or about 1.68"

Specs are 155 lbs @ 1.780", 380 lbs @ 1.180", 400 lbs @ 1.130, coild bind @ 1.070"

vettenuts

iTrader: (4)

Based on the specs provided by DietCoke, I get a stiffness of 377 lb/in. I get an installed height of 1.727" or 43.86 mm.

In my experience with 241 heads, they won't set up at 1.858" unless the valves have been sunk deeper into the head. Stock they set up around 1.76".

What was done to the heads?

dcskinx

Thanks for the reply's. The heads were just dismantled, hot tanked and reassembled with the BTR spring kit. Is there anything that could of been done wrong, anything I can check if I take them back off and re-install?

vettenuts

iTrader: (4)

You could pull two springs and check installed height. Simple to do but you do need a valve spring compressor and a valve spring micrometer. If the valves weren't ground then the installed height should remain as stock. Also, if you really want to disassemble, I would lap the valves if that wasn't done.

It appears you are in Australia, correct? That is why he probably gave you the installed height in mm.

Brian Tooley Racing

iTrader: (13)

We get this call weekly. We have machine shops getting anywhere from 1.660"-1.880" installed height and anywhere from 120 lbs to 200 lbs on the seat.

Our retainers have less than .010" variance in installed height and less than 10 lbs variance on seat pressure.

The bottom line is, if your machine shop installed them as is with no shims, you're good to go. If they installed shims then you should probably remove them.

vettenuts

iTrader: (4)

Any chance of shooting a photo or two of the spring installation?

dcskinx

Thanks for the replys and very helpful info, feel a lot better bolting the heads back on now. The machine shop has not used any shims so should be good to go, will post up some pics tonight of the spring installation. Yip i'm in Australia.