Tr8 valve springs replacement thereof

[Bollen <bollen@ibm.net>]

Last night, out in the boonies, the 8 started tapping REAL loud.Oil
pressuire was OK (glad I just put a gauge in) and I gingerly drove home.
Called  the guru (woody) who suggested a broken valve spring, which
naturally was correct, ascertained by me at 4 am.
Has anyone without a compressor replaced a spring with the head in situ?
Does the string trick work for this? Want to get it running for the
weekend.
Thanks, Stu