A number of Tory MPs say they are angry about how plans to change the way their leader is chosen were put to them.
Howard: Will stand down within months
A meeting of the 1922 Committee of backbench Conservatives was described as "fiery and angry", with some saying they had been given a fait accompli.
MPs broadly agree they, rather than the rank-and-file, should have the final say on who succeeds Michael Howard.
Ex-frontbencher Damian Green is pushing for a quick election, saying Mr Howard's authority is "ebbing away".
Mr Howard has said he wants his successor in place by Christmas after the rule change.
The new system would allow grass roots members to show their views in a vote of local Tory association chairmen.
The proposed new party constitution was agreed at a meeting of the Conservative board on Monday.
But BBC political correspondent Jo Coburn said Mr Howard's attempts to explain the proposals in a private meeting on Tuesday had met with a "lively" response.
"One of the MPs described it to me as one of the most fiery meetings they have had in a very long time, and others said it was icy cold," she said.
"On the positive side it was called lively and there was plenty of heckling."
Some of the MPs wanted a separation of new rules to select a new leader from the rest of the reforms that are being put forward to change the Conservative Party.
There was a big cheer when one MP said they were very disappointed with the treatment of ex-MP Howard Flight, who was sacked before the election over comments about Tory spending cuts.
Mr Howard wants the new rules in place before he steps down as party leader by the end of the year after defeat at the general election.
But some MPs want to try to bring forward the leadership contest.
Former shadow education secretary Mr Green told BBC News: "How long can it take for 200 politicians to organise an election? It certainly won't take seven months."
Mr Green argued Tony Blair would benefit if the Tories spent too much time discussing their leadership.
Highlighting Mr Howard's departure plans, he added: "Once he has said he is going, then authority starts ebbing away. That's life.
"It's started happening and we need to get on with it."
As well as changes to the leadership rules, the constitution would for the first time contain a statement of fundamental Tory beliefs.
It is understood there would be three main stages to the new leadership race:
- Any MP with the support of 10% of parliamentary colleagues would be proposed as a candidate to the Conservative national convention
- The convention, which includes about 900 local party chairmen and other senior party figures, would rank the candidates in order of popularity
- MPs would have the final say on who becomes leader.
Full details of the changes are due to be published on Wednesday, with consultation running until September.
The constitution has to receive the backing of two-thirds of MPs and convention members before being adopted at the autumn Tory conference.
Mr Howard's predecessor, Iain Duncan Smith, is the only leader to have been chosen by grass roots members - after his rival Ken Clarke received more votes from MPs.
Mr Duncan Smith, who faced almost constant "mutterings" from within the Tory ranks and was ousted just two years later, cautioned against the changes.
"It is very difficult to anticipate taking the vote away from people," he said, arguing that MPs were probably more unrepresentative of voters generally than party members.