427 Belt question
Thread Starter
Instructor
Joined: Jun 2001
Posts: 229
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From: Uxbridge MA
427 Belt question
I have some squealing from my belts when quick revving and over 3000 RPM's. Decided to replace. 427/390 engine. I have PS only. If you have an A.I.M. and checkout belt routuing for a 427 my question may be eaiser to follow.
I have one belt from crank to water pump to PS. Another belt from PS to Alternator. In the Assembly Manual it show a 427 belt routing of: Crank to water pump. Crank to water pump to PS. PS to alternator. My question is, the belt from crank to water pump is it on other peoples 427's? How can you tension this inner belt since the crank and water pump are not movable?
Also if this crank to water pump belt is missing is the crank to water pump to PS belt being over stress and causing the slipping?
P.S. Belt dressing quieted the problem.
---Andy
[Modified by andyg, 9:16 PM 4/9/2002]
I have one belt from crank to water pump to PS. Another belt from PS to Alternator. In the Assembly Manual it show a 427 belt routing of: Crank to water pump. Crank to water pump to PS. PS to alternator. My question is, the belt from crank to water pump is it on other peoples 427's? How can you tension this inner belt since the crank and water pump are not movable?
Also if this crank to water pump belt is missing is the crank to water pump to PS belt being over stress and causing the slipping?
P.S. Belt dressing quieted the problem.
---Andy
[Modified by andyg, 9:16 PM 4/9/2002]
Drifting
Joined: Mar 2001
Posts: 1,514
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Re: 427 Belt question (andyg)
Your missing the idler pulley. It's used to tension the crank-waterpump belt.
If my memory is correct it was on the drivers side between waterpump and crank pulleys. Thee BB guys will have to add to the explaination but I believe it's a redundant belt to allow you to limp in w/o power steering and alternator but still cool the engine in case of belt failure. Considering the single belt drives water pump, power steering and alternator probably not a bad idea.
Scott
If my memory is correct it was on the drivers side between waterpump and crank pulleys. Thee BB guys will have to add to the explaination but I believe it's a redundant belt to allow you to limp in w/o power steering and alternator but still cool the engine in case of belt failure. Considering the single belt drives water pump, power steering and alternator probably not a bad idea.
Scott
Thread Starter
Instructor
Joined: Jun 2001
Posts: 229
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From: Uxbridge MA
Re: 427 Belt question (Scott78)
There are 4 pictures of belt routing for a 427. The only 2 that show an idler are for use with AC. The other 2 pics show no idler and just one belt straight from the crank to the water pump. Either I am missing someting or the book is wrong. Here is a pic of my AIM. I am looking at the top right picture.
---Andy
---Andy
Racer
Joined: Dec 1999
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From: MESA, AZ, USA
Re: 427 Belt question (andyg)
The pictures are correct, with the exception (as far as I know) that the idler presses against the belt and doesn't pull it out to adjust it. The idler is added to allow for the extra horsepower that need to be "added" to the water pump pulley and transferred to the AC. The belt that runs from the crank to the water pump has to be put on already assembled over the pulleys and then put in place over the water pump. The fit is "loose" compared to some belts, but adequate without the AC. Needs tensioning with AC.
Andy
Andy
Le Mans Master
Joined: Sep 2000
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From: Orlando Floriduh
Re: 427 Belt question (andyg)
Only A/C cars have an idler. The water pump to crank belt is tough to put on. They are very sensitive to size. Do a search on http://www.ncrs.org for some good info on this set-up. search the archives.. Using GM belts solved all of my squeeling belt problems. :cool:
Race Director
Joined: Apr 1999
Posts: 10,866
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From: Beverly Hills/Pine Ridge Florida
Re: 427 Belt question (Scott78)
There is no idler on the crank to water pump belt on the 427/390. This is the short belt which is a real PIA to put on. The crank to waterpump to PS pump is tensioned only by the adjustment on the PS pump. The PS to alternator belt is tensioned by the alternator adjustment. This adjustment is somewhat related to the positioning of the PS pump. If you have incorrect length belts, or improper pulleys, these adjustments can be a real problem. Hope this helps. Chuck
