Thanks Duke,Clem,Joe,Bill,Mark!!!!

[Alex K.]

Thanks one and all for your advice on my overheating at idle problem!!
The VC-1810 vacuum can along with full time vacuum did the trick,I appreciate all your help!!Car idles at 190 to 200 degrees in 90 degree heat.

I have a question on the can I took off the car? the vacuum can had a rubber sleeve on the vertical portion of the arm that moves the advance plate.What is the purpose of this sleeve and should I have put it on the new can?

Thanks in advance Al

[Clem Z.]

cheap way to limit the advance under full vacuum *NM*

[Duke W.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

Year and engine please, and what is the old VAC ID number.

The rubber bushing is there to limit total vacuum advance. Some had them, most didn't.

Duke

[Alex K.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

Duke,
The car is a 67 435 hp with a after market cam that had 7" of vacuum at idle.
The old can number is MS 201 15.My question is should I put the bushing on the new VC-1810 can?

Thanks Al

[Duke W.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

No, don't put the bushing on the VC1810.

Did your idle vacuum increase? The additional total idle timing should increase manifold vacuum.

You can test the VAC to determine what vacuum is required to pull it to the limit. It should be in the range of 7-9". Then set the idle speed high enough to achieve at least 1-2" more vacuum than what the VAC requires to be pulled to the limit.

The 201 15 is original to L-71. They were also OE on all '63 engines, and I think L-78. Interestingly, I don't think they were ever available over the counter as a service part or were replaced very early with another p/n, so they might be valuable for someone who wants the original ID no. for judging.

I don't recall specifially if the 201 had a limit bushing. Max advance was 15@15.5".

Duke

[Alex K.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

Duke,
Yes the vacuum did increase to 14". I took a tee off the choke hose for full time vacuum.I am going to set inital tming at 10 degrees does that sound right to you?

Thanks Al

[Duke W.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

IIRC the L-71 max centrigual is 30@3800, so if it will take 10 initial without detonating, that's about right.

At what idle RPM are you now reading 14"?

Duke

[Alex K.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

Duke,

It is pulling 14" at 850 idle rpm.

Al

[Duke W.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

Good! Maybe the cam isn't so bad afterall. I expect to see more vacuum when the VAC is converted to full time from ported, but your increase from 7" to 14" is quite dramatic.

The OE mechanical lifter cam makes about the same manifold vacuum with full time advance, but somewhat less with ported.

If you get some part throttle or transient detonation, the VC1765 or VC1808 12" VACs should mitigate it and with 14" idle vacuum a 12" VAC is fine.

Duke

[Alex K.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

Duke,
The weather is going to be in the 90 degree range this weekend here in Ohio,so I will give it the idle test and let you know the results.

Many thanks for your help with my overheating problem!

Al

[Duke W.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

Give it a detonation test, too. Hot weather is the best time.

From 1500 in top gear go to WOT and hold it to at least 3000. If it doesn't detonate with 10* initial and the 8" VAC you are home free.

If it does detonate, post a through decription including some words about intensity and the rev range where it occurs. Is it sustained as revs increase, or just transient in nature - goes away a second or two after you open the throttle?

Duke

[Alex K.]

Re: Thanks Duke,Clem,Joe,Bill,Mark!!!!

Thanks Duke, will do!