Good evening,

My 1964 110, 4 speed started running very poorly. It appears to be on the drivers side where the trouble is.

The car will not idle, but if I keep feathering the pedal I can keep it running, but it is definitely missing. It acts as if there is a massive vacuum leak, but that is not the case. I put a vacuum gauge on it and it is very erratic between 3 and 10 inches of vacuum if I can hold the throttle steady at 1200 rpm or so.

I swapped the carbs from left to right, I even put on a functioning carb from a known good runner. I swapped plugs with a new set, I even put in a different distributor and coil that I have but no luck. I was fairly certain it was not ignition, but wanted to rule it out for myself.

I verified TDC with a piston stop and the balancer is correct. I’ve verified timing, vacuum advance, mechanical advance etc. were working on both distributors.

Next , I ran a compression check, fearing the worst and came up with:
1 - 160
3 - 155
5 - 155
2 - 160
4 - 160
6 - 150

So the compression is fine.

After giving this more thought I am wondering if I have a broken rocker, bent push rod, or flat cam. Over the past couple of years I have had an intermittent issue where the car will have a very loud lifter ‘clacking’ noise but it would go away once car warms up some. It happens the most if I haven’t driven the car in a couple of weeks.

I stopped for the day and pondering the next step. I am going to pull the valve cover off the driver side. I will check the condition of the rockers, pushrods and check out the valve springs. I would expect to see a loss of compression if the valve spring was bad / broken.

Do any of you know if a valve not opening correctly would cause low vacuum / poor running but still show good compression?

Thanks,

Keith
64 Monza Convert
00 911 C2
"Horizontally Opposed"
05 GTO 6-speed (Gotta have a V8)
Chicago Burbs; the Anti-Dragon... 11 turns in 318 miles

An exhaust valve not opening would certainly disturb vacuum on thar side.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

I spent some time tonight trouble shooting the car. I really think this is some weird vacuum leak. I took the vacuum hose from the crossover off the vent tube. This is the one that goes in the top shroud. I plugged the vacuum source and it seemed to resolve the low vacuum issue.

Should there be some type of orifice in the vent tube to keep this from causing such a leak?

I grabbed a picture I had to point out the hose I am referring to.

Thank you!

Keith
64 Monza Convert
00 911 C2
"Horizontally Opposed"
05 GTO 6-speed (Gotta have a V8)
Chicago Burbs; the Anti-Dragon... 11 turns in 318 miles

Looks like the vacuum hose is in the wrong place. The vacuum hose from the crossover goes to the small nipple (orifice inside) on the side of the vent tube. The top outlet on the vent tube gies onto the air cleaner base

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

The top is going to the air filter. The vacuum is connected to the side port.

Do you know if there is any form of restriction in the pipe, much like a PCV?

Keith
64 Monza Convert
00 911 C2
"Horizontally Opposed"
05 GTO 6-speed (Gotta have a V8)
Chicago Burbs; the Anti-Dragon... 11 turns in 318 miles

keitho64 Wrote:
-------------------------------------------------------
> The top is going to the air filter. The vacuum is connected to the side port.
>
> Do you know if there is any form of restriction in the pipe, much like a PCV?

Need a better / wider picture(s). Seems like you have a non-stock air cleaner system?

What are all the braided lines for?

Not familiar with 64; but 65 and up has a side (measured) orifice (hole) that goes to the balance tube. This hole should not be modified. Do not see this in your pic.

As Craig notes; the hose circled goes to the base of the stock air cleaner housing.

Where the hose attaches to the side port of the "PCV" tube (air cleaner to crankcase vent tube sticking out of top shroud [turkey roaster Ha!]) is an obvious restriction! If the port is wide open, then the restriction is missing. Size of restriction is in shop manual.

Frank DuVal

Fredericksburg, VA

RobertC Wrote:
-------------------------------------------------------
> Need a better / wider picture(s). Seems like you have a non-stock air cleaner system?

Correct the top hose is feeding into a K&N cone shaped air filter.

> What are all the braided lines for?

I am running an electric fuel pump and the braided lines are the supply lines from the pump, and to the carbs. I have a distribution block mounted on the firewall.


> Not familiar with 64; but 65 and up has a side (measured) orifice (hole) that goes to the balance tube. This hole should not be modified. Do not see this in your pic.

I took the vent tube off and there is an orifice in it. I plan to inspect the vent tube when I am home tonight, it does look like there is a break in it. The good news is I have another one in my stash of parts. I will try that tonight and see if it makes a difference.

>
> As Craig notes; the hose circled goes to the base of the stock air cleaner housing.

Thanks for all the ideas, I'll post the results once I get back to working on it.

Keith
64 Monza Convert
00 911 C2
"Horizontally Opposed"
05 GTO 6-speed (Gotta have a V8)
Chicago Burbs; the Anti-Dragon... 11 turns in 318 miles