1963 FI with engine vibration

[Scott M.]

My dad purchased a 1963 numbers matching coupe with fuel injection late last summer. He complained of a few things, one being an engine vibration. I live in a different state than him, so he asked around and took it to the recommended mechanic. He advised him the motor has a bent connecting rod. He added this was a common problem with the FI motors due to fuel leakage when the motor was shut off after driving. I went to visit a month ago and there definately is a vibration that seems from the engine. It's at the worst around 1500 rpm. If the clutch is pushed in it seems to change a bit. Was this a common problem with these engines? Is there any other possible causes? Would a compression check show the suspect cylinder, or how could you determine if a rod is bent? thanks

[William C.]

Re: 1963 FI with engine vibration

You have a real can of worms here, Yes, bent rods with FI engines are sometimes an issue, caused by a failure of the anti-syphoning systems in the FI to keep fuel from draining into a shut-off engine and causing a cylinder to get raw gas into it and creating a "Hydraulic lock" when the engine is cranked. That said, a clutch out of balance, or flywheel balance issue can also cause the problem. Unfortunately, you MIGHT be able to see a bent rod if you pull the pan and look, but you also Might not. There is a list of things to look for to determine if you have a fuel feed problem with a shut down FI, you might find it in the archives. Sounds like a rebuild of the FI (or at least a shutoff solenoid in the high pressure line) and or the engine with balancing of the rotating parts is in order, just in time for the summer!

[Jeff C.]

Re: 1963 FI with engine vibration

Given your reference to pushing in the clutch is the vibration while you are driving? If so the drive shaft balance could also be the problem.
Jeff

[Scott M.]

Re: 1963 FI with engine vibration

The vibration is present stopped with engine at idle. I just happen to notice pushing on the clutch seemed to make a slight change.

[Clem Z.]

Re: 1963 FI with engine vibration

run a compression check and if you have a bent rod that cylinder should show a lower pumping pressure because the piston will not be coming up as far in the cylinder

[Scott M.]

Re: 1963 FI with engine vibration

that's what I thought but how much less? Im not sure how fresh the engine is so how would you know if it was a bent rod or worn components?

[Clem Z.]

Re: 1963 FI with engine vibration

that's what I thought but how much less? Im not sure how fresh the engine is so how would you know if it was a bent rod or worn components?

if a rod is bent it should show a noticeable drop in pressure compared to the other cylinders

[John D.]

Re: 1963 FI with engine vibration

Scott, #1. Find out if it has a repro harmonic balancer. Some of them have been know to be out of balance. Quick check is to look at it when the engine is running to see if its running true. If it wobbles you know the cause of your vibration. Your car has a finned harmonic balancer. By the way the Key Word is Some repro balancers.

#2. Hopefully your fuel injection unit did not cause hydraulic lockup. If a guy is lucky only the number 8 or so connecting rod with bend. If someone is very unlucky the engine will be destroyed with a rod going thru the block.
#3. Even if your fuel injection is properly restored and has all the good parts in it if a fuel car sits around for a long period of time stashed back in the corner the old gas will cause the anti-siphon valve in the fuel meter to stick,etc etc and then engine failure can be the result.

[Scott M.]

Re: 1963 FI with engine vibration

Here are some photos of the balancer. It runs true with engine running. Whats the answer for the anti-syphon valve? physically check it everytime your going to drive the car?

[Jim T.]

Re: 1963 FI with engine vibration

Scott like John (2855) mentioned in his post, your dad's 63 FI engine should have a finned balancer, your picture shows that it does not.

[Scott M.]

Re: 1963 FI with engine vibration

I don't think I have ever seen a finned damper. I wonder were I can find the correct one?

[Bruce B.]

Re: 1963 FI with engine vibration

Scott,
This is the correct type of harmonic balancer for a 63 FI engine.
Fins are on the back side.
Check Ebay or swap meets and you will find one sooner or later.
Bruce B.

[Joe M.]

Re: 1963 FI with engine vibration

front cover may need to be changed as the timing tab would be in the way of an 8" finned balancer if the front cover/tab position is matched for the 6" balancer on there now.

[Timothy B.]

Re: 1963 FI with engine vibration

The engine has a 300 HP balancer and it looks like someone has had the pan off recently.

[Scott M.]

Re: 1963 FI with engine vibration

I checked the timing tab and it is off the balancer by better than an inch so I think it's probably the correct one. I to saw the pan had been off which made me think someone new about the problem and thought it was a rod. Know I wonder if the ignition timing is correct?