65 Vette Help

[Eddie Z.]

My 65 327/365 hp won't rev past 4500 in all gears.It runs Perfect till then.Was told it sounds like broken valve spring.
Would appreciate other opinions,before I take it apart.
Thank You Eddie Zak

[Joe L.]

Re: 65 Vette Help

My 65 327/365 hp won't rev past 4500 in all gears.It runs Perfect till then.Was told it sounds like broken valve spring.
Would appreciate other opinions,before I take it apart.
Thank You Eddie Zak

Eddie------


With a broken valve spring it wouldn't run perfect at any engine speed. However, it's very easy to check. If you can rotate a valve spring by hand, you've found the broken spring.

[Mike T.]

Re: 65 Vette Help

Eddie - Welcome to the TDB. As Joe pointed out, if a valve spring were broken, it would run ragged at any rpm. Can you fill us in on some background info like how fresh is the engine, when was it tuned last including valve adjustment, etc? Any idea of the timing settings?

[Gene M.]

Re: 65 Vette Help

Was it running past 4500 recently? If so what did you change. Not enough here to go on. Points, wires, cap, carb, vacuum leaks, points dwell, timing, advance, all stock, what ever gotta tell us something.

[Eddie Z.]

Re: 65 Vette Help

Mike-Bought vette about 8 months ago.I haven't had much time till now to drive her.Jersey Winters Blahh.I put new plugs,replaced AC Delco with NGK's.New dist cap rotor.Basic tune up.It has crane electronic ignition and flamethrower coil.I thought at first the rev limiter might have been set low so I set it to max.Carb was adjusted and timing set by a friend of mine,He's runs carb shop and when I brought the car for him to see.He said pop the Hood and he made some adjustments to carb and timing.The mileage reads 33,000.I wanted to have the valves adjusted,I can't find anyone who wants the job.I never adjusted valves and a matching #'s 65 Stingray is not the place to begin.
By the way engine is 327/365hp.I believe he had to set dwell around 15btdc for it run right.I read 12 is right.I have the figures in the car,but I can't get to garage till tomorrow.I'll write then Thank You so much for your Help

Eddie Zak

[Gene M.]

Re: 65 Vette Help

Mike-Bought vette about 8 months ago.I haven't had much time till now to drive her.Jersey Winters Blahh.I put new plugs,replaced AC Delco with NGK's.New dist cap rotor.Basic tune up.It has crane electronic ignition and flamethrower coil.I thought at first the rev limiter might have been set low so I set it to max.Carb was adjusted and timing set by a friend of mine,He's runs carb shop and when I brought the car for him to see.He said pop the Hood and he made some adjustments to carb and timing.The mileage reads 33,000.I wanted to have the valves adjusted,I can't find anyone who wants the job.I never adjusted valves and a matching #'s 65 Stingray is not the place to begin.
By the way engine is 327/365hp.I believe he had to set dwell around 15btdc for it run right.I read 12 is right.I have the figures in the car,but I can't get to garage till tomorrow.I'll write then Thank You so much for your Help

Eddie Zak

Eddie,
I suggest be sure you have premium fresh gas to start. Get a set of premium points, wires, long style rotor and cap, no china stuff. Loose the after market hot rod ignition stuff. The engine should run correctly without that variable tossed in.
Dwell should be at 30-31 degrees, and timing in the 12 degree range. There is a suggestion for a good starting place. Many replaced parts can be of lesser quality than what was removed by previous owner.

[Duke W.]

Re: 65 Vette Help

The number one suspect if the engine just shuts down at high revs - like turning off the ignition - is the fuel filter.

You have confused dwell angle with initial timing. Dwell should be nominally 30 degrees and variation should be no more than two degrees as you free rev the engine to 6000 revs. You will need an old fashioned dwell meter, which I think you can still buy, and many guys with vintage cars have them. Your local NCRS chapter would be a good source to find one.

Aftermarket "electronic" points and hokey coils cause lots of problems. I don't recommend them. Install a set of points and a reproduction or generic OE replacement coil. Mechanical lifter engines need the 32 oz. points and the distributor shaft must have proper end play and virtually no side play and a wobble free breaker plate. Many were assembled with sloppy end play from the factory which can cause ignition breakup at high revs.

The above has been extensively discussed here. Use suitable search words for threads started by me on distributor blueprint overhaul and contact sets.

NGK makes a zillion plugs but only a couple are correct for your engine. What is the NGK plug number you installed?

Valve adjustment is easy and can be done with the engine off and cold. Google Williams Hinckley valve adjustment and downlaod the 9/08 version of the paper from the site lbfun.

If you have not already done so purchase a 1963 Corvette Shop Manual and 1965 Supplement. These cars are very simple and tuneups and most repairs can be done with basic hand tools.

Duke

[Roy S.]

Re: 65 Vette Help

You have a rev limiter of some type and the car only goes to 4500RPM? My guess is one of two things, either that electronic system is screwed up and choking you to 4500rpm or you have a fuel delivery issue.

[Eddie Z.]

Re: 65 Vette Help

I use Shell Premium and I add a fuel additive.Car runs Perfect,but dies at 4500rpm every gear.All the parts I bought were from Ecklers or Corvette America.I joined this website to try and get some History of vette and possibly talk to previous Owners.Tech Help has been outstanding.
This car should be an animal.I need to sort this out quick while the weather is still Nice.I appreciate everyones Help.

Eddie Zak

[Duke W.]

Re: 65 Vette Help

What is the PON rating of the Shell Premium? What "fuel additive" are you using? What is it supposed to do? As a general rule, aftermarket fuel additives are not necessary on vintage Corvette engines, and many are snake oil of dubious value.

Use a feeler gage set to measure head gasket thickness. Measure at the front corners of the head-block interface. Start with a .010" gage and increase gage size by one thou at a time until the gage slides in with a little resistance and the next thou up is a no-go. Let us know the result.

Duke

[Edward J.]

Re: 65 Vette Help

I think Duke likely hit the nail on the head at that RPM range fuel demand is high and a clogged fuel filter or fuel delivery is likely the problem. (i.e. pump or clasped hose at intake side of system)

[Mark E.]

Re: 65 Vette Help

What does it do at 4500 RPM? Does it run progressively worse as engine speed increases? Or completely and suddenly cut out? Or continues to run smoothly but just won't rev higher?

Is the symptom the same whether under load (for example, while accelerating up hill) or just reving in neutral?

If it occurs under load, does it rev strongly to 4500, then just act up? Or does it struggle/miss up the power band?

EDIT: Re-read your original post: "won't rev past 4500 in all gears. It runs Perfect till then."

Duke, Roy, Edward: If it's fuel starvation, would we expect the problem to begin at varying engine speeds, depending on engine load? And be less consistent and sudden? Maybe start with the aftermarket rev limiter if it runs perfect until 4500 RPM, and then cuts out suddenly and consistently at the same RPM regardless of engine load,?

[Eddie Z.]

Re: 65 Vette Help

Runs Great to 4500.Smooth and Quick.At 4500rpm it reminds me of a Gov as used in Military Trucks.It just bogs and if I leave the pedal down it will sputter.I shift to 2nd same thing smooth power and then same as 1st gear.Also in 3rd and 4th stops at 4500.
I thought previous owner might have set rev limiter to 4500.I removed cap and set it to max 8000.It's a Crane ignition with rev limiter 4000-6000-8000.I'm not sure what the setting was before I maxed it.I was thinking of getting another unit from crane, same thing.Here is photo:$_12cxc.jpg

[Mark E.]

Re: 65 Vette Help

It's hard to say for certain over the internet, but before changing anything else I would begin with trouble shooting the electronic ignition/rev limiter.

As Duke suggested, try putting the stock points/condenser/coil back in and see what happens.

[Eddie Z.]

Re: 65 Vette Help

It came with this set up.I didn't add it on.I was never told it had the crane ignition when I bought it.I discovered it when I replaced the cap,rotor.plugs etc.The whole idea of having different setting,isn't for me.I would have gone with petronix or any other Brand.Stock would have been fine with me.My first step as you said is to replace the rev limiter,and take it from there.The fun begins.

Thanks Mark