1961 270HP engine problems

[Ray C.]

Hi!

I have approximately 100 miles on a rebuilt 270HP engine.
Problems: 1. I seem to have an occasional break-up or hesitation at 60 miles per hour.

2. Oil leak that splashes up and leaves a small amount of oil on the rear underside of the hood, the back rear carburetor and on the intake manifold. I have retightened the oil pressure line and installed a new gasket on the road draft tube and even a seal on the draft tube bolt.

Thanks for any help!
Ray #36314

[Roy B.]

Re: 1961 270HP engine problems

Number1 Gas starvation?
Number2 Rear intake gasket?

[Mike Cobine]

Re: 1961 270HP engine problems

1. I'm guessing you are running about 2700 rpm when it does this. It could be you have carb problems and gas is dribbling in to make it run rich.

2. You need to clean this area spotless and then take it for a ride. An old trick is to get several strips of clean white cloth and tie them around the area to help spot where the oil is coming from.

----- However, since people can do the darnest things, do not let these be places that can catch fire. Do not drive with them 1000 miles or with them oil soaked. They make great torches. Carry a fire extinguisher. -----

Take a short drive and check for oil leaks. They should be noticable on a clean engine.

If the oil line is leaking, you may have to cut it back, install a new ferrule, and reinstall.

If the rear of the intake is leaking, you may have to remove the intake and install a new gasket. I'm not sure how this flies with judging, but I've found many of the rubber end gaskets to be worthless. Most of mine end up in the circular storage bin. I run a thick bead of blue silicon gasket sealer and let it tack up about 10 minutes. Then I install the intake. Let it sit overnight.

You could have a leak up the distributor. Pull the cap and check inside.

You could have oil vapor blowing out with blow-by. Pull the oil filler cap, start the engine, and watch. If you have oil smoke blowing out, then this is likely the problem.

[Robert L.]

Re: 1961 270HP engine problems

Ray,

I had a similar problem with my '57 270.

You might check the back of the intake manifold, on the driver's side, just behind the rear carb, for two holes. They are both tapped. I am not sure what they were for, but the forward one goes all the way through the manifold. Put a bolt in that location, I think your leak will go away.

Good luck!!

Bob Lemke

MCMLVII

[Robert L.]

Re: 1961 270HP engine problems

While were talking about it... Anyone know what these holes were for?

Thanks, I always wondered.

Bob

[Verle R.]

Re: 1961 270HP engine problems

I had a significant oil leak at the back of the intake manifold that turned out to be the gasket under the distributor.

Verle

[Ray C.]

Re: 1961 270HP engine problems

You are right on!

I check my parts pegboard and in a baggie were the two bolts and the diagram that I drew showing their location. I guess I need to become a better artist; I look at the drawing two or three times during the restoration process and could not figure out where those bolts went. Now on to the hesitation problem and then decide where I can go on my first major road trip.

Thanks to all!
Ray #36314

[Tom Wander]

Re: 1961 270HP engine problems

Ray,

If you are reasonably sure that they are original, will you please post the head markings, if any, on those 2 bolts?

Tom

[Ray C.]

Re: 1961 270HP engine problems

Tom:

Before I took a good look at the head markings I would have thought they were original, but now I do not think so. The second owner told me that the only engine work that he was aware of was the replacement of a single head gasket. The parts evidence through out the rebuild helped to prove this to be a correct statement. The shape of the head is the same as fuel pump bolt (Paragon chart # 1345) and has the letters NYLOK in the center. I have searched the archives for NYLOK bolt with no luck. These must be replacement bolts. Sorry!

Ray

[Robert Willis]

Re: 1961 270HP engine problems

The bracket for an Automatic Trans kickdown .

http://members.kos.net/willisb/vette.html

[Robert L.]

Re: 1961 270HP engine problems

Tom,

Thanks,

Another mystery solved.

[Ray C.]

Re: 1961 270HP engine problems

Robert, any clue to what the head bolt markings should be on the two bolts for the bracket.

Ray

[Robert Willis]

Re: 1961 270HP engine problems

Sorry, I can't help with the bolt head markings. I will see if I can find out.

Bob

[Ray C.]

Re: 1961 270HP engine problems

Roy; Thanks for the response!

I have cleaned the rear carburetor and fuel filter bowl with no results. The engine only seems to hesitate or hick-up at approximately 2200 RPM's. Some times the hick-up is single and other times there are two or more in sequence. This is not a constant problem, it happened two or three times in a 15-mile trip. There seems to be no problem with acceleration or when I kick in the second carburetor.

Thanks for all the help!
Ray