New rebuilt 427/425 hp, What oil/gas

[john lokay]

Re: Addendum

Jerry, I have a 427/450 coupe and had the engine rebuilt a number of years ago with a factory clone type cam (11:0 to 1:00 compression ratio). I change the oil twice a year. In the winter months (Long Island NY) I run a 10-40W grade oil and once the weather starts to warm up (like now) I switch over to a 20-50W grade. I have in the past used synthetic oils but given how much expensive they are and the fact that I change the oil twice a year I decided to stay with conventional oils. Also, comments on the DB concering synthetic vs. non-synthetic oils appear to lean towards the use of non-synthetics. As for the type of gas, in the hotter summer months I mix 5 gallons of racing fuel (111 octane) with 15 gallons of Texaco 92 octane. In the winter, with the colder weather, I'll mix 2.5 gallons of racing fuel with the Texaco pump gas. This has worked for me and the car runs fine. I do not use any fuel and/or oil additives as you usually can't tell what's in this stuff.

[john lokay]

Re: Addendum

Jerry, I have a 427/450 coupe and had the engine rebuilt a number of years ago with a factory clone type cam (11:0 to 1:00 compression ratio). I change the oil twice a year. In the winter months (Long Island NY) I run a 10-40W grade oil and once the weather starts to warm up (like now) I switch over to a 20-50W grade. I have in the past used synthetic oils but given how much expensive they are and the fact that I change the oil twice a year I decided to stay with conventional oils. Also, comments on the DB concering synthetic vs. non-synthetic oils appear to lean towards the use of non-synthetics. As for the type of gas, in the hotter summer months I mix 5 gallons of racing fuel (111 octane) with 15 gallons of Texaco 92 octane. In the winter, with the colder weather, I'll mix 2.5 gallons of racing fuel with the Texaco pump gas. This has worked for me and the car runs fine. I do not use any fuel and/or oil additives as you usually can't tell what's in this stuff.

[Duke W.]

Re: Addendum

The primary advantage of synthetic oil is longer life due to their higher oxidation resistance, so if you only drive a few hundred to a few thousand miles per year and change the oil at least once the year, there's no benefit to the higher price, and the CF-4 oils, which are mineral oil based, have a better additive package that will add life to a vintage carbureted engine.

All the synthetics that I am aware of are designed for spark igntion engines and their additive package is not rich enough to earn the American Petroleum Institute's (API) CF-4 rating.

Duke

[Duke W.]

Re: Addendum

The primary advantage of synthetic oil is longer life due to their higher oxidation resistance, so if you only drive a few hundred to a few thousand miles per year and change the oil at least once the year, there's no benefit to the higher price, and the CF-4 oils, which are mineral oil based, have a better additive package that will add life to a vintage carbureted engine.

All the synthetics that I am aware of are designed for spark igntion engines and their additive package is not rich enough to earn the American Petroleum Institute's (API) CF-4 rating.

Duke

[Jerry A.]

Re: Eric, just so you know-

I would also like to know as to why the engine would run cooler using 20W-50 as mine does run hot!

Jerry

[Jerry A.]

Re: Eric, just so you know-

I would also like to know as to why the engine would run cooler using 20W-50 as mine does run hot!

Jerry

[Jerry A.]

Re: Addendum

Thanks again Duke,
How about suggestions on getting it running cooler?

jerry

[Jerry A.]

Re: Addendum

Thanks again Duke,
How about suggestions on getting it running cooler?

jerry

[Duke W.]

Re: Addendum

High temperatures on big blocks is a problem. We've had discussions many times. The first thing to be sure of is that your radiator is in tip top condition. Deposit buildup in the tubes increases thermal resistance, which reduces heat transfer even if it still flows well.

Also make sure your ignition is set up to spec especially the initial timing and vacuum advance. I believe the OEM vacuum can provided max advance at 12" and it should be attached to a full manifold vacuum source , but if the engine idles at less than 12" you should consider the 8" can from the '65 SHP/FI distributor. A higher idle speed will increase vacuum and fan speed. You should idle it between about 900 and 1000. Lower idle speeds could cause higher temperatures. In general, more timing at idle will reduce the thermal load, but too much initial can get you into detonation under load. It's a balancing act.

Duke

[Duke W.]

Re: Addendum

High temperatures on big blocks is a problem. We've had discussions many times. The first thing to be sure of is that your radiator is in tip top condition. Deposit buildup in the tubes increases thermal resistance, which reduces heat transfer even if it still flows well.

Also make sure your ignition is set up to spec especially the initial timing and vacuum advance. I believe the OEM vacuum can provided max advance at 12" and it should be attached to a full manifold vacuum source , but if the engine idles at less than 12" you should consider the 8" can from the '65 SHP/FI distributor. A higher idle speed will increase vacuum and fan speed. You should idle it between about 900 and 1000. Lower idle speeds could cause higher temperatures. In general, more timing at idle will reduce the thermal load, but too much initial can get you into detonation under load. It's a balancing act.

Duke

[Clem Z.]

Re: New rebuilt 427/425 hp, What oil/gas

unless the engine has been rebuilt with very loose bearing clearance you should never run any oil thicker than 10W-30. thick oil takes for ever to get throught the oil filter and it causes the filter bypass to open letting unfilter oil into the engine. years ago i have raced BB chevy at daytona and have never used any thing heavier than 10W-30. if you do not believe me,block the oil filter bypass and see how long it takes for the oil pressure to come up on the gage.

[Clem Z.]

Re: New rebuilt 427/425 hp, What oil/gas

unless the engine has been rebuilt with very loose bearing clearance you should never run any oil thicker than 10W-30. thick oil takes for ever to get throught the oil filter and it causes the filter bypass to open letting unfilter oil into the engine. years ago i have raced BB chevy at daytona and have never used any thing heavier than 10W-30. if you do not believe me,block the oil filter bypass and see how long it takes for the oil pressure to come up on the gage.

[Jerry A.]

Re: New rebuilt 427/425 hp, What oil/gas

Thanks Clem,
Most people are saying to use 20W-50. One guy at work is saying to use valvoline racing oil which is 20W-50. I planned to use Mobil 1 10W-40 full synthetic. Please comment!

Jerry

[Jerry A.]

Re: New rebuilt 427/425 hp, What oil/gas

Thanks Clem,
Most people are saying to use 20W-50. One guy at work is saying to use valvoline racing oil which is 20W-50. I planned to use Mobil 1 10W-40 full synthetic. Please comment!

Jerry

[Jerry A.]

Re: Addendum

Thanks again Duke!

Jerry