Mechanical cam valve adjustment at engine plant

[Colin M.]

The mechanical cam Big Blocks came from the engine plant ready to install. How did the valve clearance required get adjusted as all info on the adjustment is to be made "hot"

[Joe L.]

Re: Mechanical cam valve adjustment at engine plant

The mechanical cam Big Blocks came from the engine plant ready to install. How did the valve clearance required get adjusted as all info on the adjustment is to be made "hot"

Colin------


The factory did not adjust the valves "hot-and-running". They were adjusted using the same procedure you will find in the Chevrolet Service Manual and that procedure did not specify it was to be done with the engine "hot".

So, what do I recommend? I recommend doing it the way the Chevrolet Service Manual instructs.

[Colin M.]

Re: Mechanical cam valve adjustment at engine plant

Chassis service manual 6-11 states item 1 "normalize engine" item 4 states Stop engine ? Item 6-28 (f) "readjust valves [hot and running] as outlined under"Engine tune up" I am very familiar with adjusting running but how was this achieved when the engine was not hot?

[Joe L.]

Re: Mechanical cam valve adjustment at engine plant

Chassis service manual 6-11 states item 1 "normalize engine" item 4 states Stop engine ? Item 6-28 (f) "readjust valves [hot and running] as outlined under"Engine tune up" I am very familiar with adjusting running but how was this achieved when the engine was not hot?

[Colin M.]

Re: Mechanical cam valve adjustment at engine plant

Thanks Joe, I have the 1967 "Chassis Service Manual" It was printed in 1966 . I have both original volumes. I have a Mechanical cam 1967.

[Joe L.]

Re: Mechanical cam valve adjustment at engine plant

Thanks Joe, I have the 1967 "Chassis Service Manual" It was printed in 1966 . I have both original volumes. I have a Mechanical cam 1967.

Colin------


I think I see what the problem is here. As I checked a little further in my 1969 Service Manual I see that there are two different procedures shown for valve adjustment. The first is shown in the Engine Tune-Up section on pages 6-13 and 6-14. The second is shown in the Engine Mechanical section on pages 6-29 and 6-30. I expect that the same is true of the 1967 Service Manual except the page numbers are different. It is the second procedure that I am referring to. I am very confident that this was the procedure used at the engine plants to adjust the valves on new engines. It is also the procedure that I use and recommend.

[Colin M.]

Re: Mechanical cam valve adjustment at engine plant

Thanks Joe, Still having wonder at how they did it! Firstly the 67 Overhall Manual does not touch on the subject. The Engine Section 34 pages does not go that far.
If we go to the Chassis Service Manual we have the proceedure of Static rolling the engine over and adjusting valve clearance based on the position of the Crankshaft. I am very familiar with this proceedure The final item on the list outlining the above item f as described says "readjust valves hot and running. I use this method using drippers and a cutout valve cover. On page 8 "Specifications" it calls out valve clearance .024 Intake .028 Exhaust with asterist *Engine at operating temperature and running.

What did they do at Tonawanda ?

[Joe L.]

Re: Mechanical cam valve adjustment at engine plant

Thanks Joe, Still having wonder at how they did it! Firstly the 67 Overhall Manual does not touch on the subject. The Engine Section 34 pages does not go that far.
If we go to the Chassis Service Manual we have the proceedure of Static rolling the engine over and adjusting valve clearance based on the position of the Crankshaft. I am very familiar with this proceedure The final item on the list outlining the above item f as described says "readjust valves hot and running. I use this method using drippers and a cutout valve cover. On page 8 "Specifications" it calls out valve clearance .024 Intake .028 Exhaust with asterist *Engine at operating temperature and running.

What did they do at Tonawanda ?

Colin------


Yes, I see that it does say to adjust hot and running per "Engine Tune-Up" at the end of the procedure under "Engine-Mechanical". However, I don't think this was ever done at the factory. I think the factory used the non-running procedure described under Engine-Mechanical and that was it. I've used this procedure and it worked just fine without any subsequent hot-and-running adjustment.

The factory did hot test engines but I highly doubt that any sort of "hot and running" valve adjustment was ever done. Perhaps there was an instruction under "Dealer Prep" for mechanical lifter engines to have valve adjustment checked.

[Larry M.]

Re: Mechanical cam valve adjustment at engine plant

Colin------


Yes, I see that it does say to adjust hot and running per "Engine Tune-Up" at the end of the procedure under "Engine-Mechanical". However, I don't think this was ever done at the factory. I think the factory used the non-running procedure described under Engine-Mechanical and that was it. I've used this procedure and it worked just fine without any subsequent hot-and-running adjustment.

The factory did hot test engines but I highly doubt that any sort of "hot and running" valve adjustment was ever done. Perhaps there was an instruction under "Dealer Prep" for mechanical lifter engines to have valve adjustment checked.

Joe and Colin:

I would support (agree) that the last sentence above is how it was accomplished.

I grew up with Fords during this period, and I know the 427/425 SHP Ford engine required a bit "different" Dealer Prep than the others. Dad worked at the Ford Dealership as a transmission line mechanic........and I grew up in that garage. They had a special mechanic (Freddie) who did all the dealer prep on the cars. I got to detail them, and in some cases deliver them to the new owner at his house.

They didn't get too many of the 427/425 cars at the dealership, but I remember when they did. . They also had/sold an AC Cobra and a lot of the Shelbys during that time. But the solid lifter engines were special.

Larry

[Bill M.]

Re: Mechanical cam valve adjustment at engine plant

Colin------


Yes, I see that it does say to adjust hot and running per "Engine Tune-Up" at the end of the procedure under "Engine-Mechanical". However, I don't think this was ever done at the factory. I think the factory used the non-running procedure described under Engine-Mechanical and that was it. I've used this procedure and it worked just fine without any subsequent hot-and-running adjustment.

The factory did hot test engines but I highly doubt that any sort of "hot and running" valve adjustment was ever done. Perhaps there was an instruction under "Dealer Prep" for mechanical lifter engines to have valve adjustment checked.

There is an article in Corvette News about building the 427 at Tonawanda. There is a picture of the assembler adjusting the valve lash with a feeler gage on the assembly line. The engine was not hot at that point.

[Colin M.]

Re: Mechanical cam valve adjustment at engine plant

Thank you Bill , Would you have the date on the Corvette News article.

[Joe L.]

Re: Mechanical cam valve adjustment at engine plant

There is an article in Corvette News about building the 427 at Tonawanda. There is a picture of the assembler adjusting the valve lash with a feeler gage on the assembly line. The engine was not hot at that point.

[Bill M.]

Re: Mechanical cam valve adjustment at engine plant

Thank you Bill , Would you have the date on the Corvette News article.

Sure. 1966 Vol.9 No.3 The article is also in The Best of Corvette News.

[Bill B.]

Re: Mechanical cam valve adjustment at engine plant

Page 523, photo 12 in the Best of Corvette News. Obviously cold and not running as no Carb installed and a cover atop the intake.

[Colin M.]

Re: Mechanical cam valve adjustment at engine plant

Thank you Bill. Best wishes and good health from Australia!