How to Adjust Valves in 100-6?

[hundredsixinsf]

The service book for my '59 100-6 says the valves should be adjusted HOT. How is this done? Run engine to full operating temp? Then quickly adjust the valves before the engine cools down? I've always adjusted valves in my other cars with the engine COLD.

 

[Randy Forbes]

Coincidently, while the Healey manual says .012" hot, the MGB manual (2/3s of the Healey engine) says .015" cold.

In the past, I've adjusted the Healey valves hot @ .012" and then checked them when cold: .015"

I've also done the MGB valves cold @ .015" and then rechecked them hot: .012"

Summary:
If you like touching hot metal, do them at .012" after a good long run.
If you don't like getting burned, do them at .015" cold.

Please note: loose valves will not cost you money, tight ones will.

BTW, this subject comes up often enough, and there are as many (different) answers as there are replies, so use your best judgement.

 

[hundredsixinsf]

Thanks Randy. Don't like getting burned, so I'll adjust to .015" cold.

 

[nevets]

unless you are very slow, the engine will remain "hot" throughout the valve adjusting procedure. fwiw

 

[Cutlass]

OK, all this is making me a bit confused. I've got a 66 BJ8, just completed but not run engine. My workshop manual, which supposedly is for the 100-6 also, calls for a .12 clearance, set when cold, except for competition. My mylar valve cover sticker calls for .12 cold. The information section of the Moss Motors catalog (don't laugh, cited just to illustrate the point)says .15 cold for the BJ8, .12 cold for the BN7 and BT7 as well as the 100-6. I've very carefully set mine for .12 cold, and now am fearing that the precious valves will bang into my new pistons within seconds of the first start. So why all the conflicting info, and how does a guy know what to do?

 

[Dave Russell]

There is zero danger of the valves hitting the pistons if there is any clearance at all. There is "some" danger of a valve not closing & thus burning, if the clearance is too small.

The BN1, BN2's had no tags but the shop manual recommended .012 cold.
The BN2 with 100M cam recommended .015 cold.
The BN4, BN6, BN7, & BT7 had a riveted brass plate which had .012 hot.
The BT7 & early BJ8 had a riveted brass plate that said .012 hot.
The later BJ8's had an aluminum riveted tag that said .012 cold.
The last BJ8's had a stick on foil tag that said .012 cold.

In reality, there is very little difference in actual gap between hot & cold. It won't make much difference which of the clearances you use as long as they are accurately & uniformly set. I personally would use .012 cold. If using an aftermarket cam, use the makers suggested clearances. If you want to be "extra safe" use .015 cold.

With a new engine, I would suggest periodically checking clearances until sure that they are not changing.
D

 

[Cutlass]

Now that's some straight talk that makes a lot of sense. Not only that, it's consistent with what I've already done. I remember my younger years of adjusting the valves on my '57 Chevy small block V-8, which was accomplished with the engine running, and oil squirting all over. This is a joy by comparison.

 

[Keoke]

"So why all the conflicting info" I guess its cause people don't read the number's right. /ubbthreads/images/graemlins/grin.gif Just set them at 0.015" cold on a fresh BJ8 engine and you will be good to go.---Keoke

 

[Cutlass]

So why .15, instead of .12 like the manual says?

 

[Ed_K]

[ QUOTE ]
...
With a new engine, I would suggest periodically checking clearances until sure that they are not changing.
D

[/ QUOTE ]
Thanks for the reminder. I forgot that I need to check the valve clearances more often right after a rebuild. I guess it wouldn't hurt to check the torque of the head bolts while I'm at it. I'll do both at the 1st oil change.

 

[Keoke]

[ QUOTE ]
So why .15, instead of .12 like the manual says?

[/ QUOTE ]

Because if you can hear them a wee bit you are safe.-----Keoke