Adjusting Valve Clearances - 2500 Engine

[Mr Tiger]

I adjusted the valve clearances on a 2500 engine yesterday following the order in the Haynes TR6 manual to 'avoid turning the crankshaft more than necessary'.

The order I used was:

Valves fully open Check and adjust
1 & 3 10 & 12
8 & 11 2 & 5
4 & 6 7 & 9
10 & 12 1 & 3
2 & 5 8 & 11
7 & 9 4 & 6

I found that by turning the crank clockwise the valves were opening in the reverse order to above. I thought that maybe I was turning the crank the wrong way but on starting the engine it does run clockwise (as far as I could see in the fading light).

I've found a web site that suggests using exactly the same order as above and also states to turn the crank clockwise.

I was working on the assumption that valve 1 is at the front of the engine (radiator end) and valve 12 is at the back (bulkhead end). Is this the wrong way round?

Also, the Haynes manual states 'an alternative method is to set the gaps with the engine running...' How do you do this?

Any advice would be much appreciated.

Thanks,

Chris

[Mr Tiger]

Sorry, the formatting's all over the place. The spaces between 'fully open ' and 'check and adjust' have disappeared.

[//j17]

I just turn the engine till a pair are open and adjust the corresponding pair that are closed - never had any thought/concern/issues with turning the crank a few times.

Not heard of setting them with the engine running - sounds dangerous to me and they are meant to be set cold, not in varying states of warming-up.

[Silvertop_John]

Thought it was just me - I was following the same list the other day, and assumed that I had somehow missed the next lot of valves closing. Ignored the manual from then and just watched for the next pair, wherever they were!
Although it relates to a 4 cyl engine, there's an interesting article on valve adjustment here:
http://www.macysgarage.com/myweb6/valve_adjustment...

John

[DocArbathnot]

Mr Tiger said:

Also, the Haynes manual states 'an alternative method is to set the gaps with the engine running...' How do you do this?


Chris

I tried this once, everthing got covered in oil, so gave up and went for the traditional method.

[Mr Tiger]

Thanks for the replies.

It looks like the good old Haynes manual has the order the wrong way round. If you read it bottom to top I think it'll be correct.

The Macy's article is good and clears up a couple of grey areas for me. It confirms that valve No 1 is at the front of the engine and that the crank should be rotated clockwise.

Also, the first diagram explains why having the 'open' valve precisely, 100% open is not necessary. I'd always stressed about this and turned the engine back and fore many times until I was satisfied the valve was neither opening nor closing. The article confirms this stating that 'when the valve has fully opened and just starts to close', you adjust the corresponding valve.

I took the car for a spin this evening as the weather is kind and it does seem to be running a little better. It's slightly smoother, slightly less tappety and has a little bit more go in it. It's still not right but I think that's down to the carbs. I' think I'll get new jets and needles and take it from there.

Thanks again

Chris

[tapkaJohnD]

Mr.Tiger,
You need to use the "Rule of Thirteen"
Valve One is at the front, the exhaust valve for Bore No.1
For example, when Valve One is fully raised, subtract one from thirteen. Equals twelve. Adjust valve Twelve.
Then Valve Three gives Valve Ten (13-3=10). Adjust Valve Ten.
And so on.
That's where the Haynes table comes from, but if you know the theory, you can understand when someone else makes a mistake.

I keep a pot of vaseline by me, and leave a smear on each valve I have adjusted, so no need to keep score or tick off each valve on a list, and I can start and finish anywhere in the sequence.

This works with a four cylinder engines too, by applying the Rule of Nine.
John

Edited by tapkaJohnD on Wednesday 25th September 23:40

[//j17]

tapkaJohnD said:

I keep a pot of vaseline by me, and leave a smear on each valve I have adjusted, so no need to keep score or tick off each valve on a list, and I can start and finish anywhere in the sequence.

My method is to start with whatever comes first then go all the way through till I hit #12 without having to change anything. Extra, pointless work - in theory - but if I've checked 1 to 12 without needing to make any changes at least I know I've got them all correct!