Valve gap adjustment on running engine

[2011dandd]

Hi
Pretty new to the forum but having a look round in gobsmacked on how much is govered. Pretty much everything gets discussed bh the looks of things.

I am looking at adjusting or checking the valve clearences on an old petr tracror of mine. An allis chalmers b.

There is only a hot gap listed in the manual.

I was going to have a go at the doing it whilst hot method and am after asvice on how to do this exaxtly please

Am i right in thinking.
Whilst running slowly back the nut off until hearing a tapping noise. Tighten nut hust untill the point the tapping stops. Then tighten nut 1/2-3/4 a turn just past the point of the tapping noise stopping?

Cheers

[warch]

I've never heard of tappet adjustment on a running engine although it may be a thing on vintage engines. They usually recommend hot or cold clearances, the latter being less to allow for the metal expanding slightly.

[GreenV8S]

You may find that works well enough for you if you can physically make the adjustment while the engine is running, but I've never heard of that being recommended.

Typically for an engine with mechanical followers you'd stop the engine, turn it over by hand to get each valve in turn clear of the cam lobe, then measure the clearance and adjust as necessary, repeat for the other valves. For an old engine I'd suggest using a dial gauge rather than feeler gauges since the bearing surfaces may not be flat.

[Boosted LS1]

I think it was quite common to adjust them on a running engine. The oil everywhere would put me off doing it.

[warch]

How do you isolate the clatter of a loose tappet when the engine is running though, especially if you've got to do all of them?

[Auntieroll]

Boosted LS1 said:

I think it was quite common to adjust them on a running engine. The oil everywhere would put me off doing it.

The small Vauxhall OHV engines in the Viva were checked hot with the engine running.
This had the dual effect of splashing oil all over the engine /compartment and chewing up your feeler gauges !
Most engines were checked hot ,this entailed getting the engine up to running temperature , removing covers ,leads, etc ; checking clearances before the engine cooled too much , all in a day's work for an old school mechanic.

[2011dandd]

I think the idea was to listen and identify which were tapping and start with those.

Ok failing the engine running scenario. Will the full of nine method work in a straight four with a firing order 1 2 4 3?

[tapkaJohnD]

Checking and adjusting the tappets while hot does NOT require the engine to be running!
Just warm it up thoroughly, and turn it off. Check and adjust. An engine does not cool down so quickly that your settings will no longer be valid.
Think about how you will turn the engine to get the next tappet into position while the engine is hot!
Leave it in high gear on a firm surface. Even a tractor should be pushable, if you take the plugs out.

And doing it while the engine is running chews up your feeler gauges to uselessness.
John

[rigga]

Used to adjust Opel CIH engines running, had hydraulic lifters that needed setting, used to place some card over the timing chain to reduce splash, back off the adjuster till it started to rattle, then tighten a full revolution a quarter of a turn at a time .

[Boosted LS1]

Skip to about 1.28, the guys just boring :-)

https://www.youtube.com/watch?v=xCsRPxZ2SLw

[mygoldfishbowl]

Boosted LS1 said:

I think it was quite common to adjust them on a running engine. The oil everywhere would put me off doing it.

The thing to do was get an old rocker cover and cut the top out of it and place it back on the engine. Still be a bit messy but it would stop the majority of oil running down the sides of the engine.

Edit. Just like in the video you posted which I have just seen.

Edited by mygoldfishbowl on Wednesday 20th March 12:19

[Twig62]

Auntieroll said:

Boosted LS1 said:

I think it was quite common to adjust them on a running engine. The oil everywhere would put me off doing it.

The small Vauxhall OHV engines in the Viva were checked hot with the engine running.
This had the dual effect of splashing oil all over the engine /compartment and chewing up your feeler gauges !
Most engines were checked hot ,this entailed getting the engine up to running temperature , removing covers ,leads, etc ; checking clearances before the engine cooled too much , all in a day's work for an old school mechanic.

We used to slow the idle speed down as much as we could without it stalling which cut the splashing down a lot. Also we used to have long lengths of the right size feeler guage rather than constantly wrecking a set of them.

[2011dandd]

Is it just a method used for hydraulic tappets?

[DVandrews]

Hydraulic followers generally run with zero clearance.

Dave

[GreenV8S]

DVandrews said:

Hydraulic followers generally run with zero clearance.

Dave

The comment about hydraulic lifters earlier in the thread seemed to be about adjusting the preload. I guess you could do it by ear with the engine running but it seems to me that measuring them in the conventional way with the engine stopped would be better.