Classic cars forum & vehicle restoration.

Rusty · Posted: Mon May 12, 2025 1:03 am Post subject:

Old BMC/Leyland A, B and C series engines used to be done with the engine running, as instructed by the factory, I was trained in a Leyland workshop, and all tappets (except for those done cold in an engine rebuild) were done "hot" with the engine running, and rebuilt engines had the tappets "re done running" after the head had been re tensioned after being heated up to operating temperature. After you have done them a few times, it's not hard, I still do them this way.

ukdave2002 · Joined: 23 Nov 2007 Posts: 4242 Location: South Cheshire

We could have a similar debate with tyre pressure's, they change with both temperature and altitude.

If you set your tyre pressure in Buxton on a hot summer day , then drove to the coast which by freak of UK weather was near freezing, the tyre pressures would now be around 5psi lower.....

Ray White · Joined: 02 Dec 2014 Posts: 7140 Location: Derby

...and I was wondering if anyone would have anything to say about this sort of stuff...??

It would seem there is plenty to discuss. Very Happy

Maybe someone knows why older Riley engines are so clattery? They are all like it ...which surprises me, as they have short push rods, which require closer tappet clearances.

What I am unsure about is how a cam profile can affect the tappet clearances.?

peter scott · Joined: 18 Dec 2007 Posts: 7215 Location: Edinburgh

A friend of mine had a fleet of six or seven 2.5 litre Riley RMs that he used for wedding hire and I can certainly confirm that they were all very clattery.

Peter
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Ray White · Joined: 02 Dec 2014 Posts: 7140 Location: Derby

Just out of curiosity, I looked up the tappet clearances for a Bristol 2 litre engine. (The aerodyne cars have always been a favourite and high on my wish list) and found that they should be adjusted cold...but get this... clearance is only 0.002". What is even more surprising is that it applies to both inlet AND exhaust.!

These wonderful engines are, of course, rather sophisticated and nothing would surprise me when it comes to Bristol (with pre War BMW origins).!

https://bristoloda.org/wp-content/uploads/2013/01/400-manual-Section-1-Engine-Exhaust.pdf

Miken · Joined: 24 Dec 2012 Posts: 577

Penman · Joined: 23 Nov 2007 Posts: 4866 Location: Swindon, Wilts.

I can't remember the clearances, but some, or maybe, all the OHV mid 30's Vauxhalls were supposed to be adjusted dynamically (while the engine was ticking over) definitely a 3 handed job.
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Any 2 from:-
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alastairq · Joined: 14 Oct 2016 Posts: 2121 Location: East Yorkshire

On the Ford small sidevalve engines [1172cc]...8 & 10HP types, there are no tappets [from the factory]....clearances being set by either mixing & matching cam followers, or taking a smidgen off the foot of a valve stem.
The Buckler Register ....whose prides n joie often used Ford sidevalve power....has an article in their bulletin describing how it was best to measure and adjust valve clearances using a dial indicator, with the head off[or was it, orff with his head???]...
That way, bearing in mind the minimum required clearance, the required amount of valve lift was to be aimed for....which may or may not result in the expected Ford method of setting the clearance values..to be differed from. Subject to the minimum clearances as noted above.
Might make the valve train a tad rattly, but the main thing was achieving the intended valve lift values.
Side valves, of course.
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