Thread: refacing auto valves

I'm going to ask what the valves are made from first.......As this will dictate the answer to the question.

There are quite a few videos on You Tube on engine valves, Everything from re-seating to weld buildup's and even on making new ones..
Matt

Phil Irving's book, "Tuning for Speed", describes a repair using hard face material.

Jordan

Not that I would argue with Phil, but wasn't one of the things lead in fuel did was lubricate the exhaust valve face?

Stuart

I've heard that too, but Irving was no dunce with engines.
I have some old engines that were made in the days of lead, but they don't seem to be suffering at all from not having it.

Jordan

I think Irving is refering to racing engines where the running temps. are higher and so on. Stelliting is a special process where hotter than normal temps are expected in service. I was mainly asking about normal run of the mill use . I refaced the valves ( inlet and Xhaust) of a Holden red motor in my lathe , and the original metal was surprisingly easy to remove with a HSS tool - in that case there was enough meat there left on the circumference to do it .

I didn't know that welding with Stellite was highly specialised.
It looks like you could pick some other material.

Jordan

I have reground plenty of valves over the years ( Worked as a Diesel Fitter for 26 years before I bought the business I have now ), but if they were that worn that they couldnt be reground, I wouldnt even think about building them back up with weld, I would just buy new ones.
Surely they arent that expensive to take the risk ?

Even if they are an odd size and not readily available, you can buy blanks and machine them to the correct size. This is what I did with my BSA that had been modified by a previous owner.

The amount of work needed to weld, turn, then grind, valves would be more than it cost to buy some. Though if you have the gear and time that's different.

Ric Bundesson in Brisbane can make them in stainless to a supplied sample and supply seats as well. If you do reface valves you'll need to cut new seats as well and if there's no meat left in the head you're stuffed. You'll need to add inserts.

Be aware that some exhaust valves were sodium cooled so working on these could mean a trip to the ER or a trip to Jesus.

If you want to do your own valves look around for the Warren and Brown Synchro Seater tool and a valve grinder, does a first class job and you can modify the valve grinder to do basic cylindrical grinding.
Garry

As said above it is not worth the bother unless they are fom a classic and not available any more, just replace them, if they are that far gone I would be having a close look at the seats as well

I've fooled about with lots of engines in the past. Doing things I'd mostly never want to do again!

As others have said you are better off with new valves. The forces exerted at the neck where the head meets the shaft progressively weaken the valve. We lost the head off an exhaust valve once. This necessitated a full rebuild, luckily in a sleaved 4 cylinder. Bits of valve wedged between the piston and cylinder wall can have disastrously destructive consequences.
Even the rarest of valves is replaceable and it's pretty cheap insurance when you consider the possible consequences.

Yes I understand . I have seen that business in Brisbane that will make new valves to a sample ....from stainless steel. I know it was common practice years ago to reface valves by welding ..... when new parts were unobtainable or where a situation demanded it eg. The Book 'Half Safe' tells the story of a amphibious Jeep that crossed the Atlantic ocean in the early 1950's ... they burnt an exhaust valve and it was rebuilt in the Azores , using a oxy set ! The island had a acetelyn generator . The book turns up at op shops and on EBAY .... an amazing epic by Ben Carlin .Half-Safe Across the Atlantic by Jeep*Ben Carlin 1st Ed | eBay Much of those engineering skills are gone these days ... we are spoilt . MIKE

Just a note on Ben Carlin.

His wife left him when he wanted to sail (drive?) his Jeep form England to Australia.

His Jeep is now in (I think) Perth Grammar School as he was an Old Boy of the School.

Me I'd just buy new valves, as engines are too expensive to keep rebuilding. My last two both ran $40,000+!

Originally Posted by zuffen

Just a note on Ben Carlin.

His wife left him when he wanted to sail (drive?) his Jeep form England to Australia.

His Jeep is now in (I think) Perth Grammar School as he was an Old Boy of the School.

Me I'd just buy new valves, as engines are too expensive to keep rebuilding. My last two both ran $40,000+!

Yes I don't blame her ..he was a heavy drinker . But a very clever engineer as well. The Jeep was brought over to the Eastern states from Perth, for a Jeep rally in 1998 I think it was . I was there at the rally and have seen the sailing Jeep . He was in Melbourne with it in the mid 1950's . It was on display at Myers store in the city where he was signing copies of the book. It's a good read . Mike