tips for valve seat freshen up - Methanol

[28BHKS]

I've really enjoyed reading many posts on this forum and have learnt a lot, first time posting though...

My buddy has been running a 161 ST Esslinger midget engine on 1/4 mile circle tracks locally. He purchased it about 12 months ago as a rebuilt engine with dyno sheets after build. I'm giving him a hand to freshen it up for the coming season. I'm a novice engine builder but keen to learn and I've been buying tools as I need, some new some on ebay. I've had no prior experience on methanol.

We are looking to freshen up the valve job, replace the valve springs. The bore, mains and rod journals look as new so we are going to leave as is.

It has titanium valves (not sure if they are coated) retainers and locks with copper berrylium seats. The valves look as good as new (stem and face) and the engine supposedly had very little hours on it before he purchased it. Ran mid pack most of the season as it's the drivers first year, so we are looking to get one more season then might step up to a newer model power plant.

The seats however are really wide and look to be hammered and concave. I don't have the head in my possession currently to measure, but they are twice the width that I would have expected. The seats look to be 50 degree, and the seat contact area is the full width of the valve face.

From my research I can't see that the seats should be as wide as they are, but I'm keen to hear any recommendations.

I have sioux grinding stones, pilot 11/32 (both fixed and adjustable) and stone holder, air driver, valve seat runout gauge and a valve run out gauge.

We are thinking we'll have a go ourselves at grinding the seats, a little nervous being the first time On a performance application but want to learn.

Should the seats be .040" wide or would you go wider for methanol? Should we spray the seats with WD40 before grinding, or just grind dry with breathing mask?

I'm thinking we cut the seat first and then top and bottom cut after to suit using the same angles that are there currently. Face the valves and check runout, engineers blue and vacuum test (we have a vaccum test set up)

Any help/tips would be much appreciated.

[cgarb]

Might want to think twice on grinding copper seats. That dust is real bad for your lungs. If I had to do it I would wear a respirator.

[Schurkey]

The Beryllium dust is toxic.

The dust will get on your clothing, potentially contaminating your family.

https://www.osha.gov/beryllium/health-effects

[28BHKS]

Thanks guys, I was wondering how bad it was, or how much protection was needed. Would a 3M canister typr respirator and disposable overalls be sufficient? I was wondering if using WD40 on the seat might keep dust down as I read on a post on this forum by a respected engine builder that was his process for best finish, not necessarily health reasons.

[cgarb]

Maybe for final cut...but I would think WD-40 would cause the dust to load the stone and no longer cut.

[englertracing]

You sure you want to embed abradables into a soft seat that a 150$ valve touches?

[David Redszus]

Perhaps the seats should cut and not ground. A multi-angle seat cutter allows much better consistency than ground seats.

As a general rule, seat contact area to valve head diameter ratio:
Intake valve s/b =.09
Exhaust valve s/b=.115

The valve head face will absorb heat while the seat contact area sheds heat to the head.
If the valves run hot, the seat area should be increased by increasing the seat width.

[28BHKS]

You sure you want to embed abradables into a soft seat that a 150$ valve touches?

Possibly not, hadn't thought about that as an issue. Just saw that Goodsons had a cool blue stone that they say is for for beryllium seats so was planning to use those. I'd really appreciate your input though on how it should be done and on what sort of machinery would be required?

If there was someone local that I was confident would do a good job we'd probably take it there, but I see many of the guy's on here look to have good machines Serdi/Rottler etc, I don't see many local engoine builders where I live with that sort of top specialised machinery which is why we thought we might give it a go ourselves.

[28BHKS]

Perhaps the seats should cut and not ground. A multi-angle seat cutter allows much better consistency than ground seats.

As a general rule, seat contact area to valve head diameter ratio:
Intake valve s/b =.09
Exhaust valve s/b=.115

The valve head face will absorb heat while the seat contact area sheds heat to the head.
If the valves run hot, the seat area should be increased by increasing the seat width.

Thanks very much, may have to rethink our strategy. Not many engine shops where I live that have multi-angle seat cutting machinery, may have to consider sending the head offshore.

[englertracing]

You sure you want to embed abradables into a soft seat that a 150$ valve touches?

Possibly not, hadn't thought about that as an issue. Just saw that Goodsons had a cool blue stone that they say is for for beryllium seats so was planning to use those. I'd really appreciate your input though on how it should be done and on what sort of machinery would be required?

If there was someone local that I was confident would do a good job we'd probably take it there, but I see many of the guy's on here look to have good machines Serdi/Rottler etc, I don't see many local engoine builders where I live with that sort of top specialised machinery which is why we thought we might give it a go ourselves.

There are fans of stones that say it doesn't happen...

[BillK]

He purchased it about 12 months ago as a rebuilt engine with dyno sheets after build.

Is the original builder or the shop that rebuilt it somewhat local to you ? Might be worth sending the heads to them and having them do them ?

[gofaster]

I noticed that you are fairly new to this forum. Unfortunately I can't remember who they are, but there are some real good cylinder head people in Australia and NZ who have contributed to this forum in the past. If you have time to search old cylinder head related discussions you may find them. Maybe someone here can point you in their direction.

[KnightEngines]

Take it to kelfords, they can recut the seats properly.
Don't grind copper beryllium seats unless you want cancer, I blade cut them & then just 'rub' them with a stone turned by hand.

[28BHKS]

He purchased it about 12 months ago as a rebuilt engine with dyno sheets after build.

Is the original builder or the shop that rebuilt it somewhat local to you ? Might be worth sending the heads to them and having them do them ?

Thanks, we are not sure who did the previous build, but the width the seats were cut to concerns me hence the post to try and gauge if that's normal for methanol and I suspect it's not.

[28BHKS]

I noticed that you are fairly new to this forum. Unfortunately I can't remember who they are, but there are some real good cylinder head people in Australia and NZ who have contributed to this forum in the past. If you have time to search old cylinder head related discussions you may find them. Maybe someone here can point you in their direction.

Thanks yes pretty fresh - certianly some good Australian options, not sure in NZ as yet.