Pulled out my engine today

[RaceDiagnostics]

If you need fluid, any fluid to test for a good seat you need help.

Correct, I do need help.

 

[minimutly]

Correct, I do need help.

Lol

 

[8ob]

Well you are a lucky so and so, well done!

I was thinking the same, the chances of a new guide pressed in with a hand reamed guide and the seat still being square to the valve are pretty slim, x 16 is a miracle

Bob

 

[RaceDiagnostics]

I was thinking the same, the chances of a new guide pressed in with a hand reamed guide and the seat still being square to the valve are pretty slim, x 16 is a miracle

Bob

Don't say that, another 8 to go.

 

[RaceDiagnostics]

Just tried the bounce test, some bounced better than others but didnt correlate to the drips.

 

[roofman]

What i have found grinding or lapping valves in is using a drill is the worst way possible..it cuts a regular number of grooves the full 360 of the seat and made worse by actually being too aggressive as you have no feel. Work from the top with the sucker stick on the valve surface and they need a rigorous light movement and keep rotating the valve by 90 degree between each session of grinding,this keeps the cut and mating surfaces irregular and creates a much better gas tight seal. Valves and seats that show no pitting grind better on the basis that less is more

 

[Seadog]

You'd better find yourself a valve seat cutter. They're going to need it.

 

[minimutly]

If they don't bounce have a close look at them. If you think about it, say you have .5 to 3 thou guide clearance. Any out of conc. will be taken up as the seat moves the valve over. So a slacker guide masks more out of line. The problem is any slack also allows the seat to be hit out of concentric, thus damaging it and it's seating capability.
So I degreas, clean and bounce them. You can usually feel a suspect one by leaning the valve over with your finger as it contacts the seat - you should have the same feel in all 4 directions - a rubbing on the seat opposite side to a straight "landing" will tell you it's out.
Hard to describe I know, but if you do enough you get a feel for it.

 

[Gareth_16V]

For me, this picture shows the mating surfaces as being far too wide. On a reasonably modern 3-angle valve seat machining, the actual contact area (45° angle) should be about 1.0mm wide, with the 60° and 30° angles being used to narrow the seat contact width. Do you have a Daimler service manual for this engine that covers this detail?
I am completely in agreement with you that I like to do as much of this stuff as possible myself - but for this to be 100% those seats will need recutting. Valve lapping should be done for <10s as a final finish, not to remove a huge amount of material (which can result in the seats becoming too wide).

It would be a shame for you to have done all this work, and then find the end result doesn't live up to expectation, but of course at the end of the day it's your engine, you know how the components feel as they fit together, and you're more than entitled to tell us to burger orf!

 

[Seadog]

These cutters are the mutt's, but very expensive.

https://www.newaymfg.com/parts/cutters_standard

 

[Gareth_16V]

These cutters are the mutt's, but very expensive.

https://www.newaymfg.com/parts/cutters_standard

Exactly what I used - what size are the valves in this engine?

 

[tom2207]

I think that petrol is often used. Less surface tension.

diesel is what ive always used , with no springs fitted , and left over night , petrol would evaporate.
No engineers blue , just three lines across the seats with a soft lead pencil , and then one full turn of the valve and inspect for results . Never ever lap with a drill , only recip movements.
But as much as its a slow old job its also very therapeutic.

 

[RaceDiagnostics]

Ha ha, don't forget that the engine is out so I can paint the engine bay, and this is a bit of tinkering that's got a bit out of hand.

However I really appreciate all the helpful comments as I have zero experience in working on engines. I have never done this before so need all the help I can get.

I've been looking at the Neway valve seat cutters.

Edit _ just seen the other posts suggesting Neway too.

 

[RaceDiagnostics]

Exactly what I used - what size are the valves in this engine?

Inlets are 9mm stem and 44mm across the valve, exhaust are 11mm stem and 37mm across the the valve.

 

[Gareth_16V]

You could probably get away with 2 cutters (1 x 2-angle and 1 x single angle) and 2 x pilots to cover your requirements. For the cost, I think it would be worth finding a good engine workshop near you - you've done the hard work in already replacing the guides.

 

[RaceDiagnostics]

For me, this picture shows the mating surfaces as being far too wide. On a reasonably modern 3-angle valve seat machining, the actual contact area (45° angle) should be about 1.0mm wide, with the 60° and 30° angles being used to narrow the seat contact width. Do you have a Daimler service manual for this engine that covers this detail?

It's 40 year old engine don't forget, the manual does cover all the dimensions, more from the manual tomorrow.

 

[RaceDiagnostics]

For me, this picture shows the mating surfaces as being far too wide. On a reasonably modern 3-angle valve seat machining, the actual contact area (45° angle) should be about 1.0mm wide, with the 60° and 30° angles being used to narrow the seat contact width. Do you have a Daimler service manual for

I just had a look at the manual.

Intake 1.3 to 2mm
Exhaust 1.5 to 2 mm

I will measure tomorrow but I think they are within spec.

The other angles to achieve this should be 15 and 60 degrees.

 

[RaceDiagnostics]

I wish there was a good machine shop near me. The closest is 40 mins away that did the block honing but they did not inspire confidence. They wanted to take the block from my car on a sack truck, I said what about the mating surfaces if it topples off, they grumbled and brought out a dolly. Then they said they couldn't drill out the sheared bolt from the intake manifold. So I just don't trust them.

Next closest is more than an hour away and illegal for me to drive to just now.

To be honest I don't trust anyone unless they come with a lot of very good recommendations. I've found that whenever I go anywhere and say classic Jag or Merc, eyes glaze over with £££ signes and they want to do as much work as possible at stupidly high rates. That's why I've ended up learning how to do everything myself.

 

[RichardM]

Certainly to my amateur eyes your valve seats do not appear to be 3 angle currently.
Before buying a cutter and re-cutting, does your manual state what the stem height should be after valve seat refurb?
Would be good to know approx what material you can take off before it throws up more problems.
What shim sizes did you have in, what is the smallest you can get?

 

[8ob]

Certainly to my amateur eyes your valve seats do not appear to be 3 angle currently.
Before buying a cutter and re-cutting, does your manual state what the stem height should be after valve seat refurb?
Would be good to know approx what material you can take off before it throws up more problems.
What shim sizes did you have in, what is the smallest you can get?

Sinking valves into a head does throw up a few issues if you want to be anal about it, unless all the seats are cut and valves stoned the same on something like a Serdi there will be variations in combustion chamber volumes, sinking a valve also means shimming the valve springs to bring them back to the correct installed height. It can run away a bit but on a low revving road smoker most of this is not that important.

Bob