Intake valve retainer groove wear

[Juha Vane]

Went to pick up my cylinder heads today, they had just collected some dust for 3 months...
Nothing was done, where has responsibility gone nowadays.

Took them apart and the intake valves look quite strange. The length of valve stem
tip above retainer groove varies. Difficult for a non native english to explain, sorry.

Measured the length and #1 7.4mm #2 6.9mm #3 6.2mm #4 7.2mm enclosed couple
photos, the knife is there just so phone focus on valve stem tip.

There are some very faint numbers on 38mm intake valve stem 2351, exhaust valves are
31mm TRW T 30114 and look OK.
Could it be possible that the intake valves are just some crap material and this has caused
the wear? Have you seen such before? Tried to search the forum, but didn't find.

Plan to change all intake valves, all keepers & retainers. Try to locate a valve spring tester to
see if they are OK. Various amount of shim under springs.

[David Jones]

Juha, for what it is worth. I use a drill press and a bathroom scale to measure valve spring pressure. I use a small piece of steel plate under the valve spring and then compress it to the installed height and compare them.

[Juha Vane]

Good tip, thank you David.

[Alan Hall]

Juha, On some very early engines, with 8mm valve stems, the factory used a hardened valve stem cap, presumably to minimize valve stem wear. I wonder if someone ground the ends of the two valves to accept stem caps. You might check to see if the overall length of the two valve is short compared to the other two or to the nominal dimensions shown in the manual.
Alan

[Dick Weiss]

Juha

The valve keepers and retainers will be OK for reuse since they're hardened. You didn't say which heads you have and which valve springs exist--the early dual or replacement single coil w/or w/o progressive version.
Obviously the stem wear (from the keepers) lessened the spring's "stack height" pressure and possible valve floating at upper RPMs
Also the valve stems will tend to get "barrell shaped" (not straight) from worn guides causing the valves to not seating correctly.

Finally, any worn rocker arms and their shafts will cause wear including the tips-to-the-valve-ends--especially w/the steel rocker frames!

Dick

[Jacques Lefriant]

Hi Juha
it is the usual practice to grind the top of the valve when doing a valve job. This is done usually to remove the uneven rocker caused wear like the valve on the left. theoretically it should be done to have the geometry correct but with rockers it doesn't matter that much. This should explain the 6.2-7.4 variation(if the champher is very consistent they were either made that way or the last valve job was done with unusual care). After the valve job is done you can try to get a consistent tip height by trying the valves in each position but it is probably a waste of time.
j

[Juha Vane]

Thank you all for the comments. Really great to have this "hot line".

These valves have 10mm stem and the intake have about same total length.
#1. 119,5mm #2. 119,3mm #3. 119,4mm #4. 119,5mm. Exhaust are OK,
the stems and keeper groove have "no" wear.
The intake keepers have definitely worked their way up, look at photo of stem.
There is a little "ridge" where the keepers are. What puzzle me is that the keepers
butt, normally there should be a little gap so that all is tight together; valve,
keepers and retainer. Now the valve is "loose" in the retainer, is this to promote
rotation? Is it different in a 356 engine? Couldn't find anything in service manual.

Tried to measure the springs, but not with my scale, Monday I go and measure them,
the free length is 2" and wire is 3/16", non progressive. I believe these are US dimensions
as the engine was rebuilt years ago in the US. They have a flat wire damper inside.

I could not find any numbers in the heads? Enclosed is a photo of chamber, 38in, 31ex.
There is still what I believe is the factory chamber volume number, 58.5

I could not find any excessive play in the rocker shafts.

I think I have to substitute new parts for experience, safer for me to replace the intake
valves, keepers and retainers as I can't judge if they are OK to use or not. There is no
crack in the retainer, look like that in the photo. There is some strange marks in them,
look like these came from manufacturing.

If I end up changing the springs also, any recommendations? The cam is Elgin 7008.

[Alan Hall]

Juha, Those are not a factory spring. I don't recognize what they might be from or what the installed spring pressure would be, but they could have contributed to the odd wear you are seeing on the other parts of the valve gear. I would think new springs and possibly new retainers are in order as well as new valves.

[David Baugh]

Could those be Chevy valves and springs? Many (50?) yrs ago I read that they were interchangeable.

Dave

[Jay Darlington]

I'm no engine guru but I don't see how the valve could wear at that point and that much, maybe I'm missing something.
Jay D.

[Jacques Lefriant]

Hi Juha
sorry i get it now. the original valve nos were 3030 int and 3043 exh those must be replacement or later production valves probably not made by Ate Germany but a subsidiary. i believe the keepers should but up. are you using the original dual spring retainers or the later single spring ones? i can't tell from the top view. Wear like that is due to uncontroled valve motion usually due to low spring force. stock springs should work for you.
j

[Juha Vane]

Hi all,

Yes Jacques, the valves has been changed. Exhaust are TRW T 30114, so they should be some quality.
The intake have very faint markings and I had to file the stem in the worn valve to remove it.
Material felt very soft, the file bite very well.

I think the valve stem is just so soft that it has worn. Now the keepers butt so the valve is
"loose" in the keepers and therefore wear. Could someone verify if the keepers should butt
or not?
I doubt that the valves be Chevy, the stem is 10mm and Chevy probably would be US dimensions.
3/8" would be about 9,53mm. But can't be sure.

The retainers I believe are single spring type, enclosed a photo. The spring id in retainer is
21.5mm and the spring has inside did 22.2mm, 7/8". The springs are definitely with US dimensions.

Can you identify the retainer from enclosed photo?

I plan to change following parts:
- 369.05.201.01 Valve keepers
- 616.105.421.01 Retainers
- 546.05.203 Intake valves
- 616.105.432.03 Valve springs

[Jacques Lefriant]

Hi Juha
while you are at it you might give consideration to using C/SC/912 intake valves keepers and retainers they are usually more easily found and you can use valve stem seals. Don't trust the parts vendors out there since they assign part nos to non OEM parts just for identification.
j

[Dick Weiss]

Juha,

There were 2-different versions of valve keepers; The early keepers had a slight internal taper which allowed some wear on the valve's
relief notch caused by worn guides and non-straight stems. The later keepers had a straight internal bore and the later grooved keepers were a better fit and not allowing any wear except producing an edge lip/burr from long-time hi revs(?). This is noted in the shop. manual to remove the burr.

Dick

[Juha Vane]

Hi Jacques,

Good point, will do that. But will also change the exhaust retainers & keepers. I'm
aware that the numbers are mainly for reference, but have naively? thought that if
I buy parts from a reputable, well known vendor, the quality should be OK.

Measured couple springs, the free length is 2" (51mm) and when compressed to 41mm
the pressure is almost 60kp. Spec book say 35kp. This can be the reason for the strange
wear on intake valves.

I'm glad that I took the engine apart.