043 heads valve spring pocket

[1950split]

Hi Guys,

My Brothers Mid-D 043 heads with 44x 38 valves give me 39.5mm installed height with Bugpack titanium retainers.

With my new 86B cam and 1.4 Scat rockers I have 14.2mm valve lift. I’d like to be at about 3.5mm before coil bind which is not possible currently. I cannot shim the springs either.

Does anyone know how deep the spring pockets can be cut on these heads without getting into the intake ports or compromising the material?

I would like to avoid changing for longer valves or sinking the seats.

Thanks,

Phil

[Dan Ruddock]

Have you measured the springs length at coil bind and which of the two springs binds first? Must be done with the retainer in place. A vice and a set of calipers works if you don't have a spring tester. I have found the springs specs are not always what the manufacture says they are. If the inner spring is binding first cut down the inner retainer step.

Running the springs tighter is not a bad way to go either, less harmonics and reduce chances of float with a little shorter spring life. I would not cut the heads spring seat, too risky to have a hole in your intake port.

What head casting were used? Dan

[Alstrup]

You can gi with Oteva s75 springs. That will give you 1,5 mm mlre before coil bind o er most other springs in the 300-330lbs rance
I believe Tabari stocks them stateside
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[esde]

Do you know what springs are currently installed ??
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modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that.

[Ian Godfrey]

CB 650 springs should easily give the lift you need without cutting the spring seat..... it worked for me on a 86B

[modok]

1.5-2mm from bind is ideal for most purposes, racing engines sometimes run tighter.
Why do you want to be 3.5?
If the valve spring is not the travel stop then what part is?

The thickness to the intake port is probably around 3mm but if yours have been ported then it may be less.

Make a tool to check it, I made this thing 10+ years ago, just stainless sheetmetal and yet works pretty good, can reach into the port and spring pocket, the gap at one end is the same as the gap at the other.

[modok]

Another view, lower right.

[1950split]

Hi,

The idea behind 3.5mm is longevity. I have titanium retainers, TP lifters, Aluminium tapered pushrods. Therefore I think I need less spring pressure. I know not everyone agreees with GB's statement that +3mm before coil bind is better for no racing purposes.

I used CB 650's on my previous builds of the same engine and ended twice with a damaged cam although I had set idle at 1200 rpm. Therefore my idea to switch to softer springs as I am moving from a CB2289 cam to the Web 86b which will be nicer to drive in all conditions (including town).

Dan : Casting is 043 mexico.

Alstrup : I have checked Logmech's Oteva 75 sc duals which measure 21.8mm fully compressed. This could be a great choice. The would give 140 kg at 25.4mm which is more than enough with my valve train.

[txoval]

Get your idle up to 1800-2000 at break-in

Also, fill the case with oil up to the cam during the break-in.

This engine will have light weight valve train, you could probably just run the 650 outer springs

[Dan Ruddock]

If your after longevity run a set of 1.3 ratio rockers with the 86b. Most engines run very well with .500" lift for street use and this would solve your spring problem and be easier on everything else.

You can always slip in the 1.4 if you want to go racing. I have to somewhat agree modok Bergs .150" is a little much. The AA-500 heads also have a 043 number on them which is why I asked.

Dan

[1950split]

Hi txoval. During the break in the revs were maintained at 2500 rpm and I set the idle at 1200-1400 rpm afterwards but it did not prevent damage to the cam. Luckily the TP were not damaged

[txoval]

Ok, I thought you meant you did the break-in at 1200

[1950split]

Perhaps a good time to ask why my 1.4 cb rockers have been damaged so much by the lashcaps I found concave when dismantling the engine.

[Dan Ruddock]

Lash caps too soft, near race engine specs don't do well when used for the street. Very heavy springs along with border line race cams does not help either.

If you want a street engine last, limit it to .500" or build a toy engine that will need regular maintenance. Your wise in dialing it back.

[modok]

It's always a problem with Material/ machining/ oil

[1950split]

Well, lashcaps were from Berg.

Some only 2 lobes of the cam showed a damage.

I will use the scat caps that were in the box of my 1.4 scat rockers for this rebuild as I hope they match metal hardness in order to prevent a damage.

[txoval]

I would replace that rocker…Scat does sell singles