B400 - rocker adjustment

[Bela]

The time will come when the rockers have to be adjusted.
The engine is equipped to my knowledge with a B 403 camshaft.
Would that make a difference?

[Geoff Dowdle]

Bela ,
The standard valve clearance for
400 - 403(A engine) is .002 inch cold Inlet & Exhaust
late 403(AB2 engine) - 406 is .005 inch cold " "

But very few engines now have standard factory cams . Most have either
been re ground to another specification or the cam replaced and the clearance of these could be different from original standard cam .

Do you know the valve timing of the engine .
Inlet opening & closing , Exhaust opening and closing to try to identify which cam is fitted.

Geoff

[Bela]

Originally Posted by Geoff Dowdle

Bela ,
The standard valve clearance for
400 - 403(A engine) is .002 inch cold Inlet & Exhaust
late 403(AB2 engine) - 406 is .005 inch cold " "

But very few engines now have standard factory cams . Most have either
been re ground to another specification or the cam replaced and the clearance of these could be different from original standard cam .

Do you know the valve timing of the engine .
Inlet opening & closing , Exhaust opening and closing to try to identify which cam is fitted.

Geoff

Thanks Geoff

I only found a notice of a PO that a 403 camshaft had been fitted. As you mentioned there are two options - early and late. I guess less clearance will
end in troubles.

I don't know the valve timing and I don't know how to generate that data. In the files there is a drawing. I will look for it.

[Bela]

Originally Posted by Bela

In the files there is a drawing. I will look for it.

Here comes the drawing- for better reading twice. But I don't know the context of this drawing. I hope it was generated after purchasing a new camshaft.

[Geoff Dowdle]

Bela ,

although the scan is quite clear to view , the information is not written in a form to express the valve timing correctly.

But after trying to sort out the information ,my comments are as follows (assuming a 403 camshaft is fitted or camshaft ground to 403 spec )

Inlet lobe lift of .180 inch (should be .205)
Exhaust lobe lift .200 (should be .205)
So possibly a worn camshaft or reground to a completely different grind.

Timing Inlet opening 34 BTDC
Inlet closing 44 ABTC
give duration 34 + 44+ 180 = 258 degrees (close to early 403 of 260 deg)

But the original standard early 403 timing is 15 BTDC - 65 ABDC ,
So it looks like if the timing is set as per those notes and the camshaft is a 403 cam or 403 grind , it is set about 19 deg too far advanced. Probably one tooth .
But these notes could have been taken during initial assembly (how accurately is unknown) & was corrected before final assembly .

Do you have a TDC mark on the front pulley or damper with a pointer ???
If so , set the number 1 inlet valve clearance at .002 cold, turn engine over until the clearance just closes (when you can no longer move the rocker sideways) and measure the distance between the pointer and TDC mark . Then calculate the approx opening of the inlet valve.
This ,although not an accurate measurement , will still show if the valve timing is set too far in advance or they adjusted it on assembly.

I hope this helps
Geoff

[Bela]

Hello Geoff,

thanks for your comment and advice.

In the meantime I found a notice of a PO in the files that it is a late 403 camshaft. I hope I'll find more e.g. a bill.

Therefore I've to aks if I shall measure with 0,002 or 0,005 clearance or both.