Engine history

[Thowdfella]

To Grumpy dads reply The answer is yes as far as the tappets are concerned. I recently had my cylinder head converted for unleaded fuel ie hardened valve seats and new guides etc. I set tappets at 20 thou and the engine ran fine for a while then started hunting and running rough. The answer was that the head had settled in and the valve clearance was down to 16 and 15 on a couple. I reset to 20 and the engine speeded up and was running well again.
To the other replies, I dont have enough knowledge to set timing by ear as some of you seem to have so I need guidelines. yes, the book was written when 100 octane was available so how do you set the ignition timing now? I seem to remember in the past you advanced it listening for the highest revs but not sure if that is valid so how do you do it?.
I would also like assurance that a 122s is a B18D engine.

[c1800]

Try sending an email with your full serial number to:

museum@volvo.com

and ask for the build details of your vehicle.

They are currently closed due to covid, so not sure if you'll get a reply.

You can also decode your engine number from the link I posted earlier.

[arcturus]

Google B18D. lots of info. Difference between A & D,the D has C camshaft other wise identical

[Thowdfella]

I have found the address to get the historic engine details if anyone wants to contact them. It's Adm.historical.archive@volvo.com but they are currently closed because of Covid 19.

[blueosprey90]

I cannot help with your original question and merely post to suggest a work around.

I'm no big expert, but I suggest that you might try to degree your camshaft.

These links are all written for Triumph, but you should be able to adapt to the Volvo.

On this linked website, there is an excel spreadsheet that you can use to input (substitute) your data. It will generate a graph that you can then use to assess your valve lash settings.

https://www.tildentechnologies.com/C...DegreeCam.html

I have used it several times to degree an unknown camshaft, which in turn has allowed me to determine the necessary valve lash (or as you say, tappet adjustment) for that camshaft.

https://www.tildentechnologies.com/Cams/Tip_Lash.html


If your concern relates to ignition timing, you are probably aware that camshaft timing is different than ignition timing. Also that valve lash settings are not directly related to ignition timing. In other words, in the ideal world, you would set your valve lash first and then go about setting your ignition timing.

On a engine with a replaced head, you are supposed to re-torque the head after several heat cycles, so the fact that your valve lash went off after the engine ran for a while is not surprising, and in fact was to be expected, although I would think the valves would be more loose rather than more tight after re-torqueing.

In my own limited experience, I would set ignition timing with a timing light, perhaps developing a timing curve plotting the timing at ever increasing rpms until the advance "tops out". But in the absence of a spec, I would probably be shooting for an advance of about 32 degrees (I think vacuum disconnected) at 3,000 rpm. With a willingness to tweak 2 degrees in either direction depending on performance. If you still continue to suffer performance issues after doing so, it might suggest need for a distributor rebuild.

[arcturus]

Re torquing the B16 head is a bitch. you have to lift off the rocker shaft to get to the nuts. Got mine to do

[blueosprey90]

I think it is probably the same for a B18 and B20.

Maybe a torque wrench spanner adapter or a crowfoot socket wrench could be used.

Something like this https://www.kingcobraofflorida.com/p...gle%20Shopping


or even fabricated if necessary.

[Derek UK]

"..although I would think the valves would be more loose rather than more tight after re-torqueing." Re torqueing lowers the head so clearances are reduced.
On the B18 there is only one central bolt that you'd need to use a crow's foot on. You also need to factor in that length when setting your torque wrench. Removing the rocker gear on the B18/20 is easy and safer. You'll have to reset the valve clearances anyway. I don't know about the B16.

[blueosprey90]

" … Re torqueing lowers the head so clearances are reduced."

OK, makes sense. To be honest, I've never paid any attention. I just plan on re-setting the valves after re-torqueing the head.

[blueosprey90]

I've have driven us way off topic, but since we are here …

https://youtu.be/tv_KHH55qdQ