Saab B motor valve adjustment questions

[DeLorean]

So, Adjusting the valves on the silver 99-T, what is proper procedure? The tag on the inner fender says that it should be done warm, 30 minutes after running... does this really matter? Can it be done off of the car sitting on the bench?

I have the adjustment range as

INLET Checking range 0.006-0.012
INLET Adj range 0.008-0.010

EXHAUST Checking range 0.016-0.020
EXHAUST Adj range 0.018-0.020

All this look right?


My range is pretty bad. Everything is too tight, 0.005 0.015 0.000 0.010 on the exhaust side (cold on the bench) intake it a bit better than this.

Basically I know how to figure the shim size needed, I am just wondering is it's not proper procedure to do this on a bench not bolted to the motor? Also, does anyone have shim kits? I am really going to need a few shims. I can do some math and figure out what shims I am going to need if I can just do this on the bench, otherwise I guess I am going to have to put it together, run it and then check?

[SwedeSport]

It's a pain in the ass... but with a little trial and error you'll get close.

It is better to be a little on the loose side than too tight. Everything grows a little when it heats up.

[Geoff]

I usually set it to nominal on the bench and then get the car running and then I remember I should have done it warm so I check again and end up adjusting back to nominal when warm. If you set a little loose of nominal you'll probably be OK.

No matter what, you'll measure, pull things apart, replace the shims, put things back together, remeasure and find that in a SAAB 8v head the laws of physics simply do not apply.

[DougM]

Back in the day when we had a shop, we did all of them on the car, but that didn't necessarily mean the car was at operating temp. The big orange book doesn't mention doing it with a warm engine, but as mentioned, things tighten up when warm. The book even has a section of how to do it on the bench when reconditioning a head, so I assume it's OK to do it cold. It is a PITA as I recall, especially when you mix metric and standard measurements(as the book does). I remember doing it this way and making my own chart and doing conversions with a calculator. If you make a wrong calculation, and it's still out of spec, off the cam goes again to fit in the right pallet.

No spare heads to steal pallets from?

[Jordan]

No reason not to do it on the car. Just use the cam gear holder and make sure the pistons are not at TDC. There should be flats to turn the cam with the wrench. With the car hot, you should have enough time to measure the lash.

Maybe measure it, wait until it gets cold and remeasure to see what the average difference is. The MSS cam I have called for .010" intake and .012" exhaust measured cold, IIRC

[SwedeSport]

You could just measure it cold, then again when hot, and use the difference as a barometer for how much it tightens up over the heat range.

From that you can guesstimate your compensation for whatever temp it is.

Make sure you are doing all your measurements and calculations in metric. I have gotten screwed up that way many times.

[DeLorean]

Well I have to get the thing planed first off, as it has a crap load of corrosion etching on the head gasket mating surface. After that, think I could I just toss it on the oven for an hour, allow to cool for 30 minutes, and then check the clearances & do the math? Or would the fact that it's not warm, AND torqued to the head cause incorrect readings?

I am still trying to source various shims, I don't exactly have a collection of them myself... I am assuming by "setting them loose" this means I should be shooting for the high side of the adjustment range? (0.020 for exhaust 0.012 for intake) -

I mean as it sits, one of the exhaust valves is so tight that when cold there is NO clearance. Odd, because the motor this head came off of ran just fine, valves look good and clean with no damage and I beat the piss out of the motor when ever I drove it...

[Geoff]

To set them to the loose end of the spec cold you could do 0.009-0.010 intake and 0.019-0.020 exhaust. You could measure before and after sticking them in the oven. Just keep in mind that the intake valves would normally run cooler (fresh air and fuel passing by the stems) than the exhaust (hot exhaust gases traveling by the stems) so there could be a little difference there. But if it were me I'd just set them to nominal or a little loose cold and get it together.

Is that a turbo head you have? The B motor turbo cam is different than the NA cam. You can tell the difference on the 99T cams because they machined the part number off and stamped a new part number in with a punch (yeah, they re machined the stock cam lobes). I think there might be a paint stripe too. By '79 or '80 they were making them differently, I don't think they had to machine the part numbers off at that point.

[Luke]

To set them to the loose end of the spec cold you could do 0.009-0.010 intake and 0.019-0.020 exhaust. You could measure before and after sticking them in the oven. Just keep in mind that the intake valves would normally run cooler (fresh air and fuel passing by the stems) than the exhaust (hot exhaust gases traveling by the stems) so there could be a little difference there. But if it were me I'd just set them to nominal or a little loose cold and get it together.

Is that a turbo head you have? The B motor turbo cam is different than the NA cam. You can tell the difference on the 99T cams because they machined the part number off and stamped a new part number in with a punch (yeah, they re machined the stock cam lobes). I think there might be a paint stripe too. By '79 or '80 they were making them differently, I don't think they had to machine the part numbers off at that point.

Also, I think all US spec B-motors in '79 got sodium cooled exhaust valves. I had a B-motor turbo that I put a '73 EMS cam in and it ran a ton better than with the standard turbo cam.

[DeLorean]

The head I'm using should be from either a 79 or 80 900 turbo, and it IS a turbo head. So it is a good idea to run an EMS cam? Anyone know the part number on the EMS cam Vs the Turbo cam? I am not sure what one I have, I would check, but the head is off getting resurfaced at the moment. I may or may not have an EMS cam sitting around somewhere.

[Jordan]

The early cams are definitely "hotter", but also use a different carrier so check the base circle diameter..the later cars got "smogged" and were set up for better emissions. I'm not sure if EMSs ran different cams or not, but I'd guess no?

Setting them "loose" actually changes the profile of the cam a little (in practice). You get fewer degrees of duration and it gets shifted later. Also you get less lift and the valves get hammered more as they open and close more abruptly. Something like that....

[tweek's Turbos]

Agree with the oven, but use a laser thermometer to determine what the temp of the head is after running for 30 min.

Also cheesecakes will never taste the same.