• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Andrew's 122 turbo project

Check the valve guide height. High lift cams require cutting down the valve guides and re machining for the seal. The retainer could be hitting the guide/seal. Use an extra rocker shaft spring in place of the valve spring to check clearances. Put that cylinder to TDC, pressurize the combustion chamber and remove the spring with one of these tools
9_25_2007_9_8_48.jpg


If the retainers hit the seal/guide you'll need to cut down the guides or get longer valves and springs. Either way, the head has to come off. FYI, the Isky double springs require cutting the seat pocket in the head for the larger diameter spring

Rocker shims are used for correcting geometry. At ? lift the rocker should be perpendicular to the valve.
 
hiperfauto said:
Check the valve guide height. High lift cams require cutting down the valve guides and re machining for the seal. The retainer could be hitting the guide/seal. Use an extra rocker shaft spring in place of the valve spring to check clearances. Put that cylinder to TDC, pressurize the combustion chamber and remove the spring with one of these tools
9_25_2007_9_8_48.jpg


If the retainers hit the seal/guide you'll need to cut down the guides or get longer valves and springs. Either way, the head has to come off. FYI, the Isky double springs require cutting the seat pocket in the head for the larger diameter spring

Rocker shims are used for correcting geometry. At ? lift the rocker should be perpendicular to the valve.
Click to expand...

I'm just planning to let a machine shop do all of the head work. Do they just need to be machined down the difference in the lift between the two cams?

Fivehundred said:
There's something slightly odd about the adjusters on your rockers, normally they have thread still sticking out of the locknut. Are you running the correct valve clearance?
Click to expand...

.014" as per the cam card.
 
I usually have the guide machined down so there is just enough remaining for the seal. That way there's no chance of interference.
ValveGuideHeight.jpg
 
I suppose the machinist could do that for me. They also put a generic guide seal on them when I had it done. Maybe they could've been taller than the ones available for B18/B20s :e-shrug:. I'll just pick up some more guides and seals and go ahead and have my spare head worked up with the Isky springs and retainers. If I go ahead and have them mill it down to E head specs what will I need to do to compensate for that? Is there any amount of clean-up I can do to the exhaust ports myself? At this point I'm not looking to send it off for a full port job.
 
AndrewNance said:
I'm just planning to let a machine shop do all of the head work. Do they just need to be machined down the difference in the lift between the two cams?



.014" as per the cam card.
Click to expand...

How deep were the valve seats ground?

I'm thinking the seats may be in need of replacing.
 
AndrewNance said:
I did but the number of articles written about B20F engines with Schneider 274 cams is not very high. This is my first go at this. What did your sig say? "Experience comes from bad judgment" or something of the like.
Click to expand...

You need to read & learn the *basics*. You coulda asked me..........:nod: I just hope you haven't ruined the cam. (that's "ruint" in SC)

While I might not own a 380 hp turboed Volvo, I do have experience with cams, springs, etc from other cars I've owned.

I had a .500 lift, 320 duration cam in my Chevelle, and have installed countless hi lift cams in Harleys too.

Experience coming from bad judgement is quite the expensive way to learn about engines.. But it works if you have enough $$.......:lol:

And yes I've done it a few times. Didn't take me long to study up on things afterwards though.
 
Hi Andrew,

Did you have to change the length of the pushrods? When i did my engine i had to measure and get bespoke pushrods made. Also 0.014 does seem quite tight so might be worth checking. i'd need to check my emails but i think kg trimning recommend 0.5mm on their cams.

Apology for not having capital i's,somehing going weird with my wife's ipad.
 
Last edited:
It'll be worth checking out when I pull the head off. I compared them to the stock ones and the combination was the same length as stock. I think the lifters are shorter and the pushrods longer, or maybe it was the other way around. Either way they were the same length as stock.
 
I need to update so I feel like I'm doing something. Right now I'm just waiting on the machine shop. They said they didn't have the right size cutter to cut the spring seats for double valve springs so I had to borrow one from a local air-cooled guy.

Just boring stuff really...

Took the head apart:
jYNimQg.jpg


eeL7rBb.jpg


Ground my valves:
0ApXfjs.jpg


Just shaved a little off of the exhaust ports:
47RLp8j.jpg


Tried to make a better radius on the roof of the port:
do7ixkK.jpg


I just need to polish it up a little more when it comes back then it's ready to go. This time I'll check for coil bind :oops:
 
*Don't polish the intake ports mirror smooth*. A sandblasted type finish is better for intake ports.

It has to do with turbulence/tumbling of air/fuel mixture to keep the fuel suspended in the air flow.

Mirror smooth intake ports makes the fuel want to puddle/make little rivers , on the port walls/floor. Bad JuJu there.

You can however polish the *exhaust ports* mirror smooth if you wish. Since all you're trying to do is rid engine of spent combustion.
 
Last edited:
Got my head back today. Everything looks good. Milled .070" off the head (which had never been milled), smoothed out the exhaust ports and ground down the lip underneath the valve faces, 30* intake valves, 3-angle exhausts with 45* valves, Isky double valve springs with steel retainers, Isky pushrods and lifters. It's all buttoned up on the block with the valves adjusted to .016". Tomorrow I'll fill it with oil and coolant and crank it up. Fingers crossed that whatever my problem was before is gone now.
 
AndrewNance said:
Got my head back today. Everything looks good. Milled .070" off the head (which had never been milled), smoothed out the exhaust ports and ground down the lip underneath the valve faces, 30* intake valves, 3-angle exhausts with 45* valves, Isky double valve springs with steel retainers, Isky pushrods and lifters. It's all buttoned up on the block with the valves adjusted to .016". Tomorrow I'll fill it with oil and coolant and crank it up. Fingers crossed that whatever my problem was before is gone now.
Click to expand...

Did you check for coil bind this time ? Also... I take it that after removing the .070" of the head's surface, you did check the pushrods for length/operation? And valve guide length/interference issues? They *could possibly be* too long now (removed.070" from head)

Shaving the head can *possibly* make the pushrods act as if they were "longer", further complicating coil bind, and or valve guide length issues.

You may very well be OK, but... *you won't know for sure* (until it's too late) unless you check. Because just crossing your fingers doesn't check nor readjust clearances/lengths ya know.........

Also, on most engines.... the intake valve clearance is less than the exhaust valve clearance. Usually the exhaust valves are set .02 to to .03. looser than the intakes. Of course this varies from engine to engine (brand/size/designation/family etc)

This due to exhaust valve needs more clearance due to it's greater heat expansion.

The book says .016-.018 for all. JUST FOR NOW... I highly suggest to set the all valve clearances , especially the exhaust valves , a bit *on the loose side* until things break in/wear in.

Why? Because when valves have been ground, and new lifters/camshaft have been installed, you need to allow for break in of new valve train parts. You do not want the exhaust valves to 'run too tight" because you'll might burn the valve/s

This will keep you from *possibly* burning one of more exhaust valves while they bed/break in. Might want to re-adjust the valves to allow for this.......

I'd set the exhaust valves a thousandths or two looser than the intakes. At least until you get some miles on the engine and break in the valve train. You stated you set all valves to .016".

Also don't expect the machine shop to check for pushrod length/valve guide length issues. Unless of course they have the rest of the engine (and the cam installed in it) there too. You need to do this before cranking/running the engine too

Just trying to help.........
 
Last edited:
You must log in or register to reply here.
Back
Top