Jump to content
IGNORED

Hot valve adjustment


docc
 Share

Recommended Posts

7 minutes ago, gstallons said:

IDK about a MG , but you can do it on a small block Chevy . It takes practice and patience or a lot of hubris .

I've seen it done on an old in line 6, they idle pretty low. Not sure what the point was.

Ciao

Link to comment
Share on other sites

A small block with solid lifters?  Like a Z/28 302 or L79 327 or LT-1 350 or what?  Adjust while it's running?  

(When you say small bock, you don't even have to say Chevy.  It's a "small block".)

Link to comment
Share on other sites

Had a 283 bored to 292 with a 350hp/327 hydraulic cam. To keep the hyd lifters from pumping up at high revs, the trick was to loosen them (running) until the plunger was at the end of its travel - just starting to tap. Then 1/4 turn in and you were good for revs. 

Link to comment
Share on other sites

4 hours ago, LowRyter said:

A small block with solid lifters?  Like a Z/28 302 or L79 327 or LT-1 350 or what?  Adjust while it's running?  

(When you say small bock, you don't even have to say Chevy.  It's a "small block".)

Unless you're a Guzzi guy.

Ciao 

  • Like 1
  • Haha 2
Link to comment
Share on other sites

I've actually done some fairly thorough testing on this and generally with the 2V engines even running them hard on a rolling road while holding the rocker cover on by hand until they were scalding and then whipping the head off and finding TDC immediately the gaps would remain virtually unchanged on squarefin motors with the alloy rocker covers and would close up *A bit* with roundfins with cast iron rocker carriers. The only time I know of the clearances close up enough to cause problems is on engines run with the mid nineties 'US Emissions' clearances of two thou inlet and four exhaust on the squarefins. If engines are run really hard with these clearances in hot weather for extended periods the will stall if they come to a halt quickly, indicating, one would guess, that the tappet is riding the cam and the exhaust valve is being held off its seat. In 'Normal' use it isn't an issue.

With the roller tappet 1200 8V's the gaps will definitely open up as the engine gets hot and gets bigger the hotter it gets. If you look at the construction of the heads, valves and camboxes it is self evident why.

 

  • Thanks 1
Link to comment
Share on other sites

8 hours ago, LowRyter said:

A small block with solid lifters?  Like a Z/28 302 or L79 327 or LT-1 350 or what?  Adjust while it's running?  

(When you say small bock, you don't even have to say Chevy.  It's a "small block".)

Either one .  After the advent of emissions and emission controls laid all over the engines  , you would follow the service manual and bar the engine over unit the # 1 cylinder valves were overlapping and adjust certain ( I used to remember ) valves , rotate the engine 1 revolution until # 6 valves were overlapping and adjust ( I used to remember ) the rest . Install the valve covers and all the clutter & you were done . 

Link to comment
Share on other sites

4 hours ago, gstallons said:

Either one .  After the advent of emissions and emission controls laid all over the engines  , you would follow the service manual and bar the engine over unit the # 1 cylinder valves were overlapping and adjust certain ( I used to remember ) valves , rotate the engine 1 revolution until # 6 valves were overlapping and adjust ( I used to remember ) the rest . Install the valve covers and all the clutter & you were done . 

yes, but while the engine is running? 

Link to comment
Share on other sites

5 hours ago, LowRyter said:

yes, but while the engine is running? 

Uh , no . You did this on a cold engine . This was getting 1 turn after zero lash . These were factory camshafts with hydraulic lifters .

Link to comment
Share on other sites

  • 2 years later...

So, TDC is found by looking in the spark plug hole? No nifty cap to pull on the crank nose with a rotor clearly marked "TDC1" and "TDC2" on them?  

Link to comment
Share on other sites

10 hours ago, po18guy said:

So, TDC is found by looking in the spark plug hole? No nifty cap to pull on the crank nose with a rotor clearly marked "TDC1" and "TDC2" on them?  

There is typically a mark on the flywheel. But it is easier to pull the valve cover and rotate the engine until the piston comes up (a pencil in the sparkplug hole will tell you that) looking for TDC of that piston with both valves closed. One TDC will have both valves somewhat open and the next TDC will have both valves closed.

As I recall, the mark on the flywheel is typically in Italian. S for Sinistra (Left in Italian). If you want to see the mark on the flywheel there is a black plug on the flywheel bell housing you can pull. Try not to loose the plug.

 

  • Like 2
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...