Head /Cam Boxes Assy Sequence?

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RRoller123
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Head /Cam Boxes Assy Sequence?

Post by RRoller123 »

Need some guidance from those who know a lot more than I do on the subject of engine building and rebuilding! That would be just about everyone.

Just starting to replace head gasket, install new HP head and cams, adjustable cam wheels, etc.

May be a silly question, but does one assemble the cam boxes to the head on the bench, set the valves, and then install the entire sub-assembly to the engine?

Or install the head first, then add the cam boxes and set the valves?

Should I use new head bolts? The lower end will eventually be done (within a year I think), raising the CR to about ~9.8, but for now it will stay at stock 8.1. Plan to install new head bolts then. Should I do it now and then reuse these new bolts later when the CR is raised? Or just use new bolts now?

Same question regarding cam box bolts, but I don't think they need to be replaced, since the torque is so low.

Assumed engine set to TDC on #4.

Assumed won't need to fiddle with my block-mounted Computronix, since all dis-assembly done at TDC #4.

Not touching the lower end right now , but only because I just don't have the funds. So will drive it with stock CR until money falls from the heavens to my doorstep.

Thanks in advance for any guidance on this stuff.

Pete
'80 FI Spider 2000
'74 and '79 X1/9 (past)
'75 BMW R75/6
2011 Chevy Malibu (daily driver)
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klweimer
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Re: Head /Cam Boxes Assy Sequence?

Post by klweimer »

Hi Pete,

Yes, you can assemble the head on the bench and get the clearances set before it goes on the block. I set the head on a couple of wood blocks to allow the valves to face down towards the bench top without hitting anything while rotating everything to set the valves. If you have stock valves, I don't think you can turn the cam wheels such that the valves will hit each other while moving the cams independently.

Important note - Make sure the cams are in their correct positions for where the crank shaft is when you put the head back on the block and start tightening things down. Easy to bend valves if some piston is up when it shouldn't be during head install.

As for head bolts, I'd stick with the ones you have. Clean them up with a wire brush, making sure the threads are all clear before re-assembly. These heads don't use "stretch" bolts like some of the newer engines. When I did the head on my 93 BMW, you take the old ones and throw them in the trash. I will put in a pitch for Mark Allison's head studs; I used those when I rebuilt my 2 liter motor last year. Really nice. Cam bolts should be just fine.

Now would be the time to invest in decent torque wrenches. I'd get one with a 3/8" drive and one with 1/2" drive.

I have a full set of valve shims and the compression tool I'd be happy to lend you if needed.

Kirk
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joelittel
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Re: Head /Cam Boxes Assy Sequence?

Post by joelittel »

I assembled mine on the bench. Set the valve lash there too, but in doing so I turned my pulleys a bit.

Your valves will get hung up on one another so be very careful.

After driving the car a bit I checked my lash again and was surprised to see that every valve was off a little.... so check and double check.

Take the time to clean out the head bolt threads and holes.

Lots of YouTube videos on cam timing.

Guy croft has good information on his site too.
http://www.guy-croft.com/viewtopic.php?t=213
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RRoller123
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Re: Head /Cam Boxes Assy Sequence?

Post by RRoller123 »

Awesome, that is very helpful! Thanks to both of you.

Pete
'80 FI Spider 2000
'74 and '79 X1/9 (past)
'75 BMW R75/6
2011 Chevy Malibu (daily driver)
2010 Chevy Silverado 2500HD Ext Cab 4WD/STD BED
2002 Edgewater 175CC 80HP 4-Stroke Yamaha
2003 Jaguar XK8
2003 Jaguar XKR
2021 Jayco 22RB
2019 Bianchi Torino Bicycle
narfire
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Re: Head /Cam Boxes Assy Sequence?

Post by narfire »

I love my Black and Decker workbench for doing the shimming. Holds the head firmly while the valves can open and close without issue.
Chris
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
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