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B20 Cam Break In Procedure

C

CRatcliff

Member
Joined
Nov 21, 2016
Location
Seattle, Washington
After breaking in a new cam, I learned a ton of things from making a ton of mistakes. Don't make my mistakes. Here are the steps I learned to follow:

Note, this assumes that you have already taken the cam out of your car, and to do this you removed the distributor gear and the fuel pump, as well as the timing gear. Replace the timing gear. Aluminum is great for durability and not being insanely loud.

  1. Apply Assembly Lube to each of the cam lobes. I also applied it to the bearings, but have no clue if this was a good move or bad.
  2. Slide cam in, being careful not to whack the bearings. This should be easy to do and take no forcing, just rotate as you slide in.
  3. Install flange. Paint the TDC timing mark on the crank and cam gears, and heat timing gear with heat gun. Align painted marks and slide over end of cam. You should be able to get it far enough to start threading the cam nut, and use this to torque it down
  4. Install timing cover, fan, fan belt. Make sure the oil pan gasket is in good condition. If it's not :e-shrug: Would love advice on what others have done in this case.
  5. Install fuel pump and distributor. Distributor gear should be aligned as so: (note: many people, including me, have had distributors that are 180 degree off. Not sure why, but it should be pretty obvious - particularly if you did the diligent thing and aligned the engine to TDC and marked the distributor when disassembling!)
    DistributorDriveGear.jpg
    (credit to Hipferauto)
  6. Install lifters. Dip them in a cup of oil, dab moly paste on the bottom, slide them in. If they don't slide in super easily, clean out the hole with Scotch Brite. Hell, probably a good idea to just clean the hole out no matter what.
  7. Install radiator, head, intake and exhaust. Torque down head to 58.
  8. Fill head with coolant with the temp sender and thermostat removed. Once coolant is up to top, reinstall sender and thermostat. Fill coolant via radiator cap. Finally, fill coolant from overflow, and burp with the hose going from the thermostat to the radiator.
  9. Install rods, reinstall rocker, adjust valves. Install valve cover.
  10. Fill with oil, and then add ZDDP
  11. Install hoses from PCV valves, brake boost, etc. (or just cap them off for now, so you don't mess with that during break in).
  12. Prime fuel - get fuel in those carbs somehow.
  13. Start engine and run somewhere between 2,000 and 2,500 rpm, fluctuating for 15 - 20 minutes.

This is also my list that I'm intending to follow when I reinstall my cam (thank goodness it wasn't actually wiped, but I broke a ton of these rules, and ended up spending a ton of time fixing it). Let me know if there's something wrong, or something I'm missing.
 
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Bring a garden hose in case things get hot you can spray the radiator and make sure there's gas in it you do not want to stop, get hi zinc can break in oil, comp comes to mind, are you using new lifters again? At least put them in the same holes?
 
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Great info! The rebuilt engine I recently bought had the distributor gear 180 degree so TDC for #1 has the rotor pointing to #4. Still works just took me a while to figure out. :wtf:
 
CRatcliff said:
Mine was the same. Totally freaked me out.
Click to expand...

I'm not sure I follow. When the marks on the timing gears are aligned such that they're next to one another, cylinder 4 is at TDC, and so the rotor should be pointing at #4.

It sounds like maybe these engines were assembled with the marks aligned, and then the distributor drive gear was installed 180 out. ?

Best,

Cameron
Portland
 
I battled the timing on my brothers 240 this last weekend, and after 3 attempts of lining up the marks on the belt with the crank, aux, and cam gears it wasn't working. I said **** it, and clocked crank to TDC and cam to alignment position indicated on the dust cover. Then I eyeballed the dizzy position to point to #1 and released the tensioner. I lucked out not being a tooth off on the aux shaft, but after 2 hours of ****ing with the alignment marks barely visible I had zero f%^ks to give. Runs great now!
 
CRatcliff said:
Resurfaced lifters!
Click to expand...

If those are original B20 lifters you do not resurface them. They go directly to the garbage, do not pass Go, do not collect $200. Some people do a swirly thing with abrasive paper on new lifter faces and perhaps you can resurface the replacement design; but, at the price of new ones from Isky why bother.

The rocker arms must be resurfaced because new ones are not available.
 
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volvorelix said:
I'm not sure I follow. When the marks on the timing gears are aligned such that they're next to one another, cylinder 4 is at TDC, and so the rotor should be pointing at #4.

It sounds like maybe these engines were assembled with the marks aligned, and then the distributor drive gear was installed 180 out. ?

Best,

Cameron
Portland
Click to expand...

In my quest to figure out what was going on I stumbled upon this gem of a site and excellent info here: http://sw-em.com/Volvo Ignition from Scratch.htm#Distributor_Housing_and_Ignition_Wire_Variations
 
142 guy said:
If those are original B20 lifters you do not resurface them. They go directly to the garbage, do not pass Go, do not collect $200. Some people do a swirly thing with abrasive paper on new lifter faces and perhaps you can resurface the replacement design; but, at the price of new ones from Isky why bother.

The rocker arms must be resurfaced because new ones are not available.
Click to expand...

Well ****, per John V's advice, resurfacing does the trick. I was able to get the set resurfaced (they were only slightly off from original, because I had buggered the break in procedure) for $50 locally.
 
142 guy said:
If those are original B20 lifters you do not resurface them. They go directly to the garbage, do not pass Go, do not collect $200. Some people do a swirly thing with abrasive paper on new lifter faces and perhaps you can resurface the replacement design; but, at the price of new ones from Isky why bother.

The rocker arms must be resurfaced because new ones are not available.
Click to expand...

You do know that the original lifters weren't born with the 1 degree hemispherical crown on them dontcha? That they were machined..GROUND specifically to have the slight--1 degree--curve....OK? So IF---and that's an awful big if, IF you have the right very specialised machine , then doing the same thing as the sub-supplier did for Volvo can be done for YOU..The gawddam machine is so simple anybody could correctly machine--re-surface--lifters..

Sii I snet the boy to a place that is real close by for him who does work on commercial diesels mainly..On those there's LOTs of very expensive parts so the truly bizarre attitude about routinely throwing away parts is not the norm..You re-build things to factory spec or better..Yeah I know, odd concept, huh. So they have the right machine...I've used them for 34 years..they're good..
Learn..Cultivate better resources...Learn.
 
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