It's time to replace a failed head gasket on my 510. I'm trying to do this on my own for the first time. Pumpkn210 (RIP, Dave) did this job for me about 10 years ago while I hung out. I dont want to ruin the engine, so I'm creating like a step-by-step shop checklist for myself and other learners. I found info from h2theizzo YouTube, @banzai510(hainz) is that you? as well as from @Skib's rundown, and a couple manuals. Many of you can do this in the dark, so I appreciate help from your experience, thanks everyone! If you see any corrections / additions, comment below.
Also, a couple questions:
- how do you turn the engine to TDC? Just turn the crank pulley in neutral?
- what gaskets should be replaced other than head gasket?
- head bolt torque specs: I've seen both 40 and 60ft/lbs. Any thoughts?
L Series Head & Gasket Replacement - Shop Checklist
Drain the fluids
Drain coolant
Drain engine oil
Remove auxiliary parts
Remove exhaust manifold
Disconnect hoses
Remove distributor
Verify distributor slot at 11:28 position for TDC
Time engine to top dead center, compression stroke
Take valve cover off
Turn crank pulley to approaching TDC
Verify mark on crank
Verify timed head (intake at 10 o’clock, exhaust at 2 o’clock positions)
Verify v-notch on cam sprocket aligned with dash on cam plate
Loosen cam and crank bolts
Put screwdriver through cam plate (is this a good method?)
Loosen cam bolt (19mm)
Loosen crank bolt (is this only for full-engine breakdown?)
Make sure nothing got moved out of TDC
Remove cam sprocket
Mark sprocket and chain link with paint pen to help with reassembly
Insert timing chain tensioner tool and make sure it is well seated
Take off cam bolt (19mm)
Remove the cam sprocket
Check the cam gears for wear. If gear is worn, replace with OEM Japan parts
Remove front cover bolts
Remove top (2) 10mm bolts from front cover
Below steps are for full-engine breakdown only:
Also remove remaining 10mm bottom cover bolts
Take out oil pump and oil pump drive. Keep in a clean place
Take off crank pulley. Keep in a clean place.
Take off cover, but keep bolts in cover so they go back in their same holes
Tap cover with something soft on both sides to loosen
Remove engine head
Clean oil out of Allen head bolts where debris can collect
Loosen head bolts with Allen socket (10mm)
Loosen and remove from inside to outside
Soak head bolts in carburetor cleaner to clean
Verify cam dowel is in 12 o’clock position to verify TDC timing
Put a breaker bar in an exhaust port and gently lift to separate head
Do not left head fall off!
Check head gasket, head, and block where failure occurred for defects
Remove old gasket & clean surfaces
Clean gasket surfaces thoroughly. Check with fingers for any traces of adhesive, old gasket, etc
Prep the block face and head face by removing all oil residue. A spray can of ether (starting fluid) works well, and some lint-free cloths / old t-shirts
Chase the head bolt thread holes. Remove all water, grime, grease etc that is in the bolt holes. You can use a thread tap. Use a small vacuum hose to blow gunk out of the holes if needed
Install front cover gasket (if doing full-engine breakdown)
Use blue RTV to hold gasket
May have some complications with oil pan
Install new head gasket
Seal / hold head gasket using Permatex Copper-coat (optional)
Place new gasket on block
Install head
Place head on new gasket, aligning with block dowel pins
Ensure head sits flat
Install head bolts with washers (10mm Allen)
Follow cylinder head bolt tightening sequence
Use a quality torque wrench
Torque in long, even stroke in increments of 20ft/lbs
Finish at 40ft/lbs torque (check on this, someone else said 60)
Make sure the cam dowel is at 12 o’clock position for TDC
Make sure #1 piston is up to ensure TDC
Install the two front cover top bolts (10mm - torque spec?)
Install cam sprocket and timing chain
Install timing chain sprocket, align with paint marks (when trying to put the sprocket back on, it might seen hard to get it up on the dowel and center part of the cam. If so, move the cam left or right to get slack in one side to help raise the sprocket up)
Install cam sprocket bolt (19mm, torque spec?)
Remove timing chain tensioner tool
Install remaining parts
Install valve cover (torque spec?)
Install exhaust manifold
Verify distributor at 11:28 position for TDC
Install distributor
Connect hoses
Refill fluids
Refill the cooling system
Refill the engine oil
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Sources
H2theizzo YouTube L series head replacement
Is this you banzai510 (Hainz)?
https://ratsun.net/topic/25129-quick-head-swap-write-up/#comment-376498
(From Skib's Quick Head Swap Write-Up)
…some manuals from the shelf
Parts to be ordered & replaced
Head gasket
Thermostat gasket?
Other gaskets?
Special tools and Supplies needed
10mm Allen socket
19mm socket
Torque wrench
Timing chain tensioner tool
Gaskets (head, etc)
Permatex Copper-coat
Coolant
Engine Oil