Here's how to replace your valve cover gasket

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sealica
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Here's how to replace your valve cover gasket

Post by sealica » Tue Jan 10, 2017 6:08 am

I find this thread really helpful, but one thing I'm apprehensive about before tackling the repair is whether to put sealant on the valve cover gasket itself or just the half-moon?

Also currently my only parking space is on a slight hill and I must park either facing downhill or uphill. Would either have any adverse effect on taking the rocker cover off? It did seem to exacerbate the leak when parked facing uphill.

Thanks!

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Here's how to replace your valve cover gasket

Post by Growlerbearnz » Tue Jan 10, 2017 4:30 pm

Download the "The 4D5 & 4G7 Engine Manuals" workshop manual (the one with the more useful on-vehicle service procedures here: http://www.delica.ca/forum/viewtopic.php?f=17&t=7335) and follow that. Page 11B-18 shows where to apply sealant (just to the half moon, and a little beyond) as well as all the torque settings for the various bolts. The rocker cover is a bit sensitive to torque- too much and you'll squish the gaskets, too little and it just won't seal.

As long as the engine is left to sit for a half hour or so there shouldn't be much oil to leak out, even if you're parked on an angle. There will be a *little* though, so have a rag handy to catch anything that comes out.
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Here's how to replace your valve cover gasket

Post by sealica » Wed Jan 11, 2017 6:15 am

Thank you - manuals duh. I had looked at those, but for some reason missed the rocker cover ...

I wasn't planning on using a torque wrench ... kind of hard to justify if the oil leak turns out being more serious and I need to hand it to a mechanic anyhow. But maybe rent/borrow ...

I was also curious about replacing only the half moon seal and leaving the rocker gasket in place if it hasn't sprung a leak? I gather from your posts on the alloy half moon that this is possible. It's just that since the rocker gasket comes with a rubber half moon I figured I would change it out as a practice run and then get an alloy one and install that with the new rocker gasket next time.

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Here's how to replace your valve cover gasket

Post by Growlerbearnz » Wed Jan 11, 2017 3:51 pm

I'd still buy a cheap torque wrench. Knowing what 8ft.lb feels like compared to 50ft.lb is a valuable skill: valuable as in not breaking expensive or hard to find things. It's a Delica: unless you're a millionaire you're going to be doing some of your own work eventually, and a cheap torque wrench will do the job in most cases. You can hire a better one when you're doing a full engine rebuild ;-)

(It seems Canadian Tire don't do cheap torque wrenches. $28 for a beam wrench? Madness. I was thinking of a $20 Harbor Freight click-type wrench: http://www.harborfreight.com/catalogsea ... que+wrench)

The rocker gasket and half moon are made of an odd rubbery plastic which deforms the first time it gets hot and never quite springs back, and then gets harder over time. I think your plan will work as long as you swap the halfmoon while the rocker gasket is still soft- I'd guess within a year? Though ideally you'd do the whole lot in one go. Installing the alloy half moon is a one time deal, it should never need to come out again, no matter what engine work is done.

You're going to clean up the back of the head and block while you're in there, right? The oil leak is most likely from the half moon, but it might also be from the head gasket- the high pressure oil feed is in the same area. It can be difficult to figure out where it's leaking from if everything's already covered with oil.
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Here's how to replace your valve cover gasket

Post by sealica » Wed Jan 11, 2017 4:25 pm

I'm assuming the current rocker cover gasket is more than a year old, but unsure exactly. The reason I was thinking about changing the half-moon out without doing the rocker cover is that I cleaned the area where the cover meets the head and no oil coming from there, just at the back (half-moon) ...

But honestly it could be several years old+ (didn't ask previous owner).

So the main difference with a cheap torque wrench is that it's just going to be X% less accurate then a high-end one, but still better than going by feel? Princess auto has one for $44 which is kinda the canadian harbour freight. Tekton sells one thru amazon for $50 and I've heard pretty good things about that brand for lower price point tools. But I don't really want to wait a week for shipping ... I could just return the torque wrench after using, but I kind of wish I could legitimately borrow one :p

But they both say 10-80 lbs ... so to get 8lb you just set it to the lowest and back off a bit once it clicks?

I definitely plan on cleaning the area ... I suspect my turbo is contributing to the oil mess and also a pipe with nut that I can't eliminate until oil stops dripping from above. The head gasket is my greatest fear. I don't have any symptoms like pressurized coolant, bubbling expansion tank, milky oil, or excess white smoke (I get a bit of white smoke at start up and none while running). BUT I did spot a few specks of green (assuming coolant) on the back of the area where I presume the head meets the block which has me a bit paranoid.

Anyhow - start from the top?

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Here's how to replace your valve cover gasket

Post by Growlerbearnz » Wed Jan 11, 2017 8:12 pm

The paranoia is fun, isn't it! Is that a new noise? How is coolant getting there? Was that startup rougher than usual? ;-)

Ok, it sounds like you're replacing the half moon as a diagnostic step, which is a good idea. Try and clean the oil off the mating surfaces of the head and rocker cover gasket so the RTV sealant has a chance, but if it's the half moon leaking then a new one should make it stop. If it works, then you can do the job properly with an alloy one and new rocker gasket.

You've got the right idea about cheap torque wrenches- they're a valuable learning tool, not a precision instrument. Luckily our engines are fairly primitive, and close enough is usually just fine.

Coolant at the back isn't right. There's a steel coolant line that runs from the water pump, along the block, and around behind the engine- if that was corroded or leaking a bit it might give you coolant at the back of the engine.
Nothing says "poor workmanship" more than wrinkles in the duct tape.

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Here's how to replace your valve cover gasket

Post by sealica » Sun Jan 15, 2017 6:45 pm

I bought a torque wrench (10-80 ft-lbs) and didn't have much success with it as the valve gasket bolt torque spec is 4ft-lb. I just used the wrench until I thought it was about half way to clicking (tested on some other bolts first). But it really felt pretty guessy ... I just went until the new rubber washers looked adequately compressed ... basically I learned that 10 ft-lbs is very, very tight. Removing the original bolts from the rocker cover they only felt maybe one or two turns past finger tight.

Being parked on an incline definitely made it a little tricky. Had to mop up some oil from inside the head with shop towels because it was spilling over onto the mating surface (especially at the rear of the cover where the half-moon goes). But I think I managed. See how it survives start up tomorrow :)

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Here's how to replace your valve cover gasket

Post by sealica » Tue Jan 17, 2017 3:12 pm

So my valve cover change appears to have been successful. Only driven 30km since the new gasket, but no leaks thus far; however ran into a problem. When reassembling the timing cover I over-tightened [damn dirty ape] the lower bolt (which is longer than the rest) - that's going to cause a headache - especially since I would like to inspect the front of the valve cover for leakage!

I can't find any torque specs for the timing cover, but assuming a whole lot less than 120 in-lbs?

Also can't help but being paranoid that I dropped sealant into the valves while doing the half moon. I was working one handed with the other hand holding a mirror to get a better view ... worst case?

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Here's how to replace your valve cover gasket

Post by FalcoColumbarius » Tue Jan 17, 2017 5:02 pm

The timing belt cover ~ like the black plastic cover on the front of the motor? I just do them up until it's not rattling about.

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Here's how to replace your valve cover gasket

Post by sealica » Tue Jan 17, 2017 5:45 pm

FalcoColumbarius wrote:The timing belt cover ~ like the black plastic cover on the front of the motor? I just do them up until it's not rattling about.

Falco.
Yes, directly in front the valve cover. I got three out of four bolts that way, discovered one rattling loose when idled for a few minutes - got torque wrench - tightened it to 12 ft.-lbs, then tried that for the next one down (long bolt, wheras previous bolt was short) which is now overtight and can't be loosened =/

Kind of silly, but since the first one didn't go wrong I tried on the next and I'm more familiar with a wrench or socket than torquewrench :p

I'm thinking of using vicegrips, but try to take it slow when considering such measures

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Here's how to replace your valve cover gasket

Post by sealica » Wed May 03, 2017 5:31 am

Thoughts on Fel-pro vs Mitsubishi for the valve cover gasket - rubber bits?

CCA was adamant that the Fel-pro was going to "fail rather soon"? But I was hoping for some second opinions.

My half-moon is leaking again; 4 months later. Not sure if that's an installation error on my part or rather just the fallibility of the rubber half moon ... I used Mitsubishi OEM. It was leak free for few months afterwards that I was monitoring my repair for errors :)

Plan is currently to get an alloy half moon, but for the valve cover gasket itself (not leaking) I can get a fel-pro locally (or re-use the gasket and just replace the half-moon; hoping for the best); or order a Mitsubishi OEM ...

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Here's how to replace your valve cover gasket

Post by Growlerbearnz » Wed May 03, 2017 3:15 pm

I always prefer OEM. Order one at the same time as the alloy half-moon?
Nothing says "poor workmanship" more than wrinkles in the duct tape.

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Here's how to replace your valve cover gasket

Post by sealica » Wed May 24, 2017 9:23 am

So I put on my new valve cover gasket with alloy half-moon. I noticed though that one of the rubber seals under the rocker cover bolts has cracked! I'm assuming I over-torqued the thing since my method was using a torque wrench set to minimum (10 ft-lbs) and turning without hearing a click. I think it's better to use a wrench since you can feel the tension better.

Anyhow this was a step down from my last (first valve cover gasket) job where it was leak free for 4 months.

I'm wondering if I should be sourcing new bolts, or at least new washers (the metal piece that holds the rubber seal in the bolt hole) on account that they may have warped?

Live-and-learn! On the flip side removing my radiator was a breeze! It's at the rad shop awaiting rebuild!

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Here's how to replace your valve cover gasket

Post by rtaylor6753 » Wed Oct 09, 2019 6:53 am

Thank you all for this thread. I performed this last night, took all of about 2 hours and I have never done anything like this. I set the half moon seal with high heat silicone adhesive and reinstalled everything. I will tighten valve cover bolts this evening. The silicone recommended waiting an hour to seal. I'll test drive after tightening this evening and hope all goes well.

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