Valve cover gasket replacement

[sentra]

I will be replacing the valve cover gasket of a 1994 Mazda Protege soon. However, i don't know the torque specification to keep the bolt from overtightening and neither do i have a torque wrench at the moment.

Practicing the criss-cross pattern, I plan to tighten the bolts "just tight," without applying too much force. Would that be gone enough?

Other tips would also be greatly appreciated.

 

[UNC197]

I would use a torque wrench so all of the bolts are tightened exactly the same. Try a google search for the torque specs, I cam up with 66 to 95 inch-lbs. Which is 5.5lbs - 7.9lbs.

If you feel you can get it by hand then go for it.

 

[robshelton]

if you can see the edge of the gasket, watch it as you tighten the bolt and stop when you see it starts to get barely squeezed out. That is with a rubber gasket. Of course some gaskets come with steel grommets in them so they can't be squished. Good luck!

 

[The_Jeff]

If you google around you can find standard torque values for various size bolts. The 5 lb reference is good; doesn't take much and if you overdo it you can dimple stamped steel covers so they seal WORSE. Not to mention easy stripping aluminum heads.

 

[Eddie]

Find a book at AP that shows not only the torque values but also the tightening sequence. The sequence varies for different engines. A torque wrench is a must.

 

[JOD]

Originally Posted By: CharlieJ
I would use a torque wrench so all of the bolts are tightened exactly the same.

If you feel you can get it by hand then go for it.


The problem is, a torque wrench does pretty much nothing to ensure that's actually the case in brand new systems. Take old bolts into a used cylinder head and all bets are off.

I think the best bet it to try to research angle torque specs for valve cover bolts of that diameter and tighten down with angle torque.

 

[willix]

A valve cover is less critical and tightening patterns are really not needed with the very light torque clamp loads.

It never hurts to make an effort to clamp it down evenly.

You need an inch pound TQ wrench.

 

[The_Jeff]

A stubby ratchet is useful too for limiting torque.

A rubber or cork gasket (not with RTV or PRINTOSEAL) you can go light then retorque it if it seeps. Usually you can feel when you're crushing the gasket material.

 

[sentra]

Thank you for the replies, guys.

Before starting, i used nail polish to paint a mark on each bolt and a mark on the valve cover opposite to the mark on the bolt, so i knew how much the bolts had been tightened originally. I kept the bolts in order, so each one went back where it came from.

After replacing the gasket, when i tightened the bolts to match the two marks, i found that the two marks lined up when the bolts were "just tight." I was using a 1/4 inch drive ratchet.

Of course, this exercise assumed the bolts were not overtightened before.

 

[The_Jeff]

Glad it worked, but if you used a non OE gasket or if they had a running change in thickness your "how deep are the bolts" method would have resulted in improper torque.

 

[doitmyself]

I would be surprised if many pro wrenchers use torque wrenches on covers that utilized gaskets. Any feedback? An RTV sealant would make a torque wrench more applicable, IMO.

I have found the use of torque wrenches with gasketed covers to be kind of "funky", based on my last transmission pan install with a digital Snap On Tech Wrench.

Because the gasket can "squish", it seems to me that you can arrive at the suggested torque (9 ft.lbs. in my case), then the gasket can relax a bit and you come around again and retorque it to the "same" value. If not careful, you can squeeze out and ruin the gasket.

Using a very stout Fel Pro gasket (not spongy), I torqued all the bolts up even to one value. Over several months and the appearance of slight seepage, I then retightened the pan, not with a torque wrench, but rather just an equal amount of turn (2 separate times/months)..

I think hand tightening with a 1/4" wrench is very doable, but using a torque wrench was interesting and educational.

With OCD, I do the paint trick on fasteners also. At work, it allows me to walk around and see if anything has come loose.

 

[mechtech2]

The nail polish trick can be a huge fail.
You have different parts in there now , and who knows if it was correct before.

Really, just don't gorilla them on.
The twist to initially get a lid off of a normal bottle of pickles is about right.

 

[sentra]

Well, after 2 days of about 20 miles in driving, everything appears fine. However, that doesn't mean much. I will continue to monitor it every day for the next couple of weeks.