Question: Choosing a timing cover

[hrcollinsjr]

I couldn't decide where this question should go because it possibly fits in a couple of areas, stock engine and performance(?).

First question is how to choose a good timing cover for a rebuild or in my case, do I really need to keep the dozen or so covers I have laying around. If they're good it's one thing but if they're not I want them gone!

Second question is after choosing a good cover how does one "blueprint" or match it up to the block we're going to use it on?

Matter of fact, I think it would make a great "tech tip" or "how to" that could be posted somewhere else easier to find than in the normal threads and this whole thread could be deleted at some point, just to cut down on the amount of stuff to have to search through to find the little gems that can get hidden.

Thanks in advance.

Harold

[deaner]

I've always looked for low mileage ones, Because the oil pump is part of the cover. Also the condition of the water pump area. And also whether or not you want the extra 2 holes (mostly a head gasket thing).
I even gasket match the water pump to the block, any and all Oil passage's. Were the oil goes from cover to the block I try and smooth that out and round it off (less of a 90 deg)not too much, don't want enlarge or cause a pocket. The Oil pump is the critical area for me. I blueprint the pump as per spec.'s. Mostly deburr the passage's and what I call "flow them". If a timing cover won't come to spec's in the oil pump I toss it out. Rally Bob had a great article about Oil pumps and coating them.

[yellaopelgt]

I would have to say that the biggest problem I've encountered with timing covers is that the PO has removed them without removing the front seal first. What this usually does is breaks that thin "lip". I've tossed quite a few covers because of this myself..... As far as "blueprinting" them???? I kinda think thats what gaskets and copper permatex is for!!
HTH Joe

[hrcollinsjr]

Originally Posted by deaner I've always looked for low mileage ones, Because the oil pump is part of the cover.

That was one of the reasons I asked this question. No matter how good the machine work is and how well I check the clearances I could STILL have low oil pressure due to my poor choice in covers.

Also the condition of the water pump area. And also whether or not you want the extra 2 holes (mostly a head gasket thing).

I like for them to match but on a race engine years ago, I really didn't care as long as it didn't leak. If the block is decked a significant amount you may wind up with the timing cover taller than the block.

I even gasket match the water pump to the block, any and all Oil passage's. Were the oil goes from cover to the block I try and smooth that out and round it off (less of a 90 deg)not too much, don't want enlarge or cause a pocket.

You're just using a gasket, not something else to try to match the two. I was probably making it too hard. I had thought maybe something was applied to the block that would transfer to the timing cover so that when you disassembled them you could tell where they mismatched.

The Oil pump is the critical area for me. I blueprint the pump as per spec.'s. Mostly deburr the passage's and what I call "flow them". If a timing cover won't come to spec's in the oil pump I toss it out. Rally Bob had a great article about Oil pumps and coating them.

I remember Rally Bob writing about this but don't recall how much detail he went in to. Want to post a link if it's on this website?

Harold

[deaner]

It's in the first page of this thread. It also covers dry sump system.

http://www.opelgt.com/forums/opel-en...-build-up.html

[jeff denton]

Originally Posted by yellaopelgt I would have to say that the biggest problem I've encountered with timing covers is that the PO has removed them without removing the front seal first. What this usually does is breaks that thin "lip". I've tossed quite a few covers because of this myself..... As far as "blueprinting" them????

What Joe tosses them for is step one when I prep a cover. I cut that stupid lip off, because I might want to be able to remove the cover quickly.

[hrcollinsjr]

Originally Posted by jeff denton What Joe tosses them for is step one when I prep a cover. I cut that stupid lip off, because I might want to be able to remove the cover quickly.

Old timing cover trick to facilitate removal for cam and timing chain changes on V8's. I thought he was talking about the front crank seal. It's much easier to remove after the cover is off.

Just went through and started culling covers. I've tenatively tossed seven. Three because someone used a too long bolt in the alternator bracket and broke through. One a too long water pump bolt that broke through. I was impressed with one, the timing chain had enough slop in it to actually wear through the cover. Anyone want to see pictures? While some of this stuff does't necessarily warrant tossing them, I still have probably a dozen or more to go through. If it turns out that the pump areas are scored I may have to pull some from the culled pile.

Harold

[GTJIM]

For sure the condition of the oil pump housing is the most important criteria for selection of front covers - they are alloy so most anything else can be weld repaired.

Be aware that there are oversize bores for both where the gears fit and also the drive shaft hole - from the factory! One, either or both gear recesses can be over-size as well as the shaft hole - so a lot of potential combinations.
Though, I think factory supplied o/s driven gears also have an oversize drive shaft - not sure if the idle gear has an over-size bore ... but must check that the one I fitted is not loose on the stub shaft that sticks out of the cover!

I found this out when a new set of gears would not fit - however, boring out the housing and reaming the shaft hole gave me a very good front cover.
So 'old' worn oil pumps can be 'repaired' by fitting oversize gears.

One day those 'reject' front covers may be worth their weight in oil!