Timing cover fuel pump threads stripped what are my options.
 

Just got done resealing my timing cover, new water pump balancer pulleys etc. while torquing the fuel pump screws the rear one stripped. I had my TQ wrench set to 20ft lbs. not sure if the wrench is bad or the threads were bad to start with. Now i need to figure out how to repair it. Do i need to remove the cover and helicoil it or could i do it with it on the car. If i can get away with not removing it that would be great. Any suggestions.

If they haven’t been stripped before you can go to a 3/8-16 bolt after you tap it. Will have to open pump holes also very common fix. You could use a hellicoil also if you want to stay with the 5/16 bolt.

I think you'll need a decent length tap extension if you plan to do it on the engine. No room on the rear hole to turn a tap handle since it's so close to the block. Probably at least six inch long extension.

Lots of people go with a 3/8 tap. Probably the easiest solution. Heli-coil a bit more finicky in that situation, need to drill it nice and straight (not sure if you can get a drill in there) and there is the little hard stainless tab that will probably go into the engine on installation. If just tapping for 3/8 you only have to worry about some aluminum bits. There are other types of thread inserts that might work for you too.

If you end up taking it off ... heli-coil both holes to 5/16 while you have it off. Standard procedure for me when installing a used original cover.

I can't remember if that back hole goes through or not. That would be the big question whether to do it on the engine or off. If it's a through hole I think it would be close to impossible to keep shavings from falling inside

Hole goes all the way thru. My main concern is shavings falling down into the pan. I dont want to damage the engine.

When you take the pump off you can get to the back of both holes you can make a small tape box to catch chips or put a clean rag under holes on inside and use some grease to catch chips. If you take your time it’s not a very hard fix

I have never really liked heli-colis. E-Z-locs or other solid inserts work a lot better imho.
Here is an example:https://www.amazon.com/Z-Threaded-In...ts_id=16410701

For whatever you need, check McMaster-Carr they will have most everything. Heli-coils are also available without the tab.

Others may disagree but I don't think a few aluminum shavings in the pan would be an issue. They would almost certainly remain in the pan and the pump screen should stop anything large enough to be a problem in the pump, then the filter would catch the rest. (although ... check balls get stuck pretty easy).

As Grandam suggested, there are ways to catch the chips on the back side. Heck you could probably bend up a little spoon out of aluminum foil, put some grease in it and hold it behind the hole.

I think the drilling would be the biggest issue, might need smallish right angle drill, or attachment for a conventional drill to get in there ... and I bet it still might be too close to the block to get the drill straight. Maybe a right angle drill with a long bit to clear the block might work.

I'd check if you have room before you decide on anything. Working a 3/8 tap in there with an extension, without drilling may be the only way. There may be some right angle air drills small enough to do the job.

So if i understand correctly. I could use a 3/8 tap and not have to drill it. If that is the case i can see taking a piece of duct tape and covering the backside of the hole And slowly tapping and going in small increments and vacuuming the hole as go so i dont push a bunch of savings into the oil pan. On the other hand i could just bite the bullet and pull the whole cover and either replace it completely with a new one or fix it properly off the car and reinstall. Decisions decisions.

I really like and recimmend Helicoils for the Fuel Pump Hole repair. Prehaps better than New.

Usually loading up the tap with wheel bearing grease catches 99.9% of the chips

Also you could drain the oil first and after tapping spray it down with a couple cans of carb spray with the drain plug out or use a quart of gas with a funnel and length of hose to flush out contamination whatever you use just make sure it evaporates easy

Iam about to install a brand new cover myself I may be studding the fuel pump

IMO if the engine is in the cars working on that cramped space I would pull the cover for sure to avoid any more issues than you already have.Tom

I don’t remember reading that when resealing the timing cover you installed a new timing chain and gear along with the balancer and water pump. If the chain wasn’t replaced then pull the timing cover, replace the chain and cam gear and repair the damaged hole threads before putting the cover back on.

Usually in aluminum .. yes you can go straight to the 3/8 tap. The tap drill size for a 3/8 - 16 bolt is ... 5/16". And obviously you already have very close to a 5/16" hole there so you are good to go.

Pull the timing chain cover.

This:
 

I like this idea, no more stripped threads and installing the pump is a lot easier.

I use a drill for the tap size especially in aluminum you want all the engagement you can. I'm no expert however just using the 3/8 tap without proper size drill you 'might' tear some of the aluminum you want for engagement. I've had to this before.

If you want to just FIX the problem, get yourself a bolt that is slightly smaller in diameter than the 5/16 bolt and about an inch longer than your old bolt. Insert a length of dental floss string into the bad hole and back out the fuel pump lever hole. Tie the string to the bolt a few threads from the end and pull the bolt back out of the bad hole. Thread the string through the pump hole to hold the bolt in place as you mount the pump. Put a nut on the bolt end, remove the string and add a couple more nuts to serve as "jam nuts" and tighten nuts to secure pump. I've done this more than once and it works fine. I'll bet a bunch of guys on this board have done this too!

If it is a "show car", follow Tom's advice!

1st, try a Longer bolt. Originals don't grab all the threads

Doug- to be clear you are suggesting leaving the head of the bolt inside the timing cover and having the threaded portion stick out like a stud? Great idea.

BOLT FIX
 

Yes. It has to be long enough to come through the bolt hole, pump flange thickness and room for 3 nuts. Once you get the first nut started on a few threads you can remove the string , tighten the nut down loosely against the pump far enough to get the other 2 jam nuts on. You then tighten the 2 jam nuts against each other. Then you hold the jammed nuts with a wrench and tighten the first nut against the pump with another wrench. Leave the jam nuts on for loosening it all up when you need to.

Good luck!

Lots of good ideas thanks for all the suggestions. Decieded to just bite the bullet and order a new cover. If I were to repair it I was going to remove it and do it off the car. My fear was that being 40+ years old and knowing it already had a helicoil for a pan bolt ( noticed that when I initially installed). There is always a chance that another hole might strip out. Not worth taking a chance so new it is.

Just in case you’re running a tri-power or have been thinking about someday running one make sure the replacement cover has the indentation for clearance to the tri-power thermostat housing neck.

If you are lucky enough that it is the outside hole, (closest to the fan) I was able to get a nut on the end of mine.

I had a crack running through the back bolthole, and I opted to take a pc of steel, about .312" thick, and drilled/tapped for 8/32 countersunk screws into alum. housing to secure the plate. Drilled and tapped to thread in a stud, and left the existing threads intact. Loctited a stud into the "new" hole, and i figured the width of the plate would distribute the load somewhat away from the hole. Did this in 2008 and it's still 100%.

https://i.imgur.com/jcS3Jx6.jpg

Only the rear of the two holes goes through to the interior of the timing cover. I don't know which years, but some Pontiac V8's used 3/8-16 bolts instead of 5/16-18.

I strongly recommend checking the timing chain slack with your fingers while the pump is off. If it's acceptably tight, put a piece of tape or stuff a rag in the fuel pump actuator hole catch chips. You can tap 3/8-16 threads without drilling the hole any larger. Grease in the flutes of the tap will insure a clean cut and avoid chips falling inside the cover. .