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A better oil pump for your Turbo Buick V6!

Here is a timing cover project I done years ago. It involves taking two timing covers and making a custom made one for the rear wheel drive Turbo Regal V6 engine. This involves cutting a 1988-1990 3800 SERIES 1 Buick V6 timing cover in half and welding the oil pump portion of it to the bottom of a Turbo Buick V6 timing cover. The 3800 SERIES 1 front wheel drive cover will bolt directly to the older rear wheel drive 3.8L block. However, that's where the similarities end. I'll show in pictures how I accomplished the project. Not every detail is included on this write-up.

WARNING!

This modification will require a modified harmonic balancer. You can not do this oil pump cover without repositioning the trigger wheel on the harmonic balancer. Now would be a great time to upgrade the SLOW START ignition system to the FAST START ignition from a 3800 Series 1 engine.

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You'll have to cut both timing covers where you see the parting line in the picture below just below the water pump. Try to cut as straight as you can.

 

This is what you'll wind up with after cutting them in two.

 

Now, bolt both pieces on the front of the engine block but leave all the bolts slighty loose. If there isn't a balancer seal in the cover, install one in it now. Slip the harmonic balancer on the crank nose and allow the oil pump cover to center itself around the balancer seal. Tighten the bolts that hold the cover to the engine. Now you can tack weld the covers together near the engine block on each side.

 

Once it's tack welded together, remove the cover and it should look like this. Next is to fabricate a plate to cover up the gap between the covers.

 

Fabricate an aluminum plate to fill in where the gap in between the two pieces like shown below. It will have an appearance of a knife blade.

 

Tack weld the plate over the opening in a couple of places then bolt the cover back on the block. Finish welding the two pieces together but try to keep the heat at a minimum to help prevent warping. After welding, I applied a thin coat of JB Weld over my welds because I can't weld very good...ha!

 

There is one spot on the timing cover that you'll also have to weld up. If you don't do this, oil will leak out. Below is a picture showing where.

 

Once everything is welded up and the cover is finished, you'll have to install the oil pump gears and back plate in the cover. If you have a single row timing chain (like the factory chain) your clearances should be ok. Check for interferrence with the cover bolted back on the block with the timing chain & gears installed. If you're running a double roller timing chain, your clearance with the chain and the oil pump backing plate will be tight or even touching each other. You might have to machine the oil pump plate slightly to gain some clearance. Like in the picture below.

 

Tight clearances if you have a double roller chain and gears.

 

 

Modifying the Harmonic Balancer & oil pump gears.

The harmonic balancer will also have to have some modifications done to it. Two *flats* have to be machined on the end of it so it can slip into the gear to drive the oil pump. Also, in order for the balancer to slide all the way on the crank hub without hitting the seal, the hub will have to be machined deeper to a total of 1.700". See picture below.

 

Here you see a stock 3800 oil pump gear. It will have to be machined precisely to fit over the hub of the harmonic balancer, which will also have to be machined precisely to work with the gear. Here are a few pictures & some measurements.

 

Unmodified hub...

Modified hub...

 

Here is a picture of the crank sensor aligned with the trigger wheels on my balancer. I converted my ignition over to a FAST START when I done the oil pump project. If you take your time, do plenty of measuring it will work for years. This has been on my car for over 12 or more years!