Mid- Engine Modified Sports

[manta22]

While pondering the parachute question, I got on with mounting the catch tank for the transaxle vent line. I put in Riv-Nuts and installed it with titanium 10-32 screws. One more thing done. I've started adding water into the cooling system. So far I've added 240 fluid ounces; I guess that is about half of its capacity.

Regards, Neil  Tucson, AZ

[wobblywalrus]

Neil, a comment on titanium fasteners.  They rate very noble on the galvanic scale.  The thing they are screwed into is typically less or much less noble.  There can be some serious oxidation issues when saline solutions get into the threaded areas.  Basically, it locks up tight.  This is real bad with riv nuts.  The screw and nut both turn when removal is attempted.

Riv nuts of the more noble stainless steels seem to work OK with ti bolts or screws.  I use these and lots of loctite on the threads of the ti screw or bolt.  The loctite is used mainly as a thread sealant to keep the salt water out. 

[manta22]

Point well taken, WW. I always coat stainless steel & Ti threads with NeverSieze.

Regards, Neil  Tucson, AZ

[manta22]

After adding some water to my cooling system, I noticed a small puddle under the front but I couldn't find anyplace that seemed to be leaking near there. I took off a left-side panel and found a slow drip ahead of the LR tire. I tightened the T-bolt clamp a couple of turns and the leak stopped. The water had run forward to drip since the chassis has a forward rake.

Next, flushed with success, I added a gallon more to the filler and immediately heard water splattering on the floor. Oops, big leak. I could see that water was running out of three or four holes in the front of my Donovan SBC block.    I had not expected those holes to be thru-drilled into the cooling jacket- but they were! A little research showed that those holes were originally placed there by Chevy for '55, '56, & '57 motor mounts. I had not realized that early the SBC did not have side mounts. Live and learn.

This necessitated a trip to town to buy some 3/8"-16 x 1/2" bolts. While I was there, I looked for a cooling system pressure tester but I could not find one for sale. Auto Zone loaned me one for 90 days free! They ring it up and when it is returned the charge is refunded. I'll use it to find any other sources of leaks (hopefully).

Regards, Neil  Tucson, AZ

[manta22]

I bought eight 3/8"-16 x 1/2" hex head bolts in town yesterday and installed them using a thin flat steel washer under the head of the bolt and a Teflon washer under that to guarantee a seal against the block face. To seal the threads, I used ARP thread sealer.

Before I bought the bolts I called Donovan with both my block serial numbers and asked about the thread size. Gary returned my call, verifying the 3/8"-16 thread and told me the block that I am going to use later for my race engine was a special one they made for Dan Gurney's Indy car Eagle. I can't see anything different about it- an aluminum small block with dry sump- but it does have big AN fittings on both sides of the block into the water jacket. Where to plumb those is a mystery to me.

Regards, Neil  Tucson, AZ

[manta22]

All along I've been saying that I'm putting Never-Seize on my bolts but that is not strictly correct. It is an anti-seize paste but it is called "Nikal", made by Jet Lube. I probably bought it years ago at one of the USAF auctions that they used to have here at Davis- Monthan Air Force Base. The interesting thing about this stuff is that it consists of only pure nickel flakes in a gooey binder. It is rated up to 2600F so I think it will be OK for even header bolts, etc. Has anyone else ever used this?

Regards, Neil  Tucson, AZ

[ggl205]

Auto Zone loaned me one for 90 days free! They ring it up and when it is returned the charge is refunded. I'll use it to find any other sources of leaks (hopefully).

Regards, Neil  Tucson, AZ

This is very helpful to know, Neil. I use a coil of stainless steel tubing in my oil tank (from the hot side of my cooling system) and wanted to see if I had any leaks in my bends. I hope my AutoZone is as friendly.

John

[Dynoroom]

Neil, I don't want to second guess what you have found, but I'd like to share my experience on similar issues in the past.

In the picture below I circled the 4 bolt holes you are talking about. This is a Donovan alloy small block like yours I believe. Note the 2 lower holes circled in red. The water jackets don't go low enough for these hole to break into. The upper hole on the left circled in yellow goes directly into the fuel pump push rod hole. Again no water jacket at this point. The last hole on the right in the photo circled in blue is the only one I can see that MIGHT get into a water jacket.
The only reason I am pointing this out is because if water is coming out of the yellow hole you might have water in the crankcase! This can happen when the splayed side main bolts break into the water jacket from the bottom. When this would happen we would use Teflon sealer on the bolts or studs during the build. Otherwise you can fill the engine with water.

I'm just suggesting you double check where the water was coming from.

[manta22]

Thanks, Mike. Water was definitely coming out of the blue-circled hole; it looked like water was coming out of the others, too but now that I think about it, that water was probably running across and dripping off the boss where the other holes were. There is no water in the oil- I have a sight gage on the side of my oil pan and a layer of water would be clearly visible. Now that I've closed up those 4 holes, I'll look for possible leaks elsewhere. Thanks for your help.

Regards, Neil  Tucson, AZ

[manta22]

Since Joline is in CA for a few days, I have taken the opportunity to make lots of noise and dust in the shop.

There are vent holes molded into the fiberglass body to relieve aerodynamic pressure but they needed to be cut out to make them functional.

I came up with a method to cut out the vents in the rear body and in the top of the front fenders. Here is how I am doing it:

First, I cut a template from a scrap of 1/16" aluminum that fit into the vent and then drilled 1/8” pilot holes near the ends and at regular spaces in between. These are used as pilot holes for a 1” hole saw. To prevent scarring the fiberglass, I covered the template with Blue painters’ tape. Since the holes are being drilled at an angle relative to the fiberglass, the holes must be enlarged from 1/8” to 1/4” is steps- otherwise the drill point will just skate around instead of following the pilot hole.

The 1/4” pilot drill that came with the hole saw was too short for using at this angle so I replaced it with a long one that I had. I also used the aluminum template for protection from the hole saw by taping it on the lower edge of the vent depression and then ran the hole saw through each pilot hole.

An el-cheapo Harbor Freight “air body saw” with a “coarse” 24TPI blade was used to make straight cuts between the holes. If you are careful, the cuts will be pretty good but they need to be finish-sanded to get the edges straighter. An on-sale HF “oscillating multi-tool” with a carbide abrasive blade gets into the edges of the vents and sands the fiberglass nicely. Painting the exposed cut edges will be a final touch.

The advantage of using a 1” hole saw for the end cuts is that it leaves a radiused hole instead of a square one which you would get by sawing all the way to the ends of the vents. This prevents cracking from long-term vibration.

Comments, questions, & criticism cheerfully accepted- as always.

Regards, Neil  Tucson, AZ

[tauruck]

Welcome to my world Neil.

You did good.

There is only one way to cut those slots and you aced it.

Looks neat.

[manta22]

Thanks, Mike. As I've said before, working with fiberglass is not my favorite thing to do.

That 1/4" drill that I used for the pilot in the hole saw was overkill but it was what I had in my junk box.

Regards, Neil  Tucson, AZ

[Seldom Seen Slim]

Junk box tools:  Yeah, they're in there and probably will be when your family auctions off the stuff after you've kicked the bucket, but ---  Isn't it great to use one of them, once in a while, and think to yourself "See?  I KNEW I should keep that when it broke/wore/failed!"

C'mon, admit it.  We've all done it.

[manta22]

Junk box tools:  Yeah, they're in there and probably will be when your family auctions off the stuff after you've kicked the bucket, but ---  Isn't it great to use one of them, once in a while, and think to yourself "See?  I KNEW I should keep that when it broke/wore/failed!"

C'mon, admit it.  We've all done it.

Yep, Jon, my junk box has saved the day too many times to count!

Someday Joline will have one heck of a yard sale! She'll probably sell stuff for $5 that's worth $1500. 

Regards, Neil  Tucson, AZ

[Buickguy3]

     I went to a yard sale once and on the table were two new unused Snap-On paint guns. I asked the gal running the sale how much and she said she's have to ask her husband and she yelled inside the hose and he yelled back five for both. She came back and said $5 for both. I took them home and let them sit on the bench for a week waiting for him to come and correct it. [I still have them and haven't had a paint project since, so they are still new.
    Doug