What is the purpose of the black-headed bolt between the timing cover and the fuel pump to carb hard line? Should it be there?

Bet you'd never guess that this is my first resto/rebuild...


Thanks

 

Take the bolt out and use the hole, install a longer one to hold the pushrod for the fuel pump.

C

 

OK, thanks for that info. I thought it was related to the fuel pump, but now know for sure.

Anyone not so knowlegable (like me) about such things may find these links of some use explaining how that works. All you ol' gear heads and mechanics need not waste your time looking at them...


http://67-72chevytrucks.com/vboard/s...d.php?t=138417

 

I think someone put the bolt in there just to put it somewhere! The hole that bolt in is paired to the bolt hole immediately below it. This pair of holes can be used to bolt on an accessory drive bracket. For example, on my 70 engine this pair of holes is being used to bolt on a bracket that mounts my crankshaft damper crank position timing sensor for the fuel injection.

 

Remove that bolt and you have a significant oil leak. It needs to be there.

 

Actually,that hole has(had) two uses. The tri-five chevys used front motor mounts. The hole you referenced and the hole below is where the motor mounts were bolted. Those engines did not have side motor mounts. Also as has been mentioned, a longer bolt placed in this hole to hold the fuel pump push rod really when replacing the fuel pump. Just remember to take the longer one out when finishes and replace with the short one. This basic block design has been around for a loooong time.

 

Yeah, I read that on some blocks that hole is a blind hole that doesn't penetrate all the way through. In those cases, it's a result of a common casting and can be left open or used for an accessory mount (68/70) or engine mount (beachmusic) but not for securing the fuel pump rod.

 

Why is your timing tab so far away from the harmonic damper?

 

Absolutely!

 

Because that's where my engine builder put it...

Are they adjustable other than bending it closer & why would it matter?

 

Some bolt on, some are welded on? Perhaps that's an L82 timing cover with an L48 (smaller diameter) harmonic balancer.

It may not matter except for a few degrees of timing uncertainty if you aren't lined up properly. But it also indicates mis-matched parts, which seemed to be the theme of this thread.

 

My husband makes a comment like this and got banned for a month. you should be careful as some are easily offended on here.

 

Remember I said I was a newbie to this hobby since this is my first experience with car restoration/rebuild, so the learning curve is steep (almost vertical)!

Good sharp eye and thanks for bringing the tab up!

Going back to check some old photos of the original engine, I see that the timing cover must have been changed during the rebuild (had a different stamping pattern on the front than it does now) and that the damper now appears smaller than it used to (further from the water pump).

I'm guessing that the car ('71 coupe 350/270) originally had an 8" damper as the timing tab in the old pics was much closer than it is now. The builder must have put a new cover on when replacing the timimg chain & gears along with a 6.75" damper. Perhaps he reused the tab designed for the larger damper. At least that's my guess.

I'll check my paperwork and/or ask the builder. Unfortunately, that was 3 years ago so he might not even know unless he keeps good records.

I imagine I can get a timing tab for the smaller damper that will close that gap by moving it closer. I "hear" that for my engine (mild build for cruising with roller rockers & cam) that the smaller damper can be used successfully, but I'm certainly no expert (see line one of this post ). I'll have to do more research about the timimg tab applicability and check the new damper's key and marking locations.

BTW, I didn't understand your comment about mismatched parts being the "theme of this thread." As the OP, I was just trying to find out if that bolt by the fuel pump was supposed to be there or if it could be safely removed. Now I know and also learned that I lacked knowledge about dampers and timimg tabs . No harm - no foul...

 

We're all learning! I'm glad that observation was useful. I certainly didn't mean to pick on you, and I learned a bunch when I researched my own question.

Is the tab that's on there easily removable? It's hard to tell with the paint and the camera angle. If so, this bolt on tab may work for you with the smaller harmonic damper (perhaps call Zip to confirm). Do you know what your engine was before it was rebuilt?
https://www.zip-corvette.com/69-80-b...b-bolt-on.html

Good luck with the engine install!

 

Yeah, the existing tab just bolts onto the timing cover. l've already ordered two different bolt-on tabs to see if either fits closer to the damper and, if so, which works and looks better. These tabs say they are for 7" dampers while the ZIP one you linked doesn't specify the damper size, just that it fits the base motor which I THINK originally used an 8". Hopefully, the new one will end up closer to my new 6.75" damper. I can't tell from product picturtes how the 7" and 8" tabs are different so I've got my fingers crossed that they actually are,,,

 

Verified that the timing mark on the "new" smaller damper is about 10* ccw from the keyway which I believe to be correct. At 0 on the tab, the distributor rotor is pointing at the #1 lead.



New timing tab is made for a 7" damper, but at least it's closer to my 6.75" one. Will continue to look for a proper tab...