Need help with some eng related paint/bolt details

[Brad M.]

I am getting close installing my engine for my 71 lt-1 and could use some help regarding some details on the engine area paint, the certain bolts, etc.

1. For timing tab, I have read that it was generally unpainted or masked. Is only the part with the timing marks unpainted? Should it be painted at the base where it bolts to timing cover up to last bend leading to the section with timing marks?

2. For the studs that are on the water pump upper mounting holes (which also mount alt bracket, smog bracket, etc) - do these get painted orange with engine?

3. I have read in Dobbins book that valve cover bolts for aluminum valve cover small blocks should have M or R headmarking - is that definitely correct? I have some that are supposed to be for alum valve covers which have S headmarking - are these incorrect?

4. For bolts from bellhousing to block, what are proper headmarkings for small block with 4speed (not sure if these would maybe even be same regardless of 4speed or automatic cars)? Should there be a bracket that holds the battery cable behind the upper passenger side bellhousing bolt?

Thanks in advance for your help.

[Joe L.]

Re: Need help with some eng related paint/bolt det

brad-----

1) Some timing tabs were unpainted. However, usually this involves only the portion of the tab with the degree marks on it; the rest was painted. Many timing tabs were painted completely. I can say, for sure, that the one on my original owner 1969 was painted;

2) The upper driver side stud on the waterpump was installed at St. Louis and is completely unpainted;

3) "M" was a common headmarking for the valve cover bolts used for 1969+ Corvettes with aluminum valve covers. However, there are very few applications on a Corvette where only a single headmarking is "definitely correct". In most cases, including these valve covers, other headmarks could have been used. I believe that most period-correct headmarkings are acceptable for judging. These bolts were "indented head" style (untrimmed), though; I've never seen or heard of any exceptions to that feature;

4) Bellhousing bolts were a FLANGED HEAD, "INDENTED" head bolt with 3 lines (GM 280M). "A" was a common headmarking but others (such as "M") were also used. Yes, there was a clamp which secured and supported the battery cable attached to a passenger side bellhousing bolt.

[Patrick H.]

Re: Need help with some eng related paint/bolt det

Brad,

1. See the picture below of my base motor timing tab. I would suggest (?) that an LT-1 would not have been much different. If you look to the right of the tab you see an unpainted area of the balancer. Perhaps this did not receive paint because the tab blocked it?

2. Note in picture above that mine are black. No guarantees since my water pump has been replaced.

3. M is used and is readily available in reproduction. Could you post a picture of yours?

4. Yes - see here: http://www.corvette-paragon.com/cata...C-992A144FB6AE

[Joe L.]

Re: Need help with some eng related paint/bolt det

Patrick-----

This tab appears to have been "wiped" after painting. I think that was the instruction to engine painters but it actually was carried out only "part of the time". For 1971, the timing tab for base engines was the same as that used for LT-1. For 1972, it was not.

[Patrick H.]

Re: Need help with some eng related paint/bolt det

Joe,

Given the different sizes of balancers, I would have suspected that the tabs were different in both years.
In any event, it's an example of a 72.

Patrick

[Joe L.]

Re: Need help with some eng related paint/bolt det

Patrick-----

1969-71 base engines (300 and 270 hp) used an 8" balancer. This was the same diameter as the balancer used for 1969-72 L-46 and LT-1. However, the base engine balancer was thinner than the L-46/L-82 balancer. So, the timing tab for all small blocks during these years was the same (however, 1969-70 used welded-on timing tabs; 71+ may have used welded or bolted)

For 1972, the balancer for base engine was 6-3/4" OD whereas the LT-1 balancer was 8" OD. So, a different timing tab was used for each.

[Brad M.]

Re: Need help with some eng related paint/bolt det

Joe,
Thanks.

Regarding the bellhousing bolts, if I understand what you are saying regarding the style, I think you are saying that they would basically look similar to the two intake bolts that go under the lift bracket, right? I think that I do have some of those, but was not positive that is what they were for. (I tried to label bolts as I removed them, but unforunately some engine related bolts did not get labeled, primarily as a result of the guys at the shop who helped me remove it).

That is actually interesting to me that they installed some of the water pump bolts at one place and some at another.

[Brad M.]

Re: Need help with some eng related paint/bolt det

Patrick,

Thanks for info.

The valve cover bolts that I was referring to are actually reproductions from Dr Rebuild (as v.c. bolts on my engine upon removal did not appear correct at all). I was not too confident that the ones I purchased were consistent with original ones based upon what I read. I guess that I will use them absent locating a set of OEM ones.

Thanks for confirmation on the battery cable bracket - that looks consistent with what I have, but was not 100% sure that is where it goes.

[Brad M.]

Re: Need help with some eng related paint/bolt det

My timing tab is bolted but looks somewhat different than that one from '72 most notably that I do not recall my '71 tab having the round hole to flash the timing light through.

I think I will go with the plan to tape the part where the timing marks are (rather than painting and wiping or painting completely.)