69 Valve Cover Bolts

[Don O'Connell #33101]

Ok, since I couldn't replace the felts today I started cleaning up bolts and stuff. I'll be sending my BB valve covers out for re-chroming soon and was looking over the bolts. Seems over the last 30 years its aquired 4 different types; some with "NAT" on the head, some with just 3 "tick" marks, some with what looks like a "keyhole", and some with "TR" and 3 "tick" marks. Which, if any, are correct? And should these and the "washer" be chrome or some type of cad plated?

Thanks, Don

[Joe L.]

Re: 69 Valve Cover Bolts

Don-----

They could all be correct and original. Different manufacturers often supplied fastners of the same GM part number to the assembly lines. These could be mixed in the bin that the engine plant assembly line worker drew his bolts from, so it is very possible that, even on the same engine, more than one headmark might be used. More than 2 different ones is probably unusual, though.

In any event, "TR" was a typical headmark and is pretty well accepted, so you might want to change all of your bolts to the same headmark configuration. For 1969 big blocks, all of which used chrome valve covers, these bolts were of the non-indented head type and were zinc plated.

[Terry M.]

Re: 69 Valve Cover Bolts

Don,

All one head mark on rocker arm covers for Mark IV motor will raise suspicions of savvy judges if car has radio. Details are:

A check of AIM will show you installation of spark plug wires with grounding lugs to 4 RA cover bolts, and give part numbers for bolts (see U69 section). This is clue that those bolts were installed at St. Louis with spark plug wires.

Engine is assembled with 14 bolts and washers to spread force of bolts and painted in beautiful suburban Buffalo New York, hard by the river St. Lawrence.

In balmy St. Louis, also hard by a different river (Old Muddy), the spark plug wires are added and wire shielding is grounded to 4 of the RA cover bolts. The painted New York bolts are removed and replaced by slightly (like 1/16-inch) longer St. Louis bolts, which are NOT painted.

What are the chances that the New York bolts and the St. Louis bolts have the same head mark, especially given their different length? Thus is the reason most savvy judges look for different head marks on the unpainted bolts holding the spark plug wire shielding grounds to the RA cover bolts.

I can not tell you the number of low mileage large motors I have found with 10 RA bolts of one mark and 4 of another. They are not often in the right place if the covers have been off, but are easily returnable to their rightful places. Check the lengths of your fasteners and see if there is some reason to what you have.

Terry

[Joe L.]

Re: 69 Valve Cover Bolts

Terry-----

I don't understand how the valve cover bolts got painted at Tonawanda on big blocks with chrome valve covers.

[Tom B.]

Re: 69 Valve Cover Bolts

Don,

If you're thinking of originality then I just wanted to mention a caution of which you may already be aware. The 68-69 JM shows a deduction for over-restored show quality chromed valve covers. The originals are flash chromed, what the 68-69 JM refers to as "medium quality".

Also, I think what you are referring to as "washers" I've always though of as "wedges". Maybe they are just called "washers". Regardless, with the chrome valve covers, they look nearly like bare metal, but I think they are zinc coated. TBarr #24014

[Terry M.]

Re: 69 Valve Cover Bolts

Joe,

That is one of the greater mysteries of the Corvette world. Guess I am too used to dealing with 1971-1972.

Painting doesn't affect my point about the bolt head marks, however.

Terry

[Don O'Connell #33101]

Re: 69 Valve Cover "Washers/Wedges"

Guys,

Thanks for the input. In summary I should have 10 (of possibly 2 different types zinc plated - but should they be painted?) and 4 (a little longer and of possibly 2 different types zinc plated).

With Terry's post, now brings another question. I have 2 different type of washers/wedges. I looked at pictures in Vette Vues and others (although not my year, the cover of the ZIP catalog shows the painted/non-painted bolts - not with chrome covers) and all seemed to have them with one straight edge on the side pointing away from the valve cover (which is why I didn't ask this in the first post - I assumed I had some incorrect ones). I have some with the straight edge and some with a slight "peak" on that side; and the side that "fits" into the valve cover indentation is also different. Could these different washers also have been put on in St. Louis and be different from the others?

Thanks again, Don

P.S. Tom - I did read about the "show" chrome in the JG (guess mine might be a litte "brighter" then required). They're the "second" design type.

[Terry M.]

Re: 69 Valve Cover "Washers/Wedges"

Don,

Sorry for the confusion about paint. I belong to Dale's "I forgot the question" club. Should be no paint on your 1969 bolts or valve covers.

I can not shed any light on the configuration of the washers, except to say I have not observed any difference between St. Louis washers and New York washers - that is why I didn't mention washers and stuck only to bolts in my earlier post. That does not mean there is no difference, just that I have not noticed and no one else has brought it to my attention. I have seen a few cases in which the New York washers were reused (as exhibited by paint on the washers),but most washers under the spark plug shield grounds are unpainted on those cars with painted valve covers.

Just another thought: If the AIM shows part numbers for washers then I would expect they were replaced. Otherwise I would expect them to be reused. I believe the bolts were changed for length. Not sure why they would want/need a different washer just because of the ground wires, but there might be a sound engineering reason we have not yet uncovered. Of course one would not want paint on the washer to add resistance to ground, but for 1969 and 1970 that was not an issue.

Terry

[Juliet P.]

Does the paint sequence apply to '70 350/300s?

Terry, This is great info & explanation of why they look a certain way. I love reading about that kinda stuff! Thanks. So, does this sequence of painting / no painting bolt discussion etc... apply to 1970 small blocks which came with orange valve covers? Like mine? (350/300 Auto AC, B18 build date)... ~Juliet

[Don O'Connell #33101]

Re: Mis-AIMed

Terry,

I looked in the AIM for the valve covers bolts in the L68 section, didn't see 'em there and UA69 (AM/FM Radio) section where the braided plug wires are shown and didn't see 'em their either. I'll take a couple off this weekend to see if any are longer then the rest (hopefully I don't have four different lengths!).

Don

[Joe L.]

Re: Does the paint sequence apply to '70 350/300s?

Juliett----

1969 and 1970 350/300 engines with painted valve covers were entirely painted at the engine assembly plant. So, the paint sequence for these engines is easy. Since small blocks did not use any St. Louis-installed parts which would require the removal or replacement of the valve cover bolts, the valve cover bolts should have remained just as they were delivered from the engine assembly plant.

Just one other little point here: I have examined many 1969-1970 era small block engines with painted valve covers which were used in a large number of other Chevrolet passenger cars. A very large percentage of the ones that I've looked at, including my own original owner 69 350/300, use a non-idented head bolt with a large "D" headmark. I believe that the "D" headmark bolts during this particular period were VERY common. But, as I've said before, I'm sure that many different headmarks were used. However, I'm CERTAIN that "D" was one of them.

[Roberto L.]

Re: Does the paint sequence apply to '70 350/300s?

Uncle Jack got a set of valve cover bolts from a donor passenger car built in the same period than my car (early feb 70) with original/unmolested engine. 4 bolts were big D as mentioned by Joe, other fours were A. Apparently left and right bolt boxes could be different... I just mention this as a possibility.

Roberto, NCRS #30019, RMC

[David C.]

Re: 69 Valve Cover Bolts

regarding re-chroming----- when they strip and grind and remove rust etc. and polish and remove metal ---they also remove the dripper --projection weld bumps upraised" and ruins the original appearance -- also they buff and polish the steel before nickel and chrome and inbetween etc. and make them wavy --with a low spot every where the drip rail isn't----when they are done --they are a wavy mess -- but very shiny chrome with no dripper bumps -- you can spot them at a at a show 50 feet away -- well i can--- what a "waste of money $$- so when they reproduced the 67 covers new -- the 68-69 chrome ones were a natural -- plate them once and thats it... hi-Q flash chrome super looking covers -refer to the great cover up article some time back -- contact crane's or any authorized dealer for new ones-- they have been on the market for about 10 years now. D.

http://www.cranescorvette.com/pr02.htm

[Jerry Clark]

Re: 69 Valve Cover Bolts

So Dave, long time no see.

What method of chroming does the plater use on the covers you sell at Cranes and BTW don't you think the price is a bit steep?

Jerry

[Terry M.]

Re: Mis-AIMed

Don,

In 1969 AIM - U69, Sheet A7 the bolts are item #10 180018 bolt (not that this part number will do any good, but who knows - Joe do!).

I also have a strange (to me) addition of a bolt #180020 dated 8-26-69 for RPO L36 & L71 & L88. Go figure.

BTW: This is a handy page that shows distributor terminal orientation and Mark IV wire routing. And these bolts are torqued to 38-50 LBS IN

Terry