1966 intake manifold bolt
My 66 has incorrect intake manifold bolts (incorrect head markings). Manifold is aluminum. Engine is 327/350. I purchased what I was told were correct bolts (black with M head marking). The bolts in place now have an integral washer. The new bolts do not. Are the bolts suposed to have integral washers and if not should the ones without be installed with a washer or no washer? I have also read other places that I should use Permatex #2 on the bolts before installing - is that necessary or recommended? Finally I have also read that I should torque the bolds to 25-30 lb-ft but I am having problems finding a torque wrench with a small enough head to fit on the bolts once they are in place - any suggestions?
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Re: 1966 intake manifold bolt
Roger,
I can't answer all your questions on the bolt markings. Usually LICORVETTE describes them in their sales. Yes, you need a sealer on the bolts or oil will seep from under them. About the torque, if you can't find a wrench that will fit all then you have to develop a feel using a long box end wrench and also in sequence. If you start with about 10 lbs then when you get the next pass done you can judge the torque if you have one that you torqued. I use the upper limits and also 35 lbs. 4 of the bolts do not enter the valley, they are all on each end.
The reason I use 35 is that the gasket will take a set especially after the engine is run. Good Idea to check them again. permatex is better than sealers that set up because is stays pliable. Others will break their seal if you torque after they set up.
Dom -
Re: 1966 intake manifold bolt
Mark, I took another look and if I get a 3/8" drive torque it does look like it will work for most of the bolts. I am not planning on taking off the carborator or the housing for the thermostat sp I will still not get a couple (10 or 11 correct bolts out of 12 better than 0 out of 12). Thanks for making me take another look (already looked multiple time but with different drive sizes at different times).Comment
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Re: 1966 intake manifold bolt
Dom - thank you for the answer concerning the permatex. The manifild is already installed on the engine, I am just wanting to swap out the bolts so the order shouldn't be a big deal since it will be one bolt at a time. I was already thinking about just trying to tighten by feel for the bolts I can't get to with a torque wrench. After doing the ones I can use a torque wrench on hopefully I will have a feel for how tight is tight enough but not too tight. If not comfortable at that point i may just leave a couple of the bolts being wrong bolts.Comment
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Re: 1966 intake manifold bolt
OK, Dom and Mark have helped out concerning the sealant and the wrench. I still need to know if I am supposed to use a washer with the bolts, or a bolt with an integral washer, or no washer. The judging guide does not say and there are no pictures showing a bolt. The guide does indicate the bolts were black and M with radiating lines was a proper head marker (which is what I bought) - I just don't know about the washer. I have read other places that a washer is needed to prevent damage to the aluminum manifold. By the way the current Iincorrect) bolts are marked F593C at the top and THE at the bottom of the heads.Comment
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Re: 1966 intake manifold bolt
Roger,
I never saw washers under the bolt, but I use a thin small diameter SS washer under mine. The washers are aircraft from Aircraft Spruce. So I now understand that you will remove one at a time, permatex it and move on to the next.
PS Don't loose any sleep without a washer if you have a integral washer built in to the bolt.
DomComment
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Re: 1966 intake manifold bolt
Roger,
For the sake of future readers of this thread, according to the ‘66 JG, headmarks for intake manifold bolts for the L79 include A, M, TR, UR, and FP. My notes also say NAT is a possible headmark. And maybe others. Grade 5. No washers of any kind were used; any washers detected during judging would justify either a deduct or a note that washers are NTF.
GaryLast edited by Gary B.; March 13, 2021, 11:54 PM.Comment
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Re: 1966 intake manifold bolt
Roger,
My 1967 L79 w/ aluminim intake manifold have standard (no integral washer) hex head bolts with "M" logo and 3 radiating lines indicating Grade 5.
I would also add that there is a special crowsfoot socket that can be used for the center bolts. You will need to reduce the torque setting because of the additional torque wrench length. The ratio is the original length divided by the new, combined length. Here's a photo of such a socket (9/16") made by Snap-On.
Special Crowsfoot Socket.jpgROCCO SCOTELLARO
1967 Lynndale Blue/Black Coupe L79, M21, G81 (3.70:1), A31, A82, C60, K66, N11, U69Comment
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Re: 1966 intake manifold bolt
Thank Dom. I may still consider a small washer under the bolt. The integral washer is on the bolts I am removing.Comment
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Re: 1966 intake manifold bolt
Gary / Larry / Rocco - Thank you for the additional info. So - no to the washers. The special socket wrench to box wrench converter looks intriguing. I was actually thinking of connecting my torque wrench to the box end of a box/open end wrench but that was wobbly and I would not have thought to change the torque setting. I will look to see if I can find one.Comment
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Re: 1966 intake manifold bolt
Roger,
Someone in Quebec, Canada has more than 10 of them to sell. Not cheap for a one-time use. eBay item # 143937791117
Gary
Last edited by Gary B.; March 14, 2021, 09:46 AM.Comment
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