I feel kinda dirty asking, but here goes...

[Don L.]

Hi guys.

Before I get into my issue, I thought I'd confess. This thread is not Corvette related. I am presently modifying a sweet little '67 C10 Step side truck. It's my first resto-rod, so I'm working my way through it. I've removed the 250 inline six/3 speed manual transmission and am preparing to bolt in a cast iron crate V8 (350/375/415) engine, coupled to a GM 700R4 auto transmission.

Here's my questions:
1. What bolts (size and grade), washers, and what torques are needed to connect:
a. Flex plate to crankshaft. I think these bolts have a special head, yes?
b. Transmission housing to engine block

2. Do I need to do anything specific to protect against dissimilar metal chemical reaction (IE: housing bolts, engine facing to transmission facing, etc)?

This thread might seem a bit silly, but I trust the advice from this group. I'm concerned about asking a GM dealer, as my pairing isn't stock. As well, the crankshaft is not an original, but instead, a higher performance replacement.

Any inputs and/or advice is appreciated.

Thanks.

[Tom K.]

Re: I feel kinda dirty asking, but here goes...

Don I would use ARP bolts anywhere strength is a concern. This is not a place for regular hardware store bolts. Torque values are available in shop manuals for a 350. Check ARP online. They probably have all of the bolts that you need. Sounds like a nice project. Enjoy.
Tom K

[Don L.]

Re: I feel kinda dirty asking, but here goes...

Tom, thanks and thanks. She was a bit of an ugly duckling when bought, but she's now on her way to being in a better way. It has an amazingly perfect body and frame. Practically EVERYTHING else is going to be new. I'll post some "after" photos when it's done, but certainly not until.

Interestingly, I had checked on ARP hardware earlier today, which is part of the reason I posted this thread to begin with. ARP offers 2 flex plate/crankshaft bolt sets, differing by only 0.045" in length. I suppose it'll be best for me to call ARP and get some advice and an understanding on how 0.045" makes a difference in my application. Maybe flex plate thickness is what makes the difference? Flex plate is due from Summit Racing tomorrow, so I'll wait until I have a thickness to contact ARP.

[Terry M.]

Re: I feel kinda dirty asking, but here goes...

Hi guys.

Before I get into my issue, I thought I'd confess. This thread is not Corvette related. I am presently modifying a sweet little '67 C10 Step side truck. It's my first resto-rod, so I'm working my way through it. I've removed the 250 inline six/3 speed manual transmission and am preparing to bolt in a cast iron crate V8 (350/375/415) engine, coupled to a GM 700R4 auto transmission.

Here's my questions:
1. What bolts (size and grade), washers, and what torques are needed to connect:
a. Flex plate to crankshaft. I think these bolts have a special head, yes?
b. Transmission housing to engine block

2. Do I need to do anything specific to protect against dissimilar metal chemical reaction (IE: housing bolts, engine facing to transmission facing, etc)?

This thread might seem a bit silly, but I trust the advice from this group. I'm concerned about asking a GM dealer, as my pairing isn't stock. As well, the crankshaft is not an original, but instead, a higher performance replacement.

Any inputs and/or advice is appreciated.

Thanks.

Don
The factory did nothing about the dissimilar metals, so I can see no reason you should.

[Ed S.]

Re: I feel kinda dirty asking, but here goes...

Regarding dissimilar metals - I'll take exception to Terry's comment, at least as it applies to threaded mating surfaces. I am having great difficulty removing the ferrous metal filler plug from an aluminum transmission case. My bad - it has not been moved or disturbed for about 3 years - it is now pretty well frozen in place. As I understand this is not an uncommon problem - the resolution being coat the threads with anti seize compound - and rotate the plug at least once a year. That said, I do agree with Terry in cases where two dissimilar metals are in contact but not under a great deal of stress like a threaded fastener.

[Joe L.]

Re: I feel kinda dirty asking, but here goes...

Tom, thanks and thanks. She was a bit of an ugly duckling when bought, but she's now on her way to being in a better way. It has an amazingly perfect body and frame. Practically EVERYTHING else is going to be new. I'll post some "after" photos when it's done, but certainly not until.

Interestingly, I had checked on ARP hardware earlier today, which is part of the reason I posted this thread to begin with. ARP offers 2 flex plate/crankshaft bolt sets, differing by only 0.045" in length. I suppose it'll be best for me to call ARP and get some advice and an understanding on how 0.045" makes a difference in my application. Maybe flex plate thickness is what makes the difference? Flex plate is due from Summit Racing tomorrow, so I'll wait until I have a thickness to contact ARP.

Don------


The reason that there are two sets of bolts is due to the different type of crankshaft flanges used in Chevrolet V-8's-----1 piece seal type crankshafts and 2 piece seal type crankshafts. Engines with 2 piece seal crankshafts require bolts that are 0.680" in length; engines with 1 piece seal crankshafts require bolts that are 0.725" in length. The flexplates are also specific to each type of crankshaft. Current crate engines are manufactured with both types of crankshafts and I don't know which type you have. Your description of ("350/375/415") does not answer the question.

Flexplate bolts do have a special, "low profile" head configuration. Use the torque which ARP will specify with the bolt set.

[Terry M.]

Re: I feel kinda dirty asking, but here goes...

Regarding dissimilar metals - I'll take exception to Terry's comment, at least as it applies to threaded mating surfaces. I am having great difficulty removing the ferrous metal filler plug from an aluminum transmission case. My bad - it has not been moved or disturbed for about 3 years - it is now pretty well frozen in place. As I understand this is not an uncommon problem - the resolution being coat the threads with anti seize compound - and rotate the plug at least once a year. That said, I do agree with Terry in cases where two dissimilar metals are in contact but not under a great deal of stress like a threaded fastener.

Ed
I have wrestled with this problem; most recently with a water pump on a Gen II LT1. The water pump is aluminum and the cylinder case is cast iron. The steel fasteners corroded into the aluminum water pump housing. That said, to the best of my knowledge the aluminum bell housing and iron cylinder case that Don asked about in the OP never received any corrosion protection when the factory assembled it. I have separated bell housings from engines that were in place for decades and never had a corrosion issue, but that is only my experience. Let's see what others have experienced.

I think we could debate the need for corrosion protection in that location for quite a while. Just like a prophylactic it might not be a bad idea, but is anti-seize sufficient?

[Ed S.]

Re: I feel kinda dirty asking, but here goes...

Ed
I have wrestled with this problem; most recently with a water pump on a Gen II LT1. The water pump is aluminum and the cylinder case is cast iron. The steel fasteners corroded into the aluminum water pump housing. That said, to the best of my knowledge the aluminum bell housing and iron cylinder case that Don asked about in the OP never received any corrosion protection when the factory assembled it. I have separated bell housings from engines that were in place for decades and never had a corrosion issue, but that is only my experience. Let's see what others have experienced.

I think we could debate the need for corrosion protection in that location for quite a while. Just like a prophylactic it might not be a bad idea, but is anti-seize sufficient?

I am in total agreement with you Terry - when it comes to two flat surfaces of different materials that are mated or just pressing against each other, typically, there is not a problem. Its those threaded connections that are under pressure (torque). As for my tans filler plug - I haven't attempted it yet but I have been told that several applications of "freeze off" followed by heating with a torch will frequently break the bond of the corroded dissimilar alloys. Fingers crossed - if it does work I will install a new plug and use anti-seize compound.

[Edward B.]

Re: I feel kinda dirty asking, but here goes...

Very common in marine applications: http://www.tefgel.com/contain.php?param=tefgel_infor

[Ed S.]

Re: I feel kinda dirty asking, but here goes...

Very common in marine applications: https://www.tegel.com/contain.php?param=tefgel_inforf

Ed. what is the link you attached? When I click on it my Norton anti-virus advises that it is not safe to go to. I am reluctant to override the notice.

[Don L.]

Re: I feel kinda dirty asking, but here goes...

I get the same as Ed.

[Don L.]

Re: I feel kinda dirty asking, but here goes...

Thanks Joe. I hope to receive the engine soon and look at the crankshaft flange. I'm not sure how to ascertain which of the two designs you describe is what I have. If I post a photo of it, would you be able to identify it?

[Edward B.]

Re: I feel kinda dirty asking, but here goes...

Information about Tef Gel which is commonly used to provide a barrier between dissimilar metals: http://www.tefgel.com/contain.php?param=tefgel_infor It's a good link for me as well as a product I often employ, particularly around salt water.

[Joe L.]

Re: I feel kinda dirty asking, but here goes...

Thanks Joe. I hope to receive the engine soon and look at the crankshaft flange. I'm not sure how to ascertain which of the two designs you describe is what I have. If I post a photo of it, would you be able to identify it?

Don-----


All I need is the part number of the crate engine assembly. Otherwise, a photo of the crankshaft flange will do.

[Dick W.]

Re: I feel kinda dirty asking, but here goes...

Regarding dissimilar metals - I'll take exception to Terry's comment, at least as it applies to threaded mating surfaces. I am having great difficulty removing the ferrous metal filler plug from an aluminum transmission case. My bad - it has not been moved or disturbed for about 3 years - it is now pretty well frozen in place. As I understand this is not an uncommon problem - the resolution being coat the threads with anti seize compound - and rotate the plug at least once a year. That said, I do agree with Terry in cases where two dissimilar metals are in contact but not under a great deal of stress like a threaded fastener.

When you Do get the plug out, go to your favorite auto parts store and get a tube of Loctite PST (pipe sealant with teflon) It will lubricate the threads, seal any possible leaks, and greatly reduce the effort you will have the next time you want to drain your transmission. You will not have to worry about rotating the plug once a year. It does not harden like pipe dope does.