Author Topic: 73 C20 Performance Engine Build  (Read 49553 times)

Offline LTZ C20

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73 C20 Performance Engine Build
« on: May 03, 2015, 02:53:24 PM »
This will be my official engine build thread, seeing as how I didn't do one for the first engine, so this is for the second, much nicer engine. So here we go!!

I started the build with a short block from ATK Performance Engines. I did alot of looking around and after checking out ATK's site and youtube videos, I decided to use their product. Once I got it and started checking it out, their product is really nice, great quality. It is an OE roller block for late 90's GM trucks. Here's a link to it on ATK'S site.

http://www.high-performance-engines.com/chevy-350-short-block-crate-engine-p/sp04.htm

Here it is when I brought it home.


Fresh out of the shipping pod.


« Last Edit: May 03, 2015, 03:37:06 PM by LTZ C20 »
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Offline LTZ C20

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Re: 73 C20 Performance Engine Build
« Reply #1 on: May 03, 2015, 04:00:53 PM »
After yesterday, I got it out of the pod and onto the stand, then I installed the engine mounts, flexplate and fuel pump block off plate. I have the lifters, spider plate and lifter guides but the cam won't be here till Monday or Tuesday. Also I planned to use a factory timing cover, but the cam timing gear appears that it will be hitting the mounting bolts for the cam thrust plate. So I have some checking to do, whether I need a bushing or a different cam gear or what, that might mean it will change the alignment of the two timing gears and then I might have to get a deaper timing cover. So no matter what, I've gotta figure out what's going on there before I get the rest of the bottom together and wait for the cam to come in. I also have to tack weld the oil pick-up tube.

So here are the rest of the pics I have until I get more money for parts, mainly gaskets and a few other smaller things.








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Offline LTZ C20

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Re: 73 C20 Performance Engine Build
« Reply #2 on: May 04, 2015, 11:58:53 PM »
Update: The cam arrived today, I installed it earlier this evening. Installation was easy, no problems. The cam thrust plate is another story however. I put the plate on, put the provided bolts in. Then with them barely tight, I aligned the plate to have an equal clearance around the end face of the cam (so it was adjusted equally top-to-bottom and left-to-right). Then snugged one of the bolts, removed the other, applied thread locker and reinstalled and snugged. Then I removed the opposite bolt and repeated the process. THEN, I got the torque wrench out, set it to 20 ft lbs (which from what I can find is correct torque spec, but let me know if I'm wrong). As I tightened the bolts, they didn't feel as tho they were really taking the torque properly. I was going slow and "feeling" how much pressure I was applying but the wrench never clicked to 20. So I tried it on one of the water pump bolts, torqued to 20 easily and clicked fine, I use the wrench fairly often and I know it works good. So I tried the plate bolts again, doesn't feel right. Infact it felt as tho one of the bolts was in the process of stripping out. So I just stopped. I think the bolts provided aren't the best quality, not sure. I think I'm just going to get new bolts from ARP (half of all my other bolts are ARP anyway) and try again. Any thoughts on this little problem guys? Just crappy bolts?

Here's the kit I'm working with and the bolts that were provided.

http://m.summitracing.com/parts/SUM-150123


« Last Edit: May 05, 2015, 12:01:53 AM by LTZ C20 »
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Offline rich weyand

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Re: 73 C20 Performance Engine Build
« Reply #3 on: May 05, 2015, 01:56:41 AM »
Measure the bolts, measure the hole, look up what they really are.  When you measure the bolt, look up the "tight clearance hole" size; when you measure the hole, look up the "loose tap hole" size.

You might have metric bolts for a fractional hole, or vice versa.  Some of them are close enough to seem right, and aren't, like 6mm bolt in a 1/4" hole.  BTDT.
Rich

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Offline LTZ C20

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Re: 73 C20 Performance Engine Build
« Reply #4 on: May 05, 2015, 09:57:55 AM »
Oh I see. Well that makes sense. I'm gonna have the parts department order the factory bolts used on the production line. They should be the correct size and are hardened steel anyway. Those other 2 bolts just felt a little cheap but I wasn't sure.

My second issue now is, there is a difference in opinion on the fitment of a double roller timing set. I called ATK, said I wanted to get a double roller for it. I asked them if there will be any fitment issues because I also wanted to use the factory replacement timing cover. They said a double roller will fit behind the stock plastic cover. So I said, "so if I call Summit and say I need a double roller for an OE roller block with an OE roller cam" I will be good to go. They said yes.

So I called summit, said "I need a double roller timing set for an OE roller block with an OE roller cam." They provided to two results, a Summit part # and a Comp Cams part #. The summit part has a note stating it will NOT fit behind stock plastic timing cover and the Comp part has a note that it will NOT fit behind stock timing cover. The Comp part does not specify steel or plastic cover.

So what the heck is going on here?! My old flat tappet cam engine had a double roller that fit behind the stock steel cover no problem. I don't understand. Here are the 2 parts.

http://m.summitracing.com/parts/sum-g6601-9/none/images

http://m.summitracing.com/parts/cca-3136
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Offline LTZ C20

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Re: 73 C20 Performance Engine Build
« Reply #5 on: May 06, 2015, 01:57:56 PM »
Update: I got the proper bolts for the thrust plate and spider plate. Tonight I will be installing the new thrust plate bolts, lifters, guides, spider plate and possibly tack weld the oil pump pick up tube IF my welder decides to start working again. Last time I used it, it stopped working half way thru a weld haha.

Also, I called ATK back again this morning and now I have 1 vote for the plastic cover fitting over a double roller and 3 votes that it won't fit. The guy on the phone said a stock steel cover will fit over a double roller tho, so just gonna get 1 of those instead.

And maybe if I'm lucky I'll be able to order enough parts to get this thing all buttoned up and back in the truck. I miss it so much.
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Offline Edemich

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Re: 73 C20 Performance Engine Build
« Reply #6 on: May 06, 2015, 03:31:17 PM »
I recommend the pick up tube brace that JEG's sells.  Piece of mind for your build.   Welding tin to cast iron is not always 100%.

My two cents.
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Offline LTZ C20

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Re: 73 C20 Performance Engine Build
« Reply #7 on: May 06, 2015, 09:04:52 PM »
Ok Thanks. I'll check it out.
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Offline LTZ C20

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Re: 73 C20 Performance Engine Build
« Reply #8 on: May 07, 2015, 01:50:45 AM »
Got a few things done tonight. Swapped the crappy phillips head cam thrust plate bolts for the hardened steel factory ones with a T30 Torx head. The hardened bolts torqued down quickly and easily. Also what I thought was 1 of the bolts stripping was actually 1 of them almost breaking off! Check this out!

New (factory hardned) bolt LEFT, provided (phillips) bolt RIGHT. Also, incase anyone is wondering, the dimensions for these 2 bolts are "1/4-20-1/2".



The bolt that almost broke at 15 ft lbs of torque.



Also got the lifters, guides and spider plate installed. I also got the 3 bolts for the spider plate in the factory hardened design, they worked fine also. Their dimensions are "5/16-18-.635".





Here is a closer look at the spider holding down the guides, I've never installed 1 of these before, it looks right but please tell me if I am wrong.



And 2 bonus picks for you, 1 of my gf cleaning up the heads with my new Super Scraper, I highly recommend anyone who does a lot of work with gaskets to get an original Super Scraper. They are AMAZING. Not to mention the manufacturer will sharpen them for free.



This is true love and support, once I showed her what needed to be done, I wasn't allowed to do any of it, she wouldn't let me lol. She did it all herself and did a GREAT job at that!

Lastly, a peek at the the 40 over flat tops.
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Offline enaberif

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Re: 73 C20 Performance Engine Build
« Reply #9 on: May 07, 2015, 08:47:59 AM »
My understanding regarding the timing covers is the plastic one is shallower compared to the metal one which is why the double usually won't fit.

Heck there has been know issues with double rollers and metal covers.

Offline LTZ C20

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Re: 73 C20 Performance Engine Build
« Reply #10 on: May 07, 2015, 09:40:21 AM »
Hey I think that's the issue here. The engine manufacturer said use a steel cover if you use a double roller. The double roller I plan to use says won't fit behind stock plastic covers but says nothing about the steel ones. I picked up a steel one last night, looks like the set will fit just fine.

The first engine had a double and stock steel cover so I'm just gonna run it.
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Offline 78BIG-TEN

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Re: 73 C20 Performance Engine Build
« Reply #11 on: May 07, 2015, 09:41:36 AM »
106 in\lbs on cam retainer and 18 ft\lbs on spider bolts,camshaft sprocket bolts 18 ft\lbs

Offline LTZ C20

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Re: 73 C20 Performance Engine Build
« Reply #12 on: May 07, 2015, 09:43:07 AM »
Thanks Big-Ten! That's what I did for the cam retainer and spider bolts.
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Offline enaberif

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Re: 73 C20 Performance Engine Build
« Reply #13 on: May 07, 2015, 10:04:31 AM »
Hey I think that's the issue here. The engine manufacturer said use a steel cover if you use a double roller. The double roller I plan to use says won't fit behind stock plastic covers but says nothing about the steel ones. I picked up a steel one last night, looks like the set will fit just fine.

The first engine had a double and stock steel cover so I'm just gonna run it.

Well your using the retaining ring for the cam so it can't move anywhere. That is one purpose of the timing cover as well so by using the steel one you should have no issues.

Offline LTZ C20

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Re: 73 C20 Performance Engine Build
« Reply #14 on: May 07, 2015, 10:26:09 AM »
Hey I think that's the issue here. The engine manufacturer said use a steel cover if you use a double roller. The double roller I plan to use says won't fit behind stock plastic covers but says nothing about the steel ones. I picked up a steel one last night, looks like the set will fit just fine.

The first engine had a double and stock steel cover so I'm just gonna run it.

Well your using the retaining ring for the cam so it can't move anywhere. That is one purpose of the timing cover as well so by using the steel one you should have no issues.
It's good to finally get a few votes 1 way or the other, for a while I had 1 vote for either and it was a stand off, I didn't know what to do lol.
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