Looking for engine help ideas...

[L31MaxExpress]

No, TBI truck engines from 88 - 95 came with flat tappet cams but almost all of them came with the bosses for the lifter spyder but weren't drilled and tapped. You can do that but watch out for shavings and contamination.

I have had numerous ones that were drilled and tapped. My uncle had a 94 with a factory roller cam. It had 250K on it when we did the intake gaskets and still had the engine it came from the factory with.

 

[Schurkey]

The block I am using is a 91 block. it is not prepped for a roller setup.

Wild Guess: Drill and tap three small holes. Get all the roller-cam equipment from Craigslist or a Treasure Yard. Done.

Alternatively, buy a roller-cam short block. Now you've got all the equipment, AND a block that's already set-up for the roller cam. You'll probably have to disassemble each lifter to clean out all the accumulated sludge. Do them one-at-a-time, so you don't interchange parts from one to another.

i dropped it off at the machine shop and the guy told me that if i used a flat tappet cam I would need special oil for the life of the engine. I had always thought that if i used the proper assembly lube and did the break in correctly, that I could drive with normal oil after that. He highly recommended that I go roller so as to avoid the oil issue. Is he correct in that thought?

Zddp is mostly needed for cam break in, but you can always use the High Mileage oil of the brand you like as they have slightly more of the additive.

Flat tappet cams got a bad reputation twenty-something years ago, and oil got the blame. Truth is, cam companies were sourcing junk lifters and cam cores from China, and the metal was soft. Blaming the oil meant the cam companies didn't have to admit--and warranty--their defective junk.

ZDDP is a high-pressure, anti-wear additive. However, it's usefulness has been greatly exaggerated by the cam companies and the "hot-roddy" magazines. Too much actually CAUSES failure of metal parts. The amount of wear protection of a motor oil is NOT based on the amount of ZDDP it has.

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

Don't get me wrong--when it was me, I scrapped the flat-tappet cam and shoved in a roller. A person is crazy not to use a roller cam when it's so easy to use OEM cams, lifters, retainers, etc. Might not be so true if you were building a 455 Buick, or a 392 International.

 

[cngodfather]

My block is set because of sentimental reasons. It is a two bolt block not drilled for roller. I was wondering about the flat tappet issues and I was getting conflicting information. my machinist told me to stay away from them and showed me examples of what happens. That scared me. I started looking retro-lifters and thought "Damn - i didn't realize this cost so much" I just wanted a little more oomph out of this wimpy engine. It is going to cost thousands. I keep thinking about all the engines that have used flat tappets in the past and they work just fine. My last engine I built had it and worked great. It was close to 400hp and i drove it like i stole it. Now for some reason I am worried? I have seen a video about the cheap lifter problem and that does seem like a reasonable cause. I am going to stick with the flat tappet keeping in mind about the amount of zddp in it. Funny thing is that the first plan was to re-ring it add new bearings and let it roll. Now it is a real project... Originally i bought the truck while my union was on strike for something to keep me busy. I wanted a c-10 to keep it simple. It has been not simple with nonsense with it.

 

[cngodfather]

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Here is the engine simulation board I made to test the megasquirt fuel injection system. I made it from a kit to make sure the sensors and ignition system works properly. I have not checked the fuel injectors for function yet. Made from spare parts...

 

[cngodfather]

Also---Merry Christmas everyone!!!

 

[Schurkey]

My block is set because of sentimental reasons. It is a two bolt block not drilled for roller.

Why is drilling and tapping three holes such a big deal? Is this a block that has no bosses for the spider hold-down? No holes for the cam thrust plate bolts? Lifter bores not suitable for OEM roller lifters?

Roller blocks to steal OEM roller parts from are thick on the ground.

"Two bolt block" is no big deal. Four may be nicer, but two works just fine.

 

[cngodfather]

Hi guys! I just got the engine back from the machine shop. It is bored .030 over, zero decked, freeze plugs installed, cam bearings installed, and painted red. Also, I forgot there was a broken starter bolt in the block. The machinist noticed it and removed it. The crank is polished. The new speed pro flat top pistons were pressed on the rods. Only real issues were two rods were out of round on the rod to crank journals. They fixed them. The whole rotating assembly was fully balanced. The next step is to measure the clearances to verify their work and get more parts.

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[Schurkey]

Is this a two-piece rear-main-seal engine block? Or a one-piece rear main seal?

 

[cngodfather]

It is a one-piece rear main seal. I decided to bite the bullet and use retro lifters and roller cam. The tricky part is finding a good deal with quality parts.

 

[L31MaxExpress]

Is this a two-piece rear-main-seal engine block? Or a one-piece rear main seal?

Very common to see a 1 piece block without the bosses cast or the lifter bores machined for the lifter dogbones. 427 casting IIRC is the common one but some 638s were made the same way.