[Gach]

Originally Posted by mgarblik

Couple of little items for you. The main bearings would be more correctly referred to as -.010 undersize because the crankshaft is now smaller. They have a date of November, 1984 on them. 11-84. The Rod bearings are DAB brand. Detroit Automotive Bearing. Used to be pretty popular. Could not see a date on them or an undersize. The block has been line honed. Most likely, the original bearings may have spun in the block making that necessary. You can tell by the cross hatch in the bores. The rods look to have stock bolts and may or may not have been rebuilt. Most people would not re-use them. For a budget build I personally have no issue using them again with new hardware properly rebuilt. I have personally never had a rod failure with a Pontiac engine where the rod was the cause. Cast rods, new hardware, sized correctly, I would respect a 5500 RPM red line. 5800 RPM's, your in the danger zone on a 428 IMO. Overall, engine looks pretty darn good core.

Really good information.

[kyle_blake]

Thanks mgarblik!

That's friggin cool you noticed the date on the main bearing!

Yah the crank being ground down (fix wear) requires the bearings to be 0.10 thicker? to make up the difference? If i understand that theory correctly?

Not sure what 10/10 means on a crank when people say it's 10/10 on a crank. Assume it 0.010 cut down and needs a .010 thicker bearing?

I was wondering about the cross hatch under main bearings, it is good to know it was line honed... Thank you. in all likelihood meant it had "spun a bearing" from 1969 to 1984 when it was torn down for inspection and "assess and put back together" .

3 new aftermarket pistons that match stock specs.

I agree stock bolts on con rods, they were tight, like a good snug tight, i'd hazard to say 50-70 ft. pounds based on my nut turning off ability.

Can i ask whether there is a way to bore the connecting rods with a cross hatch?

[tom s]

10 10 means 10 on rods and 10 on the mains.Tom

[HWYSTR455]

Cross hatch on rods is from sizing, no real significance of that. Other than the fact that they were prepped.

Pattern in top of rod bearings suggest det was seen for a period of time.

Cam lobes are worn all the way across the peak of the lobes, it's done. But at least it didn't fail.

Line hone is standard procedure when fitting main caps, machine shop was good to do that. Not sure if it is an indication that bearings spun, would think it would have had to go more than .010 if that were the case.

Some machine shops also choose to go .010/.010 when prepping a crank to ensure roundness of journals. It is less work than polishing and finding out after you need to turn to make it all true.

Cam is in fact way too small of a profile for that engine. Maybe if it was intended for a boat it would kind of make sense, but more likely just a poor choice by previous owner. Might just be PO had it on hand or got a deal for it.

Overall, it appears the machine shop did good work, and suspect it was a 'budget' build, due to parts selection/mismatches. Appears to be a good candidate for a core/new build.

Forget what was mentioned on the other thread, what's the intentions for this engine again?


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[HWYSTR455]

Suggestion, don't buy pistons or bearings until a machine shop checks out the block & crank, it may still need cleanup.

Those pistons you found are for a standard bore. Also, you may want to choose a piston with a dish if you plan to use those heads.

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[kyle_blake]

Hi Hwystr455, my decision is to use the block and everything else I'm keeping ,if I ever sell the car. Here it is fully numbers matching 428 parts to go with it. I just used the block. I think awesome story to go along with my gto.

I might use the ram air manifolds or the current hooker headers that are in my car on my 406 pontiac.(that will be repurposed one day)

Yes I'm getting ready to take block to machine shop! I've found a great machinist and found the Lee Atkinson, assembly build PDF that was on PY years and years ago to refer to.

I wanted to buy a full balanced rotating assembly from Eagle but they do not sell it for the 428.

For now focus is getting block machined and researching to make sure i ask all questions prior - learn the most i can.. Can't wait!!!! Exciting times 2024!

[HWYSTR455]

Butler makes kits for the 428 block:

https://butlerperformance.com/c-1234...495-cu-in.html

If you buy a rotating assembly, and the block needs to go bigger to clean up properly, you will have to buy pistons again.

Same with bearings. Even new cranks sometimes need to be turned to .010/.010 to clean them up.

Blocks are bored to the piston specs. That's all I'm saying. The machine shop will tell you what you need after they check the block.


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[mgarblik]

I like the fact that Butler has kits for your 428 engine specifically. I would spend some time looking at all the options they have available. From all cast, "budget" kits to high quality street/strip set-ups. There are a variety of piston choices to get the compression in a safe zone for lousy pump gas. IMO, if using the iron high compression heads, static compression should be 9:1-9.5:1. with the use of a dish piston. This would be for crappy pump gas. If you switch to aluminum heads, that's a whole different story. Butler can be a one stop Pontiac shop for your engine parts and more. Family owned and good people to deal with for 40 years. Yes, you may pay 5% more going through them than piecing together a pile of misc. parts from Summit and Jegs that may or may not work together. It's all about how much aggravation your willing to deal with.

[gtospieg]

Just an FYI...Molnar can also supply you with crank, rods and pistons for a stroker build for your 428.

[kyle_blake]

HWYSTR455 - > Thanks for the link, that really helps. For sure I'm going alum heads mgarblik. Oh yah I know butler , I've seen videos upon videos and before I engage them in dialogue because I am sorta new to this I want to make sure I do things that machine block to find out piston size like hwystr455 says.

I messaged Molnar and went to their site. Thanks.

[blueghoast]

I like the factory cranks, pretty strong and good for some serious HP
Plus I like the 4-inch stroke too.

GT

[Gach]

I see Butler offers quite a list of rods including Molnar. $7500.00 for whole package heads included. Get out your credit card. Or maybe just use the dividend check…LOL really nice that he offers a whole package. There’s many YouTube videos of guys who have bought Butler package deal. Only bad one is the guy with the HR that went south on him.

PS: also comes with all gaskets big time saver from chasing after gaskets

[kyle_blake]

Yah i saw $7500 for the whole thing the there is a bunch of things to consider options wise.

that could be a big time saver and you'd think there would be some dyno numbers somewhere out there someone out there who has done that combo. wonder if you can upgrade heads to some porting level by them, I'm sure.

i didn't see where i could choose std bore for a 428 though. but might not be doing it right.

[Gach]

I could tell you this with set of e-heads and the right cam you can easily make 500 hp. Even with hydraulic cam . Not sure if he offers anything for a standard bore tho.

[Gach]

OK I went back and read it from the beginning and viewed all the pictures.. some great eyes and tremendous help from the contributors. I don’t know what your goal is what you want to accomplish. Also what your budget is. This is just my opinion, you probably won’t end up with a standard bore looking at those pictures of the cylinder walls. So I don’t know if $7500.00 is in your budget. If it is then you could definitely make 500 + hp. On pump gas to boot And all you’d have to deal with is getting the block machined for the new Assembly.

[kyle_blake]

Thanks Gach for looking back on that. My goal is to build an engine and yes get 500 - 600 hp. I had no idea on cost until now and i need all my info and options before making an informed decision. Why would a company not offer std size pistons in a kit as an option and purposely exclude it? i also don't need performer rpm as i have one. i can see piston scuff marks slightly on some bores , not sure if a hone would take that out but again that is the machinist call. i'm not gonna get a drill with proper tool like we did in school and start cross hatching it.

[HWYSTR455]

428 pistons are less common, and believe most 'replacement' pistons only come in like .030 and .060 over, and cost more than 400 or 455 pistons. The 4" stroke requires a particular pin height, so less common = less are made/demand = more expensive.

If you're going thru the trouble of rebuilding an engine, you don't want to compromise the build by trying to use the existing bore. 9 times out of 10 it takes at least .010 to clean up a bore.

Different pistons require different clearances, the manufacturer provides the specifics. So the machinist needs to have the pistons in hand to determine the final bore. Final bore is usually accomplished by honing. The initial bore is determined by measuring bore taper after 'squaring' the bore to pre-honed sizes.

It can cost more to do the machine work on a crank than what a new stroker crank costs. And although OE Pontiac cranks are good, they can still be compromised and pass inspection. For any small difference in cost a new crank, it's good insurance, and you get a longer stroke to boot.

As like pistons, aftermarket stroker cranks are more popular, and still need to be checked. (more popular = more made/demand = less expensive) Many require work right out of the box.

The Butler 'builder kits' are a nice option, the more you buy = better pricing. I'm sure you can call them and have them delete the intake, but you will have to test fit the intake you have, and it MIGHT need to be cleaned up. I've seen many that are out of box that don't sit flat against the head. So maybe get the intake with the kit, and sell yours to offset the cost, and you won't have to go thru the one you have. Just make sure you ask Butler if the intake surfaces are verified or not. If not, ask them to verify it.

Upgrading to aluminum heads is a great option, and you wouldn't have to do it down the road once you realize 'I should have gotten the heads when I built the engine to begin with'. Many get stuck having to go back thru the engine because they bought pistons with a dish to use iron heads.

Same thing with cast/forged crank. If you're going thru the engine now, build it as best you can, because later you don't want to go thru the 'I want more power but got a cast crank' phase.

A 'performance' build doesn't matter what the purpose is (initially), so don't use mentality of 'I'm not going to race it'. It makes no difference, you build an engine to last, and that's what makes it a performance engine. If you build an engine to last, and design it for low RPM and longevity (no intention of 'racing'), it costs the same, and it is still considered a 'performance' engine.

That's why it drives me nuts when people say 'I don't plan on racing it'. Makes no difference, you still build the engine the same way, for the most part. Shoot, I beat stuff on the street harder than many do 'racing'. Even idling for long periods of time is tough on an engine.

Do it right, do it once.

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[steve25]

If you go the custom piston route then take full advantage of that.
the most productive way to go is to first get a set of rings for lets say for the sake of discussion.060” over.

Then fit a top ring into a big hose clamp and tighten up until you reach the needed ring gap for your .060” over bore size.
Now you know what size piston you need to get made , but of course minus the recommendation bore clearance for the piston material.

[HWYSTR455]

Assuming you retain the existing bore.

Again, I would bet my left xxx that the bores have taper and need to be cleaned up. Not to mention the cost of a set of custom pistons.

Then there's the error factor = risk thing.

Why compromise a build just because one is bent on retaining the existing bore? Shoot, even from the factory they weren't perfectly square.

Even if it only takes a .005 hone to clean it up, you still have to go .010. Why wait months for someone to make a custom piston?

Just go .030 and be done with it. You will KNOW it's right. And it's not like you are planning to rebuild the same block 3 more times either.

A hobby car takes 15-20 years to get 100k miles on it.


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[kyle_blake]

HWYSTR455 - > Thanks for your help again! Alum heads for sure and alum forged aftermarket crank will be chosen and I assume alum forged pistons. Makes sense my Performer RPM may or may not fit.

I had a look at butler again and the 4.150 bore is .030 over 428 and that seems to be what will need to happen to conform to the kit's pull down menu. I'll expect the machinist to tell me that he has to go 0.010 or 0.020 over but from what I'm hearing from you guys now is I'm into a custom piston and a hell of lot more money than a 0.030 over? since 30 over and 60 overs are soo common and mass produced, right?

I firmly believe and was told you want to keep as much material as possible , i guess I fail to understand if the cylinders clean up well (miracle) why isn't a forged alum piston such as these from summit not being offered by butler in the kit?

https://www.summitracing.com/search/...tiac/model/gto ( PART # Part Number: SLP-L2262F )

Is the butler kit pistons somehow better or they just want to steer everyone to the mass produce 30 overs?

I can see why the pistons should be in the hand of machinist PRIOR to over bore.

Essentially me dropping it off is him is telling me it has to be over bored which brings us to what I wrote above.

I think I have good handle on what is happening now?

steve25 -> Thanks, i'll consider that if it gets to a place where that is something I'd do on my own to get that answer.