[Ramairnacho]

Yeah! I'll be removing mine this wi.ter but just a stock nothing crazy for me

[racerboy]

Got engine torn down to bare block. Was really clean (only about 5000 mi since rebuild in 2011). Just the dreaded 8-eyebrow pistons and cast rods.









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[racerboy]

You can see crosshatch in the one picture. I’m hoping this means that it just needs a cleanup hone and no additional boring. It was bore .030 at last rebuild.


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[racerboy]

I’m going to drop the block off at the machine shop tomorrow to have it hot tanked and get the bores checked out. Like I said earlier, the motor is already .030 over and I’m hoping it just needs a clean up hone.

Should I try taking an electric die grinder to the lifter valley to clean up some of the sharp edges, or just leave it as is?






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[racerboy]

Instead of a die grinder, I just used a couple of files to get rid of the casting flash.



Dropped off the block at the machine shop.


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[Neil E]

What machine shop is building the engine?

[70TA-RAIII]

Good job with the files! That looks a lot better.

John

[racerboy]

Originally Posted by Neil E

What machine shop is building the engine?

LRB Machine is just going to hot tank it, replace cam bearings, and check the bores. The block is already .030 over from a rebuild in 2011, but only about 6000 mi on that rebuild, so I’m hoping it just needs a clean-up hone.

I don’t know who is actually going to build it yet. Hopefully one of the Pontiac guru builders from the forums, but I know everyone is so busy. The stroker crank probably won’t be here until next Spring. I also want to have somebody go through the #12 heads.


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[racerboy]

Originally Posted by 70TA-RAIII

Good job with the files! That looks a lot better.

John

Thanks John. I was reading some posts on the Street forum and someone said he likes to use files instead of a die grinder. It let’s you become one with the block, like a zen moment. I was just worried I would screw something up with an electric die grinder, so I followed the same path and used some files. Took me less than an hour.

Frank


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[racerboy]

So I got my block from machine shop. The pic below shows all the work they did:


The machinist is someone I’ve known for 25 years and has built 3 engines for me in that time. He doesn’t have the bandwidth to build this one (I think he wants to retire at end of year). Anyway, I called up a Pontiac engine builder today that’s within driving distance and now have more questions than answers. The fellow I was talking to was super nice and I’m not posting anything negative, but I am definitely in a bit of a pickle now.

Here are my highlights/questions.
1. Builder will only use my block if he blueprints it himself. He said having it honed w/o a Pontiac torque plate was a waste. He said he would need to bore it to .040 with a torque plate. I was trying to keep it at .030, but am not opposed to going to .040 if that’s the safe bet. He also talked about squaring the bores and having to machine the mains. Way over my head.

2. Heads. He would build my heads with new valves, 7/16 studs, porting, etc. the thing that surprised me was that he would not install hardened seats. Says he never uses them. He would just recommend using an additive in the fuel at each fill-up. Again, I’m not being negative, but I thought installing hardened seats was kind of standard. In fact, for all I know, my heads already have hardened seats.

3. Carb. He was saying that running a q-jet was going to be problematic because of all the ethanol in the fuel. I told him this was a numbers-matching car, so running anything else was a non-starter.

4. Intake. He was saying that a standard Performer was a better option from a driveability perspective than my stock intake. Again, a non-starter (besides, I have a ‘70 intake currently getting the Cliff Ruggle’s modifications by someone who used to work for him).

5. Camshaft. Doesn’t suggest using hydraulic roller cam because they don’t make Pontiac-specific lifters. Also suggested that the required bronze distributor gear could not endure daily-driver use. I’m not looking for every ounce of power, but I thought one of the advantages of a HR cam was that it reduced friction and made up for low zinc levels. My Trans Am gets driven, but certainly not a daily-driver.

6. Stroker crank/rods. I currently have a deposit on a Molnar 4.00” stroker crank (3.00” mains) as well as a set of Molnar Pontiac-length rods (6.625) with BBC journals. He thinks I should just go with a Scat 4.250 stroker because I would be getting a bigger engine w/ more torque for same money. I have an M21 with a 3.73 rear. I’m pretty sure that the torque from a 433 is going to be perfectly adequate. I understand that the bigger engine is going to make more torque, but I’m really not looking for every ounce of power.

My biggest question has to do with boring the block to .040 with a torque plate. That does seem to make sense to me, and I’m not opposed to it, but just wanted to throw this out to the experts. I’m assuming that any builder I wind up going to may tell me same thing.

I know this was a long note and definitely want to hear some thoughts from the experts out there.


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[tom s]

maybe find another builder?Tom

[Formulajones]

Originally Posted by racerboy

So I got my block from machine shop. The pic below shows all the work they did:


The machinist is someone I’ve known for 25 years and has built 3 engines for me in that time. He doesn’t have the bandwidth to build this one (I think he wants to retire at end of year). Anyway, I called up a Pontiac engine builder today that’s within driving distance and now have more questions than answers. The fellow I was talking to was super nice and I’m not posting anything negative, but I am definitely in a bit of a pickle now.

Here are my highlights/questions.
1. Builder will only use my block if he blueprints it himself. He said having it honed w/o a Pontiac torque plate was a waste. He said he would need to bore it to .040 with a torque plate. I was trying to keep it at .030, but am not opposed to going to .040 if that’s the safe bet. He also talked about squaring the bores and having to machine the mains. Way over my head.

2. Heads. He would build my heads with new valves, 7/16 studs, porting, etc. the thing that surprised me was that he would not install hardened seats. Says he never uses them. He would just recommend using an additive in the fuel at each fill-up. Again, I’m not being negative, but I thought installing hardened seats was kind of standard. In fact, for all I know, my heads already have hardened seats.

3. Carb. He was saying that running a q-jet was going to be problematic because of all the ethanol in the fuel. I told him this was a numbers-matching car, so running anything else was a non-starter.

4. Intake. He was saying that a standard Performer was a better option from a driveability perspective than my stock intake. Again, a non-starter (besides, I have a ‘70 intake currently getting the Cliff Ruggle’s modifications by someone who used to work for him).

5. Camshaft. Doesn’t suggest using hydraulic roller cam because they don’t make Pontiac-specific lifters. Also suggested that the required bronze distributor gear could not endure daily-driver use. I’m not looking for every ounce of power, but I thought one of the advantages of a HR cam was that it reduced friction and made up for low zinc levels. My Trans Am gets driven, but certainly not a daily-driver.

6. Stroker crank/rods. I currently have a deposit on a Molnar 4.00” stroker crank (3.00” mains) as well as a set of Molnar Pontiac-length rods (6.625) with BBC journals. He thinks I should just go with a Scat 4.250 stroker because I would be getting a bigger engine w/ more torque for same money. I have an M21 with a 3.73 rear. I’m pretty sure that the torque from a 433 is going to be perfectly adequate. I understand that the bigger engine is going to make more torque, but I’m really not looking for every ounce of power.

My biggest question has to do with boring the block to .040 with a torque plate. That does seem to make sense to me, and I’m not opposed to it, but just wanted to throw this out to the experts. I’m assuming that any builder I wind up going to may tell me same thing.

I know this was a long note and definitely want to hear some thoughts from the experts out there.


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1) 100% on par with how I want my engines done. I've had "honed" engines rehoned with a torque plate and the difference is rather horrifying and makes you wonder how rings seal at all, and at the very least would last any length of time. I'm talking 40-50,000 miles before issues arise. Ring seal is a big player in longevity and HP as well as oil consumption, blow by, all kinds of things.

2) That's been a debate since the 70's. These days I do hardened seats just because it seems I'm in there changing the valve job or valve size anyway, and replacing guides on heads that are 50+ years old, so why not.
That said I still have engines here with original 50-60 year old heads with original seats and still running perfectly fine on unleaded gas. With mild lobe camshafts and mediocre spring pressures you aren't beating the seats out of them anyway :shrug:

3) No problems Q-jet or Holley carbs here on todays ethanol gas and I've been daily driving them for years.

4) Stick with the 70 intake.

5) That's BS, there are in fact hydraulic roller lifters made with different oil band heights. I'm running them. Been talked about to death on here and we've all posted pictures of the differences in the past. There are hydraulic rollers that work just fine for Pontiacs. The problem these days is getting them, like anything else. I don't have any problems with Brass, Melonized, or Composite distributor gears, even with big 80psi pumps that everyone says kills the distributor gears. Old wives tail. Dress the drive gear on the cam and it'll live a long happy life.

6) I agree with the bigger crank. Darn things cost about the same and with not that much of a price difference for these rotating assemblies I hate to spend my money and get less. That's just me, I prefer more bang for my buck, and I've never had anyone complain about a bigger engine making more power for the same money LOL.
Eventually you'll likely ditch the M21 anyway if you really want to drive the car anywhere so that's a non starter for me. I'd be tossing in a 5 speed right off the bat. It's only money

That's my take on it anyway :shrug:

[PAUL K]

If you have to buy new pistons, you can order custom for any more size that rings are availble. Let your guy know that (you are buying pistons) and the block will most likely clean up at .035 or .036 over with a torque plate.. Have the piston made for that bore size. It's worthwhile to "square the decks" and get the pistons level with the deck..... IMO it's important to keep an original block like yours at the smallest bore possible. We have built several rare/original blocks using .005-.020 over sized pistons.

[Formulabruce]

@Racerboy >> "Block check Align Bore" and this was done after a hone Without a plate?>
Did you buy a UNDER-sized Timing chain?, if not, is yours tight?>
When a real "align bore" is done the crank moves UP in the block. NOTE: Your front timing cover SEAL and rear main seal DO NOT move UP WITH the crank.
I would Borrow or make a smoker for this engine when its built and on the engine stand to be SURE you have NO oil leaks at front and rear of crank....

[R 70 Judge]

Like Tom said, maybe consider another engine builder. I like the idea of putting a 4” stroke in it. I’ll be putting one in mine as well. I’d think you could get away with a hone on an engine with only 6,000 miles on the rebuild. I assume it was bored with torque plates when it was initially rebuilt in 2011.

[Formulajones]

What does a bore gauge say? Any taper? Assuming it was bored and honed correctly the first time.

Just to elaborate on one example I built. Was bored and honed (no torque plate) and the engine only had maybe 10k miles on it. Was using a little oil for a couple reasons but we'll just talk about the bore for now. During the refresh/reconfiguration it was decided a fresh hone with a torque plate should be done. Pistons were too tight anyway. First pass with the hone and there were huge voids where the hone didn't even touch the cylinder. So how do you think that ring seal was? Made a few very light passes, eventually taking the bores another .003" over and there were still voids in the bore where the hone wasn't touching it. Unfortunately that was the limit of proper piston clearance and couldn't go any further unless oversized pistons were ordered.

So it still wasn't perfect but it was at least 80% better than it was. Just never know with these things until you start touching it with the hone and a torque plate, then what you see is pretty shocking. We were lucky on that one simply because the piston to bore clearance was too tight to start with and gave us a little wiggle room. If your piston clearance is spot on, and you want to hone with a torque plate, chances are it won't clean up and you have to order a set of pistons.

I'm 50-50 on your engine builder. Some things he says makes sense and other things I think he's maybe not aware of.

[racerboy]

Originally Posted by R 70 Judge

Like Tom said, maybe consider another engine builder. I like the idea of putting a 4” stroke in it. I’ll be putting one in mine as well. I’d think you could get away with a hone on an engine with only 6,000 miles on the rebuild. I assume it was bored with torque plates when it was initially rebuilt in 2011.

I really can’t say for sure that a torque plate was used when it was bored back in 2011. I can look through the paperwork that the PO gave me. It was basically a stock rebuild (8-eyebrow pistons and all). The PO was pretty hands-off when it came to working on the car. Fortunately, he was pretty emphatic about keeping all the original parts on the engine.

The builder I spoke with was also pretty emphatic about running an in-tank electric fuel pump. He also talked about using a different Pertronix distributor, a vacuum pump for brakes, a blueprinted mini-starter and even a different flex fan. Again, I’m not being critical of his ability to build strong Pontiac engines, I’m just not sure we share the same vision for my car.

Happy Thanksgiving to all my PY family!


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[Formulajones]

Originally Posted by racerboy

I really can’t say for sure that a torque plate was used when it was bored back in 2011. I can look through the paperwork that the PO gave me. It was basically a stock rebuild (8-eyebrow pistons and all). The PO was pretty hands-off when it came to working on the car. Fortunately, he was pretty emphatic about keeping all the original parts on the engine.

The builder I spoke with was also pretty emphatic about running an in-tank electric fuel pump. He also talked about using a different Pertronix distributor, a vacuum pump for brakes, a blueprinted mini-starter and even a different flex fan. Again, I’m not being critical of his ability to build strong Pontiac engines, I’m just not sure we share the same vision for my car.

Happy Thanksgiving to all my PY family!


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He's definitely right about in tank pumps. If you're planning an electric fuel pump, in the tank is the only way to go. Longevity, quiet, there's a reason why the OEM's have done that since the beginning of EFI.

[PAUL K]

A torque plate wasn't used on the last go around, if the guy said it will need to go to .040 to clean up with a TP now.

Align boring may or may not move the crank closer to the cam. It depends on the reason for the line-bore, equipment used and the skill of the machinest.... Done right it doesn't matter. There are "short" timing chain sets available and most Pontiacs are usually loose in this area anyways.

I'd expect a basic rebuild seeing the choice of pistons used last time.

PS.... The deburring job on the valley looks great.

[Jay S]

Flex fan instead of a factory fan, Pertronix dizzy instead of stock, performer instead of stock intake, no q jet, all on a original RA car that the intent is to keep it stock appearing?? Plus a 4.25” crank instead of a 4” because the 4” doesn’t make quite a much TQ..for a 4 speed car with street tires???…he would not get any work from me. A blueprinted 400 with the stock parts would probably wip that guys 4.25” engine.


Even though the engine does not have many miles, the top rings on the 8vr pistons don’t come up as high as the stroker will, and that needs to be very true to get good ring seal. It needed the tq plate on there when it was honed. I have done that (top ring higher in the bore with only a hone job), it did not work out well. It likely needs an slight overbore like Paul says, preferably as little over size as possible.

How much power is it going to make? I can’t picture it needing an intank pump for fuel supply. I have a electric booster pump in-line with the stock mech pump with a bigger needle and seat on the q jet on over 500 HP, no issues at all on the street. Big slicks with the front end coming off the ground at a race track is when I switch to in tank electric.