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Location: Colorado Springs Colorado/Thousand Oaks Ca
Posts: 1,721
Originally Posted by olds 307 and 403
The problem probably won't be binding, probably too much play for proper preload. If it has .0065" clearance on any guides, those heads need more work, not good. My fresh #6 heads had around .003" according to my measurements. You want that on the center exhaust guides or valves can stick.
I wouldn't use those. CHE precision is what you want in .341, you then will ream them to .3422 and then hone them to final size based on your valve dimensions, .0015 Intake and .0018 on the exhaust clearance. I always put a step at bottom of the guide on the exhaust 1/8 deep. Your then ready for some killer seat work!
Last edited by VORTECPRO; February 18th, 2021 at 05:38 PM.
CHE precision is what you want in .341, you then will ream them to .3422 and then hone them to final size based on your valve dimensions, .0015 Intake and .0018 on the exhaust clearance. I always put a step at bottom of the guide on the exhaust 1/8 deep. Your then ready for some killer seat work!
Nice looking guides. Thanks!
I forgot to post the pic of the Muskegon catalog with SBO part numbers. I couldn't find this anywhere online.
Please explain. I know guys have had the center exhaust valves in stick in Olds heads, my understanding is .0028" minimum on center exhaust guides due to Olds large crossovers, 73 and later look even larger. Or are you talking about guides with excessive clearance binding?
Location: Colorado Springs Colorado/Thousand Oaks Ca
Posts: 1,721
Originally Posted by olds 307 and 403
Please explain. I know guys have had the center exhaust valves in stick in Olds heads, my understanding is .0028" minimum on center exhaust guides due to Olds large crossovers, 73 and later look even larger. Or are you talking about guides with excessive clearance binding?
The guides I use you can run tight IF the machine work is correct, as explained in the post above. I always fill any cross over with aluminum, so I didn't consider your point. A cast iron inferior guide run tight could be a problem, I never ran them so I couldn't say, but if a person is going to do the job right a CHE bronze guide is used honed to size, a round strait properly clearenced guide allows for a perfect valve seat that will transfer the heat from the head of the valve through the valve seat due to a prefect contact patch, heat is also transferred through the valve stem to the valve guide, this makes for a happy clean valve seat. This is complex work thats labor intensive to get it right, most machine shops will have problems. With excessive clearance the valve will bounce off opposite sides of the seat which causes a vicious cycle of wear. Examples:
Last edited by VORTECPRO; February 18th, 2021 at 07:15 PM.
I think filling the heads makes a big difference and yes, bronze guide liners seem to help as well. I bought the Hughes Ram EQ heads for my 5.9 Magnum. Hughes adds bronze guides, they were a few stuck valves in the EQ heads with the stock cast iron guides. I know one guy who had issues had unfilled heads and cast iron guides set at .002". One of his center exhaust valves kissed a piston and nearly destroyed his fresh Olds 350.
Location: Colorado Springs Colorado/Thousand Oaks Ca
Posts: 1,721
Originally Posted by olds 307 and 403
I think filling the heads makes a big difference and yes, bronze guide liners seem to help as well. I bought the Hughes Ram EQ heads for my 5.9 Magnum. Hughes adds bronze guides, they were a few stuck valves in the EQ heads with the stock cast iron guides. I know one guy who had issues had unfilled heads and cast iron guides set at .002". One of his center exhaust valves kissed a piston and nearly destroyed his fresh Olds 350.
Just keep in mind, if the valve contact patch isn't good and the head of the valve can't transfer heat through the seat.......it creates heat.
Interesting and makes sense. Hopefully his next machine shop experience is more positive. I need to call mine and see if it will be done next week. I need to pick up a dishwasher in city, hopefully I can bring my block home.
Just keep in mind, if the valve contact patch isn't good and the head of the valve can't transfer heat through the seat.......it creates heat.
Makes perfect sense to me.
I was finally able to get in touch with the Lunati tech line and asked them about a spring substitution for the springs & retainers in the SM272H10 kit. I explained the difference in pocket depth between an Olds non-rotator head (#5) and my rotator heads (7A). The springs in the kit are P/N 73262-16. They have a 1.495" O.D, 1.660" Installed Height, 96lb pressure at seat, 238lbs open, and a spring rate of 346 lbs/in. The tech didn't have a substitution available but agreed that a 0.125" difference in spring seat depth exceeded a distance one would want to shim.
Looking at the specs it appears the factory valve springs will work, provided I can find the correct overall length. GM Part numbers for 72 are:
Anyone know of a good aftermarket replacement for the 411225 or 411226?
Lunati lists in their catalog two 1.500" OD single w/damper valve springs that should be workable with your heads, p/n 73126-16 and 73815-16. Lunati or your machine shop should be able to recommend which would be best for your application. Comp Cams also has a single, p/n 920-16; I'm sure that the other manufacturers have suitable listings as well.
Here's where I need some help/advice. I have the Nodular crank from the '72 engine that the shop supposedly balanced. I have the 7A heads the shop rebuilt, although I believe it was incorrectly done. I ordered the Mondello gauge and measured the valve stem and rotator height on one head. A few of the valve tips were really beat up prior to the rebuild. It looks like they simply ground the damage off and reinstalled. Based on the '69 FSM the difference should be 0.030", however, that doesn't have rotators. Stem height on the head I checked was 0.040"-0.048" although one was 0.060". The 2 in bold are the ones I'm worried about. Are these measurements ok?
Next none of the rocker hardware was kept in order. I got everything back from the machine shop in a big bag. I have all of the hardware, in order, from the #8 heads. Can I use #8 rockers/pivots on a 7A engine? I did some searching but couldn't confirm the hardware was the same.
Is the '73 crank nodular? There's no "N" but, based on my research, the casting number says it's nodular. The 72 crank was polished, balanced, and stored horizontally by the shop that I had all the problems with. I'm thinking I'll take both cranks to shop #2 (when I find one) so there are options as needed:
I have to start looking for pistons again. I'm aiming for a 9.5:1 engine but the budget really took a hit with this debacle. Another set of DSS pistons is probably out.
And perhaps most importantly: does anyone have a recommendation for a good machine shop in the TN tri-cities area (Bristol, Johnson City, Kingsport), WNC (Asheville), or some reasonable driving distance from this area?
My experience is mostly with Chevrolet engines, and the way to tell if a crank is forged or not is to check the casting line, if it is narrow, it is cast, if it is wide and has been ground off, it is forged. You can also tell if the crank is out of the engine, Set it upright and tap it with a hammer,. a cast one will make a dull sound and a forged one will make a sharp sound.
The only forged SBO crank is the 330 crank. You can tell if you have that one because it has the early flexplate/flywheel bolt pattern. All the 350 cranks are cast. Nodular is mildly stronger than non-nodular, but nothing to lose sleep over. Use whichever crank is in the best condition.
The crank question has never been answered completely. The couple of 76 350, 78 403 and 80's 307 cranks look different than the N and my unmarked 73 350. Slightly different colour, smaller front counterweight and no doubt lighter in weight. If the N crank has already been ground, it is the way to go, if done properly.
Update on the nightmare with machine shop #1. The credit card company finished the investigation and decided in my favor. The case has officially been closed.
Stay away from White Performance and Machine in Kingsport, TN. Fred White is responsible for the mess chronicled above and owns machine shop #1
Been quite a while since I updated this thread but the engine is STILL at the machine shop. I've been calling religiously every 2 weeks and finally have an update. The heads needed everything: 15 bronze liners, 1 guide (cracked), the heads hadn't been cut evenly (he took 0.004" off one and 0.012" off the other to even them up), valves were excessively worn, exhaust manifold mating surface was pitted/warped, and White's had spray bombed the heads inside and out. As the paint broke up and dropped into the pan it would have blocked the pickup.
Block has been bored & honed, still needs to be decked. I continue to wait as patiently as I can...
I hear you, in the same boat, it took nearly 7 months for my block to be completed. Still waiting for them to grind the crank, harrassed them on Monday. They need to hone fit the pins on the Molnar rods so the Mahle pistons can be installed. Then off to a different shop, apparently they send out their balancing. I aiming on having the new motor running before the snow flies here. Unfortunately it looks similar for you.
Awesome! I beat you 10.5 months so far. The first shop forgot to hone fit the small ends on the Molnar rods, so told a week at Precise here in Saskatoon. I may it 11 months yet. Both examples, pick shops that make you a priority and do things right.
I hope so! Planning to put it in over Christmas, provided I can get the other parts needed. Debating what plugs as the AC Delcos are now made in China. Haven't been too deep into the other bolt-on components (fuel pump, water pump, etc.) yet.
Awesome! I beat you 10.5 months so far. The first shop forgot to hone fit the small ends on the Molnar rods, so told a week at Precise here in Saskatoon. I may it 11 months yet. Both examples, pick shops that make you a priority and do things right.
9 months on shop #2. Shop #1 had engine #1 for 5 months. Hopefully yours comes home soon as well...
All in my posession except the rods and pistons. Also waiting on the last parts from Cutlassefi. Yeah 14 months is bloody awful.
You're close to the finish line on the engine too!
In addition to a complete engine I have a balanced assembly (nodular crank and the DSS Pistons/rods from shop #1) along with a bunch of small parts (oil slinger, oil filter adapter, etc.) Once the new engine is up & running I'll sell off what isn't needed. Those DSS pistons are a shame. IMO 3 of them need to be replaced due to sloppiness.
I used Murphy's Law to my advantage and figured that, if I started on the 200-4R conversion the engine would appear when I was right in the middle of it. Worked like a charm...
I think the 200-4r will be worth the effort and I'll put the complete TH350 up for sale once it's done. It hurt a bit to pull the TH350 back out as I had to have it rebuilt in early 2018, when the trans cooler in the rad leaked and coolant contaminated the trans
I also did the 2004R conversion. It has been 81 days since I ordered parts from CK Performance for it, nothing yet, including no response, PayPal now involved 🤔.
Oh man! What are you waiting on from them? I'm currently waiting on a 4th gear pressure switch. I actually took her for a ride last week but the TCC lockup was all over the place. Turns out the GN trans uses a normally closed 3rd and 4th gear switch and it appears the TCC solenoid was on until it burned up. My trans guy didn't catch this but I've been talking with him about the apply issues. I didn't find many good pics/threads on the installation. Maybe I should start one?
Oh man! What are you waiting on from them? I'm currently waiting on a 4th gear pressure switch. I actually took her for a ride last week but the TCC lockup was all over the place. Turns out the GN trans uses a normally closed 3rd and 4th gear switch and it appears the TCC solenoid was on until it burned up. My trans guy didn't catch this but I've been talking with him about the apply issues. I didn't find many good pics/threads on the installation. Maybe I should start one?
Yeah start one. I bought their pump, shift kit and seal kit. I already have a TCC lock up kit installed, a deep pan with 4L60E filter, modified by me governor and a 2350 flash stall converter. I also bought their boost valves and the improved GN servo. I put a pressure gauge on it after installing the big .555" boost valves, maybe 200 psi in the foward gears, not enough. Last 2 purchases, no issues.
The crank question has never been answered completely. The couple of 76 350, 78 403 and 80's 307 cranks look different than the N and my unmarked 73 350. Slightly different colour, smaller front counterweight and no doubt lighter in weight. If the N crank has already been ground, it is the way to go, if done properly.
The late year crank are Grey iron and soft. Fine for mild engines but not suitable for anything making decent power
The late year crank are Grey iron and soft. Fine for mild engines but not suitable for anything making decent power
The 73 crank is the one I am taliking about. No "N" on it but psychically larger and a different colour than the later, lightweight weak cranks. I am using a 330 crank in my 400ish hp 357.
I cut the break-in oil filter open to see how it looked. Also ran a magnet through the oil. Everything looks good from what I can see. A little bit of carbon (I think from the inside of the push rods) and a few specks but that's it.
Yes! It's been an odyssey for sure!! I really, really wanted to get it done over the Christmas break and, with some late nights this week, I was able to make it happen!
I fixed the 2nd link to show the exhaust video. Both links had, for some reason, gone to the same video.
@ olds 307 and 403. How's your engine? You've run into a number of issues too.
All the machine work is finally done! Just file fit rings, double check clearance, assemble, degree cam and wait for the last parts to come in from Cutlassefi along with the new Edelbrock heads.
All the machine work is finally done! Just file fit rings, double check clearance, assemble, degree cam and wait for the last parts to come in from Cutlassefi along with the new Edelbrock heads.
Good news on the machine work! Any idea when the remaining parts and heads are due? I know the supply chain is a mess.
February 18th, 2021, 05:27 PM
. I'll check both of them out when they come back from the machine shop. I took both so as to give the machinist options.
