Long Rod 300 Build

Discussion in 'Small Block Tech' started by Duffey, Mar 6, 2018.

  1. Jim Nichols

    Jim Nichols Well-Known Member

    Jim, He used the 350 capscrew rods. Wasn't zero deck because of the shallow dish. He had 10.2 compression but when he had the cooling issue he had the heads skimmed so probably around 10. 3. He did smooth out the chamber, unshrouded the outside of the valves and ground out the lug in the chamber.
     
    Last edited: May 16, 2018
  2. Jim Nichols

    Jim Nichols Well-Known Member

    Duffey, Chris used 231/3.8 Buick V6 front seal and Best Gasket rear seal for 300 and Nailhead V8.
    Rear seal shown in Jim B's thread.
     
  3. Duffey

    Duffey Well-Known Member

    Thanks Jim Nichols.

    Jim Blackwood, I already have a set of reconditioned cap screw 350 rods so I won't be getting the rods Derek posted, though they do look great for this application.
     
  4. 300sbb_overkill

    300sbb_overkill Well-Known Member

    Cap screw rods at the power level you'll be at was totally an unnecessary weight penalty because either set can't handle much more than 6,000 RPM and you definitely won't be anywhere close to 450 HP where the earlier rods are suppose to be good too.

    If you have an early crank and you want to run the later around 50 grams heavier per rod rods, you may have to have heavy metal added to the crank to even external balance it? The lighter pistons may be your saving grace for that though?

    If you have the later crank with the later cap screw rods, more than likely weight will need to be removed from the crank to balance the rotating assembly(which there isn't an extra charge for removing extra material but is for adding extra weight). Just so you're prepared for that I thought I would let you know. Old style rods around 630 grams, cap screw style rods around 680 grams.
     
  5. Duffey

    Duffey Well-Known Member

    You hit the nail on the head--I figured an early crank would be the ticket with the cap screw rods but lighter pistons.

    Like I said before, I don't think the price would have been any different with early 350 or 340 rods so I figured I might as well get the better ones.
     
  6. Duffey

    Duffey Well-Known Member

    Also, I'm curios to know what the source of the cooling issue was and how skimming the head helped it?
     
  7. Jim Nichols

    Jim Nichols Well-Known Member

    Chris used the later crank with the capscrew rods but had his internally balanced at extra cost. No Mallory metal, just drilling. I think you can lighten the capscrew rods quite a bit by removing most of the large balancing pads on each end. On the cooling issue, he tried to eliminate the bypass hose which created air pockets and hot spots until the thermostat opened. While trying to figure out the problem he changed from the Felpro to the Victor Reinz head gaskets and just wanted to insure the heads were flat.
     
    Last edited: May 16, 2018
  8. Duffey

    Duffey Well-Known Member

    Oh ok, good to know. So what exactly does an internal balance do for you? Does it open up options as far as flywwell and flexplates go?

    If Chris ended up just needing drilling, shouldn't I be ahead with the lighter crank?
     
  9. 300sbb_overkill

    300sbb_overkill Well-Known Member

    I think you're misunderstanding what I wrote.

    Adding weight costs $100 PER 1.00" Mallory slug added to the crank. Drilling weight out of the crank is included with balancing.

    With the heavier rods you may need weight ADDED to the earlier crank with the later heavier rods when balanced even with external balancing at an additional cost.

    IMHO, the earlier lighter rods are the "better ones" for a build such as yours that will probably be just south of 300 HP. Actually you would of probably been able to free up about 5 to 10 more HP with the lighter rods.

    Unless you plan on adding boost or laughing gas later on you will never see over 450 HP to take advantage of the "stronger" cap screw rods. And I mention boost because without being able to spin the engine much over 6,000 RPM, would need to spin above 6,500 RPM if you had enough air flow through the heads to make that much without some sort of power added to raise the power while staying at lower RPM where the rods are rated to not break.
     
  10. Jim Nichols

    Jim Nichols Well-Known Member

    Duffey, Chris still has the original pistons and would like to sell them. I asked Chris to PM you here.
     
    Last edited: May 17, 2018
  11. Duffey

    Duffey Well-Known Member

    Thanks Jim! I'll look out for his message.

    Derek, I get what your saying about the balancing situation, but I guess I'm not too worried about it at this point. I already have the rods and the crank, and it sounds like Chris didn't have any problems with the setup.
     
  12. 300sbb_overkill

    300sbb_overkill Well-Known Member

    Chris had a later cap screw rod crank with the cap screw rods that he is running, that's why he didn't have an issue, more than likely they had to remove weight from the crank.(remove= included in balance price, add = extra cost) You said that you have an early nut and bolt rod crank and you're running the heavier cap screw rods = may need weight added?

    You might be ok because the pistons are lighter than the factory early 350 pistons, my fingers crossed for you.
     
  13. cgill

    cgill Well-Known Member

    I thought my ears were burning! Ha.

    Jim definitely knows my build inside and out because he literally build the engine over email messages.

    I have two sets of the 98-01 Ford Ranger 2.5L SOHC L4 Pistons & Moly Rings standard bore collecting dust in my garage if you are interested. But shipping might be a killer given that I'm in Canada.

    I had an overheating issue because of where I had positioned the temperature sensor for my EFI , plus my first rad was not doing a very good job of cooling. I re-positioned the sensor and put in a much larger rad., which fixed the issue.
     
  14. Duffey

    Duffey Well-Known Member

    Oh ok I misread Jim's post. I thought he had an early crank. Yeah we will see how it pans out and I will report my findings. We should have Jim Blackwood weigh the rods from the 340 he's tearing down so we can have all the weights on file.

    Chris, I will send you a pm. Jim has been a wealth of useful information. Its nice having people around who have worked on these engines enough to not speak in theory but from experience.
     
  15. Jim Nichols

    Jim Nichols Well-Known Member

    Duffey, Try to get the ID of the pin hole in your capscrew rods too if you can. The smaller size DOM I mentioned earlier may be perfect to press in.
     
  16. Duffey

    Duffey Well-Known Member

    Will do Jim. Looking at my response I guess I didn't misread your post. I think I figured since there is only a 1.2 lb difference in the cap screw and 300 rods, there was probably half that difference with the early rod. So maybe it will end up just about right? I'm thinking it will probably be pretty close at any rate, but who knows until its on the balancer?
     
  17. Jim Blackwood

    Jim Blackwood Well-Known Member

    Those rods are now gone so a moot point. But Chris, since you're here I'd like to know how far down in the hole those pistons ended up? If there happens to be a forged version I might consider using them if I can get a suitable rod. Pretty tricky taking squish, pin size, and ring placement all into account.

    Jim
     
  18. Jim Nichols

    Jim Nichols Well-Known Member

    Jim, I used a compression calculator to determine original piston compression ratio. I remember that it was .030 or .035. 5cc shallow dish. 58cc chamber as he unshrouded the valves on out side and removed the lug in the chamber. 10.2 compression with the stock capscrew rods. Very little squish/quench with the open chamber heads. For zero deck you would need a deep dish to keep compression reasonable.
     
  19. Duffey

    Duffey Well-Known Member

    Pin holes are micing .937-938. Reaming them to fit the 1 inch wouldn't be the worse thing in the world but I will see if I can find something closer. If I hadn't sold the lathe I just bought I could have whipped out what I need very easily, live and learn I guess.
     
  20. Jim Nichols

    Jim Nichols Well-Known Member

    Duffey, Thanks! Sounds about right. So, .003 interference stock. For the 1" DOM tubing you would need a .996 hole for .004 interference. That is only .059 bigger. .0295 per side of hole. If you can find .941 OD and press in would be perfect.
     
    Last edited: May 18, 2018

Share This Page