Without a bushing that hole is heat treated so plan on using carbide to bore that hole bigger before honing to size. Not sure if those rods are case hardened or hardened all the way through so you may need a bushing or re-heat treat or hone to make the rod a press fit if it is only case hardened.
Duffey, Is that for the 1.85 Honda journal and are you using stock stroke or offset for more stroke as Derek suggested? Also you have to copy width and offset of stock rods at the big end.
Those types of rods are usually through hardened but the material has problems with work hardening anyways.
That’s .039 per side. It may be fine But custom Pistons from Scott Brown would be a better choice as he has .827 pins. Also you may need to check big end width and possibly narrow it for your crank, I ended up with 2 sets of narrow (.820) rods before Derek told me the spec on my 350 rod. You should mic the pin end and see how much material you have.
The rods are .900 wide, so .055 of the chamfered (or is it non chamfered?) Side should put me right there, correct? The listing states they are 1.974, but I'm assuming that's the rod measurement for a 1.850 crank journal. The current recipe doesn't include room for offset grinding. Though I have no doubt that with some more work we could find one that does, I don't know if the extra
Duffey, Look in the Silvolite catalog for 88-92 3800 Hyper Buick V6 pistons. Large dish will drop compression about a point.
That's odd it didn't include my whole post. I was going to say I don't think the offset grinding is worth 7 more cubes. I was hoping to land the cr about 11:1, I figure I might as well extract as much benefit as I can from the aluminum top end.
Duffey, Unless you have a supply of Aviation gas you will be much happier around 10 to 1. Aluminum heads? 64 Buick or T/A? Spacers I mentioned for 215/Rover Edelbrock, Offy 360 or Willpower single plane intake?
Great, now I just need to find the part number for the bearing. I'm planning 64' heads with the 64' 4bbl intake. Perhaps I've been misinformed. I was under the impression that 11:1 was completely manageable with pump gas on an aluminum topped engine. I've even read about Rover guys pushing 12:1, but maybe the aluminum block has something to do with it?
Normally 10.5 is pushing it but if you go a little hotter on your cam and lower your Dynamic compression you can get by. You have to be careful though if you screw up and have real low vacuum and it won't idle. You do want to be able to drive it on the street? It is all a balancing act. Years ago I built up 300 aluminum heads with 2.3 Ford SOHC valves, 1.75 IN and 1.5 EX. New seats and Chevy Z28 springs. They are softer aluminum and threads will pull on rocker shaft hold downs. Good place for steel thread inserts. We just had an article on Mgexperience engine swap site about heat treating the head to T6 hardness. You could also check our very long 300 Stroker thread on there. I milled mine .030 because I used them on a 215. I know a guy who just had steel adjustable rockers done for his.
It's .055" off of the non-chamfered side to get close to the Buick sbb offset. BUT, make sure the rods you get are on center, if not you will need to compensate if in they're not. I had a set of Pankl rods that were .900" wide and already around .020" offset so .040" needed to be removed from the non-chamfered side and .015" from the chamfered side to mimic the factory sbb Buick rod's offset. I'm sure the guy measured the big end with calipers because the actual size should be closer to 1.976" and yes, that's for the 1.850" crank journal size. The 2.008" housing bore size(the big end) has bearings for the 1.850" AND 1.889" journal size! The 1.976" housing bore is for the 1.850" journal size ONLY and the 2.015" housing bore is for the 1.889" journal size ONLY. If you don't need to add stroke, try to look for the rods for the 1.889" journal size if in you can find them in that size so you don't have to have as much ground off of the crank's rod journal(less $$ to grind).
Completely manageable when you push the rpm range way up, and the cylinder pressure curve along with it. You are talking about a low rpm stump puller in this post. Today I have in my lap a $9k engine with some fairly respectable parts in it... that after 2 hrs run time has very obvious detonation evidence. Only a few disappointing full throttle/load blips. Aluminum heads at 10.5 and a much bigger cam than most would run on the street, let alone call a stump puller.
If he's using the '64 aluminum heads then 11.5:1 to 12:1 would be pushing it with a bigger cam. I would agree if it was with cast iron heads but aluminum heads will dissipate more heat than cast iron.(10.5 to 11:1 is pushing it with cast iron) Good post, it is a balancing act, if he wants to drive it on the street he'll need to stay closer to 11:1 with '64 heads as long as the cam is big enough and the car is light enough.
Derek, I'm much happier with driveability with 9.5 max with cast iron and 10.5 max with aluminum heads. The gas we have in AZ and WA where I reside is 10% Ethanol and 91 premium. I like Dynamic compression ratio of close to 7. It cost Chris $400 to turn down the 350 crank. He brought a 300 crank in too to compare. Had to chamfer over the oil holes to recenter. Best Gasket has the Neoprene rear seal(also fits nailheads). Front seal was V6. Only rod interference was front of oil pan(dimpled with ball peen) and windage tray spaced down with washers. He used Crower 50233 cam. I would recommend Fitech or Holley TBI over the 4 barrel TB and Port Fuel Injection with Megasquirt he used. Much simpler.
Boy am I glad I decided to ask to help. Those rods I was looking at are Pankls, so I will be sure to look out whatever the case is. I've also seen some of the 2.015 rods, which I was curious about. If a point of compression is going to limit me that bad on cam choices, I will just find another combo that lands me on the 10:1 side of things. I recall finding one but passed over it because I thought 11 was where I wanted to be. It's too bad I'm very likely to have substantially more in labor than I will in parts, but I guess that's the nature of the beast.
10-10.5 is good. Give me cam specs and I can run them on my Performance Trends Analyzer for Dynamic Compression. I would need Duration @ .050, Lift and IN and EX Open and Close. I wouldn't go over 235 Duration or .520 lift on the street. Most HiPerf Cams require 10-1 or higher compression. Brand and Part# may be already in program library. Here's an example one step higher than Chris's. That's what we are here for, to help! https://www.crower.com/camshafts/rover-hydraulic-flat-tappet-camshaft-9536.html https://www.crower.com/searchresults/?part_num=53234&x=0&y=0
It helps to Not build your engine around a compression ratio, but keep it as another variable to factor into your build. Riding the high side of tolerance with compression is a certain way to find misery. Master that first before pushing that particular limit. There's better ways of finding power or cylinder pressure than the extra 1/2 point's edge of destruction threshold. The aforementioned build was a professionally machined, by the book deal run on Avgas. The internet suggested a plug two heat ranges hotter than what similar altitude dyno operators use and it also suffered a horrendous port angle mismatch causing fuel wash out making it impossible to tune, despite the huge cam 'hiding' the problems. It has CNC'd heads and is sold as an engineered top end package. Just something to think about.
I agree that a certain ratio is not the best things to shoot for but I still think over 10.2 is asking for trouble.
