See post #18 that the OP posted. 0ver 10.2:1 compression with a relatively mild cam with iron heads IS somewhat of a concern even on a street driven car. The 8:1 that was posted was the dynamic compression, not the static. With the dynamic approaching 8:1 IMO 160* would be ok but the 180* would be a better choice. Now if in the dynamic was over 8:1, then the 160* thermostat might be a crutch to be considered? The weight of the vehicle needs to also be considered because that will increase WOT load which can cause detonation if the timing is to aggressive and or the fuel doesn't have enough octane. The OP may want to keep the timing at a max of 32* total and try to have it come in a bit slower than what is in the timing thread because of the weight of the vehicle, maybe 500 to 1,000 more RPMs than the all in by 2,500 that is recommended in that thread because of the extra load the extra weight puts on the engine? What grade of gas is available for this build?
93 is available and all I will be running (might toss in 100LL from the local airport for the track). Currently 32* of timing (18* initial, 14* mechanical, 8-10* vacuum advance). Makes 15" of vacuum at idle of 800. 4500 lb Riviera with the addition of the B4B. Advance curve coming in at 2500, right when the cam begins to really eat 67* intake closing with 10.2 compression. 219/238 Scott brown cam 109 LSA Next time it's running, I will verify timing with someone watching the tach and letting me know at what rpm the whole advance is in by. I have heavier springs ready to go. Issue is, the heads are currently off and new ones are ready to put on. Gotta wait til thanksgiving
When you run it at the track, toss in some 110 leaded gas, problem solved. On the street, my guess is it will run just fine unless you go WOT for extended periods of time. I doubt you drive like that on the street, I certainly don't.
Well, I do like to exercise it, but it certainly won't be hooking and pulling like it does at the track. Especially on 235/75/15's
I've met John, seems like a pretty level headed guy I doubt whether he is going to do something stupid or we will have a brand new sympathy thread.
Exactly, so it should be fine. You know what detonation sounds like. Be careful at first, that's all.
I'm not talking race engines. I'm talking street engines, all my street engines including my daily driver get 160 t stats. The big engine is a 13.5:1 compression 552" stroker, and I have the t stat gutted in that, and it runs 32 degrees total timing with 12 initial and will run on 91 octane pump no problem. That's because the set-up is optimized to work together and at my elevation. Car has been to the racetrack a couple times, but other than that, it's been 30k miles of street and highway use with this engine. Is my stuff a little more radical than what most would consider a street engine? Probably, and if you put some guys in my daily beater they'd probably think they were driving a top fuel car. But I can drive them all the time, and the big block in the daily gets driven between -20 and +110 degrees outside, 24/7/365 in winter, summer, spring and fall from sea level to 7000 feet elevation. It has 12.5:1 compression and 36 degrees total timing and runs on pump swill because the combo is made to work that way. This next part is a generalization and has nothing to do with John's question: A couple other questions that I NEVER see get asked on this forum from the tuning gurus that HAVE to get asked on other forums before anybody will even venture tuning or parts recommendations: 1. Intended use 2. Vehicle info (weight/gearing/trans) 3. Elevation 4. Fuel desired to use ( racing gas/av gas/E-85/methonal/pumpgas(include octane available)) 5. Parts you already have 6. Proposed Budget 7. Location If somebody is trying to tell someone what cam, carb, timing, etc to run without asking for that info, guys, please find someone else to help you. I'm no BBB master, but watching some of these tuning guys just regurgitate what they've read over and over and over on this forum is comical. If you want your car to run exactly like everyone elses, by all means run a Quadrajet carb set up by one of the guys on here, a B4B intake, a TA ____ cam, some headers, some Walker 2.5" exhaust, and then "port" your heads with absolutely no advice on how to do it other than just make them bigger, then go for it. You'll run exactly like everyone else's engine and it will run better than it did, but will it be anywhere near optimized? Hell no. Don't take guys who know a recipe and can tell you what parts go into that recipe as some kind of tuning or engine master. They're not. I would LOVE to hear you "tuners" answer how in the he** you can tell someone what cam and ignition timing settings to run without asking them what elevation they're at first? What about what fuel they run? How can you tell someone what static compression ratio they can get away with without knowing how many feet above sea level they are? How do you know what t-stat for them to run without knowing what fuel he's got and what timing he's running. All this stuff ties in together to make a combination. If you're one of the guys that starts spouting off parts info on what somebody can or should run without asking those 7 questions I posted plus many more, then you are not a tuner. You are a parts recipe repeater. There's a big difference between a chef and baker. You can make some great brownies at home by reading the Betty Crocker book, but would a real chef who knows what ingredients do what and why make better ones? Yes. Don't listen to bakers. You can be a baker yourself real easy. Try to be a chef. If someone tells you to run such and such, do you want to run the same as them or better? Sorry if this was out of place or harsh sounding, but I just get tired of reading the same old things over and over with no proof of concept other than they read it on the forum so that's the way it is.
I never said he would be "stupid", just that he may like to drive more spirited than you. On ramps are good places where WOT can be applied relatively safely to the speed limit-ish.
Thank you, Derek, that's exactly what I was talking about. You actually ask the questions that needed to be asked before suggesting something.
1. Intended use 90/10 street/strip and scaring my friends and family with the elegance/quickness of the Riv 2. Vehicle info (weight/gearing/trans) 4500 lb/3.42 posi/ST400 with 1800/3200 switch pitch 3. Elevation About 500, so pretty much negligible 4. Fuel desired to use ( racing gas/av gas/E-85/methonal/pumpgas(include octane available)) 93 octane pump/mix in 5 gallons of 100 LL when heading to Lebanon in the future 5. Parts you already have 430 shortblock - well set up oil pump 219/238 109 LSA cam .490/.453 Steel shim .020 headgaskets Early Q-jet B4B - 1/2” divider drop Ported/polished Stage 1 replacement heads- 280/180 at .550. 430 rockers 1.6 ratio Everyday Performace 750 Q jet (I know this is small) 6. Proposed Budget I have pretty much what I need 7. Location Canton, CT
Agreed, but with age comes wisdom. I get on my car in those exact places. Like I said, I have met him at our club functions. I think I am a pretty good judge of character. I'm not worried about John.
Yeah and bad eye sight, slower reflexes and bad hearing. And the wisdom to know that the above needs to be considered!
Like I said, wasn't intended toward you and your question, John . Just a glaring generality I see from guys on here over and over. To answer your question, the 180 would probably be safe, but with your compression ratio, a 160 would be a good little safety net to help keep pre-igntion away with your iron heads and the fact (I'm assuming) that you don't use the car during the winter and don't need your heater to be that hot. The reason they upped the degrees on t-stats in later cars is indeed for emissions. You worried about emissions, John? Didn't think so. Plus, you're running a big iron head big block. Not some puny little aluminum 4 or 6 banger that is ok to go with a 195.
No worries I assumed it wasn’t towards me, but I thought I should do my part as well by adding that info. Thank you for the help once again, I’m still mentally teetering between the two, but 160 seems to make sense and is winning.
Fortunately for me, eyesight and hearing are fine, might be slower reflexes but 99.9% of safe driving is experience.
