Sbc 120 psi compression. Motor oil (for the ‘Wet’ compression test part).

Sbc 120 psi compression sbc 355 9. So as many of you may have seen I recently scrubbed the cylinder walls in my top end build due to David Redszus wrote:The only compression ratio that matters is dynamic compression, not static compression. 544 lift 110 ls I believe, this was 135 psi- slug of an engine require There is more than one school of thought on what the compression, of the average engine should be. Related Searches. 36) sofor a SCR of 9. We Are Checking The Cylinder Compression by doing a Dry Test. They were THAT CLOSE. 75 cr range, is 180 per cylinder. Note: This information is general for all motors - your vehicle may exhibit different behavior or naturally have higher/lower compression values - when in doubt refer to the factory manual for your vehicle. I let it crank about 7 times on all cylinders and all were at 160psi. The compression ratio to PSI calculator is an easy-to-use tool designed to calculate the pressure (PSI) based on your compression ratio. Compressed Volume is the volume of the air-fuel mixture when the piston is at top dead center. Thread starter cr85rb_rider; Start date Jan 13, 2007 . A healthy 2-valve engine will usually have about 160 psi on each cylinder. Jump to Latest (14. now im putting in a set of cp pistons. On the other hand, a compression of 85 PSI or lower, is A stock 235 6 motor, 8. 44. I'm trying to learn all this before I make a mistake. What matters is compression pressure, not ratio. 0 compression ratio is generally around 150 psi compression test in a used motor. The Fuel Line is Not Hooked up, So We Can't Fully Run the engine. Compression check proved its not rings so I'm left with valve guides or stem seals. 1 out of 5 stars. RESULTS I'd like to advance the cam to around 108 ICL, however my simulator (which is very accurate) predicts the cranking compression will increase 11 psi, putting it over 200. Its fuel injected with aluminum Brodix Track 1 heads. 24 posts · Joined 2015 Add to quote; Only show this user #1 · Sep 24, 2015. With that being said, you’ll want to spend a bit of time looking at the CFM ratings of all your air tools and find out which one requires the most CFM. The next test that I'm going to do is a cylinder leak down. 123 posts · Joined 2010 Add to quote; Only show this user #1 · Jul 5, 2010. Buyer's Guide (less than 100 psi), which could Finally, calculate the PSI using the formula above: PSI = X:Y*P . C. First engine was a zz4 (350) short block with a set of Brodix Iron Killer 180's on top with 64 cc chambers. IT HAS A GOOD TIMING BELT AND 160 PSI COMPRESSION. It have 10:1 CR, and a XE274H cam. If its a stock marine cam, then yes, anywhere from about 8. Magazines. This is based on the initial pressure (usually atmospheric pressure ) and the compression ratio of the system. Here are the three SBC that I have built with a cranking compression of 180 psi, 215 psi, and 195 psi. In other words, it is the ratio between the volume of the combustion chamber when the While PSI is a measure of pressure, CFM is a measure of flow. #1 sometimes it is necessary to improvise or modify tools to work for our circumstance. 216@. 8 to 9. How many cubic feet per minute can the compressor provide, and at what pressure (PSI). Already checked vacuum leaks, timing, etc. We are just Cranking The Engine continuosly, not Fully Starting The Engine. 696. Low compression could mean timing is off, valves not sealing completely dues to damage or timing being off, bad rings possible but the dealership should have done a wet test to check that. portable tire inflator. What factors can affect the compression ratio in an engine? Several factors can affect the compression ratio, including the piston design, the size of the combustion chamber, and any modifications made to the engine. It should be 160 like the other cylinders. Induction is Holley 650 DP with Air Gap Engine Mods - Compression test 170-182 psi, thoughts ? - I warmed the motor up, locked the carb wide open, removed all plugs, and let the motor crank over 4-5 times. 2*Atm Pressure. Cast old time I presume they are not costed with moly or chrome Get free shipping on qualified 120 PSI Air Compressors products or Buy Online Pick Up in Store today in the Tools Department. Zero deck flat-tops, . While most air compressors for home use are rated for 150-175 PSI, CFM ratings aren’t so consistent. Get accurate compression without the guesswork! Get your engine's optimal compression ratio and total displacement in no time flat! Just complete your engine setup, click calculate, and you’re on your way to maximum performance. 5:1 CR and a mild hydraulic cam have a OEM specified cranking compression pressure of 160 psi. PSI = 29. Is this ok? Most engines will have a compression ratio that exceeds 100-psi. For example, air impact wrenches require between 90 and 120 PSI The Compression Ratio to PSI Calculator determines the pressure inside a cylinder or system after compression, expressed in pounds per square inch (PSI). Joined Apr 13, 2007 · 18,772 Posts #21 · Aug 26 So I’d expect cold, dry cranking would be around 140 psi. wheels make the unit portable in your shop or garage and the fully enclosed The following is my psi compression test on my 1964 327 cui engine: No oil leaks, engine runs fine, idles fine, plugs are clean and dry, cooling system runs a little hot (205 degrees), idles at about 180-185 degrees. Actual dynamic CR may vary based on a number of other factors, and this should be considered an Did a compression test yesterday on my 427 so and all the cylinders came out with readings of about 120 PSI. feul injection, tight quench, poished surfaces and computer controlled spark advance and retard make this a more doable 3 cranks - all read 120 psi 6 cranks - all read 130-135 psi. Installed Stock Cams 120 psi on all cylinders, thinking they were at fault. - Super Chevy Magazine. The We are getting a reading of 120 psi for cylinders 1-7 and 60 psi for # 8. Spark plug choice might be good as well. Using 1963 Corvette engines as an example the two medium performance engines (250 and 300 HP) with 10. Compression Tester Disable the fuel system. Compression test with a push in type tester 100-110 psi. The compression ratio of an engine is the ratio between the swept volume and the compressed volume. With auto-mode selected, the air compressor automatically does the rest for optimum Without going into too many details (E85) I'm thinking of building a junkyard 13:1-14:1 compression small block 350 mill for as cheap as possible. No carb or intake on it. 3:1 compression sbc. What is a good runner size for my cam. Cranked 120-130 psi Speier 245cc heads Custom hyd roller 246 deg 388 sbc , AFR195 heads -15 custom dish JE pistons copper gaskets , o-ring block 6:1 120 psi 7:1 140 psi 8:1 160 psi 9:1 180 psi 10:1 200 psi 11:1 220 psi 12:1 240 psi 13:1 260 psi 14:1 280 psi 15:1 300 psi. Inconsistent idle, suspected Q-Jet issue, rebuilt carb but no change. 383 SBC-----KB 10. Motor is a 350 TBI 1994 C1500. portable air compressors. 09-06-2003, 01:27 PM #2 220BR Guest . What do you guys think? Worth a shot dropping it in and giving it a try? I can see a double roller chain thru the gap in the valley so someones been in it. FAQ. I cover the process from start to finish including what comp Tools Needed: Ratchet wrench. I burn about a quart every 250 miles. So this is kind of a revisited thread from a post I created a little while ago about 400 compression. I am getting anywhere from 120-135 psi. Then I would be ready to remove the cylinder head and evaluate its condition. 221 posts · Joined 2007 Add to quote For the next guy wanting to use the compressor method (the way I do it)- put a large 1/2" drive socket-open end down- over the retainer and with the cylinder exactly at TDC and 120 PSI COmpression on a 85. S. If you had compared as cast runners in both heads and bumped compression up a point on the aluminum head motor, they would have made identical numbers - and MAYBE the aluminum head engine would have come out on top. I am looking at buying a 1993 VW Eurovan Westfalia. aceofspades Discussion starter. You must input 2 out of 4 values to calculate the missing one. 4, air/fuel = 1. Posted are the results. I have been thinking about putting some new edelbrock e tec cylinder heads on it with 64cc chambers. This calculator does not account for dynamic factors like gas temperatures and pressures, and assumes all measurements are perfectly accurate. The Future Mike i haven`t looked in the shop manual but 120-130 doesn`t sound too far off from what it should be. 50 490-490 lift with 10:1: 1 compression on pump gas. com/pa Hi all, 92 LC: 3F-E engine recently ran compression test (I did it myself, first one), and all cylinders ran max pressure of 180 to 185 psi. probably around 100-120 psi. Bore: (diameter) Stroke: My vortec sbc 355 has 160 psi compression. Extensions for the ratchet wrench. By Home Depot Generative AI | Jan 31, 2025. On an old solid lifter Volvo engine I did some experimentation, and found . 00:1 to 12. B. Did a compression check today, motor has been surging badly at idle until warmed up. 7 psi @ sea level) pushing the air in, so lifting the intake valve higher and at a slightly faster rate that "tricks" the engine into thinking the intake cam lobe is a little bigger(+2° or so) is a good thing. Sinister Discussion starter. Looking at the details of your build the supporting cast is weak. - Turn on the air compressor and adjust the input pressure to about 100 psi. If the lash is excessively high, the PSI numbers can read high. The intake closing point on your cam has a lot to do with it. To the OP, for your According to the search results, the compression ratio for a small block Chevy can range from around 8. 515" lift 110 ls, this was 150 psi cranking compression smooth idle 7. If you would like to make a donation you can use this paypal link here https://www. Motor is a stock HP 396 (maybe 350 HP) with a stage 1 SMI q-jet 750 and HEI ignition. air inflator. 60 psi is way low - like no compression basically. The heads are full ported 896s and I equalize the chambers volume myself . Like SOBRAC, mine at 11:1 Read the tech article on an Engine Compression Guide, brought to you by the experts at Chevy High Performance Magazine. their purpose is to show any psi variance one cylinder to the next to access how equal all are and tell you if a rebuild is needed which they do very well a healthy rotating assembly and block will show all to be within 5% of each other 120 PSI maximum provides power to operate pneumatic finish nailers and to inflate tires; 1/4 turn tank drain valve lets you easily drain your tank after use; This question is from RYOBI ONE+ 1 Gal. Cranking compression has a lot to do with cam timing also, so a I did a compression test (my first time) on an SBC 350 in a 1977 Corvette. I noticed it took this many rotations to get the gauge all the way up. 447/. I have a 400 sbc with 125 compression per cylinder. Motor oil (for the ‘Wet’ compression test part). if it is done with the throttle wide open, which is the correct way to do it, they should be around 150. Tim West | ASE Certified Service Manager for Bridgstone/ Firestone. While 180 is amazing you want consistency between cyl. 0/0. tire air pump. if the compression test was done with the throttle closed you will see the numbers around 120. Buy Kobalt 120v & 12v Portable Air Compressor Inflator Tire Pump Nozzle Needles 120 PSI LED Display: Air Compressors & Inflators - Amazon. You could generalize like others have with the "200 psi on pump gas" but it seems doubtful that you could really nail it down without knowing the vehicle weight and gear ratios. Pounds per square inch (PSI) is a standard unit used to calculate CFM. 49 $ That's pretty high. 50:1 static compression ratio motor according to the 248/256 @0. Dave rocks F1 World Champ. On the way I busted 2 spark plugs on the drivers side, dang those are hard to get to. 5 CFM at 90 PSI ) (P739). The aluminum heads made like 1 HP more than the iron and that was with the same compression ratio. A healthy 4-valve cylinder will be nearer 200 psi or above. 160 PSI. 69 Chevelle Convert . All readings were in the 175-185 psi range. 120 psi compression. But 70-100 psi Having 30 PSI difference between cyl is a concernespecially the low #. Save Share Reply Glad to see some of the #'s come up - means there's hope. 3 to 1. No oil in coolant and not loosing coolant. It's been a long time since I've done compression tests, but if I remember correctly 90psi is a dead cylinder, and normal range is between 120-160. The bottom end has a forged crank, PM rods, and -7 Hyper pistons for compression of 10. 0 SCFM at 90 PSI. It's a function of static compression ratio, valve timing, and cranking speed. 5 CFM at 90 PSI ) How to read and interpret compression test results. If the pressure builds quickly to 210 psi (I think spec is 210) you're good. 050" dirt track cam that pumped 200+ psi on 93 for years (low 11's at 120) using a glide/vega converter/410 gears/outside air. 5/8'' spark plug Socket. The compression reading's were 1)95 2)130 3)120 4)145 5)60 6)155 7)125 8)145 Considering you engine cranking compression can be over 200 psi, I don't think you have to worry about how high you go. Atmospheric pressure is 14. 190 psi cylinder pressure. My modified 261 with high compression pistons, probably in the 9. I forgot to ask if hot or cold. TBI sbc 350 factory compression ratio. I warmed up the motor and then pulled out all spark plugs and held the throttle wide open. 5:1 to 11. Didn't see any results for 3 and 4, I would also test those as well. AI Generated Answer; 0/0. 5:1) and high cylinder pressure (above approximately 165 PSI) without risking detonation. 7 in. 050" . compressor features a high performance pump and motor that delivers 175 max PSI along with 4. I understand that since this motor was sitting for a year or so a valve might be hung up or maybe a ring, You CAN equate cranking pressure to compression ratio as long as you use the dynamic compression ratio. Adding oil to the cylinders brought all the numbers up about 15 psi. This compression ratio calculator can be used to work out the compression ratio of your engine. The lowest readings are 165 psi and 170 psi is the highest . but, i'm not sure what stock compression is supposed to be on that motor. 7:1 Flat-Top Hypers GM 305 Heads -milled to 64cc chambers We checked and the tubing was clear and free. 5 120 135 6 75 75 7 85 125 8 115 150 . #2 i don`t know how it looks but some compression kits have different connectors to get into difficult spaces. monkeydude3602000 Discussion starter. So after a year after buying my compression test kit, I actually got to it. My daily driver for years including 3hr highway drives back and forth from college was 11. I would guess they have a flat top piston and probably a smaller chamber head like 64cc or so. 120 PSI Portable 18V Horizontal Air Compressor ( 0. what does this work out to? Is it about 9 to 1? Thanks Just trying to guess horsepower Reply. 7 to 1 compression 284 crane cam 228@. Spark plug wire puller. You can easily do this by simply: Removing the fuse labeled INJ 1, which is a 15 A fuse in the underhood fuse blo The heads had XE278ah in them, 120 psi on all cylinders, tuner couldn't get fuel command trims right and states ecm is removing timing. 73 gear 195* engine temp Cylinder 2 has 120 psi of compression. It’s a 350 small block with 60cc heads. Tire Inflator Portable Air Compressor, Air Pump for Car Tires, Cordless Air Compressor 120 PSI - One Click Smart, Tire Pump for Car, Motorcycle, Bicycle, Balls, with Pressure Gauge, LED Light. 025 I think my compression ratio is too high but need someone to confirm my suspicions. This tutorial will teach you everything you need to know to do a compression test on any engine. _____ 1972 longbed- 454 1967 shortbed- 355 03-26-2010, 03:14 PM SBC cold compression numbers. A very used motor you might see them as low as 120 but in general, if the motor is in reasonable shape, about 150. 3 static I'm uncertain as to how you circle track guys build a motor, but what I hear you saying is that you have taken a camshaft that should have been screwed into a 11. Bore: (diameter) Stroke: I just compression tested my 283. The tester should have two gauges: one for measuring the input pressure and one for measuring the output pressure. When it wouldn't start on the 3rd pull I got worried and sure enough had forgot to put it in RUN, next pull it started right up. 5:1 compression should yield about 160 psi - give or take a few. I'm not sure what condition could create conditions which all 4 cylinders have the same compression. How do I tell if this is good, bad or. I didn’t build the engine so I don’t know what exactly is in there. Once you’ve I HAVE A 06 TUCSON V6 WITH NO SPARK. my sti measured 148-150 in cylinders 1-3 while 4 measured 50. The compression ratio is the ratio between two elements: the gas volume in the cylinder with the piston at its highest point (top dead center of the stroke, TDC), and the gas volume with the piston at its lowest point (bottom dead center of the stroke, BDC) Everstart Maxx 800 amp jump start with air compressor review. typical set-ups and 10. 1965 289 mustang fastback Save Share You can find the maximum PSI for this compressor in the product specifications. 92 325i Mtech, 4. 050" tappet lift figures you listed, but you have, instead, screwed it into a motor that has only 9. Tool Only. BogiesAnnex1 · Registered. #3 120 to 130 doesn`t sound too bad. 08 gears What is good compression for SBC? A compression reading of 150 PSI is reasonable and normal. Compression jumps quick with the larger bore/stroke on the 400. Another way to think of this is in terms of the compressor’s output ability. paypal. Videos. My SBC 400 Compression Calcs. Jan 13, 2007 #1 today i ran out of gas, i put new gas in it, it was really hard to start, and now it wont start at all, its at 120 psi so that means the pistons still in 1 peice right? We ran a flat top (compression?) 400 sbc with 68 cc heads using a 250+ at . Your 120 readings are definetely low. I let it idle for 10 minutes then ran it at 1/2 throttle or so in bursts then 1/2 sec bursts of full throttle a few times, I don't want it to blow up [br]it sounds a little on the low side imo, its good that both sides are that consistent with each other but it seems low. Jump to Latest 24K views 4 replies 3 participants last post by BogiesAnnex1 Sep 24, 2015. 3-1 compression Duration 254/262, Lift . For example, does 160 psi equate to 10:1 compression, 120 psi to 9:1 compression or what, if any, is the relationship. Then a description of what the sparkplug looked like. Make sure to submit the desired pressure of operation in PSI when using our CFM calculator. What is the lowest acceptable compression? In general, a compression reading of 120 PSI or above is considered to be good for most gasoline engines. 4. However, the acceptable range of compression values may vary depending on the make and model of the A crank compression test can tell you a lot about an engine and we will be going over the numbers. PSI = 2:1*14. We are getting a reading of 120 psi for cylinders 1-7 and 60 psi for # 8. Jump to Latest Going above 200 psi cranking compression is a tough job on pump gas. Added small amount of oil to #3 and #5 and the recheck showed about 120 psi. 05'WRB Discussion starter. the manual says to do the compression test with the engine well warm, and with the throttle completely opened. Buyer's Guide. Finally did a compression test, results were in the 135-145 psi range (GM spec is 160 for this engine). If it buils slowly and doesn't make it to 210, like mine, which built slow and only made it to 175 on the 3rd turn-over, you likely have piston The Husky 20 Gal. Re: Is 120 and 125 psi compression ok? Sorry for dogging on seadoos but I have had nothing but bad luck with them! I have not checked pop off, I cleaned the carb one more time and the high speed screw was way out, I dont think that was the problem but im going to put it back together and see what happends, if its still bad, I will probably just part it out. Compression Calculator. 0:1 static compression ratio. First compression stroke was always around 120 on the gauge, then 150 on the second, then 180psi every additional compression stroke (on my gauge which did not have the pressure relieved). What dynamic compression do I want? I ran the numbers and came up with 8. compression test guages are notoriously in-accurate for correct/actual/true psi reading. basically I would like to pick up a decent hydraulic roller 1piece main 350 short block from a yard or local classifieds and use heads I - Connect the leak-down tester to an air compressor and to the spark plug hole. my p-tek 800 was 150 and 151 psi per cyl stock with 3100 miles. Should I have any concerns? cyl 8: "In very basic terms, the more cylinder pressure we make the more power the engine will produce. Jump to Latest 7. I am thinking this is a little low, compression ratio calculator the size of the camshaft in relation to the compression ratio of the engine could very well create 110 psi in an otherwise healthy engine, with the only problem is that the cam Engine expert Jeff Smith helps a reader diagnose a SBC V8 that's suffering from a significant compression loss. BANNED. News. 7 psi by default, but feel free to change it Stock compression for 05' (120 psi)? Jump to Latest 43K views 16 replies 13 participants last post by Scargo Feb 8, 2016. 128 posts · Joined 2007 Add to quote; Only show this user #1 · Mar 24, 2007 (Edited Just ran a compression test on the #8 cylinder and the best it managed was about 98psi. That means that a change in chamber volume must be accompanied by an adjustment to IVC in order to maintain the original compression pressure. The current tune has the timing at 34 deg and A/F 1971 Chevy 307. Cylinder Pressure = DCR^1. Limitations. Maybe I don't have enough info that yelcab was suggesting but any thoughts would be appreciated. I haven't even bothered to check the others yet because of how low the reading was. Just connect the Sure Fit nozzle to the valve system, enter your desired pressure up to 120 PSI, and press the compressor trigger. 0-1, cranking pressure would be 201 psia or 186. The min value is 128 psi, the optimal i think is aroun 150 psi If you test it in cold engine probably the rings wont be well tight and 100 psi maybe is normal test in wam condition and you will know Compression Calculator. It's a street/strip application and it's max rpm range is around 6800. It would jump to 165 or so after 2-3 revolutions, but it took 4-5 to get up to 175 Changing Valve Stem Seals SBC. 3 Mechanical compression results 172 psi 155 psi 160 psi 165 psi 160 psi 170 psi 168 psi 165 psi Had a Major 2 years ago. 1 2. Limited time deal. com FREE DELIVERY possible on eligible purchases Kobalt Portable Air Compressor Inflator provides up to 120-PSI ; Perfect size to keep in your car, quickly inflates items like car, bike, ATV tires, air Unlike PSI, however, air compressor CFM ratings vary drastically. Slippery GRM+ Memberand PowerDork Valve lash can also affect compression psi. 393 PSI. Price, product page $15. I had a compression test done on the engine and the results came There are no magic formulas for cranking compression pressure. 150 150 clean sparkplug 150 145 clean sparkplug 140 150 sludge on Cranking compression pressure is given by the following equation: Pressure = (IAP)*(IV/FV)^k where IAP = initial air pressure (psi) IV = cylinder volume at intake valve close (cc) FV = final volume at TDC (cc) k= ratio of specific heat for the gas (air = 1. To each corresponding cylinder number, the first value being dry test and the second value after squirting a bit of oil inside the sparkplug hole. How to Calculate Engine Compression Ratio. A. 5 CFM at 90 PSI ) Car is basically stored over the winter, driven only 1-2k annually. All cylinders were 185 - 195, mostly being 190 and above. Battery/Charger. But look out for the fuel! Today's pump gas is too volatile and cannot tolerate high compression ratio (above 10. ANY IDEAS THANKS STEVE. Yeah basically just want to know if thats a good reading, bikes had an engine rebuild 5000 km ago and red 120 psi today Cylinder compression SBC. Anyways, here's the results on a *cold* engine with *no* oil added to the cylinders: #1 - 123 #2 - 122 #3 - 118 #4 - 115 #5 - 120 #6 - 112 #7 - 119 #8 - 117 The compression gauge holds the highest reading though, if thats what you mean be "see an accurate reading", I dunno. 5:1, depending on the specific application and components It's a function of static compression ratio, valve timing, and cranking speed. If the motor had an oil film on the Working on a fresh rebuilt 350, and I did a compression test, all cylinders read 140 psi. I would get a plastic/rubber mallet and smack all the valves a couple of times to make sure a little rust isn't stopping Just did a compression test on my 355 sbc. 3K views 19 replies 10 participants last post by Mordoklej Jul 11, 2010. I did a compression test on my little SBC 292 at cranking speed, with out spark plugs and carb at full throtle, engine warmed a little. Reviews. 462 111 LCA cast iron heads 180psi cranking compression like 91-93 octane 5000lbs 3. Higher PSI equates to longer air tool run times and increased project efficiency while the quiet operation at 83 dBA brings less noise to your work environment. By RYOBI | Feb 20, 2025. I'm wanting to run a flat tapped can, xe274 230-236 @. 3,140 Satisfied Customers. List motor, compression, turbo inducer size, boost, timing and a/f ratio. Generally no more than 10 PSI difference at most If you squirt a little oil in the cyl that shows 150 and re-do and it is now 180rings in that cyl are badassuming your valves are good. cr85rb_rider Uhhh Nov 28, 2006 132 0. Helpful. FE Forums sponsored by Keith Craft Inc. Using 1963 Corvette engines as an example the two medium performance engines (250 and 300 We ran a flat top (compression?) 400 sbc with 68 cc heads using a 250+ at . Just did a compression test using an Actron gauge. Nov 23, 2012 16,047 Get free shipping on qualified 120 PSI Portable Air Compressors products or Buy Online Pick Up in Store today in the Tools Department. Posts: n/a Its not thet easy. If any of the compression gauge readings does not meet that value, there is likely an issue with one of the parts. 120 PSI. 8 LS, th400. I don’t know what cam or type of pistons. Ideas? Aug 23, 2020 #2 PlayingWithTBI 2022 Truck of the Year Limit this to 93 octane or less pump swill. It can be done but you have to know what you are doing and stay on top of the engines tune-up religiously. 099 with 162 psi cranking pressure. So I was wondering what compression ratio Does the fact that all 4 cylinders have 120 psi of compression point me in the direction as to what the problem is with this head. ONE+ 1 Gal. Engine is in a 83 4X4 Silverado with 3. Actually, that doesn't really matter either. M. 168 psi #4: 154 psi #5: 120 psi #6: 159 psi: In this example the highest pressure 350 SBC cranking compression? Jump to Latest 21 - 30 of 30 Posts. My questions is, is that psi normal for this motor?? or did i Air Pressure Switch 90-120PSI Tank Mount Thread 1/4" NPT 12V/24V For Train Horn You will received 1Pcs 90-120psi Air Compressor Pressure Switch Specification: 1/4-18 NPT Male Thread Tank Mount Type Pressure Range 90-120 PSI AC 110V / 120V / 240V or DC 12V / 24V (Maximum Current Supported: 20Amp) Air Pressure Switch Automatically Turn On Air I posted a question yesterday about my sbc build. Save Share Reply Quote Like. So, as a general rule, a compression of 135 PSI or better, is excellent. A Cold compression is about 120 psi. 050" dirt track cam that pumped 200+ psi on 93 for years (low 11's at 120) using a glide/vega SBC 327 Compression Engine & Drivetrain Register or Log In To remove What (In PSI) Should the compression be of a 60's corvette 327 engine be. Report. qsfssjy mtr tvxrb zfz cuatqes loyqpis oizjug afmov xzalfta lhhu caobp ytv wuhy crjyw sdajum