lars49 Larry Barnes Colorado Springs (177 posts) Registered: 06/11/2009 02:12PM Main British Car: 1980 MGB GM LA1 3400 V6 |
Valve to Piston Clearance
Does anyone know offhand what the valve to piston clearance is on a '02 GM 3400 V6 engine? I am considering milling the heads to increase the CR.
I could do it with clay but I was hoping that I could find a quick answer instead of trying to track down where to buy modeling clay locally. Cross posted to MGE |
MGBV8 Carl Floyd Kingsport, TN (4514 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: Valve to Piston Clearance
Larry,
Spend some more time mulling this over. There are other places to get more bang for your buck. Your engine is already rated at 9:1. This is an all iron engine. It's not going to tolerate as much compression as an all aluminum engine. A wee bit more compression is not going to do much, especially for the money & effort involved. If ya really want to wake up this engine, swap over the late aluminum heads & intake from a FWD engine. This requires a piston change, though. Add a bigger cam, too. ;) |
Moderator Curtis Jacobson Portland Oregon (4577 posts) Registered: 10/12/2007 02:16AM Main British Car: 71 MGBGT, Buick 215 |
Re: Valve to Piston Clearance
If you're swapping heads and/or doing a valve job anyhow, milling heads is actually pretty cheap. But how much bang do you get? Bruce Bowling (of the "Bowling and Grippo" who originated MegaSquirt") has a handy little online calculator for estimating the horsepower benefit of boosting compression ratio. It's an extremely simplified estimator, but it'll give you a ballpark figure. Link: [www.bgsoflex.com]
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MGBV8 Carl Floyd Kingsport, TN (4514 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: Valve to Piston Clearance
Bowling's Compression Ratio -> HP Calculator
Computation Results: Engine Horsepower (peak) is 160 Old Compression Ratio is 9.0 New Compression Ratio is 10.0 Computation Results: Computed New Engine HP is 165, a 3 percent change |
lars49 Larry Barnes Colorado Springs (177 posts) Registered: 06/11/2009 02:12PM Main British Car: 1980 MGB GM LA1 3400 V6 |
Re: Valve to Piston Clearance
It is an aluminum head engine with a current CR of 9.6:1 But looking a the numbers and after talking with my machinist, I've come to the conclusion it is not worth it. New pistons would do it but I am not willing to fork out another $1K on parts and $600 to balance the engine. .I'm hoping that a 25% increase on the input flow volume will do something worthwhile.
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MGBV8 Carl Floyd Kingsport, TN (4514 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: Valve to Piston Clearance
Is this a FWD engine?
Bowling's Compression Ratio -> HP Calculator Computation Results: Engine Horsepower (peak) is 185 Old Compression Ratio is 9.5 New Compression Ratio is 11.0 Computation Results: Computed New Engine HP is 192, a 4 percent change Edited 1 time(s). Last edit at 06/29/2013 10:50PM by MGBV8. |
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Valve to Piston Clearance
Also increases gas mileage.
Jim |