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  #51  
Old 08-11-2017
todd reid todd reid is offline
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Default What's the most power you've been able to achive

Kelly,
The guy you runs Team Blitz (Norm?) once told me that (in his opinion) raising the compression was the single most important thing to do to increase the performance of the 2.8 V6. Of course he was also more than willing to sell hot cams, 4 bbl carbs & Offy intakes as well!

How high did you raise your compression? I would love to see the data on your engine after the change to quantify what you have gained.

Thanks in advance!

TR
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  #52  
Old 08-11-2017
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kmathis kmathis is offline
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JE Pistons. I had custom pistons made that took up all of the deck clearance, my deck clearance is zero...and probably about 10.5 compression. Not sure I recommend this route...however. One of the things that Jose had recommended to me was to shave the heads .030 and that is probably the route I would recommend. I did that with my first engine and that engine was perfect...but my throttle stuck when racing a guy and without thinking about the consequence I pushed in the clutch and blew my motor. My second build I did the custom pistons and such...the motor is not quite as friendly around town as I like, it is more for the track. If I build another one, I will stick with the stock pistons and probably shave the heads. Having that porting and polishing done is absolutely necessary as well. all of the power in these little motors are in the heads. I will get on the Dyno soon and let you know the data.
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  #53  
Old 08-12-2017
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DanR DanR is offline
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Kelly, Great to hear of how you built your engines and any changes you did and/or will make.

Mine too was by jose's recommendations pretty much, 8:5, p& p (not to the extreme) & his grind on the cam and of course my Straight back headers.

It is not a good driver around town either, as you say Quote: "...the motor is not quite as friendly around town as I like, it is more for the track."Unquote

It will pull through all gears very quick. It just doesn't like a low idle !
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'67 SV Commodore Blue 2.8 V6/T5/Heat &Air
'67 SV BRG 2.8 V6 T5/H&A & EPS
Convert your Alpine utilizing my Special Designed Components including Straightback Headers similar to the Tiger system. Optional Electric Power Steering (EPS) available.

GOTO: http://danr.mhartman.net/
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  #54  
Old 08-12-2017
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kmathis kmathis is offline
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Actually, the first engine that I did to Jose's specs was perfect, and it idled really good, as well. it was wonderful to drive till I blew it up. The second one I went my own way with and am not quite as happy as I was with the first one. I have another block and I may build another one, but this time I will hold to the tried and true. I may change my mind once I get this one on the Dyno...stay tuned.
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'67 SV B 3950008716 LRX
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Don't let your throttle stick!
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  #55  
Old 08-12-2017
Bill Blue Bill Blue is offline
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Kelly, did you make any other changes in the build? It does not seem logical that decking the pistons instead of milling the heads would make that much difference in performance characteristics.

I would think the changes your describing would result from changes in cam, timing or carburetion.

Bill
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  #56  
Old 08-12-2017
260Alpine 260Alpine is online now
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Zero decking benefits by maximizing quench and helping to prevent detonation. Piston same height as block. It allows more timing too. Usually you can get by with more compression also. Say 10.5 instead of 9.5.
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  #57  
Old 08-12-2017
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I didn't make any other changes, the cam was the same, same carb. However as 260Alpine says, because of the increased compression I get way more timing...I am running a lot of timing (25 BTDC static) with no detonation. It comes on real strong after 3K rpm. it hauls a$$.

I kept moving the timing up until the smoothed out and the vacuum was the highest. That's where it likes to run. No overheating, no detonation, no dieseling when I shut it off...so I guess it's good.

The deck clearance was .090 plus .040 for the gasket, I made the compression height of the piston .090 higher. And I mis-spoke earlier; on my first engine I milled the block .030 instead of the heads because of the bigger increase in compression due the piston area versus the relatively small area of the combustion chamber. On the second motor I did the higher pistons instead.

Got it on the road today.
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File Type: jpg On the road.JPG (33.4 KB, 31 views)
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Kelly Mathis
'67 SV B 3950008716 LRX
V6 Conversion done, and what a ride.
Don't let your throttle stick!
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  #58  
Old 08-12-2017
Bill Blue Bill Blue is offline
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Kelly, I think your problem is somewhere in the timing. Way too much advance down low and the engine finally catches up with the timing at about 3000. You may even have too much advance on top. Just because it is not pinging does not mean the spark is not over advanced. If you remove about ten degrees of static timing, what effect does it have on performance across the entire rpm range? Do you know what your advance curve looks like?

Bill
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  #59  
Old 08-13-2017
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Kelly has his car back on the road? Going back south in September.
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  #60  
Old 08-13-2017
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kmathis kmathis is offline
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Quote:
Originally Posted by Bill Blue View Post
Kelly, I think your problem is somewhere in the timing. Way too much advance down low and the engine finally catches up with the timing at about 3000. You may even have too much advance on top. Just because it is not pinging does not mean the spark is not over advanced. If you remove about ten degrees of static timing, what effect does it have on performance across the entire rpm range? Do you know what your advance curve looks like?

Bill
I have forgotten some of this, as it has been awhile since I have looked at it, but I think I have 36 degrees total...maybe a degree or two higher. It won't idle at all with any consistency with lower timing. It took me a bit to figure it out, but once I hooked up a vacuum gauge and started to advance further
my idle smoothed out...the power band is between 3K - 7K rpms. It really pulls hard after 3500 RPMs.

Hey, Nick: By September I will have my exhaust redone, and my front end aligned, then I will be ready to give you a ride around town...We can head through the canyon.
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'67 SV B 3950008716 LRX
V6 Conversion done, and what a ride.
Don't let your throttle stick!
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