Combustion Chamber size between heads
Thread Starter
|
Post Fiend
Joined: May 2004
Posts: 5,277
Likes: 0
From: St George, SC I-95
Combustion Chamber size between heads
I need to know the combustion chamber size in D3VE heads and in 88-92 EFI heads. I need both please.
Here is why. I tore into my motor because it was obviously tight somewhere. ( I didnt build it myself ) My first guess was either main bearings or piston rings but tolerances where within norms. I started checking part numbers to make sure everything was correct for my engine and here are my numbers. I have a D1VE Block .0010 off deck, D3VE heads .0010 off, 460 standard crank, D0OE A rods and Sealed Power H535P pistons. The only thing that was out of wack was the pistons. My book says they are for 88-92 efi engines. The only thing I can guess now is that the reason for being tight is that the compression is too high. It took 2 batterys and a battery charger with a high torque starter to crank the motor. Im thinking maybe the efi pistons caused the increase in compression over the stock pistons.
Am I correct in thinking the combustion chamber size will make a difference in compression? Anything else that could cause this? Im at a loss for options. Thanks in advance.
Here is why. I tore into my motor because it was obviously tight somewhere. ( I didnt build it myself ) My first guess was either main bearings or piston rings but tolerances where within norms. I started checking part numbers to make sure everything was correct for my engine and here are my numbers. I have a D1VE Block .0010 off deck, D3VE heads .0010 off, 460 standard crank, D0OE A rods and Sealed Power H535P pistons. The only thing that was out of wack was the pistons. My book says they are for 88-92 efi engines. The only thing I can guess now is that the reason for being tight is that the compression is too high. It took 2 batterys and a battery charger with a high torque starter to crank the motor. Im thinking maybe the efi pistons caused the increase in compression over the stock pistons.
Am I correct in thinking the combustion chamber size will make a difference in compression? Anything else that could cause this? Im at a loss for options. Thanks in advance.
Hotshot
Joined: Dec 2003
Posts: 18,423
Likes: 9
From: iowa
I don't think you are having a compression issue, the comp difference isn't that high. I run 13.5:1 compression on a stroker and have turned it over and started it all last year on a single group 27 battery with a high torque starter so if it's taking that much to turn it over you have a problem somewhere else, granted I went to dual group 31 batteries this year due to some starting problems, but even at my compression ratio it cranks it over very fast. I also race with a guy that is running 12:1 compression using a factory starter and one battery, and has been for years without problems even after rebuilding the motor this year.
I would check your piston to wall clearence for the first place to look thats more common, another issue could be binding springs on the valves (you don't say what cam and how much lift adn whether the springs are appropriate for that cam.) Also did you check the timing this will make them turn over very hard if too advanced.
I would check your piston to wall clearence for the first place to look thats more common, another issue could be binding springs on the valves (you don't say what cam and how much lift adn whether the springs are appropriate for that cam.) Also did you check the timing this will make them turn over very hard if too advanced.
Last edited by monsterbaby; Aug 15, 2006 at 08:29 PM.
Thread Starter
|
Post Fiend
Joined: May 2004
Posts: 5,277
Likes: 0
From: St George, SC I-95
Ive got a real screwed up motor. I bought it from a guy who apparently didnt know what he was doing. I seriously doubt he ever thought about matching valve springs and the cam so that could be my problem right there. Ill check the clearences again to be sure on the pistons.
What is the part number for the correct pistons for this block? 74 LTD Im pretty sure. What is your opinion on Comp Cams 4x4 Cam? Part number 34-239-4 with matching springs #924-16
What is the part number for the correct pistons for this block? 74 LTD Im pretty sure. What is your opinion on Comp Cams 4x4 Cam? Part number 34-239-4 with matching springs #924-16
Last edited by STGFordCrazy04; Aug 15, 2006 at 08:48 PM.
Hotshot
Joined: Dec 2003
Posts: 18,423
Likes: 9
From: iowa
Thats a nice cam, I like it bieng dual pattern should be a little lumpy at idle and most likely going to need a little more stall than stock.
As far as the pistons I recall the only difference is the amount of dish to raise the comp ratio a little. shouldn't be anything wrong with them unless your valves are hitting them.
As far as the pistons I recall the only difference is the amount of dish to raise the comp ratio a little. shouldn't be anything wrong with them unless your valves are hitting them.
Thread Starter
|
Post Fiend
Joined: May 2004
Posts: 5,277
Likes: 0
From: St George, SC I-95
Comp Cams web site recommended them to me and said I didnt need a new converter. Not doubting you just trying to stay on budget. What are the adverse effects of not having a higher rpm converter? Weiland Stelth intake and Holley 750?
Hotshot
Joined: Dec 2003
Posts: 18,423
Likes: 9
From: iowa
better recheck comps web site, I have a comp catalog sitting here and it says to run a 2000rpm stall with that cam. downside to running with a stock TC is you will lose alittle low end torque below 2000 rpm but not real noticable, and it's something you could do later if you decide that you need it after driving it around awhile.
Thread
Thread Starter
Forum
Replies
Last Post
Nathan Plemons
Ford Inline Six, 200, 250, 4.9L / 300
20
Nov 20, 2015 04:29 PM
85lebaront2
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
4
Apr 3, 2015 02:53 PM
SillyValleyF250
1967 - 1972 F-100 & Larger F-Series Trucks
2
Jul 23, 2008 08:04 PM
