raypratojr Posted March 2, 2012 Author Share Posted March 2, 2012 The flat top pistons i was looking at will increase compression to 11.2:1. Is this too high for 93-94 oct pump gas. I dont want to run race fuel. If i had to mix 1 gal of race fuel for every five of regular, i could do that. I dont want to pay for race gas though. Ray Quote Link to comment Share on other sites More sharing options...
Mystic_Cobra Posted March 2, 2012 Share Posted March 2, 2012 I'm not an expert but I'm running flat top pistons on 93 octane pump gas with a safe tune. I think my CR is about a half point above stock. Quote Link to comment Share on other sites More sharing options...
99cobra2881 Posted March 2, 2012 Share Posted March 2, 2012 Im at 11:1 with domed pistons and run 91 octane. I wish I could get 93-94 octane like they do back east. A few years ago I pulled into a Sunoco station in Kentucky and couldnt beleive it when I saw 93 at the pump. Then taking into account that the cheap ass that just got gas in front of me bought 87 octane and the hose is still full of 87 octane when I start to fill my fuel jugs with 91, Im probably not even at 91 octane closer to 90 if I had to guess. Having a jug of race gas doesnt seem like a bad idea. 5 gallons of race gas to add to pump gas would last through a typical race weekend and then some. Quote Link to comment Share on other sites More sharing options...
raypratojr Posted March 3, 2012 Author Share Posted March 3, 2012 The other concern I have is the Melling oil pump I switched to last year. The pump is listed as a high volume and if i remember right, i bought it because it had forged gears. My concern is with the high volume aspect. These motors don't have good oil return but im running 9-1/2 qts. Its impossible to evacuate 9-1/2 qts out of the pan. Should i just install a set of forged gears in the stock pump or continue to use the Melling high volume? I'm probably going to at least take the pump apart to see if something let go. From what I hear, no one has heard of a mod motor spinning a main bearing. I guess i should pull the cams and look for hints of lubrication issues. Jimmy, 365hp, is that with the stock displacement? Thats a crap load of power with a stock reciprocating assy. Did you port the heads? Im getting excited to get this car back on track. I need a reliable season under my belt. This will be my 3rd year racing. Last year i missid 4 races due to mechanical failures. Ray Quote Link to comment Share on other sites More sharing options...
Mystic_Cobra Posted March 3, 2012 Share Posted March 3, 2012 The other concern I have is the Melling oil pump I switched to last year. The pump is listed as a high volume and if i remember right, i bought it because it had forged gears. My concern is with the high volume aspect. These motors don't have good oil return but im running 9-1/2 qts. Its impossible to evacuate 9-1/2 qts out of the pan. Should i just install a set of forged gears in the stock pump or continue to use the Melling high volume? I'm probably going to at least take the pump apart to see if something let go. From what I hear, no one has heard of a mod motor spinning a main bearing. I guess i should pull the cams and look for hints of lubrication issues. Jimmy, 365hp, is that with the stock displacement? Thats a crap load of power with a stock reciprocating assy. Did you port the heads? Im getting excited to get this car back on track. I need a reliable season under my belt. This will be my 3rd year racing. Last year i missid 4 races due to mechanical failures. Ray Every time I hear or read about people using high volume oil pumps, they are telling someone NOT to use them. I am using a stock casting with upgraded gears. That is what was recommended by both of my builders. You can modify the pump to increase pressure but I don't think you need increased volume. Stock displacement + .020 on the pistons. Heads have been cleaned up but no real porting. Quote Link to comment Share on other sites More sharing options...
99cobra2881 Posted March 3, 2012 Share Posted March 3, 2012 (edited) Which Melling billet oil pump did you buy? The 10227 or the 10176? I have the 10227 high volume/ std pressure pump. The 10176 is hi vol/hi press. Is that the one you have? I dont know how much more pressure I would want to run on an engine. With 5w30 synthetic the car is already at about 100 psi on cold start up. 25-30 psi hot idle then 70-80psi at rpm. **Edit** I had to go back and do some research on the oil pumps but even the stock DOHC oil pump is considered high volume. http://www.americanmuscle.com/ford-racing-oil-pump.html The stock DOHC pump is an upgrade for the SOHC engines as far as flow is concerned. If I remember right the DOHC oil pumps impeller is 2mm wider than the SOHC oil pump. The DOHC oil pickup has to be used with the DOHC pump. Edited March 3, 2012 by Guest Quote Link to comment Share on other sites More sharing options...
AJ Hartman Posted March 3, 2012 Share Posted March 3, 2012 Where can these oil pump gears be found and what brand would you recommend? Quote Link to comment Share on other sites More sharing options...
Mystic_Cobra Posted March 3, 2012 Share Posted March 3, 2012 There are several companies that make billet oil pump gears for the modular engines. I've never heard bad things about any of the billet gears. I think they go for around $300. Ask google. NO Modular RACE engine should EVER run without them. I would never rebuild any modular engine without them. I've learned a lot recently about the cast parts used in mod motors that are fine for the street but should not be used in a race engine. Speaking of which, I need to get back to mine. Quote Link to comment Share on other sites More sharing options...
raypratojr Posted March 3, 2012 Author Share Posted March 3, 2012 Cast parts scare me. I watched a video of a 96 cobra seizing the motor while going around LRP. Apparently the oil pump gears broke and the cams seized. Thats why i went with the melling pump. And thats exactly why im putting forged pistons in the motor. I think im going to spring for a set of forged rods too. 7k rpm is scary with cast crap. Ray Quote Link to comment Share on other sites More sharing options...
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