LJDB

Ok so i finally got back to driving/tuning the car. The carb is currently set up like this. 60 primaries, 61 secondaries, 6.5pv with wire restriction, 31 squirter, white pump cam and split pins in idle air bleed circuit, silver secondary spring. I've still got a little rich WOT at 11.7, idle is high 13 to 14 and cruise around high 14. Ignition timing is at 30. Im trying to sort a lean bog when i floor it at cruising speed. The gauge drops to around 17/18 when flooring it for a second then quickly makes it way to 11.7 wot. I cable tied the secondaries and the bog is still there but not as bad. I changed out the white pump cam to the green in hole 2 and it made it alot better still with the secondaries closed but still evident. I played with ignition timing but no change, I'm in the process of trying pump cams but theres a lot of conflicting info online about pump cam volume and profiles. I have the cam kit minus the blue cam, I'm going to try the pink cam in position 1 next as it seems to have more volume. The bog gets slightly worse when the secondaries are as normal and heavier spring only delays the bog alittle, lighter makes it worse. Also while the secondaries where cable tied shut i still had a rich WOT at 11.7, should i take more out of the secondaries or lean out the pv further on the primaries as i would like a a/f around high 12

The best wot af I have got so far is 11.0. I used to run alittle more timing but it feels stronger at what it is on now. Car doesn't run hot or ping ATM. Are u suggesting I try advancing or retarding the timing. Il worry about the fuel first then play with timing

No screw in air bleeds. What sly said about the pinging I did have pinging issues before I sorted it by changing thermostat, colder 6 plugs and took timing out I think it is at 28-30 can't remember and octane booster. If I went back to the 5's and took more timing out would that get a better burn and better af at wot?

The cars a Corty with a 250 ACL bottom end 10.3ish comp, mildish cam, tfi with street fire. I decided on the a/f gauge instead of getting it dyno tuned so in the future if I change the build I can retune it myself. I thought I had the jetting pretty close by seat of the pants and plug reading but It goes to show what technology can do.

I put wire in the pv hole and found it slightly better so il try thicker wire when i get some. I also tried the 350 metering block and it was way richer. wouldnt idle unless the mixture screws where all the way in and the af was 12 at best. WOT was low 10's which got my looking at the differences in metering blocks. The main difference i couldn see was the street avenger has a jet/restrictor in the idle feed restrictor location in the metering block. So i followed the channel and found it came out in the choke tower. After some googling i found it to be the idle air bleeds, the air bleed holes on either side are way bigger than the inners or the bleeds on the secondary side. So the street avenger is to lean and the 350 is to rich at idle so i put cut down split pins into the main body to restrict the idle air bleeds the same way as the pv and checked it. What a difference, the mixture screws are responsive it idles way better and the vacum signal was strong at 13. I had to remove the carb to close off the secondary blade because it was idling perfect with the idle screw all the way out just on the secondaries and i can pretty much set the af where i want it at idle. Now just to sort out the wot. Thanks for the help guys.

Good read on the aussiespeed link exactly what I was after. The secondary plate doesn't have a PV only changeable jets. Il play around with the wire and see how it goes.

If I try hooks in the pvcr what are the chances of it getting sucked into the engine? By jetting the secondaries to compensated do you mean run smaller jets in the secondaries compared to primaries and iv heard of people blocking off the PV and rejetting.

Focusing on the rich wot. If the cruise af is ok I shouldn't be leaning out the jetting the only other aspect is the PV which must be the cause of the rich mixture so I need to lean that out am I correct or heading in the wrong direction. The O2 is just after the collector basically under the drivers feet

Focusing on the rich wot. If the cruise af is ok I shouldn't be leaning out the jetting the only other aspect is the PV which must be the cause of the rich mixture so I need to lean that out am I correct or heading in the wrong direction. The O2 is just after the collector basically under the drivers feet

I tried the smallest PV I have at hand a 4.5 and it still was pretty much the same. i went up on the jets just to be sure while i sort out the wot a/f. It does smell rich at idle but reads lean and the screws have little effect. Il check the blades, it has a cam and needs to idle alittle high, how should I set the blades on the secondaries so I don't need to screw the primaries open more to idle. Not to sure on how the air bleeds work. By drilling the high speed will that restrict the PV flow? I have a metering block off a 350 holley would it be wise to wack that in to see if that has any change?

So i brought 2 xflow bottom ends off ebay as a bit of a mystery buy. the guy told me one was a reco that had done 20,000k and the other a speedway engine built by a pro strong speedway cam, better timing chain, pistons, balancer ect. When i get them to work on wednesday il strip them down and have a better look. limited atm due to engine stand being used and shit everywhere. So what i know so far, start off with the one he told me was the speedway engine. 86da block, Its got a modified sump but damaged, pistons part number RA4101z 030. I took the balancer (which looks standard) & timing cover off and no double row timing chain. Removed the chain and gears, cams stamped 250r pull it completely out and its got a ford part number. So this is starting to look dodgey. Turn my look to the other engine with no sump and spin it on its side. bingo i can see a double row chain and a standard JP oil pump. Remove the balancer which looks similar to the standard but alittle different and timing cover. Its a rollmaster multi keyway timing chain set, Remove chain set, cams marked 570, no other real marking. Pistons look shallower than the 1st engine and part number RA9411x 040, 84da block and looks to be balanced as some crank counterweights look to have had some taken off. Any info on the build would be appreciated or anything i should check or anything people want me to look at/pull apart let me know. i know most speedway guys have there own little tricks maybe we can dissect this engine to see what was done differently to improve/hinder this engine cant upload pics it tells me they are to large

Put the 3 engine details into a comp calculator using the unmarked head 46cc. 84da =12.5.1 8cc zero deck 78da= 11.3.1 8cc .040 deck 86da= 9.5.1 22cc .040 deck Seems like I'm going to need a different head if I want to use the 84da bottom end on pump fuel. Will a bigger cam bleed off enough cylinder pressure. 12.5 is massive

When I measured the comp on the 78da engine with the unmarked head I got low to mid 11 I cant remember exactly. I was having problems with pinging using the first cam and ignition timing was way down. Which head would bring the comp down to a safe level using the 84da with a bigger camshaft.

i was thinking the 84da aswell but i dont wont the comp to be to high for pump fuel. i have a redline 4 barrel manifold. i also uploaded a pic of the head combustion chamber and the best pic i have of the inlet ports (which is old i now have an electric fuel pump). i dont mind having to buy a bigger cam as i can build the 84da up then just swap the head over when it time to install it all. Thanks for you input by the way.

Ok what i have in total to work with, 3 blocks, 2 heads, 3 cams. What would be the best way to go for an awesome streeter/drag. Keep in mind its a cortina, 3.7s 4 speed and i already have streetfire msd, tfi dizzy, rollers, 4 barrel 570 street avenger, 'hitech' extractors 2.5 exhaust 78DA .030" acl 8cc pistons jp hv oil pump think standard deck height not sure if balanced 84DA .040' acl 8cc pistons standard jp oil pump balanced zero decked 86DA .030" 22cc acl duralite pistons .040" deck height standard oil pump no balance early unmarked alloy head hf4 slight porting milled to around 47cc h/d springs standard c1a head cam 1 inlet 226@.050 .506 lift exh 234@.050 .524 lift cam 2 inlet 222@.050 .515 lift exh 224@.050 .521 lift cam 3 suspected standard 250

also found out that the ra4101 pistons have a 21.8cc bowl and the deck height is .040"

So I pulled to sump of the reco engine again. No1,2,3 conrod bearing cap arrows face to the front of the engine and 4,5,6, arrows face to the rear. on the side of the rods/caps they are stamped with which cylinder number they suit and they line up. I thought all arrows are to face toward the front or is it correct, its a 86 da block. pic on photo bucket. Also the pistons are marked acl duralite on the underside.

Had crow read the cam. very similar to my current cam. Uploaded pics to photo bucket. Pic in top row is new cam, bottom row is cam in current combo.

Nothing on the other end of camshaft, the only other marking are CWC, C2 AND H 23 which are all cast into the shaft not stamped. i dont plan of using the sump only put photos up for peoples amusement + my cars a corty. He did give me a good falcon sump also. I already have a pretty good combo in my corty, but i like to tinker and the blocks where cheap.

i tried that but no good. http://s1378.photobucket.com/user/lezzy23/library/xflow%20engines?sort=3&page=1

wont let me add more pics

I stripped the engines alittle more this morning. The reco engine pistons have ACL on the underside and a deeper bowl than the speedway engine. Everything else looked good and clean so i only removed the modified sump which i damaged. Pulled the speedway engine down. Looks to be balance and has arp conrod studs, bearings all looked fine except No.1 & 2 conrod bearings. The block also looked to be zero decked.

iv been trying to find a lh one for a corty for ages.

I have a slight delay when flooring it from cruising in any gear or any speed. I think its the secondaries opening but changing from one spring to another makes the car feel flat. I have the short yellow spring in ATM , flooring it from standstill the car pulls strong and no delay or flat spots ect. The next spring up doesnt feel as strong. Can I tune the primary accelerator pump to compensate for the secondaries opening quickly with a longer duration pump cam. I currently have the orange in hole 2 , it stops pumping around 1/2 throttle?

I wired the secondaries and found the delay is just the secondaries coming in hard. It felt alittle doughy on the primary's and the butterflies where soaked from a massive pump shot so I changed to a white cam and a 28 squirter and it felt more responsive. When I get a chance I'm gonna do a plug chop on the primaries to see what jetting is doing. Should I do it at full noise so the PV is in also or cruise to check just the jets