Standard valve springs for cam break in

[LJDB 103]

Timing is locked at 34 with tfi no module now. i use the nylon booster as i found it the best. i only use half a bottle to a tank and it works a treat for pinging down low. the car get street driven with most times a baby seat in the rear so it mainly pings down low if im being lazy and dont down shift or on a hot day. i already run bp6 plugs and a colder thermostat. the temp normally sits on 1/4 on the gauge and doesnt ping but when its hot or driven in anger it sits closer to half thats went i notice the pinging.

Gerg i think its and accelerator pump issue as its when i mash the pedal. havent really looked at it yet. a/f gauge leans out then comes back

heres a link to my photo bucket with some pics of the corty and engine 

http://s1378.photobucket.com/user/lezzy23/library/cortina?sort=3&page=1

[ando76 4,354]

Um 34 degrees on petrol with that cam and compression is a bit ambitious. If you ask me its detonating. I would have the timing at 28-30 maximum.

These things are very timing critical and one degree either side can make a big difference. I'd pull timing straight away if you want to keep rings in it.

There would not be that much compression bleed off based on the cam specs on the web. Can you post up the cam timing so I can work out overlap, should be on the cam card.

I think a move to 28 degrees and take it for a run and see how she goes. I like to do radical changes when I'm trying to diagnose. I've found it gives a better result than just a degree or 2.

To give you a guide as to why I say so little timing - most of my meth race motors take not much more than 28-30 to make the best power. I keep them around the 12:1 mark but they have more compression bleed off because of the bigger cam. A mate who owns a performance shop in Toowoomba did one recently and it didn't take more than 28 on petrol with a bigger stick. Granted both my race motors and the head on his engine were very efficient so therefor they need less timing.

[LJDB 103]

Intake open 35btdc closes 86 abdc

Ex open 74bbdc closed 37

I only chucked it on 34 to take it for a quick spin cos it was cranked right up from the night before when I was going from extremes to see if it made a difference to the rpm issue. When I first broke in the cam I had it at 28.

There's a pic of the cam card, inlet ports ect on the photo bucket link, I can't manage to work how to upload pics direct to posts.

[gerg 10,871]

Gerg i think its and accelerator pump issue as its when i mash the pedal. havent really looked at it yet. a/f gauge leans out then comes back

 

Your pump arm might need adjustment. Also, on those avengers, there is a known design fault with the pump arm riding up on the throttle spring instead of following the pump cam. This means there is no pump for the first few degrees of throttle. The fix is easy and there are YouTube vids all about it.

[ando76 4,354]

Cheers mate. That will teach me not to look at the link. Not much overlap there so I'd pull timing asap. Off to go and look at photos.

 

PM slydog or Ryan as they use photo bucket I think

[ando76 4,354]

Nice corty. Head looks ok. Bit of bowl work there. With the right tune it should be a fun streeter.

[broken-wheel 659]

Timing is locked at 34 with tfi no module now. i use the nylon booster as i found it the best. i only use half a bottle to a tank and it works a treat for pinging down low. the car get street driven with most times a baby seat in the rear so it mainly pings down low if im being lazy and dont down shift or on a hot day. i already run bp6 plugs and a colder thermostat. the temp normally sits on 1/4 on the gauge and doesnt ping but when its hot or driven in anger it sits closer to half thats went i notice the pinging.

Gerg i think its and accelerator pump issue as its when i mash the pedal. havent really looked at it yet. a/f gauge leans out then comes back

heres a link to my photo bucket with some pics of the corty and engine 

http://s1378.photobucket.com/user/lezzy23/library/cortina?sort=3&page=1

 

Start at 24 degrees with that head, can't see the pistons so don't know what dish you have but those heads with any dish will not be too happy over 28 degree with your static compression. From the pics I see a few things that are disturbing:

 

1. Your seat. Way too wide looks like .100  and I don't know anyone who puts a face of more than .050 on a valve. This will do two things: will build carbon around the seat and it will not seal properly and you will loose flow, massive amount at low lift.

 

2. Carbon build up is huge with will only increase the issues in 1.

 

 

I think from one photo ... this one:

 

 

you can see the seat being founded up with carbon

 

If this head is relatively new I would go back and have some serious worlds with the dickhead who did work on it

 

Ditch the avenger and go Double Pumper

 

See int his pic: 

 

The accelerator arm is right on the edge, looks like you have to align it

[ando76 4,354]

Tells me the spark plugs need indexing as well. Yes I am that anal

[broken-wheel 659]

I'd  steam clean the head, blue it and lap the valve and see what the seat looks like but that valve job looks shit, can't see a pictures of the valves thou maybe someone did put a .100 seat on it but if you look below you see what I mean

 

probably head work was one on a friday

[LJDB 103]

This isn't a new head. When I got the car the owner said it had work but didn't know what. All he knew was it had rollers because he could see them through the oil cap. From the look of the bottom end (suspected ACL rebuild kit 8cc Pistons) when it was apart it had done some k's. Iv owned it Since 2012 and before that it was off the road for many years. I got it coz it was straight and interior clean with no rips and cheap $1200. The motor was a plus I didn't even start it. Slowly I have added the manual conversion, msd, 4 barrel, camshafts x2 when ever something has popped up cheap. The most expensive thing I have done would be this cam and lifters. Iv done all the labour ect myself and my uncle painted it. Thanks to you lads it's where it is today in terms of performace and modifications. My crossflow addiction had well and truely set in.

[wagoon 2,429]

I got these pics here clicking on the pic, then when it's just a single pic on your screen look to the right for 4 boxes. Left click on the bottom box that has IMG next to it then come across to oz falcon and right click then paste the link. Only the link will show up in your reply box but when you post it will show as a pic

 

 

 

 

[ando76 4,354]

That's a good score for the money mate. Don't be discouraged about the seat cut, just means another area to feed your crossflow addiction. Trust me, I know all about it

[slydog 7,873]

Got a bit of lift @ TDC. Prob a tad louder than the last too is it ?

 

Far from a small cam,once sorted it should provide you with heaps of fun. We all started somewhere and mine wasn't as fast as yours would be for sure. The head will work fine for you ATM and maybe down the track if you go for more camshaft mod the head further.  

[PRO250 1,506]

I also think you run a little to much timing we run that cam in chris beacon but I moved the cam centre line as I run NOS on that engine, that is on its arse at 5600 but on NOS will go past 6200 no worrys we only run 28 degrees on his and his engine has a full point less comp, that cam just does not like timing i can still run 32 on my big engine with way more comp doing it again i would have gone a solid

I like the 570 streets i run 2 250s with them good carby easy to work on and rear metering plate and seem to work well on the little 2fiddys out of the box

 

[LJDB 103]

i cant touch the car for a few days so il start sorting the tune during the week. Pro what jets do u run. When I got the 570 it was jetted pretty big, I put it back to standard and it felt like it was surging but went well wot. I think they come out with 54/64. Mines at 60/61 atm with 6.5 pv.

[gerg 10,871]

They must run very small primary bleeds to run jets that small standard. Your current jetting sounds more like what it should be. If you say stock jetting is 54 but it now runs ok on 60, are you sure nobody's messed with the bleeds and made them bigger? That's a huge jump in size with no other changes.

 

Eliminating that, have you tried bumping the float up a tad? This brings the main on sooner and holds the transfer on longer. Could be an issue when a carby this big is used on a smaller engine like yours.

 

If you think it might be an acc pump issue, look down into the carby and check that it squirts the instant you touch the throttle. It needs the check ball and pin under the squirter screw, otherwise the fuel will just bleed back to the bowl. The pump arm looks like it could do with some tweaking like Broken Wheel also mentioned. There are videos for that too.

 

Can't think of anything else that it might be, just throwing it out there.

[LJDB 103]

Got back into it last night. Set the timing at 28 and went for a spin. Pulled good and didn't ping so played with the tune. It had 60/61 with 8.5 with wire in the pvcr. Still has the flat spot on acceleration and a/f was alittle rich. Took the 8.5pv and wires out and fitted a 6.5. Vac is around 12-13, put 59 in and pulled Alot stronger in the mid range, I think it had something to do with the pv not being restricted but still rich at wot mid to high 11 a/f. Tried to clean up the bog when accelerating hard. Checked the pump arm and it was running on the spring, adjusted to suit but in some postons u run out of adjustment on the pump arm spring. Played with squirters and cam holes. I'm using the pink with 35 squirter. Tried 25/31/35 best I could get it was pink cam hole 3 pos 2. What's everyone's thoughts on pump cams? I also may have found another contributor to the rpm miss/ rev limiter. One time after I pulled over it wouldn't crank like a flat battery or dead starter. Pulled the starter out today and bench tested it all ok. Check wiring ect found the earth terminal at the battery corroded between the terminal and post. Cleaned them all up and she turns over nicely. Maybe that's why it sounded like the rev limiter cos the msd wasn't getting a good earth under load. Gonna take it out again tonight and play with the pump cams ect. I also went 60 in the secondary's .

[broken-wheel 659]

not sure in Corty's but I like to run an earth strap from starter to chassis but well done on the progress 

[LJDB 103]

I ran one awhile ago from the engine mount bolt on the block to the rail but it's only a shitty piece of wire. Might have get a good earth strap for it.

[slydog 7,873]

Im still scratching my head as to why such a small jet ? I ran 76 fronts and 86 rears on that 750DP in East/West configuration for AFR's around 12.8 @ idle and WOT. Yes its more engine but the air bleeds must be super tiny on the avenger ? Are you getting to run it the whole way thru 1st and 2nd or just a stab here and there cos that could show a rich or fat AFR as it is getting a squirt plus PV shot as well.

 

35 squirter is very big too,I'd almost say 31 at most and I adjust the acc pumps so there just barely touching then run a 2.5 PV and jets plus 10 if east/west and square jet if north south.

 

My TE had a strap from bell to chassis. 

 

 

But it seems your closing in on it. Props and keep pluggin along bro.

[gerg 10,871]

Yeah agree with sly, could actually be a rich bog, especially down low where atomisation is poor. 35 squirters would drown a small V8 let alone a crossy, 31s might still be too big. The smallest they go is 25 so I reckon that's more like what you want. Black pump cam (gentle) and on the lower setting. The acc pump is there to cover the hole in delivery, so if you're getting good mixtures throughout the curve, you need a minimal amount of pump. Have you adjusted the pump arm as per holley instructions? They say go full throttle, and measure arm to pump clearance with feeler gauge. Pump should bottom out at 0.050" clearance to the arm.

 

My Holley is the Autolite type and has non-replaceable squirters, yet at 0.028" they are fine on my mild 302.

 

Any time you make a tuning adjustment, do one at a time and record the results. Doing more than one thing will have you guessing which adjustment made the change.

[slydog 7,873]

Any time you make a tuning adjustment, do one at a time and record the results. Doing more than one thing will have you guessing which adjustment made the change.

 

This is very important...record results and only one change at a time.

[ando76 4,354]

+1 on the squirters. I don't run that big on my meth engines. Back it back to 28's and soften th delivery with whatever cam does that for your carb.

+1 on keeping a log. When I dyno tune I write everything down in a book as I go. Really helps when you can just got back to the book for reference

[TF_250 398]

I used to run 74/71 336pump cam 28 squirters and 3.5 pv front and rear. Good enough for 11.9 @112ish. man I wish you guys would stop talking in AFR and start talking in Lambda!!!....LOL

[LJDB 103]

Wont be going anywhere soon.