2110 down on top end power

[Karlos99]

Hi all

Right: got a 2110, FK 8, twin 44 IDF's, facet pump, Holley reg and DRD L5 heads with an 009 dizzy. Problem is, normally the motor pulls hard from idle right round to 6500 rpm and even when sitting at 70mph (4000 rpm) if I floor it, it will comfortably pull round to 6500. At the moment however it pulls hard through the gears but if I plant it at 70 it doesn't seem to wanna know.  Motor starts, idles and cruises around fine it's just the higher revs it seems  unhappy with. First thought was cam had gone flat but it would have the bottom end, so I'm wondering if the carbs are full of shit or the timings moved? Cleaned jets, plugs checked valve lash and carb sync. Proper puzzled, can't get to my engine builders place till Friday for him to loom hence asking here.

Cheers Karl

[Donny B.]

I would still check cam total lift to see if it's less than it was when fresh.

[Karlos99]

It only started doing last week, surely it would have been more progressive than that? Just had it running, let it warm up then revved it up. Hit 6500rpm easy. So it only seems to be sluggish whist under load.

[benlawrence]

I had a cam go flat and never developed those symptoms, if your timing is still correct, i'd look at either a fuel supply problem, or try swapping out the coil although you say you can pull hard through the gears so i wouldn't be leaning towards spark. Make sure your tank is vented and breathing properly.

[Karlos99]

I think it is fuel related tbh, it pulls hard through gears but does stumble now and then.

[Jim Ratto]

What kind of carburetor linkage?

[Karlos99]

CSP bell crank, both carbs open fully as I already checked that. I stripped and cleaned the carbs out earlier and it seems to be a fair bit better not still not perfect. Hopefully going to see my mate Friday who built the motor, so he can check everything and hopefully a tune up will cure it.

[Jim Ratto]

Ok just want to make sure you checked the easy to fix stuff before you get too far into cams, etc.
Too much total advance will take away top end.
Dwell and/or point gap going whacko, same thing.
If it was fuel related, you'd definitely feel something somewhat harsh. And it would be more pronounced in 3rd-4th gear under a load. My 48's were running out of fuel when I first started running them and before I changed needle valves/modified carbs/did pump and larger line and it would run into a wall in 4th gear, up a grade, if I asked alot of it. But was not at specific RPM. If you suspect it is starvation go wring its neck up a hill, when it lays down, kill the engine and pull over. Remove air filters and advance linkage,  which will make acclerator pumps admit fuel- IF there's fuel in the bowls. If nothing squirts, then yeah you're going dry. I ran a Facet pump way back when and even after going to 3.3 Gross jet needles then Weber 3.00 needles, it still wouldn't keep up. You can roughly calculate your lb of air and  GPH demand and see iif that pump is the issue.
If the cam is going away, you may not hear it/notice it. if the LIFTERS are going away, you will definitely hear the valvetrain making tons of noise. If it's just the cam, the lifters will mostlikely track the cam and maintain lash, as it's the nose of the cam that dies, not the heel. if the lifters die, then the lash gets really wide and you'll know. Does the oil look metallic or pearly black? Run a clean paper towel along lower lip of the heads, into the oil, and look @ towel... if it's dark pearly grey/black... something's going away. You can pull oil pump cover off and check there too. If the cam/lifters are dying, you'll find debris in the pump.
Good luck. Prob something simple and easy.

[Karlos99]

Well that's my oil, pretty safe to say that's not got cam in it in my opinion. Running a lot better now I've cleaned out the carbs. Good tune is in order I think.

Cheers for your help 

Karl

[TexasTom]

How many miles?
Sounds like insufficient valve spring pressure ...
TxT

[Karlos99]

About 2000miles on it I reckon. Drove the bus to work this morning, ran a lot better and was a lot more free revving. Will take it down the main road on my way home and see if the top end is better. Even if it is, it will need a decent tune up I think.

[hector]

Well it made 155bhp and 162ftlb torque with the belt on so I'd say it's fixed

[Karlos99]

Well it made 155bhp and 162ftlb torque with the belt on so I'd say it's fixed

Agreed, goes like fook again! You build a good motor Hector