ton van der sluijs

Hi y'all
Been busy a long time now with making the V8 351 efi perfect running.
First i,ve swapped the Impco LPG for a Prins LPG injectionset; the ignition timing remains correct now BUT..... the engine runs rough at idle and sometimes while driving. I've been to one of the best USA Ford carmechanics in the Netherlands yesterday and after an OBD1 test came out that the motormanagement was perfect; nothing wrong. What he discovered was, that the valvesprings are weakened. When this is the trouble, the engine starts neatly but when the valve lifters come on their pressure, the valves are not closing properly. I could hear them "tingeling" when accelerate with the bonnet (or hood) open!
Next week my wife and I are changing them for new ones
Is anyone familiar with this problem?

greetz Ton

Kattumaram

Before you install all new springs test that the push-rods are not too long or that the rockers are not pulled down too far on the studs taking all the lash out of the rocker-to-valve stem clearance. With the lifters fully compressed there should be about 0.050" clearance between the stems and rockers. That clearance will be taken up when the lifters are pumped up by oil pressure.

That same clearance is the reason the rockers will sometimes clatter a little bit on cold start.

ton van der sluijs

Hi Mr Kattumaram
Good to read from you I shall take your advices with both hands! Reading your statements, brings me up to the fact that LPG is hotter than petrol and if I could not get any clearance, I shall put some spacers underneath the rockerarmholders so that I can drive on for a couple of years. Maybe then it's time to refurbish the valveseats by boring them out and shrink LPG resistant one in place, but nevertheless I believe in good American casted iron grinn.
Next weekend I'm gonna change the springs and keep you posted anyway.

My regards to you and your wife.
Ton

Kattumaram

Hey Ton,
Take a look at this:

http://www.ehow.co.uk/how_7313161_ad...e-running.html

Maybe you can save the price of new valve springs.

ton van der sluijs

Goodmorning Mr Kattumaram

Thanks for the link; i've read thar with a lot of interest.
I've allready ordered a complete new set for 210 dollars. When I read this I should think , one can give the valves some new play to expand when hot but the problem with the valvesprings of the V8 from ford seems to be, that they become "tired", especially in the first mm of lifting. The bloke who investigated my engine told us that this occurs a lot around the mileage of plus 160000. I do believe him because he is a very good car mechanic and if someone can't resolve a problem on an American car, He's the man here in the Netherlands who find and fix it.
He told us that he has done dozens of EFI engine where there was a bad running while there was no faultcodes and at the end the valvesprings were the badguys .
I shall ask my beloved wife how I can place photo's here; I don't have a clue I'm better with machines.
Well, have to go to work... We did start our own machineshop in Januari last year and since then I have not had a single day with nothing to do. The orders for machining, repairing, welding keeps on coming, sometimes to much. But. I must not complain; for us there was no crisis! Here in Holland skilled people become less and less and the youngsters are rather behind their computers than doing and learning something. Nowadays skilled people from 50plus are much wanted for a good wages!

regards Ton

ton van der sluijs

Good morning Everybody
I've read the link from Mr Kattumaram with great interest.... I've understood the "messy method" and the one with the engine not running... BUT... How the hell do I adjust those in my truck? Do I have to built up the whole stuff, warm up the engine and do I have to remove the inletmanifold and then hope that the lifters are stil under load?!?!?!!?
I was thinking about removing the oilpressure sensor (temporarily) , and connecting an external oilpump or is there someone who has better ideas?
when the lifters are empty (or not under pressure) is the spring inside still pushing the seat against the C ring?

greetings

Ton

ton van der sluijs

Hooray

Kattumaram

Greetings Ton,
The clearance between the valve stems and rockers can be set two ways: (1) Lifter completely compressed and the clearance set 0.02"-0.06" with the lifter riding the heel of the cam lobe. (2) Lifter all the way out, fully extended, and the clearance set to zero plus one turn down on the rocker stud nut with the lifter riding the heel of the cam lobe. This way is essentially what you get with the engine running at idle and the adjustments made according to the link I sent you.

Either way is not very easy since it's hard to tell if a lifter is completely compressed (1). And the only way to get a lifter pumped all the way out is by engine oil pressure (2).

One way to set the clearance with the engine running at idle would be to modify a couple of spare rocker covers by cutting out the top sections to gain access to the rocker stud nuts. That would probably require a lot of disassembly and reassembly of the rocker covers and the various parts that are in the way over the rocker covers.

ton van der sluijs

Good morning Mr Kattumaram, how are you doing?
I think I'll go for nr one; In the lifter is a spring who allways try to push the inside piston to the top. when we built up a complete new Harley Davidson engine, the lifters are empty. My mate turns the play of the pushrod to zero and tan he add a half turn. It's hard to adjust an EFI while running; the inlet manifold makes that nearly impossible and my engine is completely dry and clean.
I was also thinking about removing the rockers and the sparkplugs, giving the engine a spin by the starmotor to fill the lifters an then adjust them. I shall also write down what the adjustment of the bolts of the rockerarms are and I keep the right rocker to the right valve.
what is you oppinion about all this?

Best regards to you and your lady
Ton

Kattumaram

That may be your best approach. It's easier to get a lifter filled and pumped up than it is to bleed it down.