Leaded or unleaded

[Kegco]

Hi All,
Im after some advice my tiger is 205 pinto block with a big valve 1600 head by the 4th spark plug it's got a stamp 5C does anyone know what this means?
I'm trying to find out if it's unleaded or not with out stripping it down yet. The guy I bought it off said he adds lead substitute but not sure if needs it as the pinto has been rebuilt with fast cams and big valves but not sure if been converted I believe the car was a 1987 Sierra so not sure if leaded or not
Any info will be much appreciated
Cheers
Kev

[steve m]

There are two ways of checking, if the head has been converted to run on unleaded

first one involves taking the head off, and inspecting round the valves for a feint line, if it has one, (or four) that would indicate its had inserts fitted on the exhaust valves

the second way is much much quicker, but could be expensive

drive the car for the next year, but don't add any additive, if its still running in a year or so, and the valves havnt snapped, or need adjusting, you could have an unleaded head

personly I would just add the additive,

steve

[Kegco]

Thanks Steve
Think I'll keep on with the additive for now

[Fury1630]

I drove a 205 block "leaded only" Pinto on unleaded as my daily driver for a couple of years with no issues. Because the "problem" is the valves wearing, you can check & record the valve clearances, drive it on unleaded, & re-check the clearances every 3 months. You only need to worry if the clearances are increasing. If they are, re-adjust & run on lead substitute, if not - happy days

[Larkingabout]

I did some research into this area when I was running a Pinto. As far as I can remember only those heads stamped with a P or and R or PP or RR are the unleaded ones. Only was to make sure is get the head off and have a look. Alternatively run additive which is the easiest option.

[steve m]

" You only need to worry if the clearances are increasing. If they are, re-adjust & run on lead substitute, if not - happy days "

I am pretty sure the valve gaps decreases, as the valve eats away the metal in the head
the valve stem will get closer to the follower/cam,

if I am wrong, I applogise

steve

[andyf]

I drove a 205 block "leaded only" Pinto on unleaded as my daily driver for a couple of years with no issues. Because the "problem" is the valves wearing, you can check & record the valve clearances, drive it on unleaded, & re-check the clearances every 3 months. You only need to worry if the clearances are increasing. If they are, re-adjust & run on lead substitute, if not - happy days

That's the advice that the AA give as well. They do recommend checking the compression as well.

[Kegco]

Cheers guys
Thanks for info
I think I'm going to keep with the additive for now and see how it goes.
Had a mechanic had a quick look at the compression, they were all the about 180.
Just need to get carb's balanced and running a bit smoother as plugs 1 & 4 are ok 2 is a bit sooty 3 a bit oily