Hi all,

I've got a 1600 crossflow and i'm just wondering whether its worth the money (which is tight) having it converted to run on unleaded fuel?

Ive read on piston heads that it will be years before any damage is done to valve seats and is using lead additives a suitable alternative?

Ben

for the money you would spend on having it converted you could easily afford to remove the crosflow and fit a zetec

i want to keep the crossflow as its simple to set up, light, and for insurance purposes (im 17) a zetec wouldnt work for me

in that case just run it with led replacement until your a bit older and can afford the insurance on a bigger engine not worth the bother/cost of machining it and fitting hardened valve seats for the year or so that it will take for your insurance to go down.

Ive run my crossflows with and with out an unleaded head for years, and just use lead additive
personly, im a crossflow fan, and have no inclination to fit a zetec or any other modernish engine

Also, with my car, a zetec will not fit without fitting a bloody great bulge in the bonnet, for the cam pullys to fit under
and that is with a shallow sump fitted

As for the unleaded heads, there fine if you dont want the hassle of adding some additive, but apart from that its £400 wasted

Unleaded valve seats are approximately £30 + VAT each fitted

This is an engine that I sold Ben. It's a 1700cc which was rebuilt in 1998 or 1999. The only receipt I could find for it just said "Reconditioned Crossflow".

I would imagine the valve seats would have been done at the same time but the previous owner and I both used fuel additive just in case because we don't know for certain.

That Kent crossflow is a nice traditional engine thats simple to work on. Ive rebuilt a few in the past and remember them being so relatively light I could do an engine change with a rope and a couple of mates rather than hiring an engine hoist.

I'd suggest you stick with what you have, use a bit of lead additive for now and it should be fine. I'f you plan to have the head ported and polished at some stage it would make sense to do the unleaded valve seat conversion at that time. Dont forget so long as you set the timing right the only parts of the head you'd risk damaging running long term on unleaded fuel would be the exhaust valve seats- the bits that would be replaced in the conversion.

Wisdom on most classic forums is use it as is, with slightly wider (.015 intead of .012 in my case - A series) exh tappet clearance, either with or without the FHVC tested lead substitutes (not the snake oil bits of tin in the tank).

Check tappet clearance more regularly & adjust as necessary.

Phil.

quote:

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Originally posted by Furyous
This is an engine that I sold Ben. It's a 1700cc which was rebuilt in 1998 or 1999. The only receipt I could find for it just said "Reconditioned Crossflow".

I would imagine the valve seats would have been done at the same time but the previous owner and I both used fuel additive just in case because we don't know for certain.

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I had my head 'done' by Lyons Bros in Swansea a few years ago.
Sent the stripped head - £15 carriage via Parcel Force. (Now I'd use a different carrier; CDS - £12.90)
Chemical clean, all mating surfaces trued up, inlets opened up slightly, new hardened valve seats to take large (biggest) valves, new bronze guides and seals, new valves and springs, £220 + vat + return carriage.

I would be inclined to use as is, no changes, no additive. I have run my Triumph OHV engines for many thousands of miles like that. Keep an eye on valve clearances, of they close up ad you start to suffer seat recession, then get unleaded seats fitted. As above, £200 all in for just seats and a 3 angle cut etc.

cheers for all the replies.

I guess in the interests of my wallet and getting the car finished i wont have the conversion done and just to be on the safe side, use additives when i fill up.

Ben

All my ancient crappy old cars built way before the idea of lead free seem to suffer no ill effects of lead free fuel tbh and have never seen increased wear.

Personally I think it was all a bit of a scam

That is so weird, Whippy, as earlier i was thinking exactly the same

HYPE!!!!!

If the motoring press at the time was to be believed people could barely drive down a road without the sight of several cars laid up due to damaged cylinder heads from being driven with unleaded fuel. I can't say it was a total invention of the press beause there is a proveable effect- just a very slow one and even slower on cars that cover low annual mileages.

Bit like the millenium bug really for those who remember that, a load of fear and nonsense about a non event

Doing 20,000 plus a year using unleaded in an old engine would be a serious issue. However, most kits cars do less than 2,000 miles a year thus even thought the valve seats are wearing and the tappets closing up its going to take a long time for them to get to an unservicable state. By doing regular checks you can avoid the potential for damage to cam/followers if the gaps close. Checking a couple of times a year is no hardship, checking every 2 weeks (especially in winter) would soon become a chore.

Many cars built up to the late 80's with alloy heads had valve seats fitted that were made of cheese and are just a liable to wear as a x-flow head with no seats fitted.

My personal opinion is if the engine is in bits and the head being worked on it makes sense to get the seats fitted. Other than that keep using the additive, I used Millers and the tappets never needed adjusting.