- When it comes to building performance engines, obviously there's a lot of
technology that goes into making the engines both powerful,
but more importantly, reliable.
Now we're here with Julian Godfrey from Julian Godfrey Motorsport.
Now while Julian's got a long history behind him, we're here at Goodwood
and he is looking after Ken Block's Ford Escort Cosworth.
Now Julian was responsible for the engine and electronics as well as the
tuning on Ken Block's Escort Cosworth.
We want to talk to him a little bit about his history with engine building and the
development of that.
So I think what I want to start with Julian is how did you originally get
involved in engine development?
- I started back in the '80s doing engine building and I started my own company
up in '89.
Got involved with rallycross in '90 especially with Pat Doran,
did a lot of work with him in '91, '92, did the European Championship.
Before that I was doing some rally engines for Dave Maslen doing the
British Rally Championship.
That's where I got first involved with the YB engine, we had a 4x4 Sierra
we've been rallying.
- Just going back, I think one of the problems we see with engine building
as a career path is predominantly the engine builders out there,
all around the world, maybe more in kin to engine reconditioners
and they're more familiar with really just rebuilding everyday pedestrian
road cars where power levels are low, RPM ranges aren't that high and the
tolerances really aren't that critical.
So getting into the actual performance engine building, generally that's a little
bit more tricky.
So how did you actually learn how to build performance engines,
is this self taught or where did that knowledge come from?
- It was all self taught, I never went to college, I originally started doing road
engines from when I left school, did nine years of building road engines.
Then went into some more race engines, I did a lot of work in the evenings,
looking at my friend's rally car and then I got enough work to set my own
business up and just really concentrate on race engines.
- So when you talk about the difference between the road engines that you build
for nine years as you just said, and you start moving more into
high performance race engines, where would you say the most critical
differences are, what are you really focusing on getting right and what's
most important in a race engine.
- Well obviously the bearing clearances, all the piston clearances are very
important in the race engine.
But once you go into the race engine, it's all the porting inside you get
involved with, different cams.
And just really, just changing that side of things, you get a little bit more from it.
Obviously when I very first started, there was a lot more normally aspirated
engines out there, turbos were only really just coming in.
Obviously the YB was a turbo engine from the very start and that's where I really
learned my turbo experience from, doing the YB engine.
- Now that YB Ford Cosworth engine, it's been in develpment for a number
of years and I know back when I first started getting involved in building
engines myself and tuning cars, that was an engine that I really
looked up to, we saw the development in Europe and the sort of power levels
that they were getting out of those engines back then were insane,
600 plus horsepower.
These days of course we see everyday road cars making much more than that
but that's a different thing.
What I'd like to talk about though is where you've seen the advances
in technology aid improving that power level, what's been the most important
changes there?
- Really with the YB it's actually trying to keep it reliable with the bigger
power figures.
We did a lot in the early '90s with a stock block fitted with a steel nikasil liner
the dry liner to try and stop blocks cracking.
And then eventually probably in I think 2002 we actually went to a wet liner
conversion on the block.
To literally try and stop it from cracking and keep the head gaskets
alive on them.
- So there's a couple of things you've mentioned there, so just about the
liner, so the original on the YB Cosworth was a cast iron block.
So the problems you were seeing there, was this to do with the thickness
of the casting from the factory?
- Yeah they weren't particularly accurate, the actual castings and we'd have them
where under high boost they'd just split the bore from top to bottom.
So then we went briefly to a still liner which worked for a few years but then
we get more and more torque, then the restrictors came in in rallycross.
So then we're concentrating more on torque than horsepower and then we're just
cracking more and more blocks.
And then having head gasket problems, so then we went to a wet liner block.
And that really cured the head gasket side of things.
- So again there's a few things I just want to unpack there.
So first of all, you talked about the accuracy of the block production.
So I'm going to assume here you're talking about core shift during the
actual casting process of the block where sometimes you can get innacuracies or
inconsistencies in the bore thickness in factory castings?
- That's right yeah you get a lot of core shift in the factory casting and they're
fairly sort of lenient on their tolerance with that of course.
Obviously on a standard engine it's not a problem, it lasts for years with no problems.
But when your standard engine has has about 200 and somethings pounds of torque
and we're running up to sort of 700 pounds of torque so there's a big
difference.
- Now also you talked about the liners.
Now this is a modification we see probably I guess predominantly on alloy blocks
where they really aren't made for anywhere near the power we're seeing and it's
quite common to put in a ductile iron sleeve as an aftermarket modification
requiring a lot of machining work to the block to allow that to be fitted.
What we do here, a lot of people complain about with aftermarket sleeving technology
though is that that in itself can fix one problem with the bore strength but in
itself creates more problems with the potential for those sleeves dropping and
hence head gasket problems.
Is that an issue or how do you get around that if so?
- When we did the first still liner Nikasil blocks, we used a flange liner.
So they'd never drop but what we had trouble with is 'cause we pulled from,
long studs on the block we pulled from the bottom of the block,
the top of the deck is very weak so the liner under really high cylinder pressure
would actually drop down slightly on each time it fired and then come back up again.
And then you started to see a bit of movement in the gasket and then it
started to leak.
So when we went to the wet liner, then that stopped that problem.
'Cause the wet liner sat on the base of the water jacket and the studs
pull from the base of the water jacket so.
- Compressing it essentially.
- That's right, compressing it, keeping it all together.
So we did that and that sort of solved that problem.
Then we came into the problem of cap split in the main housings.
Pushing the crank out the bottom.
- So you shift the problem from one place to another?
- That's it yeah 'cause we got more and more torque out of them.
So then we had to go for the billet sump which held all the main caps in place.
- We'll come back and talk about that stuff in a second but I still want to just
dive in a little bit further with these sleeves.
So you talked about using a steel liner.
Now that's a little unusual in terms of a material selection.
I've just mentioned quite common now is the ductile iron.
So can you talk about the advantages and disadvantages of the steel material
and around that Nikasil coating and why that's important?
- The steel liner, you'll never ever crack one but they do go out of shape,
they don't hold their roundness as well as, especially like the ductile iron liners,
they do hold their shape really well.
And I think probably when we started doing that, ductile iron wasn't so
common thing back in the '90s.
It's more something that's in the 2000s and especially the last 10 years there's
been a lot of ductile iron liners being manufactured, even local companies
in the U.K. now are making ductile liners.
So obviously on, like Ken's engineer, we use a ductile iron in the aluminium block
with no problems just a parallel line down to stop at the bottom.
- And that Nikasil coating, why are you using that?
- You can't run a ring in a steel bore so you have to run some sort of coating
on the steel, so we use NIkasil which is obviously very hard, it's actually very
low friction as well.
But you have problems with rings trying to bed into it sometimes and we have
to try nitrite the top ring to stop it from picking up on the Nikasil.
- Now that Nikasil coating, as well as the technology that we see,
is not uncommon in OE engines where they're now using an aluminium
block entirely with no sleeve whatsoever and that Nikasil coating is placed right
on the aluminium so that the rings can run on that.
So not uncommon there.
Now the other thing I wanted to dive into there is head gasket sealing
technology.
You sort of mentioned there a little bit about the problems with keeping the
heads on.
From my own drag racing experience, that was always really our limiting factor,
we could make as much power as we wanted, as long as we could keep the
boost in the engine.
And we've seen a lot of development with the YB engine, it's used obviously
in group A circuit racing.
Power levels were insane, particularly for qualifying.
What was the development in head gasket sealing technology that you've used?
- With the YB we've always used the Coopers ring.
Even with wet liners we still use the Coopers ring.
- So can you just explain for those who aren't familiar, what exactly is the
Coopers ring?
- Coopers ring, it's a stainless steel ring, it's made out of multi layers.
Then they're wrapped around all four layers and the intermediate
layers are slightly interwoven slightly so you get a slight spring effect on that.
So it's not like a solid ring.
So it gives you a bit of a flex if it starts to lift the head it will spring
back up a little bit.
So with that you're only talking like two or three thou, it's not 10 thou
or anything like that.
We have found that's still the most reliable way of keeping the gasket.
We tried the four layer gasket in with the wet liner.
We still had a little bit of leakage on that but the Coopers ring's always
been out best solution on the YB.
- And what sort of boost pressure on some of the really high output engines
are you talking about sealing in there?
- We've been running up to 3.1, 3.2 bar of actual boost so 4.2 absolute.
So it's a fair bit of pressure inside of there.
- Now you mentioned earlier as well about the restricted engines that are
used in rally and rally cross and I think a lot of people probably don't understand
that technology so this is designed to keep a cap on maximum power.
There's a restrictor which is literally an orifice through which all the air
must flow, the entrance to the turbocharger, so that limits air flow.
So these engines don't make a lot of high RPM power but of course you
mentioned the low RPM torque.
And you're running a lot of boost down low so you kind of alluded to this already
but do you find that high torque at low RPM, so this is really air flow,
is more problematic than making a lot of power at say 7000 or 8000 RPM
in terms of engine reliability?
- Yeah a lot more, 'cause torque is, or the explosions, they're much longer,
the piston's travelling much slower so you don't release the torque from
the pressure very quickly at low RPM.
So say at 4000 RPM it goes away at a certain speed but at 8000
it's twice the speed, it goes away the load.
So the block can then relax or the head gasket can relax each time after
it fires much earlier.
So the big torque is what really breaks engines.
You can have big horsepower and it doesn't really hurt an engine but you
have big torque low down and it just kills everything inside an engine.
- Now I think that's important because it is so easy for people to overlook that aspect.
Now you also mentioned about the billet main caps and how you solved one problem
and then started pushing the crank out of the bottom of the engine.
So can you talk to us about the development and the requirement for that and what does
the YB block use in stock form.
- So in stock form, the YB just uses an aluminium sump, cast aluminium sump.
It's just two bolt mains, cast iron caps, and we kept having them cracking
through the main housing trying to push the crank out the bottom.
So probably in 2003, 2004 we made our first billet aluminium sump to hold
all the main caps, so the main cap bolts have to go through the sump
and you can do them up from the outside.
And that stops all the problems with cracking the blocks.
- So essentially you're sort of tieing the main caps also out to the outside
of the block sump rails?
- Yeah that's right so the sump flanges, tie it all down.
With the YB, the crankshaft centreline is actually the sump faceline.
With a lot of modern engines the sump line is actually below the crank centreline
so it helps to support the block.
'Cause the YB's a very early designed engine, it's actually really designed
in 1972 with the mach3, it's a pinto block basically.
That's what it started off life as.
It has really evolved over the last 30 years.
- Now as you've just mentioned, really we are talking about what is a very dated
engine design, we've seen a lot of technology come through over those
decades but is there still some life left in the YB, still some development
left for you?
- Yeah we still do a lot of YBs.
We've done, obviously going onto the aluminium blocks now.
And yeah we have good success with the aluminium blocks now.
It's taken a bit of work to get them reliable.
Like with Smith and Jones as well we had them do the long studs right
through to the main caps to try and keep the head gasket on that one.
We have been introducing some big horsepower onto the YB.
I think the most we've seen is 1040 horsepower.
- Yeah that's not messing around.
- No that's right, we've done it out of our aluminium block and it all held
really well so that was our record so far in the YB engine.
And we've still got a lot of work to do, we obviously try and get them even
better and better.
So it's a never ending task.
- Well look Julian it's been great to get that insight into the development
of that engine and how you've faced those challenges and found ways past
those weak points.
Now if our viewers want to learn more about you or your company, how can they
reach out?
- We're at racetuners.com on the website so it's quite easy to find and remember.
So racetuners.com yeah all our information is on the website there, where to find us
and some of the work we do, all the billet machining stuff we've got on the website.
And parts, we've got a little shop there as well.
- Well that's awesome, thanks for the chat Julian.
- That's alright, no problem at all, thanks a lot.
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