engine builder advice

[wayovermyhead]

G'day folks,

Looking to get a good pinto race head whipped up to better do my large bottom end justice (unless someone has a good YB head at a realistic price?) And was curious as to weather anyone knew of anyone in Sydney who might know what they are doing in this department?
Or if not, it can be anywhere really as long as they freight. Just want to know i'm getting a good finished product and be able to speak to someone who knows their stuff when it comes to these heads. Any pointers would be appreciated.

And also, Iv'e read everything around I can find on pinto heads and it seems everyone bangs on about the Vizard/Hamill stuff which has gotten me thinking, times have changed and while the physics haven't the techniques and technology have. It seems to me from reading through some of that stuff it's a little bit... out of date? Anyone have any similar thoughts? Just out of interest.

Llewellyn

[Danny M]

I'll answer this tonight Llew but you're not going to like what I say

[wayovermyhead]

Hahaha.... it seems how much anyone likes what you say Danny is inversely proportional to how much following your advice is going to cost them relative to their expectations/hopes.

I have just enough time playing motorsport now to have abandoned all expectations, and the hope was crushed out of my bank account long ago.

So do your worst..... I like it already.

[Danny M]

It's catch 22 really as a good pinto head is around the 3500 mark depending on what manifolds you're using but to be honest I don't know of anyone in Sydney and not seen anything good out of Sydney. But there are guys in Qld that can do it and freights not a huge issue
As far as a YB head at reasonable price is unrealistic as to get one that will make a big enough jump over an 8 valve to make you justify the cost of changing pistons pulley's pipes etc but I would budget 8-10k for the head plus inlet and exhaust manifolds

[wayovermyhead]

Cheers mate,
Those figures are about what I was expecting for a yb. A little more than I thought for the pinto but still in scope. And yep, I didn't think much good came out of sydney either from what I can find. Here's my conundrum, with the bore/stroke of my bottom end and what I can tell from peering in at the piston tops and my current compression ratio. I have a pretty good feeling my bottom end may be suitable as it stands for a yb head. It was built after all to have a warrior head bolted straight on. Unfortunately as I just bought it as is I can't do the all important measurements required to make an informed decision here. But I would be happy to pull the head and do so once I have decided on a direction and someone who can do the head work for me.
So I feel like I'm already half way there which makes the pinto even less value for money really.
My reference to the yb head at a reasonable price is because everyone I've seen people seem to want about 3.5k for something that is a totally stock, unknown quantity and already had a few skims.... They are just not worth that much!! You can get a bare prepared one from cnc heads landed for about 4k!
The only other thing is I'm still planning on doing Tasmania in 2017 with at least another small rally before then so am trying to be realistic with my money and other things I want to do to. And I think the head I've got is getting due for some love especially if I'm doing Tasmania I want it 100%
So if I could get a decent yb head at a good price I might snaffle it up and go that way in a little bit.
Otherwise I may still go to 8v and put the yb off for the future. Who would you recommend for either option. And Incidentally, have you any thoughts on the cnc heads for the money?

Cheers,
Llew

[jsa]

Au3.5k for skimmed is too much. That's about the money for unskimmed low mileage good used by head.

Rick wood's cnc heads are well regarded by some on UK forums. I've not seen negative comments about them.

If your budget can stretch far enough look up Smith & Jones , they do new yb castings appropriate to n/a.

You're best off getting a yb head out of the UK rather than starting with something that is skimmed to death here.

[Clayton]

I have a complete YB head, 3 bolt thermostat housing. Comes with cam cover, cams, valves, springs, vernier cam pulleys and measures 5.459” / 138.65mm.
I also have std YB aux and crank pulleys, old belt tensioner, new belt and weber manifold to make the conversion on a Pinto.
PM if you’re interested.

Clayton

[wayovermyhead]

Clayton, i'll send you that PM

Ok.... I can't bring myself to do a pinto for for what is close enough to half the price of a YB. And more so after having some time to think I know i'll just look at the pinto and still wish it was a YB, so that's the way i'll go. I might just have to do it bit by bit for now, just collect a few bits and pull the trigger in a little bit and get it all together.

To that end, i'll have a few more questions along the way which i'll more appropriately add to the engine section. But to keep this thread on point if anyone can give any advice as to someone who can do the required port work on a YB that would be fantastic. I would still love to chat to someone who might do it first before I go out buying up heads.

And unless someone has any game changing advice on the matter i'm still finding it hard not to see the value in one of those Ric Woods CNC heads. My budget won't stretch to a new casting though JSA.

I know you may not be too partial Danny as I'm sure you would prefer something a bit more bespoke. But like I said, seems like great value when you consider what people want for untouched ones here.

[Danny M]

Have they got any flow figures and port diameters and will they tell you what they've done with the chambers

[wayovermyhead]

I need to call them next week to find out about the chambers Danny, but see below for a flow chart and some basic port data.

Keep in mind these charts show two versions of their heads, a standard head and their big valve version. they also do a CNC'd standard valve version too. I was leaning toward the big valve though due to my near as 2.4 capacity.

cossie_bv_graph.jpg (34.95 KiB) Viewed 18406 times

cossie_bv_data.jpg (61.71 KiB) Viewed 18406 times

Llewellyn

[Danny M]

Llew

I've got to dig up the flow figures from mine but there are some things on there that just don't add up.
first of all the inlet throat diameters are not possible on a YB casting and the inlet valve sizes are basically standard.
Also the exhaust ports are too small as they're barely 70% of intake as your need 80%
I'll dig up my figures when I can but too me it looks like it's a very shallow port with poor low lift flow and you're going to struggle to get a camshaft to give you the flow at .500" and are you prepared to spend the $2000 on the valve springs to be able to use them

[wayovermyhead]

Ok, so it seems that info which I pulled off their website is a bit erroneous and not quite correct. I've had a chat to them and the valve sizes are indeed 36.2 and 32 and they can do any chamber volume you want as part of the CNC process from a 2wd or 4wd head although if you want it built up at all that's another kettle of fish. I'm still hoping I won't need to change pistons but will pull my head of to measure and be sure, but i'll do that first and if that's what needs to happen then i'll go down that path. But rough calculations based on "all things being equal" with the capacity increase and what we know about YB heads indicates that I should be ok and safely into 98octane territory, which is where I want to be as I want a safe motor that doesn't cost me an extra 4 thousand in fuel every tarmac rally I do in future.

Having said all that, no I don't really want to spend 2k on valve springs but was expecting I would use a slightly smaller cam than .500 that could use more economical springs (or am I oblivious to something here) but even that figure on the chart still shows the best part of 180cfm which I thought still seemed good.
I don't know enough about how a good one of these flows at low lift, so if you could shed some more light on this that would be fantastic Danny. And I'm not fully sold on this head yet, but it still seems like good value compared to buying one and doing all the work here.

And here is a pic of the intake port, which as you can see from the profile may be at or close to the very large suggested above, but as you can see it makes a bit more sense when you can see what they've done. It tapers down quite a bit after entry.

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[Danny M]

What pistons do you have and have they got any fly cuts for the valves

[wayovermyhead]

All I can tell you is they are CP's, appear to be flat top and they do have valve cuts outs to suit a 16v head. That's from peering down the spark plug hole so I can't be too accurate.

And before you write it off as being too low compression height, remember that all things being equal the 93/88 bore/stroke give approximately an extra 2 CR points for a given chamber size over a standard 2 litre spec. And remember I want this to run safely on 98 octane.

[jsa]

11-11.5:1

[Danny M]

Depends which head and how deep the pockets are
I've got my guy searching through for my last figures as the only ones I can find are from early on and they're better than those
Have a look at the photo they've sent you as they got that throat diameter by extending down which gives it a very ordinary short turn and why the low lift flows are poor
Unless you're going to run a 14-15mm lift camshaft or one with very sharp ramps to get to the higher lifts to make that head work it will result in a very unimpressive engine and I should also remark that both those style camshafts will need a better than average valve spring if you get my hint

[wayovermyhead]

That's roughly the sort of numbers I was thinking and hoping for John. But like I said, if I had to change pistons I would be prepared to do so. Although, I have been wondering if it might be a better option doing some welding to the combustion chambers if i'm close enough to where I want to be and retain a flatter piston with perhaps better flame front charachteristics. I can't help but feel given the compression issues associated with a YB NA head that having a large stroke engine opens up other avenues of tuning like that which offer advantages beyond that of just added capacity, and you then don't have to make so many compromises to other aspects of the engine to compensate for CR problems.
The deeper I go, the more I realize I need to go deeper.... And I am starting to lean away from the Ric Woods head for the reasons you mentioned Danny, which given this is a Tarmac rally engine low lift flow is very important to me. I'm also starting to think that maybe I do want/need a particular cam setup that will require very expensive valve springs as anytime you try and model a different setup you end up trapping yourself in a direction that just doesn't seem promising enough to justify the extra cost of going down this path in the first place.

[jpayne]

zetec or duratech!

JP

[wayovermyhead]

Rules, must use standard block but heads are free. That means only good options are yb or warrior. Can't afford warrior.

[jsa]

Flat tops are fine, if you have enough cr.

Big lift cam needs more duration for the same ramp rates as a lower lift cam.

The more duration the more static cr needed.

The more duration the more revs you need.

Targa tas seems like lots of corners and not many peak rpm straights.

88mm stroke is not really 10krpm match.

To me it all points to something with moderate duration.

Decide what rpm you want to push that stroke and what sort of powerband you think suits the event. Target a cam and port flow to suit.