Wel looking at the linear displacement of the cam lobe, and the actual lift at the valve, the rocker ratio is 1:1.1

So your 280* newman with its lift of 8mm, would give a valve lift of 8.8mm, which sounds about right!

The 284* newman has 8.7mm of lift, or something like that.

This.

This is emphasized further in the 16v engines.

The 1.4 16v 100bhp AFH was a twin cam version of the 86c/6n1 single cam engines, with camshaft lobes pushing against a hydraulic bucket tappet directly in line with the valve. Therefore the valve lift is the same as the cam lobe height.

In the other small block 16v design including 1.4 16v 100bhp engines found in the 6n2/9n, the head is a twin cam version of the old mech heads (but with hydraulic stem tensioners in place of static rocker adjusters).

This type also limits the lobe size as the cam slides in the side through the bearings. The lobes on the second 100bhp engine have nowhere near the lift of the AFH cams.

This doesn't mean the valves don't lift much though. The rollers are not at the valve end of the rocker. They're nearly halfway along - so this gives them a leverage effect, the gear ratio I don't have to hand but it means the lobe has to be a very different shape to an AFH's in order to lift the valve in the same way. So the cam appears to have a very wide duration with very little lift compared to the AFH, but once translated by the geared roller rocker, the operation of the valve is about the same as the AFH.

Therefore a less aggressive cam in this could prove to be more aggressive in practice. So yes, the non-rocker heads need bigger lobes to achieve the same lift as the rocker heads.

Aaaah I see, thanks for explaining that.

I had both of them links in my favourites from googling the other day Max.

I'm waiting on a couple of motorsport camcovers showing up in the post.

Edited 17 December, 201213 yr by Winston

I had both of them links in my favourites from googling the other day Max.

I'm waiting on a couple of motorsport camcovers showing up in the post.

Whats the difference in the "motorsport" camcovers then dude?

I've been thinking about taking some measurements...

They are made of ally and look pretty. The fins might aid cooling, they do on the big block motorsport covers but the fins are larger.

I'm sure you could make your own at work tbh

The 280 cam in mine seems mild, but I haven't ever run it in a 1.3. The schrick 268 in my other saloon on an otherwise stock 3F setup seems much more jekyll and hyde, the power only comes in above 3k. The 280 mech on the ABD would pull fine from low down even with the very tall 5th I was running.

Ah have you got the newman 284* in your set-up your running now gaz?

I never had a newman anything!

1.4 ABD - Mechanical head - Schrick 280 - Setup details on page two, I had it up and running in 2010 although it's currently mothballed it will be back on the road in the new year. In Jan '11 it made 95bhp at the CP RR day. I could make several excuses as to why it didn't make more than that, but I will wait and see what happens when I run it again.

1.3 3F - Hydro head - Schrick 268 - Not much more I can say about it. It's decatted. If it has a chip I've no idea what it is.

Out of the two the 1.3 setup seems to have it's power band come in higher up the rev range, but that was always the advantage of the ABD; Torque comes in from about 2k with the 3F cam and management. I have a few printouts somewhere.

okay, I've been waiting for a thread on this to be out up for a while!

firstly, the abd bottom end, is it literally a bottom end swap or is there more to it?

secondly, where can I get a cam for my hk? nowhere I've looked lists them!

I want to keep engine, so feel like doing some bits too it, already have carbs to put on

any help is appriciated :)

okay, I've been waiting for a thread on this to be out up for a while!

firstly, the abd bottom end, is it literally a bottom end swap

That depends... On a 3F; yes, on a HK (I assume it's a HK you're interested in), Swap the ABD crank pulley and water pump for some square tooth items (from a late mk2/very early mk3) and then you also have a yes.

secondly, where can I get a cam for my hk? nowhere I've looked lists them!

German ebay, newman I guess, based on above discussion?

The newman 284 or schrick 280 sound perfect then cheers Gaz :)

1 of 2 packages

Sorg Motorsport by Winstang, on Flickr

Cool bit of reading i found;

http://www.cpgnation.com/forum/comp-cams-l...-tech-2629.html

How much were they winston! I hate you...

The newman 284 or schrick 280 sound perfect then cheers Gaz :)

1 of 2 packages

Sorg Motorsport by Winstang, on Flickr

Looks orite i guess

Forced induction mechanical head... what valves would be classed as a upgrade to run say, on a G40.... I like the sound of them being more reliable with revs....

Edited 19 December, 201213 yr by v dub polo shaun

Looks orite i guess

Forced induction mechanical head... what valves would be classed as a upgrade to run say, on a G40.... I like the sound of them being more reliable with revs....

Standard hyrdo head valve sizes are 36 & 29mm arent they? So not much bigger than that dude.

Still think youd be better off with the hyrdo

What's all this revs talk....surely solid tappets and upgraded springs in a Hyd head will be better for revs too

Edited 19 December, 201213 yr by harris.racing

Looks orite i guess

Forced induction mechanical head... what valves would be classed as a upgrade to run say, on a G40.... I like the sound of them being more reliable with revs....

Standard hyrdo head valve sizes are 36 & 29mm arent they? So not much bigger than that dude.

Still think youd be better off with the hyrdo

Well big valve hydro stuff, is it the same valves for solid and hydro so technically i could fit bigger valves that would fit a hydro into a solid if the valves are recut e.t.c

What's all this revs talk....surely solid tappets and upgraded springs in a Hyd head will be better for revs too

Well i can get a decent condition solid lifter basic head so seen as i could save money on lifters and skimming I'm all for it, cam i guess wont fit with the lobe being a different ramp due to valves (smoother on the solids I'm guessing?) and dizzy, well do hydro dizzy's fit, i guess so seen as you can run a mk2 points dizzy on an AFH and a hydro dizzy fits an AFH also so guess hydro will fit solid lifter?

Things like the head CC's, the same as a G head?

Edited 19 December, 201213 yr by v dub polo shaun

Looks orite i guess

Forced induction mechanical head... what valves would be classed as a upgrade to run say, on a G40.... I like the sound of them being more reliable with revs....

Standard hyrdo head valve sizes are 36 & 29mm arent they? So not much bigger than that dude.

Still think youd be better off with the hyrdo

Well big valve hydro stuff, is it the same valves for solid and hydro so technically i could fit bigger valves that would fit a hydro into a solid if the valves are recut e.t.c

What's all this revs talk....surely solid tappets and upgraded springs in a Hyd head will be better for revs too

Well i can get a decent condition solid lifter basic head so seen as i could save money on lifters and skimming I'm all for it, cam i guess wont fit with the lobe being a different ramp due to valves (smoother on the solids I'm guessing?) and dizzy, well do hydro dizzy's fit, i guess so seen as you can run a mk2 points dizzy on an AFH and a hydro dizzy fits an AFH also so guess hydro will fit solid lifter?

Things like the head CC's, the same as a G head?

I'm not too sure on the "wouldn't a hyrdo head with solid lifters be better?" - Why do 90% of the berg cup boys use them?

Standard vs standard, the hyrdo head, overall is gonna be superior. With peak power in mind, the hyrdo head has bigger exhaust ports (Inlets look to be very simular sized) and bigger valves,

The Hyrdo has 36mm and 29mm inlet and exhaust valve heads respectively, whereas the mechanical has 34mm and 29mm.

But all things considered the ports are capable of holding the larger valves, no issues your aware of with break through or smaller CC areas on the head? The cc's are the same between hydro and mechy? or more to it, mechy and G? Sorry for the questions, quess its kinda relivant and I'm really struggeling finding any specs on them.

Porting to match/improve on hydro specs my mates done a few mini ones before, hes got a home made vaccuum cleaner kinda style air flow gauge think, bloody clever thing that I've no idea how it works, it seems to do a good job on his so I'm leaving it to him. He use to build Isle Of Man TT bike engines so has a ok idea i think, one way to find out. :-)

Edited 19 December, 201213 yr by v dub polo shaun

I mean, that the Hyd head has bigger valves standard, most our engines have them (or the right bottom end anyway)

So we express higher revs...solid lifters & stiffer valve springs should allow a hyd head to rev higher too?

Not moaning that anyone's using a early head - just wondering, it's still a head with solid lifters, cams available off the shelf.

Was thinking in my case of an AFH head fitting solid lifters and upgraded springs it will be able to rev more.

If i wanted to rev my 8v more I'd fit solid lifters to the hyd head, not swap it for another head and make effort of big valves to match the later head.

Ok if you want a BV hyd head you're paying out for valves and new seats anyway so makes no odds which head you use..and can run cam covers like above

They're flat heron design heads dude, so there will be no change to compression ratio if thats what your thinking.

The valve and port centre dimensions are the same mechanical vs hyrdo, so realistically should house the same size valves as the G40 BVH's

From what i've read, the a 36mm inlet valve is about the right size you want, however the exhaust valve is on the small side, which will be sorted if your getting a BHV, as IIRC thats all that is enlarged with the jabba BVH?

I still need to do the propper calculations and see what they come as, but supposedly the material between the valve seats gets dangerously small with anything bigger than 2mm bigger seats, and is not reccommended.

If i was you, and i was set on using a mechanical head (i'm only using one for the sake) i'd get a quote for getting the valves enlarged upto 36mm and 29mm, and some major port work (yes you could just up the boost to get the same air flow, but then your contending with extra heat etc).

Also get a decent camshaft thats specced for a supercharger, double valve springs and a full rebuild.

HK, GK and GL heads will fit onto a G40 block, other mech head engines have a different combustion chamber design; with flat top pistons and recessed valves.

I'm not sure you really need to bother with a mech head on a G40? The main problem with revs on a G40 is that the superchargers aren't overly fond of them. People have been running 8k chips on hydro head GTs and G40s for years - Has anyone ever had a serious problem with the valvetrain on one? (broken springs, valve bounce issues, dropped valves) I don't recall.

Exhaust valves are already bigger on the mech head than later hydro (not sure about 6n 8vs) by a colossal 0.1mm, it's just the inlet valves that are smaller.

When you fit vastly bigger valves there's a chance that the head can crack between a valve seat and a spark plug. I've seen this happen on a stock mech head that we assumed had overheated. There was talk years ago of this being a thing on G40s but it doesn't seem to have become a serious problem with them AFAIK

HK, GK and GL heads will fit onto a G40 block, other mech head engines have a different combustion chamber design; with flat top pistons and recessed valves.

I'm not sure you really need to bother with a mech head on a G40? The main problem with revs on a G40 is that the superchargers aren't overly fond of them. People have been running 8k chips on hydro head GTs and G40s for years - Has anyone ever had a serious problem with the valvetrain on one? (broken springs, valve bounce issues, dropped valves) I don't recall.

I dont think anyone actually fits them to get them to rev to a high speed, but because they tend to be a "Free-er revving engine"

Like i say, they don't offer any performance advantage standard vs standard. I'm using one soley because of the above reason, i've never used one and they're cool as fuck.

The main reason for doing it is its a cheap option to the solid lifters and I'm converting to BVH anyway so the work still has to be done. secondly it is a reason to use a rather nice rocker cover I've bought/buying/dibs on.

Oh and I'm not sure on charged boost, I'm looking at alternatives.

I'll explain to my mate about the plug to valve over heating issue also, see if he can work something out for me. Maybe make the chamber abit smoother on the edges around the plugs at a small compromise to CR . I'm not sure, i'll speak with him :-)

They're flat heron design heads dude, so there will be no change to compression ratio if thats what your thinking.

The valve and port centre dimensions are the same mechanical vs hyrdo, so realistically should house the same size valves as the G40 BVH's

From what i've read, the a 36mm inlet valve is about the right size you want, however the exhaust valve is on the small side, which will be sorted if your getting a BHV, as IIRC thats all that is enlarged with the jabba BVH?

I still need to do the propper calculations and see what they come as, but supposedly the material between the valve seats gets dangerously small with anything bigger than 2mm bigger seats, and is not reccommended.

If i was you, and i was set on using a mechanical head (i'm only using one for the sake) i'd get a quote for getting the valves enlarged upto 36mm and 29mm, and some major port work (yes you could just up the boost to get the same air flow, but then your contending with extra heat etc).

Also get a decent camshaft thats specced for a supercharger, double valve springs and a full rebuild.

Ye thats what i was thinking, thanks Max. LIke i say, I've no idea. Just discovered pictures of some in your thread actually which has helped!

So 2mm increase, thats perfect, BVH here i come then i guess well, its bigger but not exactly big.... lol.

Full blend is sorted, cam however is a issue i need to address, i shall look into specs, will the spec be same as a hydro head but designed for a mechy but same numbers? -__- i feel a right tit asking these questions as I'm sure its very obvious I'm just missing something so thanks for being patient.

Edited 19 December, 201213 yr by v dub polo shaun

Yeah the same overal spec camshaft in the hyrdo head will work in the mechanical head the same way,

But bare in mind that because the mechanical head uses rockers with a lift ratio, the linear displacement of the camshaft, is not the overal valve lift.

The cam lift is 6mm on the HK, but the valve lift is 6.8 (approx) which gives a rocker ratio of around 1:1.1

Contact JMR Racing regarding the headwork, they quoted me £450 for the port work and a total rebuild, new guides etc, with the results found from Tav's head on here, its well worth the money.

Also, regarding the distributor, either the cam or the dizzy will need to be modified. The hyrdo dizzy's are not compatible, drive wise.

I'll be machining a little housing to covert between the two.