1446 replies to this topic

[Tomf]

Very interesting thanks DO you think that it would be hard to make a custom bracket? Does that one mount on the alternator brackets? If so does the fan belt not get in the way?

[The Matt]

It picks up two of the bolts for the timing cover.

The problem is with the trigger wheel. I'll have to seperate the engine mount to change the fanbelt because the trigger wheel is too close to the engine mount to allow enough clearance for the belt to be changed! Ooopsies! That's one benefit of using a modded crank pulley instead of a trigger wheel setup I guess.

As for making a custom bracket, not at all hard really. Using the trigger wheel means that the mount doesn't have to be accurate, as you can set your trigger wheel position after the mount is fabricated, but with using a modded pulley, you can't adjust the position of the 'missing tooth'.

[Tomf]

OH yea i forgot about that, i was planning on laser cutting my current pulley. Ill have to search around a bit and find out about mounting the sensor. I might make it so its adjustable, so i could just adjust that to get the correct position.

[The Matt]

OH yea i forgot about that, i was planning on laser cutting my current pulley. Ill have to search around a bit and find out about mounting the sensor. I might make it so its adjustable, so i could just adjust that to get the correct position.

You got a copy of that drawing that I did for the machining of the pulleys? It's in technical and problems somewhere if you search for 'megajolt' topics. Might be of some use for you??

[Dog]

You've got a 286 cam havn't you Matt?
Can I just be a PITA, and ask what Comp ratio your running (or hoping to)

[The Matt]

You've got a 286 cam havn't you Matt?
Can I just be a PITA, and ask what Comp ratio your running (or hoping to)

Yup, it's a KCMD286. I am also running 1.5:1 roller rockers once the engine's run in though, so I've had to opt for different spring poundage and ensure that they are capable of taking full lift without binding etc.

With the head as it was, it would have been 11.5:1 CR, but I've taken the dremel to the chambers to take it down closer to 10.5:1 (he says as if he did it really accurately). It was fun doing that, I tell you!

At the end of the day, I really, really wanted to do this head myself, if it turns out to be a dog (no pun intended Dog), I'll buy a decent one from elsewhere using one of my MG Metro ones as a donor!

[Dog]

Ahh fair enough, Thanks for the info, atm, I am running 9.5:1 but the engine is designed for a SW5, but after looking at it, I'll need to rebuild a "mild" 1380 after 8-10k miles, so I've now decided say stuff it, and I'm getting a MD286SP (286 scatter).

But I am thinking the same as you, run normal bits still its run in, then swap the bits over. Only thing is, I am tempted to run 1.5 rockers, straight off, as I have 1.3 forged Cooper S rockers, and I was going to shove the higher lift followers on.

I've also, considered going megajolt, as I've been for a spin in a 1293, with a 300deg cam, and well, its smooother than my standard 998!!! So megajolt is a mod I am looking into, but I don't like the idea of running it, one a fresh engine - as I don't like the idea of shoving it on the rollers freshly built. So I was going to run it in, with a dizzy then upgrade....


Anyways, back to your project

[The Matt]

and I was going to shove the higher lift followers on.

How can different followers give you any increased lift? Whaaaaaaaaaaaaa? That's not possiblelablleablle??

[Dog]

They are aftermarket "ultimate" followers, they are machined slightly different on the inside, to give more height by making them shallower.

Minispares sell them, think their about £35 a set... tis what I am getting

[The Matt]

Yeah, but they don't give you any increased lift at the followers, they can't do.

Oooh, hang on, I'd guess they are for use when using high-lift cams to alleviate any clearance issues up top with larger lobed billet cams etc? I've never heard of them, that's all. I fitted the Kent ones that came in the cam kit, they are just chilled iron ones, but I think they are the same shape as OE ones???? At least they're matched to the cam though I guess.

[Dog]

Well they give the same chaircaters (sp) as if u were running 1.5 rockers...

[The Matt]

Don't see how they can Dog. They're a part of a rod, that is directly seated on a cam lobe. That'd mean that if you shortened the pushrod you'd get more valve lift???

I am pretty certain that they are for avoiding clearance issues when using high-lift kit. Rather than providing more lift themselves.

[The Matt]

Meh, me head's nearly finished.



Rubbish photo because it got dark early last night (well cloudy) and there's not much light in my garage. Not as neat as it could be, but we'll see how it performs. The throats are reasonably smooth and sooo much less restricted than before. The valve guide bosses were the main area that I concentrated on. I took them down a lot (got a book that showed me how far to take them) and I also belnded in the direction changes. To be honest, I don't think I'd ever try and do another cylinder head (not to this level) again. I am quite happy stripping them, inspecting them, lapping valves in etc. but the amount of work that's involved in doing porting and chamber work is far more than I expected. I would now be quite happy to spend £500 on a good head, or even a lot more. I can now really appreicate the value of them!

As it stands, it's got 36mm inlet valves and the 29.5mm exhaust valves. I think that this head may be just a temporary one, until I can afford something special. Basically a 'running in' head. But I'll see how it runs before I make any decisions.

[Dog]

Nice work dude!

Open the ports a bit more IMHO, to get the most from your weber....

[The Matt]

Well, I was going to, but to be honest I'm sick of doing it now!

It's taken out so that the outer face matches the gasket (well, pretty much) and there's about 2mm of metal around the pushrod holes. I could take it out alot further, but I'm pretty convinced that I'm going to end up going for something pro-built once the engine's run in.