Heads Questions - soooo many choices!

[Warks_Dubber]

Evening Folks

More daft questions from me...

Following all the decisions made about upgrading the bottom end with new cam etc.... that has been put on hold...

Now the current thinking is replace the heads this winter to get the most from the new 48's I've got.. and increase the compression ratio...

So......

I currently have a pair of Magnum 044 Sport Heads with 40 and 35.5 valves... these I believe are too small...

Can somebody give me an idea of the value of these with and without the Scat 1.25 ratio rockers is?

I have a set of 1.4 ratio rockers waiting to be used, can they be used with my current FK7 cam or should I stick to the 1.25's for now?

The engine is a 2110 with 90.5 long stroke pistons.

Also what heads are suitable for use? I have been looking at a similar make to what I have now but with the larger valves?

I can't afford expensive ones as most upgrade money has to go to pay for a cage... I am hoping selling the current heads will pay for a significant chunk of new ones (good used ones are fine)

Many thanks as always for your help....

Jas.

PS... If anyone fancies sponsoring the new VWDRC Sportsman Champion and Rookie of the Year... please get in touch!!!

[Mike Lawless]

You will be limited on valve size by the small bore. Maybe a 44mm intake would fit with the existing exhaust size. But the port configuration is what is important. There are some pretty potent motors with the valve sizes you already have. It's all about balance and optimizing what you have, not so much about bolting on new parts.

If you need to change heads, the CB CNC head line is a lot of bang for the buck and there are several configurations to choose from.

If you decide to move to 1.4 rockers, a few things need to be checked. Firstly, coil bind at the valve spring as well as retainer to guide clearance. Then valve to piston clearance.

I would rely NOT on what people say. It needs to be physically checked to be CERTAIN.

[Zach Gomulka]

Mike is right about that...

Since the cam is on the smallish side, huge valves may not give you what you're after. All parts of the engine need to aim toward the same goal for best results.
Your FK7 was designed for 1.4:1 rockers, use them.
If you want to dive deeper than that, consider flycutting your current heads and/or lowering the deck height to increase CR (to about 9:1).  Possibly a valve job/port work while you have them off. If you want to go deeper still, upgrade to "slip in" 94's for 2276cc (increasing displacement will also raise CR). Personally, I believe 40x35.5 valves work great with that cam. If you go to bigger valves you may just hurt the torque, and not gain any HP up top because your cam will already be done by then.

[Udo]

I am with you both . with that cam bigger valves make not much sense - or if you think about changing the cam later ...
I had 3 82 x 90,5 engines for street with 195 hp - that was a lot of fun. all are with pauter cams and hand ported heads

Udo

[Warks_Dubber]

Thank you as always folks...

Good to have advice from those who know!

I am learning fast, but still have limited experience of performance engines... Not yet on the curriculum for the 7 year olds I teach! lol

I like the idea of increasing to 2276... Can that be done with no machining? if so, certainly a viable option...

I will definitely move to the 1.4 rockers, and get manifold and porting work done to the heads..

This may be the best way forward for me given the advice you have all given about my current heads...

Jas.

[Zach Gomulka]

I like the idea of increasing to 2276... Can that be done with no machining? if so, certainly a viable option...

The base of the cylinders need to trimmed down to fit in the 90.5 hole, they can be purchased this way.
The heads need to be opened up for the 94's.
No case machine work though.

[Neil Davies]

You could always go to 2180cc with 92mm pistons. No machining needed at all, although you may want to flycut the heads to up the CR.
My Dad and I built a 2180 as our first performance motor about 10 years ago using a set of 041 heads that had 40 x 35.5 valves in them. They were cut for 90.5/92mm P&Cs when I bought them so we went for the 92s. We had the compression set at around 11:1 IIRC with an FK89, and I seem to remember we went very low 13s before it broke. We learned a lot about rod bolts with that motor though...
I've still got the heads and I'll be getting them cut for 94's at some point in the future so I can build up a STF 2276 with some of the other spare parts I've got kicking about, but that's simply because I've got a set of lightly used 94mm P&Cs!

[steve_pugh]

Don't the 92s have very thin walls?   I know you can get thick wall cyls but then you'd need to do the same as 94s and have the base trimmed to fit, and also the top.
Makes more sense to go 94mm with the smaller base for the case.   
Machining the heads to 94 won't be a bank breaker either.     Join the 2276 crew Jason!   

[Warks_Dubber]

It's certainly looking that way Mr Pugh!!
I'm sure I'll be bending your ear tomorrow night about it!!

[Neil Davies]

Don't the 92s have very thin walls?   I know you can get thick wall cyls but then you'd need to do the same as 94s and have the base trimmed to fit, and also the top.
Makes more sense to go 94mm with the smaller base for the case.   
Machining the heads to 94 won't be a bank breaker either.     Join the 2276 crew Jason!   

I was using them in a strip-only motor, but as long as you're not racing a bus you should be fine! You won't get 100,000 miles out of them, but hell, you wouldn't expect that from any motor you're racing!

[Warks_Dubber]

I like the idea of increasing to 2276... Can that be done with no machining? if so, certainly a viable option...

The base of the cylinders need to trimmed down to fit in the 90.5 hole, they can be purchased this way.
The heads need to be opened up for the 94's.
No case machine work though.

Hi folks
I've decided to go for the increase to 2276.... I have bought some wedgeports to sort the head issues... now I need to get the B&P's...
Can someone please point me to where I get the ready trimmed ones or suggest what I need to get?
Reminder I currently have 90.5's, on 82mm crank and 5500" h beams
Many thanks
Jas.

[richie]

I would open the case for the 94 barrels, that way if you ever have a problem you can just replace a commonly available part easily, but otherwise you can get any 94mm cylinder machined down to fit the case as it is now

cheers Richie