18 replies to this topic

[Icey]

The block gets pocketed not the head.

The main cost, if you're not doing the work yourself, is getting engine out of the car and stripped to a bare block then reassembled. The actual machining I don't believe should be all that expensive (I've never commissioned such work so don't know figures).

 

Over-carbed means that those carbs are too large (or there are to many of) for the capacity/output of the engine. Main issue will be getting them to flow a low enough volume of fuel to not be overly rich, there are other secondary problems as well (poor air/fuel mixing etc..).

 

 

What to do next? Depends what you want the car for. If it's just to tool around in as a daily-driver then you might find it behaves better reverted to a stock 998. If it's a play thing then you could start looking at what performance changes to make next, treating this as someone's unfinished project.

[Staddon]

The block gets pocketed not the head.

The main cost, if you're not doing the work yourself, is getting engine out of the car and stripped to a bare block then reassembled. The actual machining I don't believe should be all that expensive (I've never commissioned such work so don't know figures).

 

Over-carbed means that those carbs are too large (or there are to many of) for the capacity/output of the engine. Main issue will be getting them to flow a low enough volume of fuel to not be overly rich, there are other secondary problems as well (poor air/fuel mixing etc..).

 

 

What to do next? Depends what you want the car for. If it's just to tool around in as a daily-driver then you might find it behaves better reverted to a stock 998. If it's a play thing then you could start looking at what performance changes to make next, treating this as someone's unfinished project.

Thanks for replying! i could take the engine out and strip it all down to get the block pocketed, that shouldn't be a problem... so, if the block is pocketed to allow for the 1275 head, will that help the dual carbs on the small bore with the fuel mix?

 

it won't be a daily driver, just for a summer toy, so can manage to do a bit of work on the engine, however, don't want to do a lot as I've heard you don't get a huge amount for your money when upgrading a 998, and are better off sourcing a 1275. 

Edited by Staddon, 22 June 2015 - 02:07 PM.

[Icey]

I wouldn't have thought so. If everything else is still standard you're not going to have increased the power output by a huge margin ( although in all honesty I don't actually know what %age gain you might see from just the head change).

 

It's a mixed bag with the 998 vs 1275 thing. Yes, the 1275 is a better base if you're chasing power but a good number of people prefer the way the 998 drives (and that they are cheap should you bust one).

 

My personal preference for single carbs - twins do produce better results for outright power but until you've exhausted the capacity of a single I don't see added complexity as a worthwhile trade-off when there are other areas worthy of attention.

 

So - maybe sell the twins and go to a single HS4 or HIF38? Then sort out the head and block combination with any excess cash generated? Just one suggestion.

[Staddon]

Alright, ill look into it all and see where i go next, thanks for the advice - appreciated!