Engine Build

[Matt_]

Building a new engine for my chimp at the moment and thought I'd share the spec/plan all suggestions welcome.

4 Litre base engine w/ circa 40K on it
Piper 270i Cam
New followers
New Valve springs (deciding if it's worth going harder or not)
New Vernier cam gear, chain etc.
Ported heads with a mild skim to bring the C/R up slightly
New oil pump
New Rings
New Bearings
New gaskets, fasteners etc. all round.

Hoping it'll make around 240bhp when all done.

Best Regards
Matt

[Boosted LS1]

Or, you could leave the engine alone and fit a turbo

Boosted.

[Matt_]

Boosted LS1 said:

Or, you could leave the engine alone and fit a turbo Boosted.

Which is much more my style as you know

Twin Turbo LS6 has got to be the way to go though if that's the route to go, this one will at least get it up and running again for very little cost whilst I think about what to do..... have a 2.5 Litre Noble Spec Duratec spare which would go in without too much bother using an S-Type box.....

[Boosted LS1]

Matt_ said:

Boosted LS1 said: Or, you could leave the engine alone and fit a turbo Boosted. Which is much more my style as you know Twin Turbo LS6 has got to be the way to go though if that's the route to go,

Got one of those here and a titanium 427 on the way!

Boosted.

[Matt_]

Boosted LS1 said:

and a titanium 427 on the way!

Now that would go well in the chimp!!

[mongoose]

Matt_ said:

Building a new engine for my chimp at the moment and thought I'd share the spec/plan all suggestions welcome...... Ported heads with a mild skim to bring the C/R up slightly....... Best Regards Matt

Just a thought,but rather than skimming the heads,you might get the higher cr you want by just using different gaskets,thus saving some of the life of the head for a time when you might really need to skim it.

[Matt_]

mongoose said:

Matt_ said: Building a new engine for my chimp at the moment and thought I'd share the spec/plan all suggestions welcome...... Ported heads with a mild skim to bring the C/R up slightly....... Best Regards Matt Just a thought,but rather than skimming the heads,you might get the higher cr you want by just using different gaskets,thus saving some of the life of the head for a time when you might really need to skim it.

Have had a look at that route, can't find one that will increase C/R over the standard steel ones, Composite gaskets seem to drop compression a fair bit (so good for a turbo conversion). Do you know of any off the shelf?

Best Regards
Matt

[Mongoose]

Matt_ said:

mongoose said: Matt_ said: Building a new engine for my chimp at the moment and thought I'd share the spec/plan all suggestions welcome...... Ported heads with a mild skim to bring the C/R up slightly....... Best Regards Matt Just a thought,but rather than skimming the heads,you might get the higher cr you want by just using different gaskets,thus saving some of the life of the head for a time when you might really need to skim it. Have had a look at that route, can't find one that will increase C/R over the standard steel ones, Composite gaskets seem to drop compression a fair bit (so good for a turbo conversion). Do you know of any off the shelf? Best Regards Matt

If youve already got the thinnest 'tin' gaskets,then obviously theres not much more you can do here,but whats your cr at the moment then?Just one other thing,have you heard about the new 'stealth' cam?(it sound the business)

[Matt_]

Looking at 9.5:1 at the moment so not particularily extreme but seems lowest I can go with different head gaskets is 9.3:1, not a lot of difference really so perhaps I should just stick with 9.3:1.

Heard the 'Stealth' cam mentioned, my main priority is reasonable poke in the 1500rpm - 5500rpm range. Who sells the 'Stealth' cam?

Best Regards
Matt

[GreenV8S]

Matt_ said:

Ported heads with a mild skim to bring the C/R up slightly

It seems that skimming the block instead produces more benefits because it increases the squish, but I would want to talk to an engine specialist before making that decision.

[Matt_]

GreenV8S said:

Matt_ said: Ported heads with a mild skim to bring the C/R up slightly It seems that skimming the block instead produces more benefits because it increases the squish, but I would want to talk to an engine specialist before making that decision.

Time to get my books and slide rule out and do some math

Matt

[Mongoose]

Matt_ said:

Looking at 9.5:1 at the moment so not particularily extreme but seems lowest I can go with different head gaskets is 9.3:1, not a lot of difference really so perhaps I should just stick with 9.3:1.

I've read this a couple of times and i'm not quite sure what your saying there?Do you know for sure you have the thinnest tin gaskets?

Matt said:

Heard the 'Stealth' cam mentioned, my main priority is reasonable poke in the 1500rpm - 5500rpm range. Who sells the 'Stealth' cam? Best Regards Matt

This is the new cam from Rob Roberts(v8 Racing/V8 developments)

[Boosted LS1]

GreenV8S said:

Matt_ said: Ported heads with a mild skim to bring the C/R up slightly It seems that skimming the block instead produces more benefits because it increases the squish, but I would want to talk to an engine specialist before making that decision.

True but this can also be achieved with thinner gaskets or no gaskets If previously using a composite then a tin gasket could be used instead. That would help Rover pistons run so far down the bore that there's probably virtually no squish effect. A thinner gasket would certainly help 'get in the zone', just.

Boosted.

[Mongoose]

Boosted LS1 said:

True but this can also be achieved with thinner gaskets or no gaskets If previously using a composite then a tin gasket could be used instead. That would help Rover pistons run so far down the bore that there's probably virtually no squish effect. A thinner gasket would certainly help 'get in the zone', just. Boosted.

I know when i enquired with Ray at V8D,the thinnest tin gasket would increase my CR by almost one whole unit,ie from 10:1 to 11:1,from my standard composite gasket.

[Matt_]

99% sure I've ordered the thinnest tin gaskets available but will have to check. Based on the thickness I have for them C/R with my current engine spec would be 9.3:1 based on book values.

I'll give Rob/V8D a bell to discuss cams and gaskets. Thanks for pointing this out, much appreciated.

>> Edited by Matt_ on Sunday 30th April 22:43