replacement engine ideas for 91 classic

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Originally Posted by 350RRC

Go for a top hatted 3.9 or 4.6 and get a quality LPG system installed. A bloke at Crafers could assist here. :)


cheers, DL

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Pardon my ignorance, but what exactly is a 'top hatted 3.9' ??? - another set of (better or longer-lasting or more expensive) fancy heads ? What are the advantages with (a) Petrol and (b) LPG

Do 3.9's benefit from a cam modification? - something more suited to LPG perhaps. - A mechanic aquaintance explained it in terms of timing of valve opening and the (faster) rate of opening as well as time open/closed.

Heading towards LPG if I decide to keep the EH....

Thanks.

top hat bore liners, they stop the liners shifting. Have a search on here, plenty of info

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Do 3.9's benefit from a cam modification? - something more suited to LPG perhaps. - A mechanic aquaintance explained it in terms of timing of valve opening and the (faster) rate of opening as well as time open/closed.

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IMHO there are few cams better than a standard 3.9 cam for an RV8.

There are several posts on here where people have fitted a different cam and been disappointed with the result.
While "hotter" cams can give benefits to light road cars , if done with other mods such as heads, extractors etc, they can make a 2 tonne unloaded 4WD gutless at the revs you use on the highway, and introduce a need to change down on every decent hill.
More torque at low revs is what is needed in a 4WD and CCs are the best remedy.
Regards Philip A

Thanks Vern, - the "Thanks" icon seems to have vanished...

PhilipA, ditto. - makes some sense as the '89 I was using to pull a 1.5 ton sweeper/trailer had been fitted with a warmer cam...pulled great from stopped, but was gutless at 90+ km/h, whereas a D1 with the 4cyl diesel was painful for the first 60 metres...then quietly got faster and fasterandfaster to.... easily beyond 100km/h pulling the same boat-anchor.

So, keep my 3.9 standard until the liners shift too much, then replace with shift-less 'Top-hats'. Makes sense to the wallet! (gunna be lightened with the LT-230-in / BW-out then the LPG conversion.

Holiday in SA is sounding good :D

CC's ???

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CC's ???

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As in Cubic centimeters
As in 4600CCs (or 5000Ccs) vs 3950CCs.

Regards Philip A

Ah.... cc

- undercanstumble. :D