The V8 Owners Forum -

Hi all after a engine refurb mainly to get a bit more torque and eliminate pinking! advice needed on timing, jets, needles.

It's a P5b original 38k 10.5-1 now with Efi heads new guides with latest seals, composite gaskets, Crower High Torque Cam Kit + 22 BHP Over Standard, new lifter chain etc, Std Hs6's, SD1 timing cover and 35D dizzy.

Engine runs fine in the garage at the moment set 4 degrees btc, cam has been run in mixture set roughly on a colourtune , this sort of mod is a bit out of my comfort zone used to original spec stuff I have owned the car 40 years this year doesn't time fly

Thanks for any input.
John.

Hi John,

The engine bay of your P5B looks absolutely magnificent.

Which needles are you currently using? Have any modifications been made to your distributor at all? Are you still running points?

Ron.

Thats a real stunner John!!

I wonder how many coats of polish you have put on that since you bought it

Not answering your question I know but I have to say that engine bay is definitely much loved! A credit to you!

Regards Ged.

You'll do well to eliminate pinking with 10.5:1 on unleaded!
That engine was meant for 5* petrol, now sadly unobtainable.

Chris.

Thanks ChrisJC, ged, mgbv8, RoverP6B Ron

I know when I had the car I could get 5 gallons of 5* for a £1 if I shopped around with Green Shiels Stamps!! anyway back to reality.

The composite gaskets and the heads should take the CR down to 9.5ish -1 so that is good for 95 oct! needles KL 0.090 Jets Aud 9148 and 9149 dizzy RR 35D electronic, I just want to get the set up correct while she is laid up

The polish is free flowing MGbV8 the arms get weak though

johnwp5bcoupe wrote:Thanks ChrisJC, ged, mgbv8, RoverP6B Ron

I know when I had the car I could get 5 gallons of 5* for a £1 if I shopped around with Green Shiels Stamps!! anyway back to reality.

I remember 5 star being introduced in the late '50s, and it was 5 bob a gallon then. And don't remember it ever going down to 4 bob a gallon. You could get 5 gallons of 2 star for a quid, though. But before everyone talks about the good old days, the average working man was lucky to get 10 quid a week then.

By decimalization, in 1972, 4 star was just over 32p a gallon.

The composite gaskets and the heads should take the CR down to 9.5ish -1 so that is good for 95 oct! needles KL 0.090 Jets Aud 9148 and 9149 dizzy RR 35D electronic, I just want to get the set up correct while she is laid up

The polish is free flowing MGbV8 the arms get weak though

If the mixture is weak it's more likely to pink. My SD1 EFI is 9.75:1 and doesn't pink on 95 octane - although the timing is mapped by a MegaSquirt.

Thanks Dave 9.75-1 that will be fine I hope?

5* was available in Cambridge as you say 5/- a gall on but there were two garages who has frequent offers/fights at 4/- not many cars needed 5*'' my old P5 3lt was happy on 2* but this one and the P5b Coupe I had before it were happy on 4* leaded.

I was on £14 for a 6 day week to get a Mortgage

Hi John,

As the HS carburettors run with fixed needles as opposed to the swinging needles in the HIF6 model, the range of needles available is not quite as extensive.

Go for a test run over a course that includes some long gradual hills. At different speeds, say at 1500, 2000, 2500 rpm etc pull the choke out while driving and note if there is a difference in running. If there is none, then the KL needles at that point are pretty well spot on. If there is an improvement, then the needles are too lean at that point, and if the engine bogs down, then they are too rich at that point.

The ideal way to have a needle that suits your engine given the changes that you have made, is to have them polished to suit while the car is on a rolling road, by someone who really knows what they are doing.

My P6B which has a custom built 4.6 litre engine was set up that way and the end result is just brilliant.

Does your engine ping at all with the current ignition timing and the KL needles?

Ron.

Hi Ron I don't know if the Old Girl pinks as I haven't had a test drive yet also I still have the AED so the choke is not an option, also hills to test under load are few and far between in the Fens, I have a pair of HIF6 Pots and Pistons which may be useful?
My intention was to find someone local with the knowledge and a rolling road so that may happen

Thanks,
John.

Hi John,

As far as I am aware, there is no problem with fitting a pair of pistons complete with swinging needles from a pair of donor HIF6 into your HS6. So you have that as an option should it prove necessary in the future.

See how the current set up goes once you have had a test drive. It may well be ok.

Ron.

Do you know whether your EFI heads were 36cc chambers or 28cc chambers? (It could be that the 14 bolt heads were all 36cc but I can't quite remember)

If they were 28cc then your CR will still be very high even with comp gaskets.

Hopefully they were 36cc chambers therefore when they were used with comp gaskets they would have pulled the CR down quite a bit. In my humble the chamber design puts you on dodgy ground at anything over 10:1 if you are using a 'normal-ish' cam and 'normal' fuel.

Assuming that your CR does turn out to be lower than 10:1 you should be able to run 36 degrees all in, you could run a little less if you want to be safe.

RoverP6B wrote:Hi John,

As far as I am aware, there is no problem with fitting a pair of pistons complete with swinging needles from a pair of donor HIF6 into your HS6. So you have that as an option should it prove necessary in the future.

See how the current set up goes once you have had a test drive. It may well be ok.

Ron.

Thanks Ron I will let you know how it goes

sidecar wrote:Do you know whether your EFI heads were 36cc chambers or 28cc chambers? (It could be that the 14 bolt heads were all 36cc but I can't quite remember)

If they were 28cc then your CR will still be very high even with comp gaskets.

Hopefully they were 36cc chambers therefore when they were used with comp gaskets they would have pulled the CR down quite a bit. In my humble the chamber design puts you on dodgy ground at anything over 10:1 if you are using a 'normal-ish' cam and 'normal' fuel.

Assuming that your CR does turn out to be lower than 10:1 you should be able to run 36 degrees all in, you could run a little less if you want to be safe.

Hi thanks for the message they are 36cc chambers 14 bolt ERC 2016 so I am looking at 9.5-9.75-1 ish

http://www.v8forum.co.uk/forum/viewtopic.php?t=133

I had an early 10.5:1 P6 3500, and it was IMHO the best 3.5 version of the RV8 until the Vitesse. None of the later lower compression versions quite got the same power back. Despite claims. Again, IMHO.