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shims
Nov 1, 2015 10:19:25 GMT
Post by guidedog on Nov 1, 2015 10:19:25 GMT
I am in the thro,s of fitting SD1 heads with a Piper camshaft. I am finding that I require shims of over 100 thou to set my preload is this normal ? or have I got something quirky happening. Has anybody else have this come up?
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shims
Nov 1, 2015 13:22:56 GMT
Post by johnwp5bcoupe on Nov 1, 2015 13:22:56 GMT
I am in the thro,s of fitting SD1 heads with a Piper camshaft. I am finding that I require shims of over 100 thou to set my preload is this normal ? or have I got something quirky happening. Has anybody else have this come up? No you should't get it wrong it is all down to the Camshaft Profile I did't need that thickness doing mine, did you fit composite gaskets? have you gone for something wild or just better torque? or more or less standard?
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shims
Nov 1, 2015 15:15:54 GMT
Post by guidedog on Nov 1, 2015 15:15:54 GMT
Hi John I purchased a pair of heads from Geoff Arthur. I have got a short 3.9 from RPI with composite gaskets with all the other goodies. I remember looking at the new heads which have been worked and noticed the valves were a lot shallower than my original heads. I have to assume this the difference between the two. Bob
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shims
Nov 1, 2015 15:32:32 GMT
Post by johnwp5bcoupe on Nov 1, 2015 15:32:32 GMT
Hi John I purchased a pair of heads from Geoff Arthur. I have got a short 3.9 from RPI with composite gaskets with all the other goodies. I remember looking at the new heads which have been worked and noticed the valves were a lot shallower than my original heads. I have to assume this the difference between the two. Bob Ok Bob what do you mean the heads have been worked? have they have been skimmed? a 3.9 short from Rpi why a 3.9? sorry for all the 's but you are working with unknowns The valves in the SD1 are different to the std 3.5 as are the EFi to the SD1
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Post by guidedog on Nov 1, 2015 16:01:48 GMT
Hi John I said the heads have worked they look so different from my original heads they look so shallower with larger valves. Why 3.9? I am trying to achieve the same output as my daily driver, a 2.2 litre diesel output 197 HP. The heads were purchased from a fellow member
I Love my old P5B I feel it needs a bit more.
The original engine will be overhauled and kept for a future owner.
All that I am doing. I know is against the grain. At my time of life I want to experiment.
Bob
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shims
Nov 1, 2015 19:00:05 GMT
Post by johnwp5bcoupe on Nov 1, 2015 19:00:05 GMT
Hi John I said the heads have worked they look so different from my original heads they look so shallower with larger valves. Why 3.9? I am trying to achieve the same output as my daily driver, a 2.2 litre diesel output 197 HP. The heads were purchased from a fellow member I Love my old P5B I feel it needs a bit more. The original engine will be overhauled and kept for a future owner. All that I am doing. I know is against the grain. At my time of life I want to experiment. Bob I was just being curious Bob no other reason Have the heads be planed to allow for the composite gasket? not planed? just curious what the Compression Ratio will be? the SD1 was 9.35:1 you really need to know Bob I go fed up with the pinking Bob roverp5.proboards.com/thread/6559/having-new-headsThe std 3.5 was 158 bhp at 5200 rpm my Coupe was 146 bhp at the wheels which is around 180 bhp at 4000 rpm I didn't go above 4000 rpm as it was pointless! If your trying to match your Diesel look at the Torque at a given RPM and compare my engine gave max Torque at 2500 rpm. Keep up the good work 158 5200
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shims
Nov 1, 2015 19:19:52 GMT
Post by guidedog on Nov 1, 2015 19:19:52 GMT
Thanks for the information John.Yes composite heads have been fitted.So hopefully I will be on 9.35: 1. But with my pre-load being so big I am a little suspect on the skimming of the heads.As you know to much will give a higher compression. Now that the heads are fitted I cannot do check until complete then I will do a compression test.
I know I will not match the diesel, it has a 8 speed auto box fitted. I'm afraid I am getting to the stage I prefer to drive the daily.
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shims
Nov 1, 2015 20:43:50 GMT
Post by guidedog on Nov 1, 2015 20:43:50 GMT
I don't expect to much I just want a little more. I am bound to improve the old girl I had ring gaps of 37 thou. Back to compression ratio's to determine that I will have to take the heads off, At least in retirement it gives me something to do.
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Post by johnwp5bcoupe on Nov 1, 2015 21:03:00 GMT
I don't expect to much I just want a little more. I am bound to improve the old girl I had ring gaps of 37 thou. Back to compression ratio's to determine that I will have to take the heads off, At least in retirement it gives me something to do. You can measure the head thickness Bob if you Google it there is a lip where you can check it! You may need a drag strip to test it
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shims
Nov 1, 2015 22:22:09 GMT
Post by enigmas on Nov 1, 2015 22:22:09 GMT
Your problem may stem from using an aftermarket camshaft (not a 'reprofiled' original camshaft). Reprofiling an original camshaft reduces the base circle...this is how additional lift at the lobe is gained. The heel (base circle) of the camshaft you've fitted may be improperly ground/profiled, although .100" is enormous!
The only other issue as John has pointed out might be due to excessive skimming of the head surface. I'd measure the combustion chamber volumes (cc them using ATF as the medium). This will also indicate the compression ratio.
PS. I posted combustion chamber volumes of various cyl heads on the board some time back so a search may locate it.
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shims
Nov 1, 2015 22:22:45 GMT
Post by petervdvelde on Nov 1, 2015 22:22:45 GMT
I bought as set of shims from V8 tuner. You get 3 sizes. I measured one i didn't need and it is approx 1,2mm I assume you already have a instruction how to deal with setting the preload. If not please let me know and i can post the instruction
Peter
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shims
Nov 1, 2015 22:58:39 GMT
Post by guidedog on Nov 1, 2015 22:58:39 GMT
Yes thank you Peter I understand the system Its the extra shims I seem to need. Which is not normal. Tomorrow will remove head to determine volume.
Enigmas, the camshaft is a Piper which is used a lot in the U.K
Good idea, John I can compare the old heads to the new.
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shims
Nov 2, 2015 9:03:10 GMT
Post by guidedog on Nov 2, 2015 9:03:10 GMT
Who's a silly B****r then? It helps if I measure the right follower. I set up N0 1 on Friday (inlet valve) Got new feeler gauges on Sunday morning went to the pub as one does on a Sunday. I got back from my little drinkys. Tried my NEW feeler gauges and yes I tried them on the exhaust valve. We know have a pedestal gap of 68 thou. insert 50 thou shim = 18thou gap X 1.6 = 28.8 thou there is my pre load. There's a motto there. Don't play silly B****rs with mechanics when you have been drinking. At my age I should know better.
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Post by guidedog on Nov 2, 2015 12:36:08 GMT
Plan B . Having checked all the pre loads I have changed the shims to 32 thou.
I am now putting all the ancillaries back. Then waiting for the manifolds & rocker covers to come back from powder coating.
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