My Compression test results are all over the shop

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Originally Posted by djam1

What sort of running do you do in it short distance??
If so give it a really good flogging for 1000 ks or so it may come good either that or it will finish it.
3.5 l Rover motors dont mind a bit of hard work try it you may be suprised by the result.
I say this of course for an engine that the only evidence of a problem is a compression test if there are other signs then dont waste your money.

Ps was the engine hot or cold when you did the test??

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The engine was hot... well hot-ish, you can't exactly work on an engine that has just been shut down. Kinda hard to flog this engine, since even on LPG it will detonate at around 4,000 rpm. It really needs the mechanical advance curve to be changed on it to suit the characteristics of the engine.

I just did a quick calculation. For 12:1 Compression I shouldn't get anything higher than 175psi. Something is fishy with number 8.

Stirsilver
I wouldnt get too hung up about cylinder 8 I personally in the past have spent thousands in this situation and achieved little.
Give it a good run then test it again maybe even ignore it I recall another post where the compression is 80psi that I would be worried about but your minimum is still fine yes I understand the 10% rule but does it matter that much.
Well I guess thats a matter of opinion if you want to drive it to London today then maybe its an issue but if you are going to hoon around Victoria but youself another block and build it up in your spare time.
Sorry to be so simplistic but is it really worth the cost
I would be trying to look into the detonation issue though may be a better allocation of your resources

Just drive it thrash it enjoy it and sell it off when its finished

Duane

When you want to sell it email me

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Originally Posted by stirlsilver

, since even on LPG it will detonate at around 4,000 rpm. It really needs the mechanical advance curve to be changed on it to suit the characteristics of the engine.

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I'd be getting onto this weeellllllllllllll before worrying about compression tests:eek:

They're only little springs and wieghts

Stirlo last weekend when you gave it a gutfull there was a puff of blue smoke and a smell of oil.This happened a few times.Cheers Brett

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Originally Posted by djam1

Sorry to be so simplistic but is it really worth the cost

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Duane I think you hit the nail on the head there. It's sorta how I was actually starting to look at the issue. And the whole "don't fix it if it ain't broke"

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Originally Posted by djam1

I would be trying to look into the detonation issue though may be a better allocation of your resources

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Yeah I have looked into this, I found a place that would do an overhaul and re-curve of the distributor for $200. Trying to decide whether I should do it. I'm running the engine without any vacuum advance as it made the problem worse by detonating when you give it a quick squirt. 12:1 compression is just a can of worms. It was a good little project though I learnt a lot from it.

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Originally Posted by djam1

When you want to sell it email me

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I was given strict instructions by my dad not to sell the car under any circumstances since so much time, effort and money has gone into it. But I am beginning to reach the stage where maybe a new project would be good. Something coil sprung to begin with. We will see.

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Originally Posted by rovercare

I'd be getting onto this weeellllllllllllll before worrying about compression tests:eek:

They're only little springs and wieghts

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Really don't like my chances of getting it right doing it myself... What do these engines usually rev out to? 6,000rpm? because at 4,000rpm it sounds like it's reaching the end of the chain (vibration) but I'm pretty sure the reason it becomes rough at this speed is because it is being over advanced.

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Originally Posted by V8Landy

Stirlo last weekend when you gave it a gutfull there was a puff of blue smoke and a smell of oil.This happened a few times.Cheers Brett

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Thanks Brett, under engine breaking the engine pulls some oil into the cylinders I think it's down the valve guides. Something it has always done, I think the valve guides are a bit worn letting oil in.

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Originally Posted by stirlsilver

Really don't like my chances of getting it right doing it myself... What do these engines usually rev out to? 6,000rpm? because at 4,000rpm it sounds like it's reaching the end of the chain (vibration) but I'm pretty sure the reason it becomes rough at this speed is because it is being over advanced.

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Just need various springs and wieghts and a timing light, then play around, if no vac advance, which you disconnect to set up mechanical advance anyway, you just change the springs and wieghts, then rev it and check the timing with the light;)

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Originally Posted by rovercare

Just need various springs and wieghts and a timing light, then play around, if no vac advance, which you disconnect to set up mechanical advance anyway, you just change the springs and wieghts, then rev it and check the timing with the light;)

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You make it sound too easy :p

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Originally Posted by stirlsilver

You make it sound too easy :p

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If you can build a 12:1 3.5, you should be able to change the mechanical advance curve;), It is that easy, not sure on where to source bits for rover motors though, I never play with them, I pull them out and put something worthwhile in usually:angel:, only one I ever kept was the supercharged one and timing was controlled via the unichip:eek:

Would love to build something electronically controlled. Something with the megasquirt ecu or something. Electronically controlled fuel and ignition. Ohhh that would be a cool project. Maybe... one day, I would probably try to get an LPG injection kit in there too Oooooo. Ok now i'm talking big bucks. Dreaming... again maybe one day.