Compression test

[olderisbetter]

I did a test in on my 58 traveller today , It has a 948 engine that has a few rattles and noises, The compression was 160 -170 on all cylinders and went up by 5-10 psi per cylinder when i added some oil, It does gives a bit of bluey smoke if i rev it, I do not do many miles in it so hard to say if it is using oil but i was wondering if it could be valves seals or worn rings, I know its a bit of guess work but i was looking for any advice on simple tests or maybe something i can look at trying.

[les]

You would expect it to go up if you add oil. The figures quoted before you did that sound good. Can't see you have a problem there!

[Budgie]

With 160 psi I wouldn't worry too much if I were you. My tourer has 120 psi on all four cylinders and runs like a Swiss watch , uses no oil an pulls like a good un.

[olderisbetter]

Thats good compression then, i just need to get it running a bit nicer, the rattle makes me think timing chain so it looks like a bank holiday monday job for me.

[les]

If you don't mind a modification a marina set up has a tensioner for the timing chain. You need the back plate and cover though.

[olderisbetter]

Thanks Les, i have a mate into marina bits i will nip round and see if he has some bits.

[dalebrignall]

those figures are very good

[philthehill]

The Marina/Ital front engine plate is not suitable for use on the Minor as it does not have the ability to be able to attach the Minor engine mountings.
The Marina/Ital engine mounts are bolted directly to the block at about mid distance along the block.
The Minor front plate can be used and is easily modified (use the Marina/Ital front plate as pattern) to accept the Marina/Ital tensioner assy. You will need the Marina/Ital timing cover as it has the required bulge to accommodate the tensioner.
If you want to use a duplex chain with the tensioner the timing cover has to have the timing sensor indent removed and the internal ring plate around the timing cover seal may have to be removed/modified.

http://www.minispares.com/product/Class ... sic/timing chain tensioner.aspx|Back to search

http://www.minispares.com/product/Class ... sic/timing chain cover.aspx|Back to search

[les]

My mistake regarding the plate, Phil is of course, right!

[olderisbetter]

Les, it is ok i do things quite slow at the moment so it may be weeks before i get into this, And Phil i think i will grab that kit while they have some left.

[oliver90owner]

i was wondering if it could be valves seals or worn rings,

Bad rings will make smoke all the time. Bad seals or worn guides typically give you a blue puff on acceleration, after idling for a while. Reason being that at idle the induction vacuum is high and that tends to drag oil down the inlet valves, which is then cleared as the air flow carries it into the engine on acceleration, giving the blue smoke as it clears.

Not a foolproof test as crankcase pressure can cause problems, too - but not a lot leaking past the pistons with those compression test results.

[SteveClem]

Well, as you're not doing lots of miles and the compression is good, I'd just live with the odd puff of smoke. Bet it'll last another ten years at least. My old beetle has been puffing out fumes on start up for years but still running well.

[IslipMinor]

If one of the main 'few rattles and noises' is the timing chain, converting to the 'duplex' chain is a very easy change. The only real work required is to countersink the 2 bottom holes in the front plate (the 2 below the crankshaft sprocket). Apart from that it is a straight swap.

We did the conversion on the original 948 engine many years ago, and never had any problems in 10's of thousands of miles.

The current 1380, being Midget 1275 based, has the duplex set-up as original fit, and again has never given any problems, even with a very high lift cam and high(ish) revs (up to 7,000rpm) used with great enjoyment!

There are duplex kits on eBay for around £30, but if you go that route, make sure that the kit includes the 2 countersink head socket screws for the bottom two holes.

[olderisbetter]

IslipMinor, Do you mean a kit like this?
http://www.minispares.com/product/Class ... o%20search
I have a few bits to order from minispares...mainly gaskets

[philthehill]

As regards the two countersunk screws for the front engine plate these are better than the two Pozidrive screws supplied with the kit.
They are what I use in lieu of the Pozidrive screws.
Use Loctite lock & seal to secure in place.

http://www.minispares.com/product/Class ... sic/duplex countersunk screws.aspx|Back to search

Whilst the correct counter sink angle required is 82 degrees for a UNF screw - if you only have a 90 degree countersink that will suffice.

[IslipMinor]

Definitely the socket head countersunk head screws - not Posidriv.

Not sure if I'm allowed to say this, but my experience with your chosen supplier has been extremely poor if there has been a problem - have not used them for a long time now.

[olderisbetter]

Thanks oliver90owner, I see what you mean, and Beetles...i have one and yes the smoke is normal even though mine has a modern fuel injected engine, Those hex screws look good, i will add to my list of bits, i might aswell get a few at that price as i think i have space in a drawer again, Thanks all.