940s 2.0 compression values.

[Vanadeo]

Hello..

New 940s owner 1992 2.0l b200f. It has piston slap, used a long screw driver to isolate the noise, it's at the bottom/middle of the red block where the circle things are xD between cylinder 3 and 4. Quietens when up to operating temp.

I want to check compression on the engine was wondering what good values are.. no blue smoke or oil loss appears to be running okay.. hope she doesn't blow up anytime soon..

Cheers for any pointers or info

[Ian21401]

Hello Vanadeo and welcome. I have the same year engine.
Haynes advises compression ratio is 10:1
Comp. pressures 9 to 11 bar, which by my calculations at 1 bar = 14.5 psi is
130.5 psi to 159.5 psi. Max. variation between cylinders = 2 bar = 29 psi.
My engine has done 224,000 miles. The only time the CH has been off was shortly after I acquired the car in 2005 when I found that no.4 plug threads needed a helicoil fitted. Nothing else was attended to as I needed the car back on the road ASAP. I check the compressions when I change the plugs. Last time (210819) they were 195, 190, 190, 195. psi, 1 - 4. That appears rather high but is probably due to the engine never having had a decoke or valves or tappets attended to. But as it is behaving itself at present I will leave it until something needs attention. It does sound rather “rattly” but it has been doing that for some considerable time.

[Jebus]

I wouldn't worry older pre oil squirter Redblocks do end up suffering from piston slap but with go 100k with it no problem, I swapped my engine it had a lot of piston to the point it sounded like an old knackered lorry, but it still drove well, burned a little oil and only started a fair but more after I decided and engine flush was a good idea

[Laird Scooby]

Originally Posted by Vanadeo

Hello..

New 940s owner 1992 2.0l b200f. It has piston slap, used a long screw driver to isolate the noise, it's at the bottom/middle of the red block where the circle things are xD between cylinder 3 and 4. Quietens when up to operating temp.

I want to check compression on the engine was wondering what good values are.. no blue smoke or oil loss appears to be running okay.. hope she doesn't blow up anytime soon..

Cheers for any pointers or info

Welcome aboard!

Those "circle things" are core plugs.



Probably you won't ever need to know more about them than that though.

The B200 is known for developing a bit of piston slap, usually on #4 but occasionally #3 as well. Unless it's severe enough to effect performance (including economy) or to make people running pile-drivers look round, i wouldn't worry too much about it.

If you do decide to change the engine, have a word with Luke aka 360beast, he often has a breaker or two in. A B230 would be good change for two reasons, first it gets rid of the known B200 piston slap scenario and second, will give you a nice improvement in power without going silly.

Ian - if your compression tester is accurate i'd suggest firstly running on 98 octane petrol (to help prevent detonation aka pinking - you won't hear it as the knock sensor will pick it up and retard the timing making it less efficient) and second that there's a fair chance the head has been skimmed at some point, perhaps as a result of a previous HGF before your ownership.

[Vanadeo]

Thank you for all the replies .. That's great info, thank you. I will take all this into consideration. tbh the clacking I have gotten used to for now, It's the brakes that are causing me problems.

The drivers side front wheel was sticking and heating up, so I have cleaned everything, and I am going to change the disks and pads this weekend. The problem is when i re-assembled it all and bolted the caliper into the carrier the top bolt is pulling the caliper towards the disk. If I tighten it up its like the brake is on. I can see the slide pin moving to the right when I tighten the bolt. So is the slide pin worn or has the hole in which the slide pin fits in got bigger?.. Or have I done something wrong.

I have had to loosen the top bolt so the wheel spins free. caliper is fine and not siezed.

Near side wheel is getting hot as well compared to the offside one so I am assuming that is the same.

Cheers for any help guys .

[Laird Scooby]

Originally Posted by Vanadeo

Thank you for all the replies .. That's great info, thank you. I will take all this into consideration. tbh the clacking I have gotten used to for now, It's the brakes that are causing me problems.

The drivers side front wheel was sticking and heating up, so I have cleaned everything, and I am going to change the disks and pads this weekend. The problem is when i re-assembled it all and bolted the caliper into the carrier the top bolt is pulling the caliper towards the disk. If I tighten it up its like the brake is on. I can see the slide pin moving to the right when I tighten the bolt. So is the slide pin worn or has the hole in which the slide pin fits in got bigger?.. Or have I done something wrong.

I have had to loosen the top bolt so the wheel spins free. caliper is fine and not siezed.

Near side wheel is getting hot as well compared to the offside one so I am assuming that is the same.

Cheers for any help guys .

A few pics would help, it sounds as if you've got something not right somewhere, the sort of thing you won't see for looking but a fresh pair of eyes will spot.

[griston64]

As Dave said we would really need some pictures to see whats going on.A 92 car could be Girling or I think DBA. Non ABS will be double piston rather than single piston. The DBA pins are a different set up to Girling as well ( they go through a sleeve )

[griston64]

Just had a thought If your brakes are non ABS and someone has replaced one of the slider pins with an ABS one which has a thinner head,it could pull it closer. It's common for one pin to seize so they may have just replaced one rather than both. It would be unusual but you never know

[TonyS9]

I got 160psi in my 360s B230FT recently after it wasn't running well, but 1 cyl was at 130psi, after taking the head of there was a small dent in the gasket on that cyl. It had always spluttered a bit on starting since the initial basic rebuild and down on power a bit. Hard to tell with the 360 because its so much lighter and faster. I must have dropped the edge of the head on it on assembly, then my old compression tester was rubbish and showed 130psi on all cyls.

[Vanadeo]

I noticed a lip round the inner part of the disk close to the hub.. I wonder if when I cleaned and freed everything the pads or something has shifted and are catching on that lip, one of the pins were seized too.. I'm collecting some fresh pads and disks tomorrow. If I get time I'll do it all tomorrow and report back..

I hope I can do it cos Its not brilliant driving round with a loose carrier bolt .. I keep checking it and it's snug but finger tight.