Is the B200E an interference engine?

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I posted a question on this forum a while ago asking if the B200E in my 740 was an "interference" type engine, ie. in the event of a timing belt break do the valves hit the pistons.
Informed opinion at the time was that all the B2** serias engines were non-interference.

Having just bought an `88 GL for spares with this engine I set about proving this one way or the other.

What I did was to remove the timing belt, valve cover and spark plugs.
With the crank at a few degrees before TDC the cam was turned to put the inlet valve on No 1 cylinder to full lift.
Then the crank was turned GENTLY BY HAND towards TDC, but before it got there the piston made very solid contact with the valve.
This was repeated for the exhaust valve with the same result.

Conclusion:- The B200E (and almost certainly the B230E) IS an interference engine and WILL suffer damage if the valve timing is lost.

Pehaps it would be useful for someone to try this next time they have a B230F or similar with the belt off, and post the result.

Is your belt overdue a change?????

I will post this on the 300 and 200 series forums also.

Colin.

some years ago #### happened to the B200K engine on the 1985 360. they need to replace some valves. have noticed different pistons may be installed to B200 engine in particular. does it consider 200/700 series - i do not know.
i do not believe that B230E and B230F are interference ones. no info about B230K.

[foggyjames]

This is very much dependant on which cam is fitted. There's an article that i've literally just read on this somewhere on the turbobricks website somewhere. I'll find the url if you can't track it down...

cheers

James

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James,
Ive had a look but could not find any answers.
Perhaps you could let me know the URL of the article you saw.

Obviously the lift and timing of the camshaft fitted will affect the outcome, but the example I checked was a 1988 740 GL, hardly likely to have been factory fitted with a wild cam!!
I`ll be removing the distributor this weekend and should be able to see which cam is fitted.

Colin.

[foggyjames]

sorry - was harder to find than I remembered...

http://forums.turbobricks.com/viewtopic.php?t=7793

The bit in question.....

"EDIT: Beyond this, just put everything back together like you removed it, and be sure the timing marks on the pulleys line up correctly. If you're using an A or a B cam, no matter how far off the timing was, nothing bad will happen. If you're using a K, H, V15/K15 or possibly with the VX cam, you'll notice that if you rotate the cam around with the piston at TDC, the cam eventually stops because the valve touches the piston. This means that if you break the T belt at high revs, there's a chance the, if one of the valves stops at maximum lift and the piston comes to TDC, you'll have damage. This isn't a very likely occurrence though, and personally I've never seen documentation of this happening on Turbobricks in the 2 years I've been here."

cheers

James

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Thanks James but this is about fitting a non-standard cam (to a B23?)
also US spec. engines are lower compression than their European counterparts, which, given the same combustion chamber volume, must mean lower piston crowns.

Colin.

[foggyjames]

Hi Colin,

It's a good point you've got there....especially as we're also talking about turbo engines...(This probably had as much to do with the time I posted....note to self: sleep before posting!)

I think the long and the short of it is that yes they are interference engines...having said that I witnessed a Sierra with a 1.8 CVH which had lost a timing belt, and it survived...I believe these are interference engines...kinda depends on exactly when it goes too then!!

cheers

James