Is the 2.8 an interference engine?

[DarkKnight]

Just wondering, since my timing chain snapped, if my old 2.8 was anygood.

[v6h.o.]

you will bend valves if the timing chain breaks. most likely youve got some good bent vavles in that 2.8L.

[geoffinbc]

Sometimes you get lucky. Last person I talked to had nothing wrong and just replaced the chain. Aluminum or Iron heads would be the first question to you.

[v6h.o.]

we had a 3400 in the shop a month ago.

only 7300 kms on the engine, kept bending exhaust valves...

what happened was the camshaft dowl alignment pin broke and the timing chain sliped only about 10 degree's or less forward. honestly it was only a few hairs out of alignment..

bent every exhaust vavle in that engine.

[3100 MPFI]

I bent every exhaust valve on my 3100 because it was one tooth off in the cam timing. Did not think that it would do that much damage by being that slight bit off.

Fortunantly, I had a spare est of heads lying around, and I now have custom RELIEFS on all of my pistons

[DarkKnight]

I have probably the only '87 2.8 made w/ iron heads.

[v6h.o.]

and I now have custom RELIEFS on all of my pistons

LMAO! yeah i guess thats the only positive way to look at it now isnt it..

[El-Stupido]

i dont really understand the term "interferance engine". please elaborate...

[pontiac92gp]

Basically, some engines are built to a close tolerance where the piston, at the top of the stroke when the valves are closed, is occupying the same space that the valves will be occupying when they are open and the piston is at the bottom of the stroke.

This is fine as long as normal timing is being kept - the piston rises as the valves close, then it decends as they open, so they never make contact.

BUT...snap a timing belt on this type of motor and...the valves stop opening and closing, but those pistons keep slamming up and down....bent valves, broken lifters, even a broken camshaft could be the outcome...

[Compufreek]

Is changing the timing belt on a 3100 easy. I am gonna be doing a head gasket on mine soon and everybody says I should do that belt too.

[bszopi]

Well, first of all... we have timing chains, not timing belts. If you are just doing the head gasket, you will probably be keeping the engine in the car, correct? If so, then changing the timing chain will be a PITA.

[Cliff8928]

Timing belts are a regular maintenance item.... Timing chains are not...


Cliff Scott
89 BerettaGT
89 Volvo740

[geoffinbc]

I have probably the only '87 2.8 made w/ iron heads.

I have a 95 motor with IRON heads

[Anonymous]

I think he means in a FWD car. RWD 60v6's were always iron, of course.

[geoffinbc]

Oldschool FWD cars were all iron heads... We all had the same beginings... But since he does have iron heads I belive it is a non interferance top end. I think he should be ok... Change the chain and before you close it up rotate the engine by hand and be sure there is no resistance. Watch each valve for proper actuation.