sr20det timing fucked need help

[mat.roberts]

hey so this is the rundown and you can go from there

last night drifting i spun the car then all of a sudden it wouldn't start
so i sat on it trying to start it for hours and no go so i needed a tow.
then i get home and pop off the valve cover to discover that my timing chain upper rail guide was missing a bolt, the chain was still in timing but has no tension even though the tesioner is still in and when i turn the motor over NOTHING in the top end moves.

my only possible guess is that the crank sprocket for my chain has skipped and or lost a tooth. what do you think?
and if im right should i just get another motor?(from a cost perspective)

thanks

[mat.roberts]

sooo i just found out my timing chain snapped... is the motor possibly still okay? as long as no valves hit?

[daryl337]

Here is what I have ascertained.


You were "drifting" This insinuates that you were in a medium to high rpm range.
Your timing chain broke.
You messed around with it for a large amount of time, and cranked it over trying to get it to start.

Its probably safe to say you have bent your valves. whether or not things are salvagable are going to come down to whether or not your guides and pistons/rods are ok. If no ringlands are crunched, the rods aren't bent, and you have minimal markings on the pistons, you may be ok to buy new valves and have a valve job completed. This is a "if you are lucky" scenario.

Sadly in my experience, this is rarely the case.



You are definately going to want to check *everything*. Remember, an impact to the piston can result in combustion chamber damage, and even rod/main and damage. Each and every one of these components should be checked for a proper rebuild.

[mat.roberts]

thanks for the info bud that helps me a lot thats what i was thinking. looks like i should just cut my losses and look at a new motor just cause it is a drift car and it seems more efficient to just get another one compared to a full teardow and partial to full rebuild. i looked as best i could in the spark plug wells to see any visible damages but id assume the valves are so close to the outside of the piston that i wouldn't be able to see much just from the outside?

[macross]

yeah, you're not going to know anything till you take it apart. You should save yourself some time and go ahead and pull the engine. some valves will most likely be bent as the engine is a interference design. that means that some of the valves were down no matter what.

just look at it as your oppertunity to freshen everything up.

[macross]

It may be easier to start with a good engine, but even if you go that route, you should open it up and freshen up everything. it's time consuming and expencive to keep replacing engines.

[mat.roberts]

yeah thats true money is an issue for me right now though :( im obviously not poor but this is my daily ( don't worry i knew there would be days like these) and the time it would take to do a tear down, order parts, and rebuild the head along with whatever needs replacing in the bottom end would be costly. im looking for forged long blocks right as that seems to be the best compromise but yes i will pull the head just for curiosity.