Q45 Timing Stuff...

[Jed]

Ok, here's a little background. I'm a new proud owner of a 1993 Q45 which I bought from a guy in Atlanta (got a heck of a freaking deal) this morning, and then trailered it down home to Florida. I purchased the car to use as the donor car for my VH45 swap into my 1995 Hardbody, and so what I plan on doing is fixing what is wrong with the Q and driving it for a while, in the meantime pulling the engine out of my Hardbody, then swapping it over to the HB, and sometime in the next few months, rebuilding it after I figure out how to make it fit. The Q45 has about 215k miles.

When I was talking to the guy, he said the timing chain had either broken or the teeth on the timing gear had stripped. He said it just stalled, and wouldn't crank. I haven't been able to turn it over, as the battery is still charging. But I read over the timing guide sticky thread and it scared me. I guess I'll start taking it apart tomorrow.

Anyways, my question is, do I actually have to pull the engine to replace the chain, or is it possible to do while still in the car?

Thanks!-Jed

[elwesso]

welcome to NICO. you dont have to pull the chains at all, youre just replacing the guide. IMO if your gonna be pulling the motor out you want to just do it, because its a pain to pull the front cover in the engine bay. Seems pointless to me to take everything apart to put it back together to take it apart even further once more.

I would just pull the motor out of the Q and redo it as you see fit. That way its on the stand and youre all good. Besides, you can test pretty much everything on the engine using a VOM.

[ScottJackson]

It's an interference motor so you'll be replacing valves too. May as well just pull the motor now, pull the heads, and see what it all needs to freshen. It may or may not be worth it as compared to getting a JDM engine and swapping in guides on that motor.

[Jed]

I was afraid of that. I was hoping that it wasn't, considering the VQ40 isn't an interference motor. So I guess I'll be pulling it and finding out the damage.

The good thing is if it does turn out to be a dookie engine, I can part it out and make well over my money back on it, easily! Minus the carpet, it's in amazing shape.

Thanks y'all!

[Q451990]

I think you're better off getting a JDM take-out donor engine for your hardbody project - assuming your engine is scrambled. It is possible, but very unusual to have the timing slip, without damaging the engine.

Please keep us in the loop on your hardbody engine conversion - I would love to put a VH in my truck

Heath

[ScottJackson]

Yeah, I had the timing chain jump on my '91 Q. I don't think it did any damage as it just lost power and the idle went down and got shaky. I haven't pulled to motor yet to confirm though. If this motor completely died and won't crank, it has almost certainly done some $$$ damage to the valves/pistons. However, if you're going to hop up an otherwise good engine, it may be best to just use your current motor. If you were just wanting to swap in a stock VH45, go with the JDM take-out. With that said, don't charge the battery and try cranking it. That will only do more damage if it isn't a serious problem (unlikely, but ya never know). Pull the spark plugs, look them over (broken plugs means broken valves/piston), and then with the plugs still out, put a breaker bar and socket on the big crankshaft bolt and turn the motor over. If you feel it hit something, stop. Then you'll know it's definately time to pull it.

[Jed]

I thought I'd give yall an update. I pulled the intake collector, manifold(s), and one valve cover, and the timing chain looks perfect. I'm going to go ahead and pull the other cover as well just to make sure, but everything looks fine.

So it's getting fuel, air, but now I need to check for spark. The plugs looked fine, but it almost looked like there was oil inside the spark plug hole (Not inside the engine, just on the outside. Looked like someone accidently poured oil into the plastic coil cover and it went into the holes.). How do you check for spark?

Also, is it possible that the Q has a chipped key?

[Q45tech]

Common for oil to pool inside spark plug well when gaskets [or RTV seal] is not replaced every 6-8 years [70-100k].

This oil eventually becomes conductive and may cause spark plug boots to have carnon paths if the oil level in well gets too high.

One of reasons plug replacement at 60k is required [along with any necessary cleaning and polishing.

The boots/extensions screw off the coil body.

[Q451990]

Jed,

No chipped key on the G50 series Q. Definintely not on the 93.

I'm not sure that you can confirm the timing chains without a compression test or pulling the front cover. I think it's possible for the chain to still be on the top valve sprockets while having slipped on the bottom.

This probably goes without saying, but I would go ahead and replace the guides if your car doesn't have the updated metal ones. The change-over was sometime in the 1993 model year, but we don't have an exact production date or model year. When you pull the front cover, you'll see that the tension side guides have a metal backing. If the slack side guides don't have this same type of backing (e.g. all plastic) then it's time for a replacement.

Good luck!

Heath

[Jed]

Well, pulled off the upper front covers, and I can feel the timing chain slack in the right cylinder bank timing chain. Doesn't feel like there is any slack in the left bank timing chain. As soon as I can get the crankshaft pulley off, I'll be able to get the lower front cover off as well.

Is there another way to get the crankshaft pulley to stop moving while I'm trying to turn it, without using an impact wrench? If not, I'll be buying air tools. I kinda needed to anyways.

I guess I'll find out if the engine is toast or not...

Btw, if you can't tell, I'm new at this. This is my first time ever digging into an engine. What damage does a timing chain do when it breaks or develops slack? Is it fixable?

[maxnix]

The VH45DE, like most high performance engines, is an interference engine.

That means if timing is lost, valves and pistons will impact each other.

[Q45tech]

Most common impact wrench don't have enough torque, you will need a special chain wrench handle wedged so it's doesn't turn and socket with a long pipe.

CRITICAL that you retighten to 275 lb/ft otherwise oil chain will slip

[Jed]

Ok, got the bolt out, but managed to damage the pulley in several places trying to get it to stay in place. Now just gotta get a puller to take it off.

I don't really think the pistons have contacted the valves yet. The reason I think so is that (before I knew the damage that could have been done) I tried cranking the engine the first day I brought it home, and it just turned over but didn't fire, but it also didn't make any clanking or metal noises.

[maxnix]

Do a compression test. That will tell if the valves were impacted.

[ASE Master Tech]

A compression test is a good place to start, but a cylinder leak down test will provide you with much more info. You will need the proper tools and to make sure that all the valves for the cylinder you are testing are closed. If there is air leakage into either the intake or exaust systems you have valve train issues, but if there is air leakage into the crankcase it is a piston or ring issue.