Just got my first DOHC motor

[67GTO]

I recently purchased a 95 GTP Grand Prix, it has the 3.4 DOHC motor. It has 61,000 miles on it.I ran a car fax on it and it is real. I paid 1400 for it. Body is very nice, interior needs some clean up. I bought the car to commute to work with and then did some investigating and found out the motor is something more than I am used to working on. I have been into cars for 30 years and have restored and raced everything from corvettes to GTO,s. I am building a 67 GTO now with a 540 chevy in it. So this motor is something new to me. I have been a chevy tech and a ford tech for about 15 years before changing professions. I have become more attached to this car than I have wanted to. A few questions...

What is the normal idle speed for this. Mine seems to idle at around 900 RPM's.
Is there a way for me to check the timing belt to see if it worn. I don't know if it was ever changed. I really don't have the extra cash right now to do it so I would like to get some more time to get the funds to get it done. Also I have read that if it goes it will bend some valves and then I have read it will not. Which is it.
Right now I am going to do the basic maintenance on it , brakes ,oil, tuneup.

And the alternator doesn't scare me, I also have a 96 Taurus that has the DOHC in it and that is a pain also.

[robertisaar]

idle speed depends on coolant temp and wether or not you're in park. in park, it ranges anywhere from 750-1400 and in drive it's from 700-1200. at full temp(195*F), you should be between 700-750. keep in mind that the tach isn't incredibly accurate either, you would need a good timing light or a scanner to get a true number.

checking the timing belt should be fairly easy, i believe there are plastic covers that protect the belt from the elements? you should be able to remove those fairly easily to inspect the belt, but i have never actually done it myself.

i've seen LQ1 belts let go and not damage a single valve. i've also seen ones that bent quite a few, so i honestly wouldn't know.

[bszopi]

If I remember right, 91-95 DOHCs are non-interference (unless the belt snaps at high RPM, then the valves might touch the pistons slightly), but 96/97 DOHCs are interference.

[robertisaar]

If I remember right, 91-95 DOHCs are non-interference (unless the belt snaps at high RPM, then the valves might touch the pistons slightly), but 96/97 DOHCs are interference.

this may be correct.... or at least i've heard it before.

alldata doesn't shed any light on it at all, just says "the manufacturer has not specified if this motor is an interferance motor" for 91-97 LQ1s...

[67GTO]

I don't think this car will see high rpm's. I have a 99 vette if I want to go fast.

[Dave96z34]

LQ1s love high rpm but the trans doesn't. That's one thing I know to well.

[robertisaar]

X2... i think the 4T60 max shaft speed is supposed to be ~6250RPM?

hell, even L82s can spin that with no problem(and could actually use it since the 1-2 gap is kinda wide)... which is why the first thing i did with the MC when i could tune it was to set the rev limit to like 6500, 1-2 WOT shift point to like 6300 and during shifts, it pulls a LOT of timing to try and save the tranny...

[RednBlack]

LQ1s love high rpm but the trans doesn't. That's one thing I know to well.

I can reiterate/relate to that. Tranny teeth, chunks of aluminum, and fluid on pavement, on more than one occasion. Make sure the pin is hardened. GM missed it. Seems like years ago.....

[Jogasz28]

You may know all this, but...
Is the Coolant orange or green?
You'll find all kinds of posts about GM's DexCool coolant causing major problems.
If it' orange, flush and go green (Prestone) fast.
The intake gaskets are a problem. I had to replace mine so I went down to the heads and replaced all gaskets up, timing belt, etc..
Also, the O-ring that was originally used on the oil pump cover (where distributor was) leaks due to wrong O-ring
material used originally.
When you replace the timing belt, the camshafts have to be held in position, so you need two hold down tools for that.
If your interested in buying 2 new Kent-Moore camshaft hold down tools(I've got two, both my Wife and I ordered a set),
I'll sell them for dirt cheap, make an offer.
Or you can make your own DIY tool for this if I remember right seeing this posted somewhere in here.
Also check the metal coolant tube (for rust/pitting) that runs from the water pump area back and up, and then
across the top firewall. Mine was leaking from road debris impacts and had to be replaced. I couldn't see an easy way
to get it in, so I cut it right after it makes a turn to across the top of the firewall and used heater hose and double clamps
on both ends. No problems since.
Some of this may or may not apply.
Good Luck,

[jman093]

N/M. Just saw this is a thread someone brought back from the dead.