Engine rebuild

rjc333 · Post by **rjc333** » Mon Sep 04, 2006 12:37 pm

Ok, so minding my ignorance with regards to this topic, I was thinking about picking up an old Quad and having it rebuilt while I still have the 3.1 in the GTZ. So my first question is, what is typically involved with a common engine rebuild? And secondly, what would the price range be for such a job?

wicked-irocz · Post by **wicked-irocz** » Thu Sep 21, 2006 8:25 pm

rebuilding the head: new guides, seals.
new rings, bearings, oil pump, gaskets, timing chain.
honing the cylinders.
checking all specs and machining if necessary.

price depends on work needing to be done and machine shop.

rjc333 · Post by **rjc333** » Tue Oct 10, 2006 10:23 am

And obviously if it's a Quad, replace the old head gasket with a heavy duty replacement, no?

By the way, say I had two GTZ's, one with the 3.1, and one with a Quad, it'd be a pretty easy swap to take the Quad out of the beat up car and put it into the better car (and vice-versa), right?

wicked-irocz · Post by **wicked-irocz** » Tue Oct 10, 2006 11:01 pm

thats included when I said gaskets. It just takes time to do that swap since you have plenty of parts.

docrodg · Post by **docrodg** » Thu Oct 12, 2006 7:35 am

The work depends on what you are trying to do to the engine. Balance and blueprint requires a lot more work. Just a simple rebuild should include boring the cylinders, machine the heads and valve seats, verify the deck and crank saddles are good, Check all clearances for bearings pistons valves etc, new bearings all around, lap the valves, replace all seals, consider a new cam (while it is out and easy to do), plus more if other problems exist (weak springs etc.). Also remember to check the damper and make sure the rubber is good, as well as other externals. IT always sucks to get the engine rebuilt and then find out another part needs replaced.

Look at the bright side tho, I do v-8 drag engines, those have more parts and need a balance and blueprint to survive the high rpms. Just the valve train requires hours of measuring and custom pushrods for each valve to get the geometry dead on.

rjc333 · Post by **rjc333** » Fri Oct 13, 2006 1:26 am

So it probably wouldn't necessarily be a bad idea to throw a W41 cam in there since it's already out.....

docrodg · Post by **docrodg** » Fri Oct 13, 2006 7:45 am

Correct. New cam and bearings is a good idea so that you do not have to do it later as it requires so much work that is already done. Just be sure to break the cam in properly when you get it all back together. RUn it at 2000 RPM for 20 minutes, do not idle at all, on initial startup. Once that is done I typically change the oil and filter before doing anything else to clean out the prelube and crud that was caught. Then it is ready to drive!

wicked-irocz · Post by **wicked-irocz** » Fri Oct 13, 2006 6:39 pm

(docrodg @ Oct. 12 2006,06:35)QUOTEJust a simple rebuild should include boring the cylinders, machine the heads
If the cylinders are within round and within spec you do not need to bore the cylinders and if both the head and deck check out to clearances they do not need to be messed with. If you check these clearances and are able to skip a bore and plane you will save a far bit of cash. I have rebuilt a few motors this way and learned it from a person who assembled street/strip motors.

docrodg · Post by **docrodg** » Thu Oct 19, 2006 9:53 am

That is assuming you have the equipment to check the cylinders and head and deck. Also, a bore can be a good thing anyway as it will show up any cracks developing in the cylinder wall. As I am assuming the engine is old and never been rebuilt chances are it is outta spec anyway. As for heads getting milled, aluminum heads rarely do not need machined to get them in spec, plus the deck is hardly ever square to the crank. This gives you a chance to bring it within square and back to the tighter factory tolerance, rather than the service tolerance. I always try to attain the service tolerances on a rebuild so that the engine is built "tighter" for a longer run.

Post by **Cliff8928** » Thu Oct 19, 2006 1:27 pm

(rjc333 @ Oct. 10 2006,09:23)QUOTEBy the way, say I had two GTZ's, one with the 3.1, and one with a Quad, it'd be a pretty easy swap to take the Quad out of the beat up car and put it into the better car (and vice-versa), right?
It's easy as long as you're keeping the transmission that's original to the Chassis. If you're going from an auto to a 5-speed then it will require a little fabrication to weld in the mounting points for the trans.

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