Continental R6602

[57lafrance]

I have a Continental R6602 in a fire truck. when the engine starts i get what sounds like a rod knock for about 6 seconds.If i crank it with the ignition off then turn the ignition on it seems to be minimal.I have removed the oil pan and it was surprisingly clean. The rod bolts and main caps are tight with the safety wires intact.New oil filters and filter drain holes are open.

Any help is appreciated.

 

[clinto]

Next you need to pull the rod caps off and look at the bearings. These are tri-metal bearings so there will be a silver top surface, with copper showing beneath when they get worn.

Here's a bearing where the outer layer of material has been worn down:



After you check all the rods, you can check the mains but a knock is usually a rod.

 

[ReoRider]

Good advice given. The rod knocks are a little higher pitch than the duller, heavier,slower main bearing kind. The cranking over with ignition off suggests that getting some oil pumped in there is enough make for a quiet start. These can be nursed along but with a fire truck application, and its extra weight, would be best to do as Clinto suggests and take a look. With a rod issue you can isolate the cylinder by individually killing the spark. I've successfully burnished rod journals in place on these motors and then with new inserts to match, all runs well. The 6602 is a heavy duty, over the road proven engine, and can provide a good long service life.

 

[57lafrance]

Thanks, project for next week ill advise what happens.

 

[clinto]

57lafrance was having some image upload issues, so he emailed them to me and I'm putting them up for him. I'm sure he'll be along shortly to add commentary.

 

[57lafrance]

Reference to bearing pics that clinot was o kind to upload. As indicated in the photo the bearings are pitted. The rod journals are smooth no sign of excess wear. I have contactes a couple places for bearings.

Now to my delima. I had a couple pistons partially slip exposing a ring. I dont think im the first one this has happened to. Any sugesstions are appreciates

 

[73m819]

Use a thin filter strap wrench or make one, oil the strap with a LOT of oil, tighten up, you should be good to go

 

[57lafrance]

I was able to get the piston rings back in. I used a hose clamp, cut off the worm gear and put a loop in each end.Took sticks and pulled the ends together. I inserted a blade between the clamp and the ring and the ring went in
Crisis averted.
Thanks for all the response.

 

[M543A2]

I have seen this kind of damage to bearings often. It is caused by moisture getting between the bearing and journal, from condensation in the crankcase and valve cover area. The bearing metal then degrades and chips off or just erodes away. This is typical of gasoline engines that sit for long periods of time and/or do not get warmed up enough for long enough to dry out the condensation in the motor when they are run. Acids form that do the damage. This is not seen as much on diesels because they typically do not form the acids in the oil gasoline engines do. I always suspect the bearings in gasoline powered motors that have had this kind of life. I would also replace the mains.You will want to be sure your thermostat is working so the motor warms up properly. If you remove the oil fill cap and see white deposit and water droplets the motor needs to be run long enough to dry it out. We have two of them; they are good, tough motors when properly cared for.
Regards Martin

 

[ReoRider]

Excellent analysis! I'm always concerned when I hear about how valuable an old NOS or distant past rebuilt gas engine is now- one that was test run back in the day and then put away. They all need to come apart and get the bearing check noted above.

The Continental 6602 is a wonderful motor, one of the times when the military selected an engine that had actually been in heavy duty truck use and it shows. Had a surprising RPM range for its displacement, giving some real advantage to the ability to shift the xfer case in the 5 tons on the move when pulling heavy loads. Biggest upgrade I ever did was to shave .120 off the heads and ended up gaining a full gear on loaded runs up familiar hills.


John

 

[73m819]

Excellent analysis! I'm always concerned when I hear about how valuable an old NOS or distant past rebuilt gas engine is now- one that was test run back in the day and then put away. They all need to come apart and get the bearing check noted above.

The Continental 6602 is a wonderful motor, one of the times when the military selected an engine that had actually been in heavy duty truck use and it shows. Had a surprising RPM range for its displacement, giving some real advantage to the ability to shift the xfer case in the 5 tons on the move when pulling heavy loads. Biggest upgrade I ever did was to shave .120 off the heads and ended up gaining a full gear on loaded runs up familiar hills.


John

We shaved 3/16 off a set of heads, waiting for this winter to do a in frame (I hope) then install the heads, The military 6602 runs almost cold, we covered part of the radiator with some card board, I also converted the ignition to 12v. , the reason is that ANY NOS coil will be so old that it will have deteriorated just sitting on the shelf, AND a standard old fashion Chevy coil is $10. after everything is done the 6602 will get electric ignition and tuned jets., not looking for a race truck, just a good running, power, and not so rich running 6602

 

[msgjd]

"" The Continental 6602 is a wonderful motor. Biggest upgrade I ever did was to shave .120 off the heads "

I would like to consider the shave, for I occasionally do all-day hauls out of quarry pits and over several hilly miles to my place, but am concerned about increased wear on the bearings.

I have 2-R6602 operational 6x6's plus one spare engine. The first long trip I did in the army was with a '56 IHC M54, about 11 hours straight through. The truck was a "T&P" thus I was carrying 1200gals of extra mogas with me, and yes they are thirsty but that's worth the extra power and speed IMO. We called them "brush burners" for a reason I would soon learn. They started many a tank-trail fire. And mudflap fires, and M127 trailer bed fires. Maybe even burned the hair off the as*es of a few bicyclists, but I wouldn't know anything about that.


The 6602's could really roll once everything got warmed up. I remember getting up to 58mph with some of them on the level. In fact, my final unit kept two M62's into the 1990's before accepting M816's. Except downhill, those M62's were too heavy to be speed demons like the other 5T gassers , but they still were hard-working brutes.

I adjusted my personal M51's governor to top out at 62mph. Somewhere I have a Continental Motors manual indicating a slightly higher allowable redline than what the TM says. I won't hold an engine beyond what the TM (and danger decal) says, but the extra "pedal" allows a good run for hills and seems to help get fuel faster and pulls better. Always hated the original holley carb. The vacuum-operated butterflies go full-open with no vacuum (thus they coughed when cold and almost always gave a bang! when starting). And they would open too slow and gradual when coming into a hill. The Holly does not have a direct linkage between butterflies and gas pedal. Plus they run too rich at lower rpms. The Zenith carb that superseded on R6602's is a good thing. But I understand purists who like the holley. I still use one of them even though I have attitude about them.

Prior to my knowing I would ever own a '53 IHC M62(A2), I sold a fresh Toole R6602 several years ago to a fellow restoring a firetruck in the midwest. Ever since obtaining the M62(A2), I have painfully regretted selling that 6602 engine. I have done everything allowed to tweak the LDS in the M62(A2). It even retains its old "gas" direct-5th tranny, which does help. But even such, that LDS is totally outclassed by a 6602. The R6602 is a real truck engine, tried and true. Just bring along your own gas station!

 

[Swampdonkey00]

We shaved 3/16 off a set of heads, waiting for this winter to do a in frame (I hope) then install the heads, The military 6602 runs almost cold, we covered part of the radiator with some card board, I also converted the ignition to 12v. , the reason is that ANY NOS coil will be so old that it will have deteriorated just sitting on the shelf, AND a standard old fashion Chevy coil is $10. after everything is done the 6602 will get electric ignition and tuned jets., not looking for a race truck, just a good running, power, and not so rich running 6602

Do you know which civilian distributor fits the R6602? I want to switch to regular wires I already have everything to convert the original distributor to pertronix but I’d rather have the regular cap and wires. Thanks

 

[Joe Bertram]

Do you know which civilian distributor fits the R6602? I want to switch to regular wires I already have everything to convert the original distributor to pertronix but I’d rather have the regular cap and wires. Thanks

I'm not sure the make but here's one I took some pics of a couple years ago when I was looking at a m-62 gasser wrecker when I was building mine

 

[m1010plowboy]

Somebody was looking for 6602 manuals and I can't find that thread. I know it was a -35 manual but not sure we have the correct numbers. We found a bunch of manuals in a truck cab at a wrecker so maybe we got lucky. Continental manuals preserved.

 

[Mullaney]

Somebody was looking for 6602 manuals and I can't find that thread. I know it was a -35 manual but not sure we have the correct numbers. We found a bunch of manuals in a truck cab at a wrecker so maybe we got lucky. Continental manuals preserved.

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And if you want them scanned, send them my way and I will do that and send them back to you...