Rod Bearing Cap Bolt problem

[terryjm1]

I kind of see the point of stretch bolts for head bolts but for connecting rods I just don’t get it. They don’t use stretch bolts for the main bearing caps. My old 3.5 engines don’t use stretch bolts on the connecting rods.

On factory camshafts, I do think they wear relatively quickly compared to the rest of the engine but it isn’t an obvious issue. They just go down on power as they wear. I have a 96 D1 with 130,000 on the engine and it runs seemingly well and quiet. It is completely original internally.

I also have a 96 D1 with 27,000 miles on the engine. There is a noticeable difference in the power it produces compared to the other one with high miles. I believe it is due to a worn camshaft. Until I drove that one I had no idea how down on power the other one was. I think many D1 owners that have high mile engines and haven’t driven one with a fresh camshaft would be very surprised how much more power they would see if they replaced the camshaft.

The next one I will be putting together is going to get a stock 4.6 camshaft. I was going to go with a higher dollar aftermarket camshaft for that one but after seeing how well my low mile completely stock 4.0 runs, I don’t think it is needed.

To the OP, looking back at your replies, you mentioned it was running a little hot. My guess is your radiator is past its prime. Once you get the engine back together, definitely consider taking it to a radiator shop for a clean out or just buy a new one,

 

[DarylJ]

Stretch bolts are largely a solution to an assembly/manufacturing problem. People like us get stuck with them later because the specs and availability for something else either aren't available or not worth messing with.

 

[robbyb20]

Before I knew the bolts are single-use, I have reused them. No adverse effects in ~30-40kmi afterwards.

I’m about 15k miles on new bearings. and same bolts. Didn’t know they were stretch bolts. I planed on pulling this weekend to check the condition but I’ll by new bearings/stretch bolts just in case. Just checked my orders, i purchased new bolts and remember having a bag of the old ones now. Too many things ive swapped to remember all the details ha

 

[p m]

I think many D1 owners that have high mile engines and haven’t driven one with a fresh camshaft would be very surprised how much more power they would see if they replaced the camshaft.

The next one I will be putting together is going to get a stock 4.6 camshaft. I was going to go with a higher dollar aftermarket camshaft for that one but after seeing how well my low mile completely stock 4.0 runs, I don’t think it is needed.

Please post which cam you go with.
I am sure I need a fresh cam for the 3.9/4.0 in my Classic.

 

[terryjm1]

Please post which cam you go with.
I am sure I need a fresh cam for the 3.9/4.0 in my Classic.

I’m just going to buy the stock one, probably from LR direct.

 

[jastutte]

I’m just going to buy the stock one, probably from LR direct.

the Crower Stage 2 Camshaft is nice. adds a little bit of power that helps quite a bit with the Ozark hills here in Missouri.
if you do any mountain driving i would think it would be helpful for that, too.

 

[terryjm1]

The stock cam (again, very low miles) in my 4.0 with 5-speed handles mountain driving very well, even the nearly 5000 ft 16 mile incline I regularly travel. However, I’m not towing anything. But, I do have heavy SG bumpers, if that matters. When I first got this one running, compared to my high mileage D1, I was quite surprised how much more power it had.

If the high mile D1 continues to run reliably much longer I will probably force myself to replace the cam/lifters and timing chain as I am sure they are original. I am optimistic that will really make a difference.

I had an Isky cam in an old 3.5 liter (listed for a Buick 215) in a TR8. It completely changed the personality of that engine in a very positive way. Aside from making it a lot more fun to drive, when it idled, it got a lot of attention from anyone within earshot. The sound of a 60s era muscle car coming from a tiny British car… I liked the attention when I was younger but I’d probably try to calm it down a bit with a quieter exhaust these days.

It also had an old school Holley carburetor and didnt benefit from the advantages of fuel injection.

I have an old Holley Projection system I will someday use. It’s programmable but I have to use an old windows 95 notebook to do that. I’m hopeful my old notebook computer doesn’t die before I can get to that project. I also have a home made FI system set for a Rover V8 that runs on an ECU from a 90s era Camaro. It ran well when it was last installed but I have no means to change the programming on it. Neither will be for a LR as i cant see the point of undoing a GEMS setup.