Rebuilt engine is a dog out of the hole

[bruceb58]

Re: Rebuilt engine is a dog out of the hole

You can get arcing if you have spark plugs gaps to wide or you have faulty spark plug wires. if you don't have a good path all the way from the coil to the spark plug, the energy in the coil is going to try and reach the path of least resistance. If that path happens to be in the cap, you will get arcing there.

 

[bruceb58]

Re: Rebuilt engine is a dog out of the hole

My shop manual for my LK model specifies total advance for all motors. Unfortunately, my manual does not have the 5.8L motor in it becuase Volvo stopped using it by then.

 

[mcleaves]

Re: Rebuilt engine is a dog out of the hole

My shop manual for my LK model specifies total advance for all motors. Unfortunately, my manual does not have the 5.8L motor in it becuase Volvo stopped using it by then.

I just find it odd they don't suggest and advance numbers. I have genuine VP manuals. It's just says to make sure it advances. Given that I guess I'll assume it's ok.

 

[bruceb58]

Re: Rebuilt engine is a dog out of the hole

As far as what firing order you have, the next cylinder that is going to fire will be 90 degrees fromthe #1. You can easily mark the balancer and turn the engine past the firing point of #1 and see if it is #5 or #3 at the top of its compression stroke.

 

[mcleaves]

Re: Rebuilt engine is a dog out of the hole

You can get arcing if you have spark plugs gaps to wide or you have faulty spark plug wires. if you don't have a good path all the way from the coil to the spark plug, the energy in the coil is going to try and reach the path of least resistance. If that path happens to be in the cap, you will get arcing there.

Thanks for the explanaion. I know the gaps were all good. Wires are a couple seasons old. I supposed there could be a problem there.

Lets forget about the reason for the arcing for a moment. Lets assume something in the setup caused the cap and rotor to get pretty trashed within the first few hours. Would what I described about the carbon dust and arcing damage cause the low end power loss, BUT still allow for good top end performance?

M

 

[mcleaves]

Re: Rebuilt engine is a dog out of the hole

As far as what firing order you have, the next cylinder that is going to fire will be 90 degrees fromthe #1. You can easily mark the balancer and turn the engine past the firing point of #1 and see if it is #5 or #3 at the top of its compression stroke.

Now THAT is a great tip!! THANKS!

 

[bruceb58]

Re: Rebuilt engine is a dog out of the hole

Would what I described about the carbon dust and arcing damage cause the low end power loss, BUT still allow for good top end performance?

Should affect all RPMS.

As far as the condition of your spark pluig wires go, run the engine at night and see if you see any arcing occuring. If you have bad wires, you would see a light show.

I didn't realize your topend was good. I thought you couldn't get up to your top end!

 

[mcleaves]

Re: Rebuilt engine is a dog out of the hole

As far as what firing order you have, the next cylinder that is going to fire will be 90 degrees fromthe #1. You can easily mark the balancer and turn the engine past the firing point of #1 and see if it is #5 or #3 at the top of its compression stroke.

What are your thoughts on a different cam yielding a different firing order? As I said, it looks the cam was replaced before I had my rebuild done. Could this ins fact cause the firing order to be different

M

 

[mcleaves]

Re: Rebuilt engine is a dog out of the hole

Should affect all RPMS.

As far as the condition of your spark pluig wires go, run the engine at night and see if you see any arcing occuring. If you have bad wires, you would see a light show.

I didn't realize your topend was good. I thought you couldn't get up to your top end!

Well now that you mention it, I did get bit while turning the cap to time it once.

Yeah the problem is she's just really slow out of the hole. I used to jump on plane in 5-6 seconds. I run a really light prop set. Once I am up she gooses up just fine. I can hit my old top speed. If she starts to fall off plane though it's a ***** to get her back. Seems like I lost my low planing speeds too.. Need to keep her a bit higher in speed to stay up.. not positive on that one though. I've only had it out twice

 

[bruceb58]

Re: Rebuilt engine is a dog out of the hole

What are your thoughts on a different cam yielding a different firing order? As I said, it looks the cam was replaced before I had my rebuild done. Could this ins fact cause the firing order to be different

M

If the cam lobes are set up so that the two cylinders were swapped, sure it could happen. That's an area I'm not familiar with as far as Fords are concerned. Both cylinders 3 and 5 are at the top of their stroke at the exact same time so either can be set up as a compression or exhaust stroke based on the cam.

I am assuming all of your fuel system is exactly the same as when you started your rebuild. You aren't running a little lean by chance are you?

I run F5 props with a 7.4L and a 24' boat which may be similar weight to yours. Our gear ratios must be different for us to be running a similar pitch.

 

[mcleaves]

Re: Rebuilt engine is a dog out of the hole

If the cam lobes are set up so that the two cylinders were swapped, sure it could happen. That's an area I'm not familiar with as far as Fords are concerned. Both cylinders 3 and 5 are at the top of their stroke at the exact same time so either can be set up as a compression or exhaust stroke based on the cam.

I am assuming all of your fuel system is exactly the same as when you started your rebuild. You aren't running a little lean by chance are you?

Thanks.. i'll try your test to see what the firing order is once and for all..

Also I'll check the wires. I did get bit and now I am wondering.

As for running lean, I don't think so. The plugs looked good when I pulled them. nice even burn, which now tat I think of it, means they must be getting good spark. The system uses a mass air flow unit. I am not sure how to tell if it's lean or not. I know there is a screw at the bottom of the assembly I am not supposed to turn. I did mess with it last year in error, but it never affected performance. As far as I know it's set OK.. Since it's an EFI I presume the computer is making sure I am getting the right amount of fuel delivered

 

[Handegard]

Re: Rebuilt engine is a dog out of the hole

13726548 (this is spec according to Volvo Penta)
15426378 - Many 302's seems to have this order when you google.

The difference seems to be cyl pairs 54 and 37 are swapped. Seems plausible to me this could be my problem sine I have had wires mixed up once or twice in the driveway and it runs fine. I AM sure it's set properly to 13726548 right now though. Since my cam seems like it may have been changed would this indeed be a possible issue?

Thanks. A lot of in and a lot of questions in here. I appreciate the feedback

Just adding a little that I can-
First, didn't you say you had roller lifters, but not a roller cam? I was under the impression that this was a bad thing. I'd love to hear evidence to the contrary, because I have a pretty bad *** hydrualic camshaft I'd love to put in my Mustang, but I also wanted to use the factory roller lifters (putting a '88 5.0 into a '69)

AFAIK Marine cams came in one firing order, and car/truck cams came in a early and a late firing order, as you've learned. I'd switch it just to see. You can always switch it back... By '95 all 5.0s I believe were the late firing order, and all were roller blocks, so my bet is you originally had a roller cam.

There might well be a gremlin in there. You're rockers, lifters, pushrods, and cam all have to go together, if you have something that is too short or too long, you might end up with valves that are open too long, or not long enough. Either can effect your power. Something like this, added to something else seemingly insignificant could add together to make a bigger power loss...

Also, I know you checked the rotor vs the balancer to see if the timing chain was correct, but have you tried rolling it by hand until #1 piston is at TDC, then see what the balancer says. I've seen numerous balancers go bad and spin. My truck has a new one right now for this reason, and my daily drivers balancer spun too, so I have to time it off the cam gear untill I get a new one...

 

[Handegard]

Re: Rebuilt engine is a dog out of the hole

What are your thoughts on a different cam yielding a different firing order? As I said, it looks the cam was replaced before I had my rebuild done. Could this ins fact cause the firing order to be different

M

I meant to address this in my last post-

The camshaft is what effects it. The crank between 302s with the two firing orders are the same. The piston is still at TDC at the same time, it just reverses which valve is open.

Late model (roller) cams use the HO firing order (1-3-7) while the earlier (non-roller) cams used the 1-5-4 order.

So if you truly have a non-Roller camshaft, it is likely a 1-5-4 camshaft, and the book lists your boat as 1-3-7 because it came with a roller cam.

I could be wrong, because there were non-roller cams with both firing orders, but I believe all roller cams have the newer order.

 

[mcleaves]

Re: Rebuilt engine is a dog out of the hole

Hey Chris,

Thanks for chiming in here. I'll try to answer all your questions.

The machine shop showed me the block and explained that it was a roller cam block, but that the cam was not a roller cam. I am completely uneducated in this area and wouldn't be able to recognize on vs the other. The block had something to do with the lifters being rounded.

Anyhow, the cam was already in there and he said there would be no problem leaving it in, although it may not make as much HP as advertised.

He felt the cam may have been replaced in the prior rebuild. He also felt that spending money on a new cam was not with the hp I'd gain, especially if I was already happy with the engines performance, which I was. He felt it was best to leave it as is in that case.

As for the balancer being correct. Here is what I did.

1. Pulled #1 plug
2. Rolled over to TDC with a dowel in the hole
3. Set the distributor and rotor to #1 position
4. Ran the timing light
5. Verified my timing was just about on the money

I have made enough changes to be ready for another water test. If when I do I don't have an improvement I will change the order then and there

M

 

[Handegard]

Re: Rebuilt engine is a dog out of the hole

Hey Chris,

Thanks for chiming in here. I'll try to answer all your questions.

The machine shop showed me the block and explained that it was a roller cam block, but that the cam was not a roller cam. I am completely uneducated in this area and wouldn't be able to recognize on vs the other. The block had something to do with the lifters being rounded.

Roller lifters are interchangeable with hydraulic flat tappet lifters, but the roller lifters need a bracket in the engine to hold them in the correct orientation. On a 302, adding this bracket involves drilling and tapping a couple small holes. People put the newer roller blocks in older Mustangs all the time to get the 1 piece oil seal and because they are easily available.

But, as far as I understand, roller lifters are a different height that hydrualic lifters (I might go measure them tonight) and the push rods are certainly different. I have been told not to put roller lifters on a non-roller cam, and I'm going to do some reading. I really want it to be OK, as I want rollers on my cam!

Anyhow, the cam was already in there and he said there would be no problem leaving it in, although it may not make as much HP as advertised.

He felt the cam may have been replaced in the prior rebuild. He also felt that spending money on a new cam was not with the hp I'd gain, especially if I was already happy with the engines performance, which I was. He felt it was best to leave it as is in that case.

My big fear here would be if you have a cam that isn't a Marine cam. But, as you said, you were happy with the boat before :shrug:

A camshaft can be a BIG change in powerband for ~$250. But I don't think there are very many options for marine cams, so they are probably all similar in HP.

As for the balancer being correct. Here is what I did.

1. Pulled #1 plug
2. Rolled over to TDC with a dowel in the hole
3. Set the distributor and rotor to #1 position
4. Ran the timing light
5. Verified my timing was just about on the money

I have made enough changes to be ready for another water test. If when I do I don't have an improvement I will change the order then and there

M

That only verifies that the distributor is at lined up with the crank, no that the timing marks on the balancer are.

The easiest way to test that-

1. Remove #1 spark plug
2. Find TDC with a dowl
3. Check timing mark on balancer vs pointer

If you manually crank the piston to TDC, the 0*/TDC mark should be SPOT ON with the timing pointer. If it isn't, the outer portion of the balancer has spun free, and needs to be replaced.

 

[mcleaves]

Re: Rebuilt engine is a dog out of the hole

Roller lifters are interchangeable with hydraulic flat tappet lifters, but the roller lifters need a bracket in the engine to hold them in the correct orientation. On a 302, adding this bracket involves drilling and tapping a couple small holes. People put the newer roller blocks in older Mustangs all the time to get the 1 piece oil seal and because they are easily available.

But, as far as I understand, roller lifters are a different height that hydrualic lifters (I might go measure them tonight) and the push rods are certainly different. I have been told not to put roller lifters on a non-roller cam, and I'm going to do some reading. I really want it to be OK, as I want rollers on my cam!

Well let's presume the cam was setup properly. It's has been in this engine for probably 6 or 7 years. I only did the rebuild becasue I had water intrusion. She has always run nice and hard and within factory specs for top end and the she jumps out of the water onto plane in about 6 seconds. That's a 302 pushing a 5500 boat into plane in that time.

So since it preformed well and hasn't blown up I am guessing it was done right.

I AM wondering about the pushrods though . We repalced them since they had some rust on them so I figured for a few bucks we should do it

That only verifies that the distributor is at lined up with the crank, no that the timing marks on the balancer are.

The easiest way to test that-

1. Remove #1 spark plug
2. Find TDC with a dowel
3. Check timing mark on balancer vs pointer

If you manually crank the piston to TDC, the 0*/TDC mark should be SPOT ON with the timing pointer. If it isn't, the outer portion of the balancer has spun free, and needs to be replaced.

OK, I'll do that tomorrow hopefully

 

[gbeltran]

Re: Rebuilt engine is a dog out of the hole

Roller lifters are NOT interchangeable with flat tappet lifters. You can't put roller lifters on a cam ground for flat tappets. Flat tappet cams have a taper ground on the lobe to rotate the lifter, roller cams are flat, and also roller cams are steel instead of iron.

 

[mcleaves]

Re: Rebuilt engine is a dog out of the hole

Roller lifters are NOT interchangeable with flat tappet lifters. You can't put roller lifters on a cam ground for flat tappets. Flat tappet cams have a taper ground on the lobe to rotate the lifter, roller cams are flat, and also roller cams are steel instead of iron.

Well then it's entirely possible I misunderstood what he was telling me. Maybe it wasn't the lifters but the block that he was pointing out?

If that is the case. If I do have a mixed setup it's pretty hard to explain how there have been no problems. I've owned the boat for 4 years and the previous owner ran it for two. The rebuild happened before that. Everything internal in the engine was in great shape. Lifters, cam etc. Remember the only reason did the rebuild was water intrusion.

If you are correct then clearly I misunderstood what he was telling me. He was talking roller cam about the block/lifters and showed me the cam which he said was NOT a roller cam. Not sure how else to interpret that info. Can you look at a block and say it is designed for roller lifters a but put regular lifters in? Maybe that is what it was. Actually now that I think of it, that may be what he was telling me..

M

 

[gbeltran]

Re: Rebuilt engine is a dog out of the hole

Yes, you can use the later model blocks that are designed for roller lifters and use a standard flat tappet cam and lifters in it.

 

[Handegard]

Re: Rebuilt engine is a dog out of the hole

Well then it's entirely possible I misunderstood what he was telling me. Maybe it wasn't the lifters but the block that he was pointing out?

If that is the case. If I do have a mixed setup it's pretty hard to explain how there have been no problems. I've owned the boat for 4 years and the previous owner ran it for two. The rebuild happened before that. Everything internal in the engine was in great shape. Lifters, cam etc. Remember the only reason did the rebuild was water intrusion.

If you are correct then clearly I misunderstood what he was telling me. He was talking roller cam about the block/lifters and showed me the cam which he said was NOT a roller cam. Not sure how else to interpret that info. Can you look at a block and say it is designed for roller lifters a but put regular lifters in? Maybe that is what it was. Actually now that I think of it, that may be what he was telling me..

M

It all makes sense now All my engine building life, I have been told not to put roller lifters on a non-roller cam, and the reasoning was sound. But here you were saying the boat has been good for years and I'm going "I wonder..."

Hopefully a new cap and rotor help you out, or something similarly simple...