More Problems With A New Engine

M

Mike Crehan

Member
The new engine that I had in storage and have loaned to a friend while his is rebuilt is a real dissapointment - in summary it has a balanced and pressure fed crank with inserts on big ends and mains. Lion III head, big valves and a B camshaft solid lifters and a new single point Mallory calibrated for an A engine (max centrifigal advance 30 degrees).

Installed in friend's car using his stock manifolds and B carb, flywheel and A clutch.

A couple of people said it was "tight" but I could turn it over with the ratchet bar from my socket set and his standard 6 volt starter has no problem starting it so I do not think it is excessively tight, just new.

There are 2 problems - at idle it sounds fluffy, it does not want to pick up speed when you drive it - basically it is gutless. And it overheats.

On a local road of gentle rolling ups and downs the old standard engine would cruise in top at 30mph and accelerate at will. This baby barely holds its own up the hills and needs first gear!

I drove it a week ago and told the shopowner it wasn't right. He has set the mixture so it is right through the range using a lambda sensor, dizzy and timing have been checked over and over, radiator and cooling system were all 100% pre-engine swap.

The choke tube in the B carb was swapped for a smaller one which gave some improvement, went back to original and improvement remained so perhaps there was a blockage or something but it is still gutless and overheating.

As this was meant to be a loaner to help out a friend I don't want him to blow his engine rebuild cash trying to sort out my engine and right now I don't want to be working on it as I am in the middle of other things.

I think I should get the car here and see if I can fix it - I'm going to start with pulling the timing cover and check the cam / valve timing - if there are no marks or it looks like it has reproduction timing gears I will probably take the suck it and see approach - move it a tooth and see if it improves! Sometimes I find this quicker than hours of measuring.

Anyone got any ther suggestions?
 
Try dropping the muffler down and try it.If it sat for a couple of weeks with the exhaust open critters will set up housekeeping in the muffler.I don't know why they love a dirty exhaust so much.
 
You should be able to tell if the cam timing is close through the spark plug hole if it is over the valves (no problem with stock head--I don't know about lion head), compare the point of valve overlap(both valves open a little) with top dead center of the piston
 
Mike,

Two thoughts:

1. Be sure that you have a Model A timing cover which starts at Zero degrees and not a Model B cover, starting at 19 degrees.

a. The timing pin on the A cover is located closer to the 9 "O'clock" position.

b. The pin on the B cover is closer to 10 O'clock.

If B cover then timing is 19 plus 30 = 49 ... way too much!

2. If the engine has an original Model B cam that has not been reground as indicated by you saying it has solid lifters, then the valve lash on exhaust MUST be .022 unlike Model A which calls for .015 or so. If this is the case and valves are adjusted too tight the exhaust valves will not seat when engine warms up and there will be a loss of power.

My experience with Lion heads is that they do not tolerate too much advance. Atleast the 7.0 Lion head III I used to have would knock with anymore than 25 degrees advance.
 
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Also the Lion head III is NOT "ported" for oversize valves so larger valves sometimes hang up on side of chambers or even get bent when they hit the head. I am not sure what valve diameter causes a problem.

Machine work must be done to the chambers to make room for the oversized valves.

I have been told that the Lion head IV will be modified for use with larger valves.

Edited: The Lion head III has plug holes over the middle of the pistons.

There was an early LH that had 8 plugs with an additional set of plugs over the valves.
 
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Thanks for the replies -

with the Lion III the plugs are over the pistons so we can't see the valves.

you are right about the big valves not having enough clearance - we did quite a bit of mill work on the head and checked lift and radial clearances over and over again pre assembly.

As soon as I get the car back here I will check the tips above re A v B timing covers (I never knew that so a very useful tip) and the valve clearance on the exhausts - another useful tip that I had neverheard before.

What a great forum. Thanks guys.
 
Attach a vacuum gauge with a long hose and take it for a ride. Vac results are very telling, if you know how to interpret them. Here's one link on how to: LINK1 Here's another: LINK2 and another: LINK3 Hope this helps.
 
Picked the car up tonight. I think it may have a B cover - the timing pin hole is above the boss at about 9 o clock whereas from your description the A should be below.

I have also noted a couple of other problems - the clamp that holds the distributor (made by the chap that fitted the engine) does not actually clamp the distributor so wherever it is set the dizzy can still float to a different position as you drive down the road!)

Any how just as I started to look there was a clap of thunder and the rain came down so I packed up for the night.
 
It is probably in the timing/dizzy somewhere. But I have noted when I ran a B carb with an A intake the power was not quite up to snuff. That may also be an issue abiet a small one.

Mike
 
Years ago a friend was using a nylon sock to plug the oil hole in his rebuilt block. Somehow it got down into the engine and tangled around the crank. It severly hampered engine performance until he dropped the pan, discovered the sock and removed it.
 
The manifold was bored to match the B carb. Right now it has got a known to be working A carb and manifold on it to try and eliminate one area of change.

The dizzy is a new Mallory that I bought a while ago from Bubbas calibrated for the A engine and checked repeatedly.

I will modify the clamp today so that it locks the dizzy in place solidly and retest. I have checked the tappets - valve lash as you guys call it, and set to .015 inlet and .022 exhaust - it wasn't far out to start with.

I still think the cam is a tooth out. Anyone tried to change this with the engine in the car? Looks easy enough but I don't want to walk into any traps someone else has already found.

PS if all that fails I'll go on an internal search for socks. ladies dainties, small children etc.
 
Mike Crehan said:
The manifold was bored to match the B carb. Right now it has got a known to be working A carb and manifold on it to try and eliminate one area of change.

The dizzy is a new Mallory that I bought a while ago from Bubbas calibrated for the A engine and checked repeatedly.

I will modify the clamp today so that it locks the dizzy in place solidly and retest. I have checked the tappets - valve lash as you guys call it, and set to .015 inlet and .022 exhaust - it wasn't far out to start with.

I still think the cam is a tooth out. Anyone tried to change this with the engine in the car? Looks easy enough but I don't want to walk into any traps someone else has already found.

PS if all that fails I'll go on an internal search for socks. ladies dainties, small children etc.
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It is quite easy to change the cam/crank timing in the car. Remove the timing cover and take the cam gear nut off. Remove the gear and align the timing marks which will misalign the pins on the cam if it is truly off a tooth. Just turn the crank till the pins align and tap the cam gear on using a piece of pipe over the cam stem and replace the cam gear nut. This might be a good time to install an aluminum cam gear since they will outlast a fiber gear if it doesn't have one.
 
Thank you - If the rain stops I'll have a go after work tonight - the car is not undercover because it is an unexpected visitor and I cannot get it inside without putting an open race car or something equally non-weatherproof outdoors just now.
 
OK. It is now flying along.

I think the front cover is a "B" - there is a letter "B" cast into the inner face which I noticed when I was cleaning it to put it all back together.

The crank gear is new as is the aluminium timing gear and neither had any timing marks they do now!). The dimple for the timing pin looks freshly drilled - pretty much like someone put it all together and then with it at TDC drilled through from the outside of the cover. No problem - it works and finds TDC. Cam is properly timed and valve clearances all correct.

So I put it all back together with the points just opening with the pin in the detent in the timing gear, took the pin out and started it up. Then I loosened the dizzy clamp and turned the dizzy to retard it - engine faltered almost immediately, marked the position and advanced until it faltered marked the position, put the dizzy in the middle and drove up the road. Fabulous. Stopped and gave it a bit more - even better, with a bit more it was knocking a bit pulling hard up hill so I went back to the previous mark.

It is my engine but not my car so I have to be a bit careful testing it but it really goes now - top gear at 30mph on the flat / very slight climb and put your foot down and straight past 65mph at which point I backed off to a very easy 50-55mph cruise. 10% gradient hill which is hard work on my mountain bike was taken from a standing start in first- no trouble getting into top gear as we climbed and still accelerating.

I know that how I sorted it is not a scientific way of doing things but it beats me why the guys that spent ages putting the engine in and setting up the carb with a lambda sensor didn't give this a try instead of saying the timing was correct by the book and the timing marks. Anyway it is all fixed now and going great - went out to lunch in it with my wife and dog and the only time the temperature gauge moved was at the end of a long climb up to the pub while I was parking and then it was just 1/4 of an inch at the bottom of the glass.

Now it is parked up waiting for the owner to come and enjoy it until his own engine is rebuilt.
 
Uh Oh - got up this morning and the sun was shining - out on the drive I had a choice between an Audi Estate or using my friend's A, didn't take long to decide.

I think the dog enjoyed the ride through the countryside to the office too. This car is running great now - top gear all the way and just a sniff of throttle to hold 50mph + staying nicely in the flow of modern cars. He better come and get it soon or my wife and dog might get so attached that they go with him and the car!
 
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