Engine info?

[A TR7 16V]

While I was out checking what filter I wanted (done that) I took some pics of the engine and wondered what you guys might be able to tell me about it and the mods that have been done to it. And what might be worth consideration, if it's not too much like work.



The nunber on the top of the block is GE45422HE, which I see is an 8.5:1 compression 13/60 engine. The number on the BMIHT PRS certificate is GE/80220-HE, which is, presumably, a bit later in the production run.

I know the wirings a bit of a snake's honeymoon, but it's working at the moment, so I'm in no rush to fix it.

[herald948]

Well, the obvious modification is the substitution of twin SU HS2s and manifold for the 13/60 engine's original single Stromberg CD150. Without knowing the stamped serial number on the head, it's virtually impossible to tell if that's still a Herald head or if it might be from a Mk3 Spitfire or ???, and without pulling things apart it's almost impossible to tell if the head has been "worked" in any way or if there have been changes regarding pistons, camshaft, etc.

If it's all stock save for the carbs, you're looking at a slight increase in power -- probably at higher revs, though, than the original configuration, and possibly a slight LOSS of low-end grunt. (I know that's true of the 1147cc Herald engines, but I'm not certain it is true of the 1296cc engines; perhaps others will confirm?)

[Mark Hammond]

I had a 13/60 with twin SUs on it and it was worse powerwise than when it was with the single Stromberg.

Mark

[Jonny-Jimbo]

If you want to make a worthwhile modification, junk off those god-awful pie-dish filters. You're getting nothing but hot air and engine bay crap into there. The much less dense, hot air of the engine bay will sap any extra power the twin carb set up MAY give. If you think it looks nice, then fair enough, each to their own, but you'll get much better power etc by having an insulated cold air feed, or at least a cold air feed from the front of the car, if not insulated entirely.

There's a reason the factory didn't just plonk air filters straight on the carbs!

[A TR7 16V]

Quoted from herald948

Without knowing the stamped serial number on the head, it's virtually impossible to tell if that's still a Herald head or if it might be from a Mk3 Spitfire or ???

Any pointers to where the head number should be?

Graham

[A TR7 16V]

Quoted from herald948

If it's all stock save for the carbs, you're looking at a slight increase in power -- probably at higher revs, though, than the original configuration, and possibly a slight LOSS of low-end grunt.

Well I'm reasonably happy, nay surprised, at how well the car drives – overall, not just the engine. But I wouldn't mind a little more power, if it doesn't risk reliability too much. And I know, going back to my motorcycle days, that I do like the responsiveness that two smaller choke carbs give over a single larger choke. I admit I've not driven a single carb Herald, so I don't know what the actual difference is, but I've always been happier with multi-choke setups. And if the head and cam are stock, then I might look for something, e.g., with bigger valves.

I have even thought about upgrading to a set of HS4s, if the carbs were still a significant limit to the engine's breathing. I'm not quite sure how to determine that without giving it a go. But I have a spare manifold, so I might start building up a set for a simple swap later. I also wondered if anybody's used a pair of HIFs?

Graham

[rustbuckit2011]

Mate it's just along a little from the cast numbers you have photographed. If you look at your first photo, the number should be stamped on the flat spot between the engine lifting eye and where the rubber hose comes out of the valve cover. Often quite hard to see so give the area a wipe

[Nick Jones]

Stamped head number is on the front right-hand corner.

Herald heads have the same valve sizes as 1300 Spitfires apart from the later MkIVs.  They do have soft valve springs and push on caps though which limit the cam choice, so I suppose the best basis would be a late 1300 Spit head.

HS4 carbs will bring you NO gains unless the engine is highly modified (flowed head, cam etc).  I quite like HIF SUs myself - had a pair of early HIF4s on my Vitesse for a while but as above you don't want HIF 4 or 38  carbs on a 1300 unless well modified.

Nick

[A TR7 16V]

Quoted from Nick Jones

HS4 carbs will bring you NO gains unless the engine is highly modified (flowed head, cam etc).

I'm not sure about "NO gains". I understand the issues with the bigger chokes having a lower air velocity, for the same volume flowing, and thus (from Bernoulli) a smaller pressure drop, across the airflow, to lift the dashpot and draw fuel up through the jet. But that's a largely a low rpm/small throttle opening thing. And, to some extent, it's correctable by using lighter dashpot springs.  

But at higher rpm, there should still be enough velocity and pressure drop to lift the dashpot, etc., especially against a lighter spring. And as the larger choke gives less restriction to the flow, the engine will get more air/fuel mix, and will thus give more torque. And if you're after more power it's important to maximize torque at high rpm, because power is just torque times rpm.

I'm not sure that the gains would be worth the losses, but I'd have to try it to be sure.

Graham

[A TR7 16V]

All I can read off the head is "218142", no prefix or suffix.

Graham

[rustbuckit2011]

Aha! Well lucky you! The head is a larger valve mk1V spitfire head.
With the carbs and the small crank block (13/60), yes, your engine should go pretty well as is.
I have built up an engine the same as this, and ran it in fairly standard (?) tune for a while. I then took it off the road, gave the head a good polish and port, a light skim,   3 angle valve cut and back cut standard valves. Replaced the guides for bronze and lightened and polished the valve gear. I fitted a FR83 cam and twin HS4's.
I dont know what kind of power it makes, and Im not about to dyno it as Ive taken it out to fit a mazda engine in! It did, however, go like stink! By far and away more powerful than the standard 13/60, kept up well with a Mk1 2litre vitesse- and being lighter- handled better.
You also appear to have an alloy bellhousing, which isnt standard for the car. Id say, somebody loved this car at some point, you could be lucky and have a good cam in it. Unfortunately, you'll have to pull the engine to check!

If I were you, Id whack a good exhaust manifold on it, and jet the carbs accordingly. Bigger valves would mean slightly richer jets, but the carbs should still be within there breathing range.
If you still have itchy fingers,
Next you want to check the cam, as this will be what is holding the engine back. You want a mk3 spitfire cam or something aftermarket. When you change this however, you will want to start thinking about ignition- so megajolt it. That should keep you busy and give you the best bang for buck!
Carburetion and head mods can come after those, as you will need to do fiddly bits like alter ignition and jetting. Thats what Id do anyway.

[A TR7 16V]

Thanks rustbuckit2011, I found some stuff on the head on the net.

I'm not sure I really want to have a go at the cam just yet, and upping the carb size is probably just idle musing - but if the cam's already been done, despite the possible loss of torque at low rpm, there may be enough to be gained higher up. And that could be an easier way to find out than pulling the engine just for a look see at the cam. Mind you, should it not be possible to get some idea of the profile from measuring the rocker movement, i.e. how much lift, and maybe angles as well? Is there enough data on the various profiles to make that possible?

But thanks all for the help identifying the head and for all the useful advice on what's likely to work.

The alloy bell housing is doubtless connected to the gearbox and overdrive, if that's not stating the bleeding obvious. I wonder if they're Spitfire too. I've still got to sort out the speedo problem that's also connected - it over-reads by about 25 percent. I have the GPS speedo as a fix, and a spare speedo head to swap to - it's not likely the problem, but it's the easiest thing to swap, and if it is that, and I only found it after pulling the box, etc., I'd be pretty p155ed off.

It does look like someone spent no small amount of time and effort here and there, but not on cosmetics. Seems that was done in Yorkshire somewhere. I suppose I could go through DVLA and try to trace the previous owner – see if they can tell me about the cam, etc.

Off the performance mod issue, I did wonder about an alternator kit: The dynamo didn't do too well on the run through Blackpool Illuminations. The Herald didn't overheat like the Sprint did though.

Outside the engine and transmission, it needs a hood – the one that's on just looks like it shrank. I've tried the adjustments that are there, but it still only fits where it touches, and that ain't everywhere it should. Took it to an auto-upholsterer nearby, who reckoned that vinyl doesn’t shrink, so it must be a wrong one. But I wasn't impressed with that, so I still don't know. It does look like it's been on twice though – many of the holes in the vinyl are duplicated, about half an inch further in.

Graham

[herald948]

Quoted from A TR7 16V

...Outside the engine and transmission, it needs a hood – the one that's on just looks like it shrank. I've tried the adjustments that are there, but it still only fits where it touches, and that ain't everywhere it should. Took it to an auto-upholsterer nearby, who reckoned that vinyl doesn’t shrink, so it must be a wrong one. But I wasn't impressed with that, so I still don't know. It does look like it's been on twice though – many of the holes in the vinyl are duplicated, about half an inch further in.

Vinyl doesn't shrink? How long has that guy been in the trimming business -- a week? two weeks? 😉

If my camera didn't need batteries, I'd be happy to provide a photo showing how vinyl shrinks. Granted, this is after some 47-48 years...but it does shrink!

[Nick Jones]

Vinyl itself may not shrink, but the fabric backing certainly does.  Mine has shrunk a bit and that has only taken about 6 years.  Was a decent quality one too.

Nick

[marktheherald]

Over reading speedo maybe diff related. Maybe a higher ratio item fitted? (or would that under read...? (my brain hurts))

[A TR7 16V]

If the speedo over-reads, the gearbox is turning faster than it should for the road speed, and the ratio is too big. So if I've got a 4.11:1 ratio, the speedo would be right for about 3.3:1. What would that be off of?

Graham

[Nick Jones]

There's 3.27 fitted OE to non-OD GT6 but more likely the wrong speedo drive gear for the speedo head.

Nick

[A TR7 16V]

I did wonder if it was more like it over-read by 12 percent, i.e. the speedo drive was right for a ratio of 3.63:1 or so. But  then sombody went the wrong way with the speedo drive, and doubled the error rather than fixing it. And then went, "Oh sod it!".

I need to find out how to determin the speedo drive ratio, prefereably without pulling the overdrive or box, and certainly without tying a pointer to the head end of he speedo cable and seeing how far it pushes for one turn. I might, jack the back up on one side and turn one wheel. But not today, it's wet.

Graham

[Nick Jones]

Does it appear to be the original Herald speedo?  The turns-per-mile is printed on the face which may give a clue.

Nick

[A TR7 16V]

Yes, it's a 1216 tpm one. And so is the spare one I have.

Graham