Valves

[Jentw...@aol.com]

In a message dated 4/9/2008 4:19:06 A.M. Eastern Daylight Time, nor...@googlegroups.com writes:

The only discrepancy is that all the 1460 pump engines I have come across
have normal FWA/E valve sizes. Are you sure about the pump valves being larger?

 

The Bearcat has larger valves.

 

 

---

Planning your summer road trip? Check out AOL Travel Guides.

[Ian Ashdown]

Hi,

I have a Bearcat motor and 2 1020 pump engines that will be dismantled
in the coming week or so so I will be able to compare valve sizes etc
for anyone that is interested.

Is there a document anywhere that has the various critical dimensions
Bore, Stroke, Mian Brg, Big End, Valve Guide etc etc? If not perhaps
this might be the opportunity to start such a reference document.

If anyone would like any dinem=nsions or photograps from either of
these engines please let me know.

All the best,

Ian Ashdown

On Apr 9, 8:01 pm, Jentwist...@aol.com wrote:
> In a message dated 4/9/2008 4:19:06 A.M. Eastern Daylight Time,  
>
> nor...@googlegroups.com writes:
>
> The only  discrepancy is that all the 1460 pump engines I have come across
> have  normal FWA/E valve sizes. Are you sure about the pump valves being  
> larger?
>
> The Bearcat has larger valves.
>

> **************Planning your summer road trip? Check out AOL Travel Guides.    
>   (http://travel.aol.com/travel-guide/united-states?ncid=aoltrv000300000...)

[Stewart Smith]

 

Hello Ian,

 

The Mansell letter from Peter Yoeman ? had an awful lot of information. My thoughts are that when using an amalgamation of parts for any engine and not following a previously designed or specified engine ( all FWA or FWE or FWB) is that you must engineer your own.

 

What rpm are you searching for, where do you want your torque to start (rpm), that will tell your cam supplier what to design and what compression he wants, what ratios in your gearbox and differential, and what flow figures would be necessary and then you look at your 1020 or 1500 (4000-13U) block and you look at your installed piston height and then determine what combustion chamber volume you will need to accomplish your desired compression and them you look at your valve and intake manifold and try to design enough flow to accomplish all of that and then look at your pump head or ? and weld-up or shave or buy a #5000 blank head to work your own magic on....it is so hard to buy off the shelf parts for a one off engine and have any hope that it will work. The neat thing about using an engine builder that has experience is that he will probably have made most of the mistakes you might make starting from scratch. I have blocks that are .450 different in height from crank center, pistons that are made for each block and heads that have been screwed around with by the best intentioned individuals and none of the parts are interchangeable. Valve and spring packages, guides retainers, buckets, and manifolds are all different..... developing an inventory of parts, a matrix of possibilities will not work unless you incorporate all variables and that is very difficult.

 

I am sure that here in the US that Hutton or Sasco or Clubine have a set of parts that will work for most applications based on 30 plus years of building climaxes and can accommodate most variables. I think that the lone members wanting to do the work ourselves will have to do diligence and measure and specify for each of our own headaches individually and alone.

 

Doctors differ and patients die, Cheers.

 

Stewart

 

----- Original Message -----

From: Ian Ashdown

Sent: Wednesday, April 23, 2008 5:53 PM

To: Lotus History

Subject: Re: Valves

 

Hi,

I have a Bearcat motor and 2 1020 pump engines that will be dismantled
in the coming week or so so I will be able to compare valve sizes etc
for anyone that is interested.

Is there a document anywhere that has the various critical dimensions
Bore, Stroke, Mian Brg, Big End, Valve Guide etc etc?  If not perhaps
this might be the opportunity to start such a reference document.

If anyone would like any dinem=nsions or photograps from either of
these engines please let me know.

All the best,

Ian Ashdown

On Apr 9, 8:01 pm, Jentwist...@aol.com wrote:
> In a message dated 4/9/2008 4:19:06 A.M. Eastern Daylight Time,  
>
> nor...@googlegroups.com writes:
>
> The only  discrepancy is that all the 1460 pump engines I have come across
> have  normal FWA/E valve sizes. Are you sure about the pump valves being  
> larger?
>
> The Bearcat has larger valves
>

[Charles Helps]

Taken from the Palgrave Publishing 'Technical Service Data' 1963
Edition for the Lotus Elite - these will obviously be the figures for
the standard engine possibly obtained from Lotus at Cheshunt as the
data headings include Transmission, Brakes, Steering etc.

Engine Coventry Climax FWE engine
Bore 3.0" (76.2mm)
Stroke 2.625" (66.6mm)
Cubic Capacity 1,216 c.c. (74.25 cu. in.)
Compression 10:1 (stage III tuning 11:1)
Brake horse-power Gross (S.A.E.) 80, net, 75; at 6,100 rpm (103 in
full racing trim)
Crankpin diameter 1.8475 to 1.8740 "
Crankpin undersizes .010, .020, .030, .040"
Big-end bearing clearance .002 to .010"
Main journal diam. 2.1235 to 2.12425"
Main bearings length 1"
Main bearing clearance .001 to .010"
Valve guide length Inlet shorter than exhaust; fitted height 0.350"
above recess in head
Valve stem/guide clearance .0015 to .0024"
Valve spring rate Renew if load to compress outer springs to 0.910" is
less than 60 lb., or to compress inners to 0.686" is less than 20 lb.
Valve working clearance Inlet, .006"; exhaust, .008" (cold);
adjustment by shims supplied with engine in cam box cover
Valve timing clearance .01" nominal.
Valve timing Inlet Opens 12 deg BTDC; closes 56 deg ABDC. exhaust
opens 56 deg BBDC; closes 12 deg ATDC

There is more data on for example piston ring clearances and gaps if
anyone is interested. I think it's worth documenting this sort of
information and I do like seeing figures rather than bald statements
that one valve diameter is smaller than another (by two fifths of a
inch or 20 thou?!)

[Vic Thomas]

Fire Pump Valve replacement.
We were asked a week or two ago
how one copes with increased valve length
when 1028cc Pump valves are replaced
by normal FWA sizes.
I have spoken to two people who have done this recently.
The FWA valve is 2mm [ 80thou] longer
and when first fitted, having increased the
seat diameter, give little or zero space for the
tappet shim. This space can be increased
in three ways.
1. Shim the cam carrier upwards with precision washers [also required if the
head has been machined to retain chain tension.]
I have used up to 60 thou in the past.
2. Relieve the "pip" inside the cam follower bucket by up to 20 thou.
3. Grind the end of the valve until it just protrudes from the collets.
A combination of these operations can add up to allow a sensible tappet shim
to be fitted.
Best regards
VFT

[Vic Thomas]

Dear All

Following the information from Stewart

regarding seemingly very high dyno readings

taken with Climax engines, I have spoken

to a couple of English guys who have achieved

excellent figures.

Tuner "A" , who has just done a head for me,

showed to me the dyno sheet for a very special 

FWB he built five years ago.

The peak BHP was 141.3 at 7250 rpm. He now

says that he could add 5 bhp to this starting

with a small valved Fire Pump head, as it is

possible to improve the port shape, compared to

an auto head.

The bad news was that this particular FWB was

not a sucess insalled in an XI at the time. 

To allow for 8000 plus rpm it had Five main

bearings , the extra two

 being supported from the bottom plate added

to stiffen all the mains. This stopped the the exchange 

of pumped air between the underside of each

pair of pistons as they "boxed". The results was 

a large amount of oil being pumped out from the

complex breathing system. 

This problem is now cured and the engine is for sale.

Hopefull your scrutineer does not bother to count

the number of main bearings in your Climax !!

 

He tells me that the above bhp figure is a DIN

standard, corrected to standard pressure and 

temperature, and as we know is the largest

of all the bhps lurking around. So this is a

very genuine output.

 

Racer "B" has a very fast XI which beats 

Ferraris and things, even though the car is very

heavy. He claims the 1460cc FWB showed 

148bhp on the dyno and that this power

comes in at 6500rpm. His car is so fast,

I do not to dismiss his claims out of hand.

BUT a Lotus Twin Cam [Elan, 26R etc]

needs around 7500 rpm to acheive 100

bhp/litre and that is a cross flow engine.

If his bhp is correct I think the revs must

be higher.  Also I have not spoken to his

engine tuner to ask the spec. of bhp 

measured. SAE horses are smaller

owing to the corrections applied 

------- sorry about my spoof about

the US pound and foot.pound being smaller !!  

 

I invite comment on the true maximum bhp

seen so far from a Climax. I will stick my neck out

and claim that

"no two valve engine can achieve

100bhp/litre under 7500 rpm."

 More like 8000 for a Climax I should think. 

Best Regards

VFT